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PHYSICS (574 journals)            First | 1 2 3 4 5 6 | Last

Nature Communications     Open Access   (Followers: 80)
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NDT & E International     Hybrid Journal   (Followers: 17)
NEUTRINO     Open Access  
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New Journal of Physics     Open Access   (Followers: 6)
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Noise Notes     Full-text available via subscription   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 9)
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin     Hybrid Journal   (Followers: 4)
Nuclear Engineering and Design     Hybrid Journal   (Followers: 9)
Nuclear Medicine and Biology     Hybrid Journal   (Followers: 1)
Open Journal of Biophysics     Open Access   (Followers: 1)
Open Journal of Fluid Dynamics     Open Access   (Followers: 4)
Open Journal of Microphysics     Open Access  
Open Physics     Open Access   (Followers: 2)
Optical Communications and Networking, IEEE/OSA Journal of     Hybrid Journal   (Followers: 5)
Optofluidics, Microfluidics and Nanofluidics     Open Access   (Followers: 1)
Organic Electronics     Hybrid Journal   (Followers: 5)
Organic Photonics and Photovoltaics     Open Access   (Followers: 2)
PAJ: A Journal of Performance and Art     Hybrid Journal   (Followers: 12)
Papers in Physics     Open Access  
Particle Physics Insights     Open Access   (Followers: 2)
Particuology     Hybrid Journal  
Pattern Recognition in Physics     Open Access   (Followers: 2)
Pergamon Materials Series     Full-text available via subscription  
Phase Transitions and Critical Phenomena     Full-text available via subscription   (Followers: 1)
Philosophical Magazine     Hybrid Journal   (Followers: 2)
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences     Full-text available via subscription   (Followers: 6)
Philosophy and Foundations of Physics     Full-text available via subscription  
Physica B: Condensed Matter     Hybrid Journal   (Followers: 5)
physica status solidi (a)     Hybrid Journal   (Followers: 1)
physica status solidi (b)     Hybrid Journal   (Followers: 1)
physica status solidi (c)     Hybrid Journal   (Followers: 1)
Physica Status Solidi - Rapid Research Letters     Hybrid Journal   (Followers: 1)
Physical Communication     Hybrid Journal   (Followers: 2)
Physical Review C     Full-text available via subscription   (Followers: 19)
Physical Review Special Topics - Physics Education Research     Open Access   (Followers: 6)
Physical Review X     Open Access   (Followers: 7)
Physical Sciences Data     Full-text available via subscription   (Followers: 1)
Physics - spotlighting exceptional research     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B     Full-text available via subscription   (Followers: 3)
Physics and Chemistry of Liquids: An International Journal     Hybrid Journal   (Followers: 2)
Physics and Chemistry of the Earth, Parts A/B/C     Hybrid Journal   (Followers: 3)
Physics and Materials Chemistry     Open Access   (Followers: 1)
Physics Essays     Full-text available via subscription   (Followers: 1)
Physics in Medicine & Biology     Full-text available via subscription   (Followers: 10)
Physics in Perspective     Hybrid Journal   (Followers: 1)
Physics International     Open Access   (Followers: 2)
Physics Letters A     Hybrid Journal   (Followers: 9)
Physics Letters B     Open Access   (Followers: 3)
Physics of Fluids     Hybrid Journal   (Followers: 29)
Physics of Life Reviews     Hybrid Journal   (Followers: 1)
Physics of Plasmas     Hybrid Journal   (Followers: 7)
Physics of the Dark Universe     Open Access   (Followers: 1)
Physics of the Solid State     Hybrid Journal   (Followers: 3)
Physics of Wave Phenomena     Hybrid Journal   (Followers: 1)
Physics Procedia     Partially Free   (Followers: 1)
Physics Reports     Full-text available via subscription   (Followers: 2)
Physics Research International     Open Access   (Followers: 1)
Physics Today     Hybrid Journal   (Followers: 38)
Physics World     Full-text available via subscription   (Followers: 3)
Physics-Uspekhi     Full-text available via subscription  
Physik in unserer Zeit     Hybrid Journal   (Followers: 1)
Physik Journal     Hybrid Journal  
Plasma Physics and Controlled Fusion     Hybrid Journal   (Followers: 3)
Plasma Physics Reports     Hybrid Journal   (Followers: 2)
Pramana     Open Access   (Followers: 9)
Preview     Hybrid Journal  
Proceedings of the National Academy of Sciences     Full-text available via subscription   (Followers: 529)
Proceedings of the National Academy of Sciences, India Section A     Hybrid Journal   (Followers: 3)
Progress in Materials Science     Hybrid Journal   (Followers: 22)
Progress in Planning     Hybrid Journal   (Followers: 1)
Progress of Theoretical and Experimental Physics     Open Access  
Quantum Electronics     Full-text available via subscription   (Followers: 3)
Quantum Measurements and Quantum Metrology     Open Access  
Quantum Studies : Mathematics and Foundations     Hybrid Journal   (Followers: 1)
Quarterly Journal of Mechanics and Applied Mathematics     Hybrid Journal   (Followers: 3)
Radiation Effects and Defects in Solids     Hybrid Journal   (Followers: 1)
Radiation Measurements     Hybrid Journal   (Followers: 2)
Radiation Physics and Chemistry     Hybrid Journal   (Followers: 1)
Radiation Protection Dosimetry     Hybrid Journal   (Followers: 2)
Radiation Research     Full-text available via subscription   (Followers: 3)
Radio Science     Full-text available via subscription   (Followers: 3)
Radiological Physics and Technology     Hybrid Journal   (Followers: 2)
Reflets de la physique     Full-text available via subscription  
Reports on Mathematical Physics     Full-text available via subscription  
Reports on Progress in Physics     Full-text available via subscription   (Followers: 2)
Research & Reviews : Journal of Physics     Full-text available via subscription  
Research in Drama Education     Hybrid Journal   (Followers: 12)
Research Journal of Physics     Open Access  
Results in Physics     Open Access   (Followers: 1)
Reviews in Mathematical Physics     Hybrid Journal  
Reviews of Accelerator Science and Technology     Hybrid Journal  
Reviews of Geophysics     Full-text available via subscription   (Followers: 20)
Reviews of Modern Physics     Full-text available via subscription   (Followers: 17)
Revista Boliviana de Física     Open Access  

  First | 1 2 3 4 5 6 | Last

Journal Cover   Physics and Chemistry of the Earth, Parts A/B/C
  [SJR: 0.624]   [H-I: 42]   [3 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1474-7065
   Published by Elsevier Homepage  [2801 journals]
  • Timescale Differences between SC-PDSI and SPEI for Drought Monitoring in
    • Abstract: Publication date: Available online 19 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Haiyan Zhao, Ge Gao, Wei An, Xukai Zou, Haitao Li, Meiting Hou
      The Palmer Drought Severity Index (PDSI) has been widely used to monitor drought. Its characteristics are more suitable for measuring droughts of longer timescales, and this fact has not received much attention. The Standardized Precipitation Evapotranspiration Index (SPEI) can better reflect the climatic water balance, owing to its combination of precipitation and potential evapotranspiration. In this study, we selected monthly average air temperature and precipitation data from 589 meteorological stations of China's National Meteorological Information Center, to compare the effects of applying a self-calibrating PDSI (SC-PDSI) and SPEI to monitor drought events in the station regions, with a special focus on differences of event timescale. The results show the following. 1) Comparative analysis using SC-PDSI and SPEI for drought years and characters of three dry periods from 1961–2011 in the Beijing region showed that durations of SC-PDSI-based dry spells were longer than those of 3-month and 6-month SPEIs, but equal to those of 12-month or longer timescale SPEIs. 2) For monitoring evolution of the fall 2009 to spring 2010 Southwest China drought and spring 2000 Huang-Huai drought, 3-month SPEI could better monitor the initiation, aggravation, alleviation and relief of drought in the two regions, whereas the SC-PDSI was insensitive to drought recovery because of its long-term memory of previous climate conditions. 3) Analysis of the relationship between SC-PDSI for different regions and SPEI for different timescales showed that correlation of the two indexes changed with region, and SC-PDSI was maximally correlated with SPEI of 9–19 months in China. Therefore, SC-PDSI is only suitable for monitoring mid- and long-term droughts, owing to the strong lagged autocorrelation such as 0.4786 for 12-month lagged ones in Beijing, whereas SPEI is suitable for both short- and long-term drought-monitoring and should have greater application prospects in China.

      PubDate: 2015-11-22T17:42:46Z
  • Assessment of the effectiveness of combined adsorption and photocatalysis
           for removal of the herbicide isoproturon
    • Abstract: Publication date: Available online 14 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Martín M. Dávila-Jiménez, María P. Elizalde-González, Esmeralda García-Díaz, Alba M. Santes-Aquino
      The aim of this research was to decompose isoproturon and adsorb its photoproducts by developing a carbon material from a juice industry waste. Carbon-TiO2 hybrid materials were obtained by impregnating carbonized guava seeds with TiO2 gels prepared from TiOSO4⋅xH2O and NH4OH using glycerol as a binder and thermally treating the materials at 500°C. Raman studies confirmed the anatase phase of TiO2. SEM images showed isolated TiO2 agglomerates firmly attached to the carbon surface. The adsorption behavior of isoproturon on guava carbon was studied and yielded S-type adsorption isotherms. The photocatalytic activities of the prepared hybrid materials were monitored to study the kinetics and elimination process both of the herbicide and its photoproducts. The reaction was monitored by UV–Vis spectrophotometry, LC-DAD and LC-MS, enabling identification of some intermediate species. Among the photoproducts produced by carbon-TiO2 hybrid materials, amino-isopropylphenol was detected.
      Graphical abstract image

      PubDate: 2015-11-18T17:26:06Z
  • Hydraulic design to optimize the treatment capacity of Multi-Stage
           filtration units
    • Abstract: Publication date: Available online 10 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): C.N. Mushila, G.M.M. Ochieng, F.A.O. Otieno, S.M. Shitote, C.W. Sitters
      Multi-Stage Filtration (MSF) can provide a robust treatment alternative for surface water sources of variable water quality in rural communities at low operation and maintenance costs. MSF is a combination of Slow Sand Filters (SSFs) and Pre-treatment systems. The general objective of this research was to optimize the treatment capacity of MSF. A pilot plant study was undertaken to meet this objective. The pilot plant was monitored for a continuous 98 days from commissioning till the end of the project. Three main stages of MSF namely: The Dynamic Gravel Filter (DGF), Horizontal-flow Roughing Filter (HRF) and SSF were identified, designed and built. The response of the respective MSF units in removal of selected parameters guiding drinking water quality such as microbiological (Faecal and Total coliform), Suspended Solids, Turbidity, PH, Temperature, Iron and Manganese was investigated. The benchmark was the Kenya Bureau (KEBS) and World Health Organization (WHO) Standards for drinking water quality. With respect to microbiological raw water quality improvement, MSF units achieved on average 98% Faecal and 96% Total coliform removal. Results obtained indicate that implementation of MSF in rural communities has the potential to increase access to portable water to the rural populace with a probable consequent decrease in waterborne diseases. With a reduced down time due to illness, more time would be spent in undertaking other economic activities.

