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  Subjects -> METEOROLOGY (Total: 113 journals)
Showing 1 - 36 of 36 Journals sorted alphabetically
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 4)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 45)
Advances in Climate Change Research     Open Access   (Followers: 39)
Advances in Meteorology     Open Access   (Followers: 28)
Advances in Statistical Climatology, Meteorology and Oceanography     Open Access   (Followers: 10)
Aeolian Research     Hybrid Journal   (Followers: 6)
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 20)
American Journal of Climate Change     Open Access   (Followers: 34)
Atmósfera     Open Access   (Followers: 3)
Atmosphere     Open Access   (Followers: 29)
Atmosphere-Ocean     Full-text available via subscription   (Followers: 16)
Atmospheric and Oceanic Science Letters     Open Access   (Followers: 13)
Atmospheric Chemistry and Physics (ACP)     Open Access   (Followers: 48)
Atmospheric Chemistry and Physics Discussions (ACPD)     Open Access   (Followers: 16)
Atmospheric Environment     Hybrid Journal   (Followers: 75)
Atmospheric Environment : X     Open Access   (Followers: 3)
Atmospheric Research     Hybrid Journal   (Followers: 71)
Atmospheric Science Letters     Open Access   (Followers: 40)
Boundary-Layer Meteorology     Hybrid Journal   (Followers: 32)
Bulletin of Atmospheric Science and Technology     Hybrid Journal   (Followers: 5)
Bulletin of the American Meteorological Society     Open Access   (Followers: 51)
Carbon Balance and Management     Open Access   (Followers: 5)
Ciencia, Ambiente y Clima     Open Access   (Followers: 3)
Climate     Open Access   (Followers: 6)
Climate and Energy     Full-text available via subscription   (Followers: 7)
Climate Change Economics     Hybrid Journal   (Followers: 33)
Climate Change Responses     Open Access   (Followers: 18)
Climate Dynamics     Hybrid Journal   (Followers: 44)
Climate of the Past (CP)     Open Access   (Followers: 5)
Climate of the Past Discussions (CPD)     Open Access  
Climate Policy     Hybrid Journal   (Followers: 51)
Climate Research     Hybrid Journal   (Followers: 6)
Climate Resilience and Sustainability     Open Access   (Followers: 21)
Climate Risk Management     Open Access   (Followers: 7)
Climate Services     Open Access   (Followers: 3)
Climatic Change     Open Access   (Followers: 68)
Current Climate Change Reports     Hybrid Journal   (Followers: 10)
Developments in Atmospheric Science     Full-text available via subscription   (Followers: 31)
Dynamics and Statistics of the Climate System     Open Access   (Followers: 5)
Dynamics of Atmospheres and Oceans     Hybrid Journal   (Followers: 19)
Earth Perspectives - Transdisciplinarity Enabled     Open Access  
Economics of Disasters and Climate Change     Hybrid Journal   (Followers: 9)
Energy & Environment     Hybrid Journal   (Followers: 24)
Environmental and Climate Technologies     Open Access   (Followers: 4)
Environmental Dynamics and Global Climate Change     Open Access   (Followers: 17)
Frontiers in Climate     Open Access   (Followers: 3)
GeoHazards     Open Access   (Followers: 2)
Global Meteorology     Open Access   (Followers: 18)
International Journal of Atmospheric Sciences     Open Access   (Followers: 23)
International Journal of Biometeorology     Hybrid Journal   (Followers: 1)
International Journal of Climate Change Strategies and Management     Hybrid Journal   (Followers: 27)
International Journal of Climatology     Hybrid Journal   (Followers: 30)
International Journal of Environment and Climate Change     Open Access   (Followers: 12)
International Journal of Image and Data Fusion     Hybrid Journal   (Followers: 2)
Journal of Agricultural Meteorology     Open Access  
Journal of Applied Meteorology and Climatology     Hybrid Journal   (Followers: 36)
Journal of Atmospheric and Oceanic Technology     Hybrid Journal   (Followers: 34)
Journal of Atmospheric and Solar-Terrestrial Physics     Hybrid Journal   (Followers: 210)
Journal of Atmospheric Chemistry     Hybrid Journal   (Followers: 22)
Journal of Climate     Hybrid Journal   (Followers: 57)
Journal of Climate Change     Full-text available via subscription   (Followers: 16)
Journal of Climatology     Open Access   (Followers: 3)
Journal of Hydrology and Meteorology     Open Access   (Followers: 36)
Journal of Hydrometeorology     Hybrid Journal   (Followers: 11)
Journal of Integrative Environmental Sciences     Hybrid Journal   (Followers: 4)
Journal of Meteorological Research     Full-text available via subscription   (Followers: 1)
Journal of Meteorology and Climate Science     Full-text available via subscription   (Followers: 17)
Journal of Space Weather and Space Climate     Open Access   (Followers: 28)
Journal of the Atmospheric Sciences     Hybrid Journal   (Followers: 84)
Journal of the Meteorological Society of Japan     Partially Free   (Followers: 6)
Journal of Weather Modification     Full-text available via subscription   (Followers: 2)
Large Marine Ecosystems     Full-text available via subscription   (Followers: 1)
Mediterranean Marine Science     Open Access   (Followers: 1)
Meteorologica     Open Access   (Followers: 2)
Meteorological Applications     Hybrid Journal   (Followers: 4)
Meteorological Monographs     Hybrid Journal   (Followers: 2)
Meteorologische Zeitschrift     Full-text available via subscription   (Followers: 3)
Meteorology and Atmospheric Physics     Hybrid Journal   (Followers: 27)
Mètode Science Studies Journal : Annual Review     Open Access  
Michigan Journal of Sustainability     Open Access   (Followers: 1)
Modeling Earth Systems and Environment     Hybrid Journal   (Followers: 1)
Monthly Notices of the Royal Astronomical Society     Hybrid Journal   (Followers: 16)
Monthly Weather Review     Hybrid Journal   (Followers: 33)
Nature Climate Change     Full-text available via subscription   (Followers: 144)
Nature Reports Climate Change     Full-text available via subscription   (Followers: 39)
Nīvār     Open Access  
npj Climate and Atmospheric Science     Open Access   (Followers: 6)
Open Atmospheric Science Journal     Open Access   (Followers: 4)
Open Journal of Modern Hydrology     Open Access   (Followers: 7)
Revista Brasileira de Meteorologia     Open Access  
Revista Iberoamericana de Bioeconomía y Cambio Climático     Open Access  
Russian Meteorology and Hydrology     Hybrid Journal   (Followers: 3)
Space Weather     Full-text available via subscription   (Followers: 25)
Studia Geophysica et Geodaetica     Hybrid Journal  
Tellus A     Open Access   (Followers: 22)
Tellus B     Open Access   (Followers: 21)
The Cryosphere (TC)     Open Access   (Followers: 6)
The Quarterly Journal of the Royal Meteorological Society     Hybrid Journal   (Followers: 28)
Theoretical and Applied Climatology     Hybrid Journal   (Followers: 13)
Tropical Cyclone Research and Review     Open Access  
Urban Climate     Hybrid Journal   (Followers: 4)
Weather     Hybrid Journal   (Followers: 18)
Weather and Climate Dynamics     Open Access  
Weather and Climate Extremes     Open Access   (Followers: 16)
Weather and Forecasting     Hybrid Journal   (Followers: 27)
Weatherwise     Hybrid Journal   (Followers: 4)
气候与环境研究     Full-text available via subscription   (Followers: 1)