      PubDate: 2015-11-14T17:09:46Z
  • Cloning and expression of vgb gene in Bacillus cereus, improve phenol and
           p-nitrophenol biodegradation
    • Abstract: Publication date: Available online 11 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Angel Eduardo Vélez-Lee, Felipe Cordova-Lozano, Erick R. Bandala, Jose Luis Sanchez-Salas
      In this work, the vgb gene from Vitrocilla stercoraria was used to genetically modify a Bacillus cereus strain isolated from pulp and paper wastewater effluent. The gene was cloned in a multicopy plasmid (pUB110) or uni-copy gene using a chromosome integrative vector (pTrpBG1). B. cereus and its recombinant strains were used for phenol and p-nitrophenol biodegradation using aerobic or micro-aerobic conditions and two different temperatures (i.e. 37 and 25°C). Complete (100%) phenol degradation was obtained for the strain where the multicopy of vgb gene was present, 98% for the strain where uni-copy gene was present and 45% for wild type strain for the same experimental conditions (i.e. 37°C and aerobic condition). For p-nitrophenol degradation at the same conditions, the strain with the multi-copy vgb gene was capable to achieve 50% of biodegradation, ∼100% biodegradation was obtained using the uni-copy strain and ∼24% for wild type strain. When the micro-aerobic condition were tested, the biodegradation yield showed a significant decreased. The biodegradation trend observed for aerobic was similar for micro-aerobic assessments: the modified strains showed higher degradation rates when compared with wild type strain. For all experimental conditions, the highest p-nitrophenol degradation was observed using the strain with uni-copy of vgb gene. Besides the increase of biodegradative capability of the strain, insertion of the vgb gene was observed able to modify other morphological characteristics such as avoiding the typical flake formation in the B. cereus culture. In both cases, the modification seems to be related with the enhancement of oxygen supply to the cells generated by the vgb gene insertion. The application of the genetically modified microorganism (GMM) to the biodegradation of pollutants in contaminated water possess high potential as an environmentally friendly technology to facing this emergent problem.

      PubDate: 2015-11-14T17:09:46Z
  • Dry spells assessment with reference to the maize crop in the Luvuvhu
           River catchment of South Africa
    • Abstract: Publication date: Available online 11 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Teboho Elisa Masupha, Mokhele Edmond Moeletsi, Mitsuru Tsubo
      Agricultural productivity in South Africa is negatively affected by drought as a result of frequent periodic dry spells and increasing crop water demands resulting in poor crop development and low yields. Thus, we embarked on this study which aims at investigating dry spell occurrences in relation to growing season of maize in the Luvuvhu River Catchment. Daily rainfall data (1945-2014) from 12 stations which represent the catchment fairly well was utilized in this study. Three consecutive planting dates were staggered based on three consecutive onsets of the rainy season. Dry spells were categorized into three groups: short, medium and long dry spells. The data was then subjected to theoretical distribution fitting using the Anderson-Darling goodness-of-fit test; and probabilities of occurrence were computed using a probabilistic model that best fits the data. Trend analysis was performed on the frequency of dry spells per growing period using the non-parametric Spearman’s rank correlation test. Out results indicated high probabilities (≥80%) of short dry spells at all the stations irrespective of the timing of planting. Further analysis revealed that a risk of yield reduction with planting following the first onset of rains was higher than that with planting following the second and third onsets. In order to minimize this risk, farmers can be advised to plant between mid-November to mid-December. Trend analysis indicated no trend for all the various dry spell lengths except for Thohoyandou with a decreasing trend and Sigonde with a weak increasing trend in long dry spells. Such findings can be used to describe drought conditions for improvement of agricultural productivity and food security, in a given area.

      PubDate: 2015-11-14T17:09:46Z
  • Joint Venture Schemes in Limpopo Province and their outcomes on
           smallholder farmers Livelihoods
    • Abstract: Publication date: Available online 11 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Everisto Mapedza, Barbara van Koppen, Pinimidzai Sithole, Magalie Bourblanc
      Joint Venture schemes based on the floppy irrigation technology are being promoted in the post-Apartheid South Africa’s Limpopo Province. Access to land and water resources in South Africa are largely viewed as a mechanism for re-dressing the Apartheid injustices. This research was part of a broader applied research to help inform irrigation practise in the Limpopo Province. The research used literature review, key informant interviews and a questionnaire survey. The overall research question sought to understand how the Joint Venture Schemes had benefited the smallholder farmers. This paper argues that the joint venture partnership created a new injustice. Firstly, the Joint Venture Scheme design is fundamentally a bad idea which disempower farmers not only to water access but also land as well. The choice of the 'efficient' floppy irrigation technology was made by the state and entailed that land had to be managed as a single unit. In order to make more effective use of this highly sophisticated new technology, the smallholder farmers also needed to go into a joint venture partnership with a white commercial farmer. By virtue of signing the Joint Venture agreement the farmers were also forfeiting their land and water rights to be used for crop production. The smallholder farmers lost access to their water and land resources and were largely relegated to sharing profits – when they exist - with hardly any skills development despite what was initially envisaged in the Joint Venture partnership. Secondly, the implementation of the JVS has been skewed from the start which explains the bad results. This paper further shows how the negative outcomes affected women in particular. As the smallholder farmers argue the technological options chosen by the state have excluded both male and female farmers from accessing and utilising their land and water resources in order to improve their livelihoods; it has entrenched the role of the state and the private interests at the expense of the smallholder male and female farmers in whose name the irrigation funding was justified. The paper concludes by offering recommendations on how joint venture schemes can be genuinely participatory and meaningfully address the rural livelihoods.

      PubDate: 2015-11-14T17:09:46Z
  • Oil refinery wastewater treatment using coupled electrocoagulation and
           fixed film biological processes
    • Abstract: Publication date: Available online 11 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Laura S. Pérez, Oscar M. Rodriguez, Silvia Reyna, José Luis Sánchez-Salas, J. Daniel Lozada, Marco A. Quiroz, Erick R. Bandala
      Oil refinery wastewater was treated using a coupled treatment process including electrocoagulation (EC) and a fixed film aerobic bioreactor. Different variables were tested to identify the best conditions using this procedure. After EC, the effluent was treated in an aerobic biofilter. EC was capable to remove over 88% of the overall chemical oxygen demand (COD) in the wastewater under the best working conditions (6.5 V, 0.1 M NaCl, 4 electrodes without initial pH adjustment) with total petroleum hydrocarbon (TPH) removal slightly higher than 80%. Aluminum release from the electrodes to the wastewater was found an important factor for the EC efficiency and closely related with several operational factors. Application of EC allowed to increase the biodegradability of the sample from 0.015, rated as non-biodegradable, up to 0.5 widely considered as biodegradable. The effluent was further treated using an aerobic biofilter inoculated with a bacterial consortium including gram positive and gram negative strains and tested for COD and TPH removal from the EC treated effluent during 30 days. Cell count showed the typical bacteria growth starting at day three and increasing up to a maximum after eight days. After day eight, cell growth showed a plateau which agreed with the highest decrease on contaminant concentration. Final TPHs concentration was found about 600 mgL-1 after 30 days whereas COD concentration after biological treatment was as low as 933 mgL-1. The coupled EC-aerobic biofilter was capable to remove up to 98% of the total TPH amount and over 95% of the COD load in the oil refinery wastewater.

      PubDate: 2015-11-14T17:09:46Z
  • SPI drought class prediction using log-linear models applied to wet and
           dry seasons
    • Abstract: Publication date: Available online 11 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Elsa E. Moreira
      A log-linear modelling for 3-dimensional contingency tables was used with categorical time series of SPI drought class transitions for prediction of monthly drought severity. Standardized Precipitation Index (SPI) time series in 12- and 6-month time scales were computed for 10 precipitation time series relative to GPCC datasets with 2.5 degrees spatial resolution located over Portugal and with 112 years length (1902 to 2014). The aim was modelling two-month step class transitions for the wet and dry seasons of the year and then obtain probability ratios – Odds – as well as their respective confidence intervals to estimate how probable a transition is compared to another. The prediction results produced by the modelling applied to wet and dry season separately, for the 6- and the 12-month SPI time scale, were compared with the results produced by the same modelling without the split, using skill scores computed for the entire time series length. Results point to good prediction performances ranging from 70-80% in the percentage of corrects (PC) and 50-70% in the Heidke skill score (HSS), with the highest scores obtained when the modelling is applied to the SPI12. The adding up of the wet and dry seasons introduced in the modelling brought improvements in the predictions, of about 0.9-4% in the PC and 1.3-6.8% in the HSS, being the highest improvements obtained in the SPI6 application.

      PubDate: 2015-11-14T17:09:46Z
  • Ground and surface water quality along a dambo transect in Chihota
           smallholder farming area, Marondera district, Zimbabwe
    • Abstract: Publication date: Available online 12 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): M. Wuta, G. Nyamadzawo, J. Mlambo, P. Nyamugafata
      In many smallholder farms in sub-Saharan Africa dambos are used for grazing and crop production especially horticultural crops. Increased use of dambos especially for crop production can result in ground and surface water pollution. Ground and surface water quality along a dambo transect in Chihota, Zimbabwe, was investigated between October 2013 and February 2014. The transect was divided into; upland (control), dambo gardens (mid-slope) and the river (valley bottom). Water samples for quality assessment were collected in October 2013 (peak of dry season) and February 2014 (peak of rainy season). The collected water samples were analysed for pH, faecal coliforms, total nitrogen, electrical conductivity, total dissolved solids (TDS), and some selected nutrients (P, K, Ca, Mg, Na, Zn, and Cu). Water pH was 7.0, 6.4 and 6.1 for river water, garden and upland wells respectively. During the wet season total nitrogen (TN) concentrations were 233 mg/L for uplands, 242 mg/L for gardens and 141 mg/L for the river. During the dry season, TN concentrations were all below 20 mg/L, and were not significantly different among sampling stations along the dambo transect. Dry season faecal coliform units (fcu) were significantly different and were 37.2, 30.0 and 5.0 for upland wells, garden wells and river respectively. Wet season faecal coliforms were also significantly different and were 428.5, 258.0 and 479.4 fcu for upland wells, garden wells and river respectively. The other measured physico-chemical parameters also varied with sampling position along the transect. It was concluded that TN and fcu in sampled water varied with season and that wet season concentrations were significantly higher than dry season concentrations. High concentrations of faecal coliforms and total N during the wet season was attributed to increased water movement. Water from upland wells, garden wells and river was not suitable for human consumption according to WHO standards during both dry and wet season.