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Meteorology and Atmospheric Physics
Journal Prestige (SJR): 0.543
Citation Impact (citeScore): 1
Number of Followers: 27  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1436-5065 - ISSN (Online) 0177-7971
Published by Springer-Verlag Homepage  [2658 journals]
  • Application of feed forward and cascade forward neural network models for
           prediction of hourly ambient air temperature based on MERRA-2 reanalysis
           data in a coastal area of Turkey

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      Abstract: Air temperature forecasting has been a vital climatic factor required for different applications in many areas such as energy, industry, agriculture, health, environment, and meteorology. This study compares the performances of two static neural networks (NNs) used for the prediction of hourly ambient air temperatures in a coastal area of Turkey. Thirteen parameters from Land Surface Diagnostics and Surface Flux Diagnostics Collections from the MERRA-2 reanalysis dataset including pressure, surface specific humidity, wind speed, wind direction, air density at surface, evaporation, planetary boundary layer height, total precipitable water vapor, total precipitation, total cloud area fraction, total column ozone, greenness fraction, and leaf area index were used as input parameters for the models. Feed-Forward Neural Network (FFNN) and Cascade Forward Neural Network (CFNN) models were applied to forecast hourly ambient air temperatures at 2 m height from the surface. The results indicated that the most accurate and reliable predictions were obtained by the CFNN model with 30 neurons, while the lowest prediction performance was obtained by the FFNN model with 5 neurons. The root mean squares error (RMSE), mean absolute error (MAE) and coefficient of determination (R2) values for training (and testing) of the CFNN model with 30 neurons were 0.358 (0.376), 0.273 (0.283), and 0.997 (0.992), respectively, whereas the same parameters were 0.430 (0.447), 0.334 (0.343), and 0.996 (0.989) for the FFNN model with 5 neurons. The CFNN model had a lower RMSE and MAE, and a higher R2 than the FFNN model. These results showed that increasing the number of neurons of hidden layers from 5 to 30 provided better model performance.
      PubDate: 2021-10-01
      DOI: 10.1007/s00703-021-00821-1
       
  • Circulation pattern controls of wet days and dry days in Free State, South
           Africa