      PubDate: 2015-11-14T17:09:46Z
  • Rural food insecurity and poverty mappings and their linkage with water
           resources in the Limpopo River Basin
    • Abstract: Publication date: Available online 10 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): M.S. Magombeyi, A.E. Taigbenu, J. Barron
      The mappings of poverty and food insecurity were carried out for the rural districts of the four riparian countries (Botswana, Mozambique, South Africa and Zimbabwe) of the Limpopo river basin using the results of national surveys that were conducted between 2003 and 2013. The analysis shows lower range of food insecure persons (0 – 40%) than poverty stricken persons (0 – 95%) that is attributable to enhanced government and non-government food safety networks in the basin countries, the dynamic and transitory nature of food insecurity which depends on the timings of the surveys in relation to harvests, markets and food prices, and the limited dimension of food insecurity in relation to poverty which tends to be a more structural and pervasive socio-economic condition. The usefulness of this study in influencing policies and strategies targeted at alleviating poverty and improving rural livelihoods lies with using food insecurity mappings to address short-term socio-economic conditions and poverty mappings to address more structural and long-term deprivations. Using the poverty line of $1.25/day per person (2008–2013) in the basin, Zimbabwe had the highest percentage of 68.7% of its rural population classified as poor, followed by Mozambique with 68.2%, South Africa with 56.1% and Botswana with 20%. While average poverty reduction of 6.4% was observed between 2003 and 2009 in Botswana, its population growth of 20.1% indicated no real poverty reduction. Similar observations are made about Mozambique and Zimbabwe where population growth outstripped poverty reductions. In contrast, both average poverty levels and population increased by 4.3% and 11%, respectively, in South Africa from 2007–2010. While areas of high food insecurity and poverty consistently coincide with low water availability, it does not indicate a simple cause-effect relationship between water, poverty and food insecurity. With limited water resources, rural folks in the basin require stronger institutions, increased investments and support to enable them generate sufficient income from their rain-fed farming livelihood to break out of the poverty cycle.

      PubDate: 2015-11-14T17:09:46Z
  • Anthropogenic pressures on productive soils in Corlu and Cerkezkoy
    • Abstract: Publication date: Available online 10 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Ezgi Tok
      Unplanned land use is mainly arising from previous regional (local) planning policies based on economic growth, which resulted in the misuse of the land. The fertile lands are converted to industrial/urban areas along with forest areas converted to agricultural zones which directly affect the flora and fauna in a negative way. This study aims to identify the land use transformations by using Remote Sensing and GIS due to prior socio-economic return focused politics resulting in environmental degradations. Additionally, this paper presents an analysis of the transformation of fertile lands into industrial/urban zones with respect to Land Capability Classes. The study area is one of the most urbanized and industrialized zones in Turkey. The reason behind this transformation lies solely in the fact that the aforementioned area is quite appealing to industrialization due to its easy access to infrastructure and its compliance with the spatial requirements. Up until now the development plans of the region have been prepared with a socioeconomic agenda promoting the economic growth while disregarding the ecological and environmental balance, which unfortunately boosted the large-scale degradation of the environment. Although the focus area is within a zone suitable for industrialization, this region also takes place within a wide river basin (Ergene River Basin) making it an ideal location for highly productive crop cultivation (LUC Classes 1 to 4), which is a rare commodity in long term.

      PubDate: 2015-11-14T17:09:46Z
  • A comparison of integrated river basin management strategies: a global
    • Abstract: Publication date: Available online 12 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Chunhong Zhao, Pei Wang, Guanghong Zhang
      In order to achieve the integrated river basin management in the arid and rapid developing region, the Heihe River Basin (HRB) in Northwestern China, one of critical river basins were selected as a representative example, while the Murray-Darling Basin (MDB) in Australia and the Colorado River Basin (CRB) in the USA were selected for comparative analysis in this paper. Firstly, the comparable characters and hydrological contexts of these three watersheds were introduced in this paper. Then, based on comparative studies on the river basin challenges in terms of the drought, intensive irrigation, and rapid industrialization, the hydrological background of the MDB, the CRB and the HRB was presented. Subsequently, the river management strategies were compared in three aspects: water allocation, water organizations, and water act and scientific projects. Finally, we proposed recommendations for integrated river basin management for the HRB: 1) Water allocation strategies should be based on laws and markets on the whole basin; 2) Public participation should be stressed by the channels between governance organizations and local communities; 3) Scientific research should be integrated into river management to understand the interactions between the human and nature.

      PubDate: 2015-11-14T17:09:46Z
  • Electrokinetic treatment of polluted soil at pilot level coupled to an
           advanced oxidation process of its wastewater
    • Abstract: Publication date: Available online 6 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): B. Ochoa, L. Ramos, A. Garibay, M. Pérez - Corona, M.C. Cuevas, J. Cárdenas, M. Teutli, E. Bustos
      Soil contaminated with hydrocarbons is a current problem of great importance. These contaminants may be toxic, can retain water and block gas exchange with the atmosphere, which produces a poor-quality soil unsuitable for ecological health. Electroremediation is among the treatments for the removal of such contaminants. In this research, a pilot-level electroremediation test was applied using a circular arrangement of electrodes with a Ti cathode at the middle of the cell surrounded by six IrO2 - Ta2O5 Ti anodes. The presence of an NaOH electrolyte helps to develop the electromigration and electro-osmosis of gasoline molecules (at 1 126 mg Kg-1) surrounded by Na+ ions. The hydrocarbons are directed towards the cathode and subsequently removed in an aqueous Na+ - hydrocarbon solution, and the -OH migrates to the anode. During electrokinetic treatment, the physicochemical characteristics of the soil close to either the cathode or anode and at the half-cell were evaluated during the three weeks of treatment. During that time, more than 80% of hydrocarbons were removed. Hydrocarbons removed by the electrokinetic treatment of gasoline-polluted soil were collected in a central wastewater compartment and subsequently treated with a Fenton-type advanced oxidation process. This achieved more than 70% mineralization of the hydrocarbons to CO2 and H2O within 1.5h; its low toxicity status was verified using the Deltatox® kit test. With this approach, the residual water complied with the permissible limits of COD, pH, and electrical conductivity for being discharged into water bodies, according to Mexican norm NOM-001-SEMARNAT-1996.
      Graphical abstract image

      PubDate: 2015-11-09T16:57:08Z
  • Determination of the water quality index ratings of water in the
           Mpumalanga and North West Provinces, South Africa
    • Abstract: Publication date: Available online 2 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Elijah M.M. Wanda, Bhekie B. Mamba, Titus A.M. Msagati
      This study reports on the water quality index (WQI) of wastewater and drinking water in the Mpumalanga and North West provinces of South Africa. The WQI is one of the most effective tools available to water sustainability researchers, because it provides an easily intelligible ranking of water quality on a rating scale from 0 to 100, based on the ascription of different weightings to several different parameters. In this study the WQI index ratings of wastewater and drinking water samples were computed according to the levels of pH, electrical conductivity (EC), biochemical oxygen demand (BOD), E.coli, temperature, turbidity and nutrients (nitrogen and phosphates) found in water samples collected from the two provinces between June and December, 2014. This study isolated three groups of WQ-rated waters, namely: fair (with a WQI range = 32.87–38.54%), medium (with a WQI range = 56.54–69.77%) and good (with a WQI range= 71.69–81.63%). More specifically, 23%, 23% and 54% of the sampled sites registered waters with fair, medium and good WQ ratings respectively. None of the sites sampled during the entire period of the project registered excellent or very good water quality ratings, which would ordinarily indicate that no treatment is required to make it fit for human consumption. Nevertheless, the results obtained by the Eerstehoek and Schoemansville water treatment plants in Mpumalanga and North West provinces, respectively, suggest that substantial improvement in the quality of water samples is possible, since the WQI values for all of the treated samples were higher than those for raw water. Presence of high levels of BOD, low levels of dissolved oxygen (DO), E.coli, nitrates and phosphates especially in raw water samples greatly affected their overall WQ ratings. It is recommended that a point-of-use system should be introduced to treat water intended for domestic purposes in the clean-water-deprived areas.

      PubDate: 2015-11-06T16:28:16Z
  • Comparative assessment of water treatment using polymeric and inorganic
    • Abstract: Publication date: Available online 5 November 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): I.K.M. Manda, R.C.G. Chidya, J.D.K. Saka, T. Biswick
      Portable water plays a vital role in improving human life, particularly in controlling the spread of diseases. However, problems associated with lack of potable water are still common especially in developing countries including Malawi. Until now little information exists on the effectiveness of available commercial coagulants used by national water boards in Malawi. Therefore, this study was undertaken in Southern Region Water Board (SRWB) to investigate the efficiency of polymeric coagulants (sufdfloc 3850 and algaefloc 19s) in turbidity reduction comparative with inorganic coagulant (aluminium sulphate) at Zomba, Liwonde, Mangochi, Chikwawa and Mulanje Treatment plants. The jar test method was used to determine the effectiveness of the water coagulants. The results revealed that sudfloc 3850 was most effective in reducing turbidity at Mangochi (99.4±0.06 %) and Liwonde (97.2±0.04 %) using 0.4 mg L-1flocculant dose. The Zomba, Mulanje and Chikwawa plants gave 19.56±0.03%, 29.23±0.02% and 9.43±0.02% total reductions respectively. Algaefloc 19s afforded the highest turbidity reduction at Liwonde and Mangochi plants (98.66±0.06 and 97.48±0.05 % at a dose of 0.4 and 0.6 mg L-1 respectively), while Chikwawa provided the lowest (9.52±0.01%). At the Zomba and Mulanje plants 20.5±0.03% and 28.4±0.04% reductions were obtained respectively. The inorganic flocculant, alum provided a 99.0±0.05 % and 98.6±0.04 % reduction at a dose of 4.0 mg L-1 and 6.0 mg L-1 at Zomba and Liwonde plants respectively. The lowest reductions in turbidity were achieved at Chikwawa (7.50±0.01%), Mangochi (12.97±0.02%) and Mulanje (25.00±0.02). The best and optimum pH ranges for polymeric and inorganic coagulants were 7.20 to 7.80 and 7.35 to 7.57 respectively. The results further revealed that sudfloc 3850 and algaefloc 19s achieved faster formation of heavy flocs than alum. At 0.4 mg L-1flocculant dosage sudfloc 3850 and algaefloc 19s required ten times lower dosages than alum. Therefore, the polymeric coagulants could be used instead of alum, the choice dependant on the type of water.

      PubDate: 2015-11-06T16:28:16Z
  • Assessment of impact of climate change and adaptation strategies on maize
           production in Uganda
    • Abstract: Publication date: Available online 30 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Duncan A. Kikoyo, Joel Nobert
      Globally, various climatic studies have estimated a reduction of crop yields due to changes in surface temperature and precipitation especially for the developing countries which is heavily dependent on agriculture and lacks resources to counter the negative effects of climate change. Uganda’s economy and the wellbeing of its populace depend on rain-fed agriculture which is susceptible to climate change. This study quantified the impacts of climate change and variability in Uganda and how coping strategies can enhance crop production against climate change and/or variability. The study used statistical methods to establish various climate change and variability indicators across the country, and uses the FAO AquaCrop model to simulate yields under possible future climate scenarios with and without adaptation strategies. Maize, the most widely grown crop was used for the study. Meteorological, soil and crop data were collected for various districts representing the maize growing ecological zones in the country. Based on this study, it was found that temperatures have increased by up to 1°C across much of Uganda since the 1970s, with rates of warming around 0.3°C per decade across the country. High altitude, low rainfall regions experience the highest level of warming, with over 0.5oC/decade recorded in Kasese. Rainfall is variable and does not follow a specific significant increasing or decreasing trend. For both future climate scenarios, Maize yields will reduce in excess of 4.7% for the fast warming-low rainfall climates but increase on average by 3.5% for slow warming-high rainfall regions, by 2050. Improved soil fertility can improve yields by over 50% while mulching and use of surface water management practices improve yields by single digit percentages. The use of fertilizer application needs to go hand in hand with other water management strategies since more yields as a result of the improved soil fertility leads to increased water stress, especially for the dry climates.

      PubDate: 2015-11-02T13:39:32Z
  • Superoleophillic electrospun POLYSTRENE/exofoliated graphite fibre for
           selective removal of crude oil from water
    • Abstract: Publication date: Available online 30 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): S.Oluwagbemiga Alayande, Enock O. Dare, F.O. Grace Olorundare, D. Nkosi, Titus A.M. Msagati, B.B. Mamba
      During oil spills, the aquatic environment is greatly endangered because oil floats on water making the penetration of sunlight difficult therefore primary productivity is compromised, birds and aquatic organisms are totally eliminated within a short period. It is therefore essential to remove the oil from the water bodies after the spillage. This work reports on the fabrication of oil loving electrospun polystyrene-exofoliated graphite fibre with hydrophobic and oleophillic surface properties. The fibre was applied for the selective adsorption of crude oil from simulated crude oil spillage on water. The maximum oil adsorption capacity of the EPS/EG was 1.15 kg/g in 20 minutes while the lowest oil adsorption capacity was 0.81 kg/g in 10 minutes. Cheap oil adsorbent was developed with superoleophillic and superhydrophobic properties.

      PubDate: 2015-11-02T13:39:32Z
  • Determination of the health of Lunyangwa wetland using Wetland
           Classification and Risk Assessment Index
    • Abstract: Publication date: Available online 31 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Elijah M.M. Wanda, Golden Msilimba
      Wetlands are major sources of various ecological goods and services including storage and distribution of water in space and time which help in ensuring the availability of surface and groundwater throughout the year. However, there still remains a poor understanding of the range of values of water quality parameters that occur in wetlands either in its impacted state or under natural conditions. It was thus imperative to determine the health of Lunyangwa wetland in Mzuzu City in Malawi in order to classify and determine its state. This study used the Escom’s Wetland Classification and Risk Assessment Index Field Guide to determine the overall characteristics of Lunyangwa wetland and to calculate its combined Wetland Index Score. Data on site information, field measurements (i.e EC, pH, temperature and DO) and physical characteristics of Lunyangwa wetland were collected from March, 2013 to February, 2014. Results indicate that Lunyangwa wetland is a largely open water zone which is dominated by free-floating plants on the water surface, beneath surface and emergent in substrate. Furthermore, the wetland can be classified as of a C ecological category (score = 60-80%), which has been moderately modified with moderate risks of the losses and changes occurring in the natural habitat and biota in the wetland. It was observed that the moderate modification and risk were largely because of industrial, agricultural, urban/social catchment stressors on the wetland. This study recommends an integrated and sustainable management approach coupled with continuous monitoring and evaluation of the health of the wetland for all stakeholders in Mzuzu City. This would help to maintain the health of Lunyangwa wetland which is currently at risk of being further modified due to the identified catchment stressors.

      PubDate: 2015-11-02T13:39:32Z
  • Impact of urbanization on the ecology of Mukuvisi River, Harare, Zimbabwe
    • Abstract: Publication date: Available online 31 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): N.A.G. Moyo, M.M. Rapatsa
      The main objective in this study was to compare the physico-chemical characteristics and biota of a river (Mukuvisi) passing through an urban area to that of a non-urbanised river (Gwebi). Five sites in the Mukuvisi River and five sites in the Gwebi River were sampled for water physico-chemical parameters (pH, conductivity, DO, BOD, TDS, ammonia, Cl, SO4 2-, PO4 2-, NO3 3-, F-, Pb, Cu, Fe, Mn, Zn and Cr) once every month between August, 2012 - August, 2013. Cluster analysis based on the physico-chemical parameters grouped the sites into two groups. Mukuvisi River sites formed their own grouping except for one site which was grouped with Gwebi River sites. Principal Component Analysis (PCA) was used to extract the physico-chemical parameters that account for most variations in water quality in the Mukuvisi and Gwebi Rivers. PCA identified sulphate, chloride, fluoride, iron, manganese and zinc as the major factors contributing to the variability of Mukuvisi River water quality. In the Gwebi river, sulphate, nitrate, fluoride and copper accounted for most of the variation in water quality. Canonical Correspondence Analysis (CCA) was used to explore the relationship between physico-chemical parameters and macroinvertebrate communities. CCA plots in both Mukuvisi and Gwebi Rivers showed significant relationships between macroinvertebrate communities and water quality variables. Phosphate, ammonia and nitrates were correlated with Chironomidae and Simulidae. Gwebi River had higher (P<0.05, ANOVA) macroinvertebrates and fish diversity than Mukuvisi River. Clarias gariepinus from the Mukuvisi River had high liver histological lesions and low AChE activity and this led to lower growth rates in this river.

      PubDate: 2015-11-02T13:39:32Z
  • The Cone Penetration Test and 2D Imaging Resistivity as Tools to Simulate
           the Distribution of Hydrocarbons in Soil
    • Abstract: Publication date: Available online 31 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): M. Pérez-Corona, J.A. García, G. Taller, D. Polgár, E. Bustos, Z. Plank
      The purpose of geophysical electrical surveys is to determine the subsurface resistivity distribution by making measurements on the ground surface. From these measurements, the true resistivity of the subsurface can be estimated. The ground resistivity is related to various geological parameters, such as the mineral and fluid content, porosity and degree of water saturation in the rock. Electrical resistivity surveys have been used for many decades in hydrogeological, mining and geotechnical investigations. More recently, they have been used for environmental surveys. To obtain a more accurate subsurface model than is possible with a simple 1-D model, a more complex model must be used. In a 2-D model, the resistivity values are allowed to vary in one horizontal direction (usually referred to as the x direction) but are assumed to be constant in the other horizontal (the y) direction. A more realistic model would be a fully 3-D model where the resistivity values are allowed to change in all three directions. In this research, a simulation of the cone penetration test and 2D imaging resistivity are used as tools to simulate the distribution of hydrocarbons in soil.
      Graphical abstract image

      PubDate: 2015-11-02T13:39:32Z
  • Reviews on Land Use Change Induced Effects on Regional Hydrological
           Ecosystem Services for Integrated Water Resources Management
    • Abstract: Publication date: Available online 23 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Gui Jin, Pei Wang, Tao Zhao, Yuping Bai, Chunhong Zhao, Dongdong Chen
      This paper proposed to provide valuable information for integrated water resources management through evaluating the research on the interaction mechanism among land use changes, regional hydrological ecosystem services and human well-being. Firstly, the driving mechanism of land use and land cover changes was introduced in this paper. Secondly, the overview of the interaction mechanism among land use and land cover changes, regional hydrological ecosystem services and human well-being was given. Based on the meta-analysis, land use changes have a profound influence on regional hydrological ecosystem services, and the variation of hydrological ecosystem could benefit or impair human well-being. Finally, two suggestions were emphasized for managers or policy makers for the future integrated water resources management: (1) Proper land use makes for the water resource management; (2) Blindly pursuing the provisioning services weakens other services of hydrological ecosystem.

      PubDate: 2015-10-25T12:36:21Z
  • An Integrated Analysis of Agricultural Water-Use Efficiency: A Case Study
           in the Heihe River Basin in Northwest China
    • Abstract: Publication date: Available online 23 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Guofeng Wang, Jiancheng Chen, Feng Wu, Zhihui Li
      The water-use efficiency has direct impacts on the water consumption of agriculture production and is vital to water conservation at both local and regional extent. The agricultural water-use efficiency is a critical indicator that reflects the effective water allocation and water productivity improvement among different agricultural sectors. Taking the Heihe River Basin as the case study area, this study explores the changing trajectories of agricultural water use based on the input-output data of 2003-2012, and estimates the water-use efficiency with Data Envelopment Analysis, Malmquist Total Productivity Index and the decomposition of total factor productivity. Further, the influence of driving factors on the water-use efficiency is analyzed with the Tobit model. The research results indicate that the average agricultural water-use efficiency in different counties is all lower than 1 during 2003-2012, indicating that there is still improvement space in the agricultural water-use efficiency. In addition, there is obvious heterogeneity in the agricultural water-use efficiency among different counties, especially prior to 2009. The research results from the Tobit model indicate that agricultural investment and production, economic growth, industrial restructuring and agricultural plants structural adjustment have significant influence on the agricultural water-use efficiency. The research results can provide significant references for agricultural water-use management in the middle reaches of the Heihe River Basin and other similar regions in Northwest China.