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      Abstract: Atmospheric circulation is a vital process in the transport of heat, moisture, and pollutants around the globe. The variability of rainfall depends to some extent on the atmospheric circulation. This paper investigates synoptic situations in southern Africa that can be associated with wet days and dry days in Free State, South Africa, in addition to the underlying dynamics. Principal component analysis was applied to the T-mode matrix (variable is time series and observation is grid points at which the field was observed) of daily mean sea level pressure field from 1979 to 2018 in classifying the circulation patterns in southern Africa. 18 circulation types (CTs) were classified in the study region. From the linkage of the CTs to the observed rainfall data, from 11 stations in Free State, it was found that dominant austral winter and late austral autumn CTs have a higher probability of being associated with dry days in Free State. Dominant austral summer and late austral spring CTs were found to have a higher probability of being associated with wet days in Free State. Cyclonic/anti-cyclonic activity over the southwest Indian Ocean, explained to a good extent, the inter-seasonal variability of rainfall in Free State. The synoptic state associated with a stronger anti-cyclonic circulation at the western branch of the South Indian Ocean high-pressure, during austral summer, leading to enhanced low-level moisture transport by southeast winds was found to have the highest probability of being associated with above-average rainfall in most regions in Free State. On the other hand, the synoptic state associated with enhanced transport of cold dry air, by the extratropical westerlies, was found to have the highest probability of being associated with (winter) dryness in Free State.
      PubDate: 2021-10-01
      DOI: 10.1007/s00703-021-00822-0
       
  • A case study on the triggering mechanisms of localized warm-sector
           rainstorm

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      Abstract: On the morning of July 21, 2017, a localized rainstorm event occurred in the Shijiazhuang area of Hebei Province, with the heavy rain mainly concentrating in the Shijiazhuang urban area and its eastern and northern parts. But this rainstorm process was omitted by both numerical and subjective forecasts. In this paper, the triggering mechanisms of the mesoscale convective systems that have caused this localized rainstorm are analyzed by using the intensified surface observation data, Doppler radar data, the four-dimensional variational Doppler radar analysis system (VDRAS), the National Centers for Environmental Prediction (NCEP) reanalysis data and the ERA5 reanalysis. The observation analysis shows that when the heavy rain was occurring, the Shijiazhuang area was controlled by the western Pacific subtropical high, and the high temperature and high humidity environment has provided favorable vapor, thermal and energy conditions for the rainfall. Three key factors are responsible for the triggering of this severe convective weather. First, the strong thunderstorm high pressure and cold pool formed in Qinhuangdao and Tangshan areas in the northeastern Hebei. The surface wind field was affected by the pressure-gradient force generated by the thunderstorm high pressure, and consequently the northeasterly wind gradually strengthened, which guided the tongue-shaped cold pool to gradually move southwestward to the northern Shijiazhuang. Thus, a long lasting cold-warm boundary (the leading edge of the cold tongue) was formed in the key precipitation area, which provided low-level convergence and the ascending motion for the occurrence and development of this severe convective weather. Second, the northeasterly wind in the east side of Taihang Mountain was forced to ascend by the topography of Taihang Mountain, which strengthened the upward motion. Third, as the direction of the Taihang Mountains shifts from a northeast–southwest direction to a northwest–southeast direction in the west side of Shijiazhuang, the surface northeasterly airflow is changed to a northwesterly airflow here, forming a convergence in the key area of precipitation in front of the mountain. Thus, an unstable vertical structure that features low-level convergence and middle-level divergence is formed. The above three factors work together in the region where the severe convections occurred, and triggered the release of the conditional instability energy, finally resulting in this short-time heavy rain. The results indicate that in the forecast of severe convections in midsummer, we should pay extra attention to the complex terrain and the effects of the cold pool.
      PubDate: 2021-09-30
       
  • Formation and track of tropical cyclones Eline (2000) and Bonita (1996)

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      Abstract: The occurrence of extreme rainfall events over mainland Mozambique associated with tropical cyclones (TC) Eline and Bonita is studied. Bonita caused catastrophic flooding in the central and some parts of northern Mozambique, thus forming the basis of the present study. Results show that the intensity of these TCs was maintained by the easterly wind from the Mascarene High. The northeasterly monsoon wind and northwesterlies from the Benguela current converged at the center of the TC, acting as a moisture source. The rainfall related to the two TCs befell in three stages and its magnitude attenuated progressively from the coastal region toward inland, concurring with the degeneration of the TCs. In stage one, for Eline, rainfall mainly concentrated in Tete, Manica, Niassa, North of Gaza provinces, the coastal Nampula, Zambezia, Sofala and Inhambane provinces. During Bonita’s inner-core circulation landfall, the northern and few parts of central Bonita were directly inundated. In the second stage, for Eline, the center of concentration of rainfall was in the central and southern parts of Mozambique. The mechanisms, including warm-air advection, vertical wind shear, could have contributed at the same time to the lifting vital for the generation of the storm during the second stage. The information herein is essential for future forecasting and monitoring of TC over the Indian Ocean. The findings form a good reference in the understanding of the recent cyclones, Kenneth and Idai that were destructive over Mozambique.
      PubDate: 2021-09-29
       
  • Inter-comparison of high-resolution satellite precipitation products over
           India during the summer monsoon season