      PubDate: 2015-10-25T12:36:21Z
  • Geological Risk Assessment for the Rapid Development Area of the Erhai
    • Abstract: Publication date: Available online 19 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Liu Yang, Zhanqi Wang, Gui Jin, Dongdong Chen, Zhan Wang
      For low-slope hilly land development to have more new land space in a watershed, it is particularly important that to coordinate the sharply increasing conflicts between mountainous and urban land utilization in the city. However, development of low-slope hilly land easily induce potential risks of geologic hazards such as landslide and landslip. It may lead to further environmental losses in a watershed. Hence, it is necessary to study potential risks of geo-hazards in low-slope hilly land development in urban area. Based on GIS spatial analysis technique, we select a study area, Dali City in the Erhai Basin located in watershed belt of Jinsha River, Lancang River and Red River in Yunnan Province of China. Through studying some relevant key indexes and parameters for monitoring potential risks of geo-hazards, we establish a composite index model for zoning the area with potential risks of geo-hazards in development of low-slope hilly land in the study area. Our research findings indicate that the potential risks of geo-hazards in eastern Dali City is relatively low while of that on slow hills with gentle slopes in the western area are relatively high. By using a zoning research method, generated maps show geological information of potential risks of geo-hazards on low-slope hilly land which provide important messages for guarding against natural geo-hazards and potential environmental losses in a watershed.

      PubDate: 2015-10-20T12:05:47Z
  • A LF radio anomaly observed before the Mw=6.5 earthquake occurred in Crete
           on October 12, 2013
    • Abstract: Publication date: Available online 20 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Tommaso Maggipinto, Pier Francesco Biagi, Roberto Colella, Luigi Schiavulli, Teresa Ligonzo, Anita Ermini, Giovanni Martinelli, Iren Moldovan, Hugo Silva, Michael Contadakis, Christos Skeberis, Zaharias Zaharis, Emmanuel Scordilis, Konstantinos Katzis, Aydın Buyuksarac, Sebastiano D’Amico
      On October 12, 2013, an earthquake with Mw=6.5 occurred in the southern Hellenic Arc, approximately 20 km off the west coast of Crete. The main shock, the focal depth of which is on the order of 40 km, was followed by aftershocks felt in the nearby cities and villages, although the aftershock sequence was poor. The epicentre was located at approximately 60 km from a radio receiver in Crete (CRE), which belongs to the European VLF/LF Radio Network. Several days before the earthquake, a clear disturbance occurred in one of the ten radio signals that the CRE receiver sampled. The disturbance, which can be considered an anomaly, appeared in the 216 kHz radio signal radiated by the Radio Monte Carlo (MCO) transmitter. The radio path MCO-CRE crossed directly over the epicentre area of the aforementioned earthquake. In this work, we present a detailed analysis of the MCO signal anomaly using spectral tools. We also investigate the behaviour of other radio signals sampled by the CRE receiver and consider other possible causes of disturbances on the MCO radio signal. We conclude that the disturbance in the MCO radio signal is a convincingly possible precursor of the earthquake in Crete. Emission of electromagnetic waves with a frequency band that includes 216 kHz from the focal zone of the earthquake can provide a satisfactory explanation of the radio anomaly.

      PubDate: 2015-10-20T12:05:47Z
  • Superhydrophobic and superoleophillic surface of porous beaded electrospun
           polystrene and polysytrene-zeolite fiber for crude oil-water separation
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): S.Oluwagbemiga Alayande, E.Olugbenga Dare, Titus A.M. Msagati, A.Kehinde Akinlabi, P.O. Aiyedun
      This research presents a cheap route procedure for the preparation of a potential adsorbent with superhydrophobic/superoleophillic properties for selective removal of crude oil from water. In this study, expanded polystyrene (EPS) was electrospun to produce beaded fibers in which zeolite was introduced to the polymer matrix in order to impart rough surface to non-beaded fiber. Films of the EPS and EPS/Zeolite solutions were also made for comparative study. The electrospun fibers EPS, EPS/Zeolite and resultant films were characterized using SEM, BET, FTIR and optical contact angle. The fibers exhibited superhydrophobic and superoleophillic wetting properties with water (>150 0) and crude oil (0 0). The selective removal of crude oil presents new opportunity for the re-use of EPS as adsorbent in petroleum/petrochemical industry.

      PubDate: 2015-10-12T11:28:29Z
  • Implementing Integrated Catchment Management in the upper Limpopo River
           basin: A Situational Assessment
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): J. Mwenge Kahinda, R. Meissner, F.A. Engelbrecht
      A three-phase study was initiated as a way to promote Integrated Catchment Management approaches in the Limpopo River basin. This paper presents the situational assessment, which should enable De Beers to understand how their Venetia Mine operations are located within a broader and highly dynamic socio-economic and ecohydrological landscape as it pertains to water risks. The second phase, Risk assessment, aims to develop conservation interventions in the identified areas; the third phase will develop mechanisms for implementing water stewardship schemes to mitigate the shared water risks. Analysis of the social-ecological system (hydrological, climatic, ecological, socio-economic and governance systems) of the Limpopo River basin indicates that the institutional arrangement of the Limpopo River basin is neither simple nor effective. The basin is rapidly approaching closure in the sense that almost all of the available supplies of water have already been allocated to existing water users. If the proposed ecological flow requirements were to be met for all of the tributaries, the basin would be ‘closed’. On-going and projected land use changes and water resources developments in the upper reaches of the basin, coupled with projected rainfall reductions and temperature increases, and allocation of the flows for the ecological reserve, are likely to further reduce downstream river flows. The coupled increase in temperature and decrease in rainfall is of great concern for everyone in the basin, especially the poorer communities, who rely on rain-fed agriculture for their livelihoods. Increased temperatures also lead to increased evaporation from reservoirs and therefore result in a decrease in water availability. This will lead to increased abstraction of groundwater, especially from alluvial aquifers, and consequently an increase in river transmission losses and a decrease in river flows.

      PubDate: 2015-10-12T11:28:29Z
  • Gender and power contestations over water use in irrigation schemes:
           Lessons from the lake Chilwa basin
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Bryson Nkhoma, Gift Kayira
      Over the past two decades, Malawi has been adversely hit by climatic variability and changes, and irrigation schemes which rely mostly on water from rivers have been negatively affected. In the face of dwindling quantities of water, distribution and sharing of water for irrigation has been a source of contestations and conflicts. Women who constitute a significant section of irrigation farmers in schemes have been major culprits. The study seeks to analyze gender contestations and conflicts over the use of water in the schemes developed in the Lake Chilwa basin, in southern Malawi. Using oral and written sources as well as drawing evidence from participatory and field observations conducted at Likangala and Domasi irrigation schemes, the largest schemes in the basin, the study observes that women are not passive victims of male domination over the use of dwindling waters for irrigation farming. They have often used existing political and traditional structures developed in the management of water in the schemes to competitively gain monopoly over water. They have sometimes expressed their agency by engaging in irrigation activities that fall beyond the control of formal rules and regulations of irrigation agriculture. Other than being losers, women are winning the battle for water and land resources in the basin.

      PubDate: 2015-10-12T11:28:29Z
  • Establishment and analysis of a high-resolution assimilation dataset of
           the water-energy cycle in China
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Xiaohang Wen, Wenjie Dong, Wenping Yuan, Zhiyuan Zheng
      For better prediction and understanding of land-atmospheric interaction, in-situ observed meteorological data acquired from the China Meteorological Administration (CMA) were assimilated in the Weather Research and Forecasting (WRF) model and the monthly Green Vegetation Coverage (GVF) data, which was calculated using the Normalized Difference Vegetation Index (NDVI) of the Earth Observing System Moderate-Resolution Imaging Spectroradiometer (EOS-MODIS) and Digital Elevation Model (DEM) data of the Shuttle Radar Topography Mission (SRTM) system. Furthermore, the WRF model produced a High-Resolution Assimilation Dataset of the water-energy cycle in China (HRADC). This dataset has a horizontal resolution of 25 km for near surface meteorological data, such as air temperature, humidity, wind vectors and pressure (19 levels); soil temperature and moisture (four levels); surface temperature; downward/upward short/long radiation; 3-h latent heat flux; sensible heat flux; and ground heat flux. In this study, we 1) briefly introduce the cycling 3D-Var assimilation method and 2) compare results of meteorological elements, such as 2 m temperature and precipitation generated by the HRADC with the gridded observation data from CMA, and surface temperature and specific humidity with Global Land Data Assimilation System (GLDAS) output data from the National Aeronautics and Space Administration (NASA). We find that the simulated results of monthly 2 m temperature from HRADC is improved compared with the control simulation and has effectively reproduced the observed patterns. The simulated special distribution of ground surface temperature and specific humidity from HRADC are much closer to GLDAS outputs. The spatial distribution of root mean square errors (RMSE) and bias of 2 m temperature between observations and HRADC is reduced compared with the bias between observations and the control run. The monthly spatial distribution of surface temperature and specific humidity from HRADC is consistent with the GLDAS outputs over China. This study could improve the land surface parameters by utilizing remote sensing data and could further improve atmospheric elements with a data assimilation system. This work provides an effective attempt at combining multi-source data with different spatial and temporal scales into numerical simulations, and the simulated results could be used in further research on the long-term climatic effects and characteristics of the water-energy cycle over China.

      PubDate: 2015-10-12T11:28:29Z
  • ENSO-Climate Fluctuation-Crop Yield Early Warning System—A Case
           Study in Jilin and Liaoning Province in Northeast China
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Zhao Zhang, Boyan Feng, Jiabin Shuai, Peijun Shi
      Crop yield is very sensitive to climate variability. The El Niño–Southern Oscillation (ENSO) is one of the most important contributors to global climate fluctuation, and therefore has a major impact on agricultural production. In this study, we structure an ENSO–climate fluctuation–crop yield early warning system to model the maize yield in Jilin and Liaoning Provinces in Northeast China. The system, which consists of a weather generator and a Model to capture the Crop Weather relationship over a Large Area (MCWLA), is not only capable of simulating the maize yield both at the provincial (regional) scale and the grid scale, but can also provide the exceedance probability of yield. Simulation results show maize yields in El Niño years to be higher on average than those in neutral years, while yields in La Niña years are the lowest. Spatially, the central part of the study area always shows a higher yield than other parts of the study, while yields in the northeast and northwest parts are relatively lower, no matter how high or low the exceedance probability and whatever the ENSO phase. Our study strongly implies that such a warning system shows considerable potential for application in other areas of China.

      PubDate: 2015-10-12T11:28:29Z
  • Assessing vegetation dynamics and their relationships with climatic
           variability in Northern China
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Yanling Sun, Yanli Yang, Yue Zhang, Zhongliang Wang
      In this study, the vegetation dynamics and their correlations with climate variability in northern China were evaluated based on the normalized difference vegetation index (NDVI) and meteorological datasets from 1982 to 2006. The NDVI showed that vegetation cover had a tiny increasing trend for whole study area in the past 25 years. However, the interannual changes of NDVI were different in each season. The part of spring and autumn NDVI values increased significantly, while the summer NDVI increased no significantly. And the interannual variations of the NDVI showed obvious spatial differentiations. The annual max NDVI increased were mainly distributed in most areas of grassland and farmland, whereas the annual max NDVI decreased were mainly distributed in forest areas. The annual NDVI and temperature had more important relationships. Thus, as compared to precipitation, the correlation between NDVI with temperature was stronger than the precipitation in northern China. NDVI and climatic variables were different in each season. The NDVI trends exhibited a close correspondence to climatological variations in region and season. In Addition, human activities also had profound effect to the NDVI trends in some regions. All these findings will make humans know more about the knowledge of the natural forces that influence vegetation change and supply a scientific basic resource to for the environmental management in northern China.

      PubDate: 2015-10-12T11:28:29Z
  • The relative roles of climate variations and human activities in
           vegetation change in North China
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Yanling Sun, Yanli Yang, Li Zhang, Zhongliang Wang
      Using SPOT-VEGETATION Normal Difference Vegetation Index (SPOT/NDVI) data from 1998 to 2011 and climate data obtained from 223 weather stations in or near North China, vegetation variation characteristics within North China were analyzed. Vegetation variation characteristics under the influence of climate variations and human activities were distinguished through a residual analysis. Based on the results of that analysis, the relative roles of climate variations and human activities in vegetation variation were calculated. The results showed that NDVI observed by remote sensing (SPOT/NDVI) increased from 1998 to 2011. The relative roles of climate variations and human activities in vegetation increase were 30.82% and 69.18%, respectively, indicating that human activities played a major role. And observed NDVI showed an increasing trend for different land cover types overall. While NDVI increase in shrub was mainly caused by climate variations, NDVI increases in forest, grassland, farmland, deserts and urban were all primarily caused by human activities. For areas with increasing vegetation, as identified by remote sensing observations in North China, the relative roles of climate variations and human activities in vegetation change were calculated at 14.85% and 85.15% respectively, again indicating that human activities played an important role in vegetation increase. For areas of decreasing vegetation, as identified by remote sensing observations in North China, the relative roles of climate variations and human activities in vegetation change were calculated at 87.72% and 12.28% respectively, indicating that climate variations had large negative effects on vegetation condition. In addition, the relative roles of climate variations and human activities on vegetation variation have obvious spatial differences in North China. Human activities played a positive role in vegetation growth in North China. However, we cannot ignore the function of human destruction on vegetation variation in some areas.

      PubDate: 2015-10-12T11:28:29Z
  • Daily Surface Water and Sediment Fluxes in Thukela River, South Africa
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Macdex Mutema, Graham Jewitt, Pauline Chivenge, Samuel Kusangaya, Vincent Chaplot
      The on- and off-site effects of soil erosion in many environments are well known, but there is still limited understanding of the fluxes in downstream direction due, among other factors, to scarce and poor quality data. A study four year to (i) evaluate water and sediment fluxes at different spatio-temporal scales and (ii) interpret the results in terms of processes involved and the controlling factors, was conducted in Thukela basin, South Africa. Five hierarchically nested catchments; namely microcatchment (0.23 km2), subcatchment (1.20 km2), catchment (9.75 km2), sub-basin (253 km2) and basin (29038 km2), were used in addition to fifteen (1 m2) microplots and ten (10 m2) plots on five locations within the microcatchment. The results showed 19% decrease of unit-area runoff (q) from 3.1 L m-2 day-1 at microplot to 2.5 L m-2 day-1 at plot scale followed by steeper (56%) decrease at microcatchment scale. The q decreased in the downstream direction to very low level (q ≤ 0.26 L m-2 day-1). The changes in q were accompanied by initial 1% increase of soil loss (SL) from 18.8 g m-2 day-1 at microplot to 19.1 g m-2 day-1 at plot scale. The SL also decreased sharply (by 39 fold) to 0.50 g m-2 day-1 at microcatchment scale, followed by further decrease in downstream direction. The decrease of q with spatial scale was attributed to infiltration losses, while initial increase of SL signified greater competence of sheet than splash erosion. The decrease of SL beyond the plot scale was attributed to redistribution of the soil on the hillslope and deposition on the stream channel upstream of the microcatchment outlet. Therefore, erosion control strategies focusing on the recovery of vegetation on the slope and stabilisation of gullies are recommended.

      PubDate: 2015-10-12T11:28:29Z
  • Effect of iron salt counter ion in dose-response curves for inactivation
           of Fusarium solani in water through solar driven Fenton-like processes
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Verónica Aurioles-López, M. Inmaculada Polo-López, Pilar Fernández-Ibáñez, Aurelio López-Malo, Erick R. Bandala
      The inactivation of Fusarium solani in water was assessed by solar driven Fenton-like processes using three different iron salts: ferric acetylacetonate (Fe(acac)3), ferric chloride (FeCl3) and ferrous sulfate (FeSO4). The experimental conditions tested were [Fe] ≈ 5 mg L-1, [H2O2] ≈ 10 mg L-1 and [Fe] ≈10 mg L-1; [H2O2] ≈20 mg L-1 mild and high, respectively, and pH 3.0 and 5.0, under solar radiation. The highest inactivation rates were observed at high reaction conditions for the three iron salts tested at pH 5.0 with less than 3.0 kJL-1 of accumulate energy (Q UV ) to achieve over 99.9% of F. solani inactivation. Fe(acac)3 was the best iron salt to accomplishing F. solani inactivation. The modified Fermi equation was used to fix the experimental inactivation, data showed it was helpful for modeling the process, adequately describing dose-response curves. Inactivation process using FeSO4 at pH 3.0 was modeled fairly with r 2 = 0.98 and 0.99 (mild and high concentration, respectively). Fe(acac)3, FeCl3 and FeSO4 at high concentration (i.e. [Fe]≈10 mgL-1; [H2O2]≈20 mgL-1) and pH 5.0 showed the highest fitting values (r 2 = 0.99). Iron salt type showed a remarkable influence on the Fenton-like inactivation process.

      PubDate: 2015-10-12T11:28:29Z
  • A diagnosis of sub-surface water table dynamics in low hydraulic
           conductivity soils in the sugar cane fields of Pongola, South Africa
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Mphatso Malota, Aidan Senzanje
      Water and land are the two natural resources restraining crop production in South Africa. With the increasing demand for food, emphasis has shifted from the sole reliance on rain fed crop production, to irrigation. The deterioration in irrigation water quality from surface water sources is, however, posing a big challenge to the sustainability of irrigated crop production. This is because more water is required for leaching, resulting in shallow water tables in agricultural lands. The installation of well designed subsurface drainage systems alone is not enough; the provision of timely maintenance is also necessary. In this study, the extent and severity of problems as a consequence of shallow water tables and their possible causes were investigated at three sugarcane fields in Pongola, South Africa, having low hydraulic conductivity soils. Also investigated were soil salinity levels and the temporal variation in the salinity of the irrigation water. A water table map of a 32 ha sugarcane field was generated, using observed water table depth (WTD) data from 36 piezometers monitored from September 2011 to February 2012. Out of the total 32 ha under cultivation, 12% was found to be affected by shallow WTDs of less than the 1.0 m design WTD. The inability of natural drainage to cope with subsurface drainage needs and the poor maintenance of subsurface drainage systems contributed to the shallow water tables in the area. Furthermore, the currently adopted drainage design criteria also proved unsatisfactory with mean observed water table depth and drainage discharge (DD) of 20% and 50%, respectively, less than their respective design levels. The salinity of the irrigation water was, on average, 32% higher than threshold tolerance level of sugarcane. The root zone soil salinity levels at the three study sites were greater than the 1.7 dS.m-1 threshold for sugar cane. The subsurface drainage design criteria adopted at the site needs to be revisited by ensuring that the slope of the land is taken into consideration in the drainage design in addition to adhering to a recommended maintenance schedule.

      PubDate: 2015-10-12T11:28:29Z
  • Analysis on urban lake change during rapid urbanization using a
           synergistic approach: a case study of Wuhan, China
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Bohan Yang, Xinli Ke
      To grasp the evolution of urban lakes accurately is quite necessary for studying on the mechanism of city ecological development. The study about extraction with different types of water by remote sensing technology has developed for decades. Many water indexes as the main methods are used to extract water information. Each method has advantage and disadvantage in different situation. A synergistic approach in this study can reduce the uncertainty of urban lake extraction by using four methods: NDWI, MNDWI, RNDWI and SPM. The basic idea behind the synergistic approach is to give each pixel a score based upon the agreement among the different products of four water extraction methods. According to the score of each pixel, the synergy map, which has been created by the products of four methods, is decomposed into sixteen sub-synergy maps. We use Bayesian Decision Theory to screen out the sub-synergy maps with low confidence level. The remaining ones are recombined a refined map. The overall accuracy of refined map reaches 96.44%, higher than any one of the four methods. Wuhan, known as the City of Hundred Lakes, is selected as the study area. We use the synergistic method to keep track of twenty lakes in Wuhan City changing from 1990 to 2013. The total area of twenty lakes has reduced from 130.2478 km2 to 102.2971 km2 during twenty-three years. The area of Shaihu Lake, which is the most serious of all observed lakes, has shrunk by 77.27%. And Nanhu Lake has lost 8.5 km2 of its area that is the most among all lakes. We also find 1990-2000 is the high tide of urban lake shrinking. After the year of 2000, the situation of lake shrinking has been controlled gradually.