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      Abstract: Water management and risk hazard analysis demand high-resolution (spatially and temporally) rainfall. The present study evaluates recently developed high-resolution satellite precipitation products such as global precipitation measurement (GPM), Indian National Satellite System (INSAT) multi-spectral rainfall algorithm (IMR), INSAT hydrometer estimation method (HEM), and Tropical Rainfall Measuring Mission (TRMM) for Indian summer monsoon during 2014–2019 against India Meteorological Department (IMD) gridded product. Overall, the GPM is remarkably captured spatial distribution of seasonal mean rainfall over India and monsoon dominated zones (i.e. western ghats, eastern and central India). Most satellite products overestimated the seasonal rainfall except the GPM (6.8 mm day−1), closely matched with IMD rainfall (6.5 mm day−1). GPM is skillful for different rainfall categories such as light (< 7.5 mm day−1), moderate (7.6–64.4 mm day−1), and heavy (> 64.5 mm day−1) on monthly and seasonal scales over all homogeneous regions. In case of INSAT products, the HEM showed improved results than the IMR for all the rainfall thresholds in all homogeneous regions. Similarly, the evaluation of satellite products for (deficit-year (2015) and normal-year (2016) reveals that GPM is superior to both the INSAT and TRMM rainfall products. The analysis of daily rainfall extremes indicates that GPM rainfall could replicate the same for the lowest, normal and highest rain categories compared with the others. The performance of INSAT rainfall can be improved by merging with rain-gauge data, suitable bias corrections, and providing hydrometeors information.
      PubDate: 2021-09-27
       
  • Comparison and analysis of SWDs retrieval from GPS/BDS and validation with
           ray-traced delays

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      Abstract: An extensive validation of tropospheric slant wet delays (SWDs) from GPS/BDS and ray tracing through numerical weather models of ECMWF was presented. The observation data of seven MGEX stations from the 120th to 130th days in 2018 were processed using the GAMIT 10.7 software. Four strategies were used to compare GPS/BDS SWD estimates and to assess the impact of several aspects of the processing strategy on the SWDs retrieval. The ray-traced SWDs based on ECMWF obtained from the RADIATE Project by the TU WIEN were taken as the references. Inter-techniques evaluations demonstrated a good agreement of GPS/BDS SWDs compared with the ray-traced SWDs based on ECMWF. The mean absolute biases (MAbias) between the GPS SWDs and the ECMWF ray-traced SWDs are about 3.7 and 4.4 cm using GPS final precise orbit & clock products and ultra-rapid orbit products, respectively. The MAbias between the BDS SWDs and the ECMWF ray-traced SWDs are about 3.9 and 4.8 cm using BDS final precise orbit & clock products and ultra-rapid orbit products, respectively. The RMSE of the GPS SWDs were about 6.6 and 7.6 cm based on GPS final precise orbit and clock products and ultra-rapid orbit products, respectively, with the ECMWF ray-traced SWDs as the reference values. And the RMSE of the BDS SWDs are about 6.0 and 7.3 cm based on BDS final precise orbit and clock products and ultra-rapid orbit products, respectively. The deviation between the GPS/BDS SWDs and the ECMWF ray-traced SWDs shows a strong elevation angle dependency especially when the elevation angle is less than 20°. The deviation is about 1 cm close to the zenith and about 6–10 cm at an elevation angle of 10°. And the deviation can reach 20–50 cm when the elevation angle is less than 3°. The above experiments show that the SWD parameters retrieved by the GPS/BDS especially using the ultra-rapid orbit products are very promising for weather forecasting and have great potential for meteorological applications.
      PubDate: 2021-09-25
       
  • An intensification of atmospheric CO2 concentrations due to the surface
           temperature extremes in India

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      Abstract: The terrestrial biosphere plays a pivotal role in removing carbon from the atmosphere. The removal processes are primarily affected by the presence of extreme temperature in the atmosphere. Little information is available on carbon removal response by the terrestrial biosphere during extreme temperature events over the Indian region. India has witnessed frequent and intense heatwaves in the recent past, and future projections about the frequency of heatwave occurrence suggest a further increase in the changing climate scenario. This study used surface CO2 flux observations and satellite retrieved columnar and mid-tropospheric CO2 concentrations to understand atmospheric CO2 variability and its transport patterns with anomalously high-temperature events such as heatwave conditions over India. Intensification of temperature up to 32 °C has increased the atmosphere-biosphere CO2 fluxes (carbon sink). But further intensification in temperature (> 32–33 °C), like those observed during heatwaves, tends to drive the ecosystem to act as a CO2 source into the atmosphere due to reduced ability to absorb atmospheric CO2. Such excess CO2 fluxes may lead to change in the atmospheric CO2 concentration via atmospheric circulation or the vertical transport of the air masses from the near-surface to the upper levels in the atmosphere. The satellite observed CO2 concentration is elevated by 2–3 ppm during the heatwave conditions over India. The impact of extreme temperature on the biospheric sink capability in the carbon cycle, leading to an increase in the atmospheric CO2 concentration, is one of the significant outcomes of this study.
      PubDate: 2021-09-24
       