      PubDate: 2015-10-12T11:28:29Z
  • Prediction and Assessment of the Disturbances of the Coal Mining in
           Kailuan to Karst Groundwater System
    • Abstract: Publication date: Available online 9 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Wenjie Sun, Qiang Wu, Honglei Liu, Jian Jiao
      Coal resources and water resources play an essential and strategic role in the development of China’s social and economic development, being the priority for China’s medium and long technological development. As the mining of the coal extraction is increasingly deep, the mine water inrush of high-pressure confined karst water becomes much more a problem. This paper carried out research on the hundred-year old Kailuan coal mine's karst groundwater system. With the help of advanced Visual Modflow software and numerical simulation method, the paper assessed the flow field of karst water area under large-scale exploitation. It also predicted the evolution ofgroundwaterflow field under different mining schemes of Kailuan Corp. The result shows that two cones of depression are formed in the karst flow field of Zhaogezhuang mining area and Tangshan mining area, and the water levels in two cone centers are -270m and -31m respectively, and the groundwater generally flows from the northeast to the southwest. Given some potential closed mines in the future, the mine discharge will decrease and the water level of Ordovician limestone will increase slightly. Conversely, given increase of coal yield, the mine drainage will increase, falling depression cone of Ordovician limestone flow field will enlarge. And in Tangshan’s urban district, central water level of the depression cone will move slightly towards north due to pumping of a few mines in the north.

      PubDate: 2015-10-12T11:28:29Z
  • Is irrigation water price an effective leverage for water management?
           An empirical study in the Middle reaches of the Heihe River Basin
    • Abstract: Publication date: Available online 2 October 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Qing Zhou, Feng Wu, Qian Zhang
      Serious water scarcity, low water-use efficiency, and over-exploitation of underground water have hindered socio-economic development and led to environmental degradation in the Heihe River basin, northwestern China. Price leveraging is an important tool in water demand management, and it is considered to be effective in promoting water conservation and improving water use efficiency on the premise that water demand is elastic. In the present study, we examine whether price is an effective and applicable instrument for restraining the increasing demand for agricultural irrigation water in the middle reaches of the Heihe River basin and how will it affect farmers’ decisions on irrigation and crop structure. Specifically, the price elasticity of agricultural water demand was estimated based on the irrigation water demand function. The results show that the agricultural irrigation water price is statistically significant, but its elasticity is very low under current low water price. Price leverage effects cannot play a significant role in the context of the current pricing regime and farmers’ response to price increase is intrinsically weak. To create incentives for conserving water and improving irrigation efficiency, price mechanism should be accompanied with clearly defined and legally enforceable water rights, restricted water quota measure, and reform of water authorities and water-user associations. Furthermore, increases of surface irrigation water price may lead to the over-withdrawal of groundwater, consequently, effective groundwater licensing and levying must take place to limit the total volume of groundwater withdrawal. In all, improving irrigation efficiency through better management and the adoption of water-saving technologies is the ultimate way to deal with the challenges facing irrigated agriculture in the middle reaches of the Heihe River basin.

      PubDate: 2015-10-04T00:18:15Z
  • Impacts of sparing use of water on farmer income of China
    • Abstract: Publication date: Available online 25 September 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Zhan Wang, Xiangzheng Deng, Jiancheng Chen
      we examine relationships between nationwide sparing use of water and farmer income of China in this article. As increasing implementation of water projects and irrigation system, the cost of water use has increased and many regions. However, as local policy-oriented urban expansion and ecological restoration have carried out during the past decade, water demand has increased. The spatial distributions of water use and farmer income are uneven and their relationships are ambiguous over time, especially it is uncertain that farmers can benefit from those so called water-saving programs when urban expansion grows faster in China. Based on consumption theory, empirical results of Blundell-Bond dynamic panel-data model with generalized method of moments (GMM) estimators indicate saving one percent of water has positive impacts at 0.085∼0.35 percent on farmer income in the following statistical year. Population has negative impacts on farmer income. Particularly in Central China, one percent of increase in population will significantly decrease 0.276 percent of contemporaneous farmer income. Particularly, in Eastern China with large population during years 2004 through 2012, the total amount of water use increases one percent, contemporaneous farmer income loses 0.04 percent. Thus, saving water can benefit future farmer income, and it indicates that urban expansion may induce the diversion of resources for agricultural production from rural to urban area. Policy implication of relationships between water allocation and farmer income distribution caused by water-saving programs needs to be further studied at regional scale, in particularly to the regions with large population and urban expansion in China.

      PubDate: 2015-09-25T23:24:44Z
  • Polarimetric scattering model for estimation of above ground biomass of
           multilayer vegetation using ALOS-PALSAR quad-pol data
    • Abstract: Publication date: Available online 25 September 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): P. Sai Bharadwaj, Shashi Kumar, S.P.S. Kushwaha, Wietske Bijker
      Forests are important biomes covering a major part of the vegetation on the Earth, and as such account for seventy percent of the carbon present in living beings. The value of a forest’s above ground biomass (AGB) is considered as an important parameter for the estimation of global carbon content. In the present study, the quad-pol ALOS - PALSAR data was used for the estimation of AGB for the Dudhwa National Park, India. For this purpose, polarimetric decomposition components and an Extended Water Cloud Model (EWCM) were used. The PolSAR data orientation angle shifts were compensated for before the polarimetric decomposition. The scattering components obtained from the polarimetric decomposition were used in the Water Cloud Model (WCM). The WCM was extended for higher order interactions like double bounce scattering. The parameters of the EWCM were retrieved using the field measurements and the decomposition components. Finally, the relationship between the estimated AGB and measured AGB was assessed. The coefficient of determination (R2) and root mean square error (RMSE) were 0.4341 and 119 t/ha respectively.

      PubDate: 2015-09-25T23:24:44Z
  • Notable shifting in the responses of vegetation activity to climate change
           in China
    • Abstract: Publication date: Available online 4 September 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Aifang Chen, Bin He, Honglin Wang, Ling Huang, Yunhua Zhu
      The weakening relationship between inter-annual temperature variability and vegetation activity in the Northern Hemisphere over the last three decades has been reported by a recent study. However, how and to what extent vegetation activity responds to climate change in China is still unclear. We applied the Pearson correlation and partial correlation methods with a moving 15-y window to the GIMMS NDVI dataset from NOAA/AVHRR and observed climate data to examine the variation in the relationships between vegetation activity and climate variables. Results showed that there was an expanding negative response of vegetation growth to climate warming and a positive role of precipitation. The change patterns between NDVI and climate variables over vegetation types during the past three decades pointed an expending negative correlation between NDVI and temperature and a positive role of precipitation over most of the vegetation types (meadow, grassland, shrub, desert, cropland, and forest). Specifically, correlation between NDVI and temperature (PNDVI-T) have shifted from positive to negative in most of the station of temperature-limited areas with evergreen broadleaf forests, whereas precipitation-limited temperate grassland and desert were characterized by a positive PNDVI-P. This study contributes to ongoing investigations of the effects of climate change on vegetation activity. It is also of great importance for designing forest management strategies to cope with climate change.

      PubDate: 2015-09-06T06:42:56Z
  • Estimation of maize yield by using a process-based model and remote
           sensing data in the Northeast China Plain
    • Abstract: Publication date: Available online 1 September 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Fengmei Yao, Yanjing Tang, Peijuan Wang, Jiahua Zhang
      Climate change significantly impact on agriculture in recent year, the accurate estimation of crop yield is of great importance for the food security. In this study, a process-based mechanism model was modified to estimate yield of C4 crop by modifying the carbon metabolic pathway in the photosynthesis sub-module of the RS–P–YEC (Remote-Sensing–Photosynthesis–Yield estimation for Crops) model. The yield was calculated by multiplying net primary productivity (NPP) and the harvest index (HI) derived from the ratio of grain to stalk yield. The modified RS–P–YEC model was used to simulate maize yield in the Northeast China Plain during the period 2002–2011. The 111 statistical data of maize yield from study area was used to validate the simulated results at county-level. The results showed that the Pearson correlation coefficient (R) was 0.827 (p <0.01) between the simulated yield and the statistical data, and the root mean square error (RMSE) was 712kg/ha with a relative error (RE) of 9.3%. From 2002 to 2011, the yield of maize planting zone in the Northeast China Plain was increasing with smaller coefficient of variation (CV). The spatial pattern of simulated maize yield was consistent with the actual distribution in the Northeast China Plain, with an increasing trend from the northeast to the southwest. Hence the results demonstrated that the modified process-based model coupled with remote sensing data was suitable for yield prediction of maize in the Northeast China Plain at the spatial scale.

      PubDate: 2015-09-06T06:42:56Z
  • Analysis of observations backing up the existence of VLF and ionospheric
           TEC anomalies before the Mw6.1 earthquake in Greece, January 26, 2014
    • Abstract: Publication date: Available online 28 August 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): F. Sanchez-Dulcet, M. Rodríguez-Bouza, H.G. Silva, M. Herraiz, M. Bezzeghoud, P.F. Biagi
      The present work integrates ground-based ionosphere measurements using very-low-frequency radio transmissions with satellite measurements of the total electron content to draw common conclusions about the possible impact that the Mw6.1 earthquake that took place in Greece on January 26, 2014, had on the ionosphere. Very-low-frequency radio signals reveal the existence of an ∼4-day anomaly in the wavelet spectra of the signals received inside the earthquake preparation zone and a significant increase in the normalized variance of the signals prior to the earthquake (approximately 1 day before). Through total electron content analysis, it was possible to identify a clear anomaly from 15:00 until 20:00 UT on the day before the earthquake that appears again on the day of the earthquake between 07:00 UT and 08:00 UT. The anomalous values reach TEC∗Sigma ∼ 4.36 and 3.11, respectively. Their spatial and temporal distributions give grounds to assume a possible link with the earthquake preparation. The geomagnetic, solar and weather conditions during the considered period are presented and taken into account. This work is an initial and original step towards a multi-parameter approach to the problem of the possible earthquake-related effects on the ionosphere joining observations made from both ground stations and satellites. A well-founded knowledge of these phenomena is clearly necessary before dealing with their application to earthquake prediction purposes.

      PubDate: 2015-08-31T06:09:29Z
  • Climate threats, water supply vulnerability and the risk of a water crisis
           in the Monterrey Metropolitan Area (Northeastern Mexico)
    • Abstract: Publication date: Available online 29 August 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Nicholas P. Sisto, Aldo I. Ramírez, Ismael Aguilar-Barajas, Víctor Magaña-Rueda
      This paper evaluates the risk of a water crisis – a substantial, sudden reduction in water supply - in the Monterrey Metropolitan Area (MMA), posed by climate threats and the vulnerability of its water supply system. Our analysis of long-term precipitation, water supply and water availability data reveals that the MMA is highly vulnerable to recurring periods of exceptionally low precipitation and scarce surface water availability. We identify two episodes in the recent past (1998 and 2013) when the MMA water supply system almost collapsed as reservoirs neared depletion in the face of abnormally dry weather. Furthermore our climate projections point to warmer and drier future conditions for the region and consequently, heightened climate threats. We conclude that the risk of a water crisis in the MMA is substantial and probably will increase due to climate change. This establishes a clear and pressing need for a comprehensive package of adaptation measures to mitigate the consequences of a water crisis should one occur as well as to reduce the likelihood of such an event.

      PubDate: 2015-08-31T06:09:29Z
  • Possible Climate Change Evidence in Ten Mexican Watersheds
    • Abstract: Publication date: Available online 29 August 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Efrain Mateos, Julio-Sergio Santana, Martin J Montero-Martínez, Alejandro Deeb, Alfred Grunwaldt
      This paper suggests possible evidence of climate change in Mexico at the watershed level, based solely on historical data. The official Mexican climate dataset was used to find the best set of stations for each watershed. Maximum and minimum temperatures and rainfall in ten watersheds are analyzed from 1970 to 2009. Maximum temperature trends show a significant increment in most of these watersheds. Furthermore, Daily Temperature Range (DTR) exhibits a positive trend (increments), thus implying an increase in temperature extremes. This study also shows that the difference between maximum and minimum monthly temperature trends is negatively correlated with monthly precipitation trends. As a result, land-use and land-cover changes could be the main drivers of climate change in the region.

      PubDate: 2015-08-31T06:09:29Z
  • Adjustment of wind-drift effect for real-time systematic error correction
           in radar rainfall data
    • Abstract: Publication date: Available online 28 August 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Qiang Dai, Dawei Han, Lu Zhuo, Jing Huang, Tanvir Islam, Shuliang Zhang
      An effective bias correction procedure using gauge measurement is a significant step for radar data processing to reduce the systematic error in hydrological applications. In these bias correction methods, the spatial matching of precipitation patterns between radar and gauge networks is an important premise. However, the wind-drift effect on radar measurement induces an inconsistent spatial relationship between radar and gauge measurements as the raindrops observed by radar do not fall vertically to the ground. Consequently, a rain gauge does not correspond to the radar pixel based on the projected location of the radar beam. In this study, we introduce an adjustment method to incorporate the wind-drift effect into a bias correlation scheme. We first simulate the trajectory of raindrops in the air using downscaled three-dimensional wind data from the weather research and forecasting model (WRF) and calculate the final location of raindrops on the ground. The displacement of rainfall is then estimated and a radar–gauge spatial relationship is reconstructed. Based on this, the local real-time biases of the bin-average radar data were estimated for 12 selected events. Then, the reference mean local gauge rainfall, mean local bias, and adjusted radar rainfall calculated with and without consideration of the wind-drift effect are compared for different events and locations. There are considerable differences for three estimators, indicating that wind drift has a considerable impact on the real-time radar bias correction. Based on these facts, we suggest bias correction schemes based on the spatial correlation between radar and gauge measurements should consider the adjustment of the wind-drift effect and the proposed adjustment method is a promising solution to achieve this.

      PubDate: 2015-08-31T06:09:29Z
  • Review and discussion of homogenisation methods for climate data
    • Abstract: Publication date: Available online 28 August 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): S. Ribeiro, J. Caineta, A.C. Costa
      The quality of climate data is of extreme relevance, since these data are used in many different contexts. However, few climate time series are free from non-natural irregularities. These inhomogeneities are related to the process of collecting, digitising, processing, transferring, storing and transmitting climate data series. For instance, they can be caused by changes of measuring instrumentation, observing practices or relocation of weather stations. In order to avoid errors and bias in the results of analysis that use those data, it is particularly important to detect and remove those non-natural irregularities prior to their use. Moreover, due to the increase of storage capacity, the recent gathering of massive amounts of weather data implies also a toilsome effort to guarantee its quality. The process of detection and correction of irregularities is named homogenisation. A comprehensive summary and description of the available homogenisation methods is critical to climatologists and other experts, who are looking for a homogenisation method wholly considered as the best. The effectiveness of homogenisation methods depends on the type, temporal resolution and spatial variability of the climatic variable. Several comparison studies have been published so far. However, due to the absence of time series where irregularities are known, only a few of those comparisons indicate the level of success of the homogenisation methods. This article reviews the characteristics of the most important procedures used in the homogenisation of climatic variables based on a thorough literature research. It also summarises many methods applications in order to illustrate their applicability, which may help climatologists and other experts to identify adequate method(s) for their particular needs. This review study also describes comparison studies, which evaluated the efficiency of homogenisation methods, and provides a summary of conclusions and lessons learned regarding good practices for the use of homogenisation methods.

      PubDate: 2015-08-31T06:09:29Z
  • Geochemical modelling and speciation studies of metal pollutants present
           in selected water systems in South Africa
    • Abstract: Publication date: Available online 28 August 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): M.M. Magu, P.P. Govender, J.C. Ngila
      Metal pollutants in water poses great threats to living beings and hence requires to be monitored regularly to avoid loss of lives. Various analytical methods are available to monitor these pollutants in water and can be improved with time. Modelling of metal pollutants in any water system helps chemists, engineers and environmentalists to greatly understand the various chemical processes in such systems. Water samples were collected from waste water treatment plant and river from highlands close to its source all the way to the ocean as it passing through areas with high anthropogenic activities. Pre-concentration of pollutants in the samples was done through acid digestion and metal pollutants were analysed using inductively coupled plasma-optical emission spectra (ICP-OES) to determine the concentration levels. Metal concentrations ranged between 0.1356–0.4658mg/L for Al; 0.0031–0.0050mg/L for Co, 0.0019–0.0956mg/L for Cr; 0.0028–0.3484mg/L for Cu; 0.0489–0.3474mg/L for Fe; 0.0033–0.0285mg/L for Mn; 0.0056–0.0222mg/L for Ni; 0.0265–0.4753mg/L for Pb and 0.0052–0.5594mg/L for Zn. Modelling work was performed using PHREEQC couple with Geochemist’s workbench (GWB) to determine speciation dynamics and bioavailability of these pollutants. Modelling thus adds value to analytical methods and hence a better complementary tool to laboratory-based experimental studies.

      PubDate: 2015-08-31T06:09:29Z
  • Simulated effects of cropland expansion on seasonal temperatures over
    • Abstract: Publication date: Available online 28 August 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Zhe Xiong
      Human activities result in deforestation, expansion of cropland, grassland degradation, urbanization and other large-scale land use/cover change; among these, cropland expansion is one of the most important processes. To understand the effects of cropland expansion on seasonal temperatures over China, two 21-year simulations (spanning January 1, 1980–December 31, 2000), using the Regional Integrated Environmental Model System (RIEMS 2.0), were performed. The two simulations comprised current realistic land use/cover patterns and the previous vegetation cover without crop expansion, to investigate the impact of crop expansion on seasonal temperatures over China. The results showed that due to cropland expansion: (1) the most obvious changes occurred in the maximum temperatures, followed by the mean surface air temperatures, and the minimum temperatures were the least affected; (2) the summer mean maximum temperatures decreased in most parts of eastern China, and the temperatures changed significantly in most parts of northeast China, north China and central China (p < 0.05); (3) the surface air temperatures, maximum temperatures and minimum temperatures in summer decreased in the different regions by between −0.03 and −0.76°C (the greatest temperature changes occurred in southwest China, and the smallest were in northeast China); (4) the net radiation flux and latent heat flux increased, while the sensible flux decreased, when semi-desert vegetation was replaced by dry land crops, in both summer and winter seasons, and the converse occurred when irrigated crops were replaced by dry land crops. In addition, the net radiation flux and sensible heat flux decreased, and the latent heat flux increased when short grass and tall grass were replaced dry land crops, as well as when dry land crops were replaced by irrigated crops.

      PubDate: 2015-08-31T06:09:29Z
  • Impacts of temperature on rice yields of different rice cultivation
           systems in Southern China over the past 40 years
    • Abstract: Publication date: Available online 28 August 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Jiahua Zhang, Fengmei Yao, Cui Hao, Vijendra Boken
      The impact of climate change on rice yield in China remains highly uncertain. we examined the impact of the change of maximum temperature (T max) and minimum temperature (T min) on rice yields in southern China from 1967 to 2007. The rice yields were simulated by using the DSSAT3.5 (Decision Support System for Agro-technology Transfer)-Rice model. The change of T max and T min in rice growing seasons and simulated rice yields as well their correlations were analyzed. The simulated yields of middle rice and early rice had a decreasing trend, but late rice yields showed a weak rise trend. There was significant negative correlation between T max and the early rice yields, as well as the late rice yieldsin most stations, but non-significant negative correlation for the middle rice yields. An obviously negative relationship was found between T min and the early and middle rice yields, and a significant positive relationship was found between T min and the late rice yields. It indicated that under the recent climate warming, the increasedT max brought strong negative impacts on early rice yields and late rice yields, but a weak negative impact on the middle rice yields; the increased T min had a strong negative impact on the middle rice yields and the early rice yields, but a significant positive impact on the late rice yields. It suggested that it is necessary to adjust rice planting date and adapt to higher T min.

      PubDate: 2015-08-31T06:09:29Z
  • Contribution of surface roughness to simulations of historical
    • Abstract: Publication date: Available online 29 August 2015
      Source:Physics and Chemistry of the Earth, Parts A/B/C
      Author(s): Ye Wang, Zhaomin Wang
      Surface roughness which partitions surface net radiation into energy fluxes is a key parameter for estimation of biosphere-atmosphere interactions and climate variability. An earth system model of intermediate complexity (EMIC), MPM-2, is used to derive the impact of surface roughness on climate from simulations of historical land cover change effects. The direct change in surface roughness leads to a global surface warming of 0.08°C through altering the turbulence in the boundary layer. The regional temperature response to surface roughness associated deforestation is very strong at northern mid-latitudes with a most prominent warming of 0.72°C around 50°N in the Eurasia continent during summer. They can be explained mainly as direct and indirect consequences of decreases in surface albedo and increases in precipitation in response to deforestation, although there are a few significant changes in precipitation. There is also a prominent warming of 0.25°C around 40°N in the North American continent. This study indicates that land surface roughness plays a significant role which is comparable with the whole land conversion effect in climate change. Therefore, further investigation of roughness-climate relationship is needed to incorporate these aspects.

      PubDate: 2015-08-31T06:09:29Z
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