  • Demonstration of a three-dimensional dynamically adaptive atmospheric
           dynamic framework for the simulation of mountain waves

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      Abstract: In this paper, Fluidity-Atmosphere, representative of a three-dimensional (3D) non-hydrostatic Galerkin compressible atmospheric dynamic framework, is generated to resolve large-scale and small-scale phenomena simultaneously. This achievement is facilitated by the use of non-hydrostatic equations and the adoption of a flexible 3D dynamically adaptive mesh where the mesh is denser in areas with higher gradients of variable solutions and relatively sparser in the rest of the domain while maintaining promising accuracy and reducing computational resource requirements. The dynamic core is formulated based on anisotropic tetrahedral meshes in both the horizontal and vertical directions. The performance of the adaptive mesh techniques in Fluidity-Atmosphere is evaluated by simulating the formation and propagation of a non-hydrostatic mountain wave. The 2D anisotropic adaptive mesh shows that the numerical solution is in good agreement with the analytic solution. The variation in the horizontal and vertical resolutions has a strong impact on the smoothness of the results and maintains convergence even at high resolutions. When the simulation is extended to 3D, Fluidity-Atmosphere shows stable and symmetric results in the benchmark test cases. The flows over a bell-shaped mountain are resolved quite smoothly. For steep mountains, Fluidity-Atmosphere performs very well, which shows the potential of using 3D adaptive meshes in atmospheric modeling. Finally, as an alternative cut-cell mesh in Fluidity-Atmosphere, the anisotropic adaptive mesh coupled with the Galerkin method provides an alternative accurate representation of terrain-induced flow.
      PubDate: 2021-09-21
       
  • Forecasting of pre-monsoon flash flood events in the northeastern
           Bangladesh using coupled hydrometeorological NWP modelling system

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      Abstract: The northeastern depressed region of Bangladesh is highly susceptible to recurrent flash flooding due to excessive rainfall over these areas and in the upstream hilly regions. Two such severe pre-monsoon flash flood events occurred in 2016 and 2017. This research attempts to forecast both flash flood events using a coupled atmospheric-hydrological numerical weather prediction (NWP) model, namely the weather research and forecasting (WRF) model. The ARW (Advanced Research WRF) model is able to predict the rainfall over these areas with a lead time of 91 h. However, the discharge and water level are overestimated by the WRF-Hydro model. The model predicts a flash flood with a lag of approximately 12 h with respect to the highest amount of rainfall. The overall performances of the models were satisfactory. The two parameters, rainfall and subsequent discharge, which are required for delineation of lag time, were almost precisely simulated. Simulated values also had fewer errors, justified by the root mean squared error (RMSE) and mean absolute error values. The Nash–Sutcliffe efficiency criterion scores for model-derived discharge were close to 1.0, and the RMSE-observation standard deviation ratio scores were less than 0.5. This finding proves that the NWP models could be considered for forecasting flash flood events over selected areas of Bangladesh.
      PubDate: 2021-09-12
      DOI: 10.1007/s00703-021-00831-z
       
  • Temporal variations in the frequency of thunderstorm days in Tabriz and
           its relationship with sunspots frequency and global atmospheric Co2
           concentration

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      Abstract: In this study, using various statistical methods such as trend analysis, Mann–Kendall (MK) test and Morlet Wavelet Analysis (MWA), the Frequency of Thunderstorm Days (FTD) and its relationship with Sunspots Frequency (SF) and Global Atmospheric Carbon Dioxide Concentration (GACDC) in the 68-year statistical period of 1951–2018 in Tabriz Synoptic Station has been studied. In terms of distribution and temporal concentration, the highest incidence of Thunderstorm Days (TD) is concentrated in the months of May and June and the lowest in the cold months of the year, i.e. January, February and December, with spring having the highest and winter having the lowest FTD. The analysis of the trend of FTD in the study area showed that except for the trends of January, February, June and December, which have no clear and significant trend, other months, especially April, have an upward and significant trend and the seasonal trend of FTD in Tabriz increase significantly in all seasons, especially in the peak of spring; Also, in the annual time scale, a significant upward trend was observed. Decadal changes in the FTD show a sharp increase in the occurrence of TD in Tabriz, especially in the second decade of the twenty-first century. The results of MWA showed that the FTD, like sunspots, has a periodic cycle in its emergence and occurrence. Based on the results of cross-wavelet analysis, there is a strong negative and anti-phased relationship between SF and the FTD in Tabriz. Also, according to the results of MWA, no significant relationship between the GACDC and the FTD in Tabriz has been found.
      PubDate: 2021-09-08
      DOI: 10.1007/s00703-021-00832-y
       
  • The extended-range forecast of tropical cyclogenesis over the South China
           Sea based on the intraseasonal oscillation

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      Abstract: By investigating the relationship between tropical cyclogenesis (TCG) over the South China Sea (SCS) and the intraseasonal oscillation (ISO), we found that the number of TCG varies significantly with the life cycle of 10–30-day/30–60-day mode of the ISO (QBWO/MJO). Considering the linkages between them, an extended-range forecast method for TCG over the SCS was constructed based on the spatial temporal projection model (STPM). By determining the phases of the QBWO and MJO from STPM, daily genesis rate (DGR) sequences at 10-day and 20-day lead time were derived. When the DGR sequence is in its positive phase, we consider that there is a high possibility of TCG over the SCS. Hindcasts for TCG in 2009–2018 indicate that the extended-range forecast method can successfully capture TCG over the SCS. For the 10-day lead time, the hitting rate is 80%, the missing rate is 20% and the false alarming rate is 32.4%, whereas with the increasing lead time, the hitting rate decreased to 74.3% and the false alarming rate increased to 35.3% at the lead time of 20 days.
      PubDate: 2021-09-05
      DOI: 10.1007/s00703-021-00830-0
       
  • Evaluation of the benefits of assimilation of Meteosat-8 observations in
           an NWP system over the Indian Ocean region

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      Abstract: This paper describes the impact of direct assimilation of Indian Ocean Data Coverage (IODC) Meteosat-8 SEVIRI Clear Sky Brightness Temperatures (CSBTs) and the Atmospheric Motion Vectors (AMVs) in a 4D-Var framework through a set of Observing System Experiments (OSEs) during May 2018. Meteosat-8 located at 3.5°E was relocated to 41.5°E and fully functional over the IODC region since February 2017. The impact of CSBTs from selected infra-red and water vapor channels of SEVIRI and AMVs derived from visible, infrared and water vapor channels is studied through identical OSEs using National centre for Medium Range Weather Forecast (NCMRWF) Unified Model (NCUM) assimilation and forecast system. The study discovered that the analysis increments of humidity and temperature are largely driven by AMVs rather than the CSBTs over the IODC region. The complementarity of AMV and CSBT assimilation is noticed in the wind analysis. Humidity forecasts from NCUM in the medium range show that the CSBT contribution is less than that of AMVs. CSBT assimilation showed near neutral impact in the temperature forecasts; however, it has contributed significantly to the wind forecast, at different pressure levels. Impact parameter estimated based on European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 global reanalysis shows that Meteosat-8 AMV assimilation produced noticeable improvement over the Indian Ocean region, particularly in the lower and upper tropospheric levels. Results from this study indicate the importance of wind assimilation over the Tropics, compared to the use of CSBTs. Though the AMV assimilation improved the humidity and wind fields, the statistical skill scores analyzed during the extreme precipitation event associated with two cyclones during the study period show that the precipitation over the IODC region is predicted well when the AMVs are denied from the assimilation.
      PubDate: 2021-09-02
      DOI: 10.1007/s00703-021-00826-w
       
  • Comparative assessment of radio occultation-based refractivity
           measurements from the COSMIC mission and in-situ atmospheric measurements
           in equatorial Africa

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      Abstract: The growing technological needs for multi-instrument datasets require proper understanding of the behaviour of the datasets relative to each other. This paper presents the first results of analysis on the relationship between in-situ ground refractivity measurements and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) refractivity measurements in the African equatorial region. In-situ measurements of surface refractivity obtained from four atmospheric ground stations in the region are compared with COSMIC-1 refractivity measurements at 1 km altitude. The in-situ datasets cover the periods from years 2007 to 2014, and corresponding COSMIC-1 datasets over the same period was used. Datasets from the recently launched COSMIC-2 mission (October 2019–September 2020) were utilized to show that the typical differences between refractivity values measured at 0 and 1 km altitudes are about 48 N-units. Interestingly, time-coincident measurements from COSMIC-1 (at 1 km altitude) and from ground in-situ measurements indicate that there is a similar typical difference (about 52 N-units) between refractivity values at the two altitudes. The reason for using COSMIC-2 measurements is that the altitudes covered by COSMIC-1 measurements start from a minimum of 0.1 km, and even at this altitude, the COSMIC-1 measurements are very scanty that there are no coincident observations with the in-situ ground stations. This is why it became imperative to first use COSMIC-2 measurements which cover altitudes from as low as 0 km. The reason is to validate that the difference between COSMIC measurements at 0 and 1 km altitudes are equivalent/comparable to difference between in-situ ground measurements and COSMIC measurements at 1 km. These results indicate that the COSMIC measurements at 0 km are comparable to the in-situ ground measurements.
      PubDate: 2021-08-19
      DOI: 10.1007/s00703-021-00827-9
       
  • An assessment of change point and trend of diurnal variation of dust
           storms in Iran: a multi-instrumental approach from in situ,
           multi-satellite, and reanalysis dust product

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      Abstract: Iran is a semi-arid and arid country in Western Asia and is exposed to numerous local and trans-regional dust systems due to its location in the global dust belt. The present study sought to investigate the change-point detection (CPD) and trend of the number of dusty hours (NDH) in Iran over a long-term period (1980–2015). The station dust frequency (SDF) of 81 synoptic stations was first hourly obtained and then processed. Furthermore, the dust aerosol optical depth (DOD) was obtained hourly from the Monitoring Atmospheric Composition and Climate (MACC). The results indicated the maximum dust frequency with 21.28 days at 12 GMT due to surface heating and the occurrence of local dry instabilities. The minimum dust also occurred with 7.76 days at 00 GMT in Iran. SDF and DOD had a direct relationship, but they had inverse significant relationships with altitude and latitude in Iran. The maximum average trend of the whole of Iran at 21 GMT with a value of Z 1.83 was significant at a 90% level, indicating an increase in nocturnal dust in Iran. The southwest of Iran, especially Bostan, Omidiyeh, and Masjed-Soleyman stations, had maximum numbers of dusty days so that NDHs of Omidiyeh station were increasing at 18 GMT (2.84 years−1 days). The year 2000 was, on area-averaged, the dust CPD in the across Iran, but 2007 and 2008 were the most frequent CPD of NDHs. None of the hours had lower amounts of dust after the CPD than before the CPD, indicating a significant increase in the dust of Iran.
      PubDate: 2021-08-14
      DOI: 10.1007/s00703-021-00825-x
       
  • A comparison of low-level wind profiles from Mode-S EHS data with
           ground-based remote sensing data

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      Abstract: The Romanian Air Traffic Services Administration is currently testing the operational production of vertical wind profiles calculated from aircraft-reported Mode-Select enhanced surveillance (EHS) data provided by secondary surveillance radars. This paper presents an estimation and a verification of the biases of the calculated wind components using a reference represented by sodar and lidar measured wind. The biases are caused by errors in the magnetic declination, neglecting the pitch angle of aircraft in the initial climb, and by errors of sodar or lidar orientation. The estimated bias of the meridional components confirms the flight direction dependence of the error of wind components transversal to the flight track found in previous studies, while the strong correlation of wind and flight direction in aerodrome traffic makes this bias to cause a bias of the wind direction more evident at low wind speeds (≃ 10°). The estimated zonal component bias is negligible with descending aircraft, but positive, depending on the pitch angle, up to approximately 50% of the component, with ascending aircraft. The verification of the accuracy of these estimates is performed by comparing the ground-based remote-sensed wind data with the Mode-S EHS derived wind data in the lower boundary layer of Bucharest Henri Coanda airport area. Results show a generally good agreement with the predictions of the measurement error model, with residual errors being assigned to intrinsic instrument measurement errors and assumptions on the average aircraft speed.
      PubDate: 2021-08-13
      DOI: 10.1007/s00703-021-00820-2
       
  • Understanding dynamics of tropical cyclones in the Bay of Bengal using
           lightning data

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      Abstract: In the present work, we are studying the dynamics of 11 tropical cyclones (TCs) over the Bay of Bengal (BoB) using the World Wide Lightning Location Network (WWLLN) lightning data during 2013–2017. Detailed investigation of Lightning Stroke Count (LSC) shows that the initial phase of the TC intensification over BoB is associated with high lightning activity both in the eye region and rainband region. The study of different category TCs shows the weak and moderate-intensity TCs during both in pre-monsoon and post-monsoon seasons are lightning populated (specifically inner bands) during and prior to the intensification phase. Peak Maximum Sustained Wind Speed (MSWS), which is linked to sea surface temperatures (SSTs), is preceded by the peak LSC with a time lag of 6–12 h. The LSC peaks in the eye region and rain band for different categories of TCs between small to moderate wind shear range. The present study highlights that the monitoring of real-time lightning activity could provide supportive information on the existing forecast techniques. But further analyses are required over BoB to quantify the relationship between TC intensification and lightning activity both in space and time.
      PubDate: 2021-08-10
      DOI: 10.1007/s00703-021-00824-y
       
  • Modeling dependence of solar radiation and sky clearness index using a
           bivariate copula

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      Abstract: The total solar radiation received by a specific region in a day is a significant weather-related parameter for most areas of application. Obtaining correct information from irradiation models reduces uncertainty in solar resource estimations, leading to improvements in solar energy production. This study introduces a copula method to correlate the sky clearness index and solar radiation at two meteorology stations in Peninsular Malaysia. Six types of marginal likelihood distribution namely; gamma, logistic, Weibull, Burr, lognormal, and normal were fitted to the data of solar radiation and sky clearness index. Using information from the best-fit marginal distributions, six copula function types were then applied to evaluate the dependence between the sky clearness index and solar radiation. The copula functions used were the Gumbel, Joe, Frank, Clayton, Gaussian, and Student’s t copulas. The Gaussian copula most accurately represented the dependence between the sky clearness index and solar radiation as measured by Akaike's Information Criteria (AIC) for testing goodness of fit. These probabilistic properties can provide useful information for solar energy planning and management.
      PubDate: 2021-08-02
      DOI: 10.1007/s00703-021-00823-z
       
  • Prediction of dominant daily modes of the Indian summer monsoon in the
           NCEP GFS model

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      Abstract: The prediction capability of dominant daily monsoon modes of Indian summer monsoon in the forecast of the Global Forecast System Version 2 (GFSv2) model is scrutinized. The dominant monsoon modes are procured by performing the multichannel singular spectrum analysis (MSSA) on daily precipitation anomalies of the Indian summer monsoon region (60–100°E, Eq.-35°N) during 2001–2014. The observation has one seasonally persistent mode and two intraseasonal oscillations with periods around 42 and 26 days, and the model has correctly simulated these modes. The spatial structure of the phase composites of the precipitation anomalies of the intraseasonal modes of the model is almost similar to the observed spatial pattern with slightly less magnitude of the precipitation anomalies over Western India and the core monsoon zone. The spatial structure of the 26-day mode is similar to the spatial structure of the 42-day mode with less magnitude of the precipitation anomalies all over the study domain. The lead forecast of the model demonstrates the robust predictive skill of intraseasonal modes. The variation of the active and break spells of monsoon precipitation over the Indian subcontinent is captured accurately by the contribution of both intraseasonal modes. The observed eastward and northward propagation features of the Indian summer monsoon have been accurately simulated by the model. The model has weak seasonally persistent signals over Western India, northeast India, and eastern land regions adjacent to the Western Ghats. The seasonally persistent mode shows a strong relationship with the equatorial central Pacific Ocean SSTs and a moderate correlation with the Indian and Atlantic Ocean SSTs. The seasonally persistent mode contributes largely to the seasonal precipitation anomalies over the Indian monsoon region.
      PubDate: 2021-08-01
      DOI: 10.1007/s00703-021-00793-2
       
  • Assessment of near-surface air pollutants at an urban station over the
           central Indo-Gangetic Basin: Role of pollution transport pathways

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      Abstract: The assessment of near-surface air pollutants has been done at an urban site, Varanasi, in the central Indo-Gangetic Basin (IGB) during July 2014 to June 2018. The various pollutants, such as particulate matters of diameter less than 2.5 μm (PM2.5) and less than 10 μm (PM10), sulphur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3) were obtained from the Central Pollution Control Board (CPCB). The annual mean mass concentrations of PM10, PM2.5, SO2, NO2 and O3 were 239 ± 128, 123 ± 89, 17.5 ± 9.6, 52 ± 35 and 30 ± 14 μg m−3, respectively. The concentrations of PM10, PM2.5 and NO2 were found to be higher than their National Ambient Air Quality Standards (NAAQS) by a factor of 4, 3.1 and 1.3, respectively; however, SO2 and O3 were always well within their standard limits. Seasonally, all the pollutants, except ozone were found to be the highest during the postmonsoon and winter seasons. The sources of pollutants have been widely characterized at this site and in general over the IGB. Further, an attempt has been made, for the first time, to elucidate the possible transport pathways of the measured pollutants, especially PM2.5 to downwind of the station using concentration weight trajectory (CWT) analyses with the forward air mass trajectories. The results show significant potential for transport of PM2.5 (~ 65%) from the IGB to downwind over the northern Bay of Bengal region, with more pronounced during the winter season (~ 95%). These results underline the importance of IGB pollution outflow towards downwind continental and marine regions, which can have significant climatic impacts.
      PubDate: 2021-08-01
      DOI: 10.1007/s00703-021-00798-x
       
  • Evaluation of rain and cloud microphysical properties of monsoon
           depressions at a hyperlocal scale from simulations and observations

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      Abstract: The study investigates the characteristics of localized rainfall and associated convective processes using observations and model data sets for three different monsoon low-pressure systems that occurred over the Bay of Bengal and moved inland. The performance evaluation of five microphysics parameterization schemes (WSM6, WDM6, THOM, MORR and AA_THOM) are carried out for a location-specific rainfall event up to a lead time of 72 h. The model forecast results are validated against available observations over the study location (i.e. Argul, Odisha, 85.7°E 20.17°N). The results suggested that both MORR and THOM are relatively better performers among all schemes in terms of timing, evolution and intensity of hyperlocal rainfall events. The WDM6 has better performance in terms of predicting 2-m temperature. In general, the results suggest a robust and coherent relationship among moisture convergence, diabatic heating and rainfall peaks with better estimates in MORR. Further, it is noted that upper-level heating and lower level cooling pattern is distinct in all the cases and AA_THOM has the lowest heating rate as compared to others. It is also found that snow and ice hydrometeors are playing a key role in better rainfall estimates in MORR. It is demonstrated that factors (i.e., moisture convergence, vertical motion, hydrometeors and diabatic heating) highly modulated by choice of cloud microphysical parameterizations are dominantly influencing the localized rainfall and associated convection. In addition, the robust impact of cloud microphysical parameterization schemes in modulating the evolution, amount and distribution of hydrometeors and intensity of diabatic heating is evident. The findings of this study have also provided valuable clues about adopting a particular cloud microphysical parameterization for the hyperlocal forecast with special reference to moderate to heavy rainfall events. The results of the study have significant implications for operational forecasting agencies to optimize their model configuration for predicting location-specific heavy rainfall events, which are on the rise due to climate change scenarios over the Indian region.
      PubDate: 2021-06-05
      DOI: 10.1007/s00703-021-00807-z
       
 
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