Subjects -> METEOROLOGY (Total: 112 journals)
 Showing 1 - 36 of 36 Journals sorted alphabetically Acta Meteorologica Sinica       (Followers: 3) Advances in Atmospheric Sciences       (Followers: 43) Advances in Climate Change Research       (Followers: 31) Advances in Meteorology       (Followers: 24) Advances in Statistical Climatology, Meteorology and Oceanography       (Followers: 7) Aeolian Research       (Followers: 6) Agricultural and Forest Meteorology       (Followers: 18) American Journal of Climate Change       (Followers: 31) Atmósfera       (Followers: 3) Atmosphere       (Followers: 26) Atmosphere-Ocean       (Followers: 15) Atmospheric and Oceanic Science Letters       (Followers: 11) Atmospheric Chemistry and Physics (ACP)       (Followers: 48) Atmospheric Chemistry and Physics Discussions (ACPD)       (Followers: 15) Atmospheric Environment       (Followers: 73) Atmospheric Environment : X       (Followers: 3) Atmospheric Research       (Followers: 69) Atmospheric Science Letters       (Followers: 36) Boundary-Layer Meteorology       (Followers: 31) Bulletin of Atmospheric Science and Technology       (Followers: 1) Bulletin of the American Meteorological Society       (Followers: 51) Carbon Balance and Management       (Followers: 4) Change and Adaptation in Socio-Ecological Systems       (Followers: 5) Ciencia, Ambiente y Clima       (Followers: 3) Climate       (Followers: 6) Climate and Energy       (Followers: 4) Climate Change Economics       (Followers: 26) Climate Change Research Letters       (Followers: 7) Climate Change Responses       (Followers: 12) Climate Dynamics       (Followers: 44) Climate of the Past (CP)       (Followers: 5) Climate of the Past Discussions (CPD) Climate Policy       (Followers: 45) Climate Research       (Followers: 6) Climate Resilience and Sustainability       (Followers: 15) Climate Risk Management       (Followers: 6) Climate Services       (Followers: 3) Climate Summary of South Africa       (Followers: 2) Climatic Change       (Followers: 66) Current Climate Change Reports       (Followers: 8) Developments in Atmospheric Science       (Followers: 28) Dynamics and Statistics of the Climate System       (Followers: 5) Dynamics of Atmospheres and Oceans       (Followers: 19) Earth Perspectives - Transdisciplinarity Enabled Economics of Disasters and Climate Change       (Followers: 3) Energy & Environment       (Followers: 24) Environmental and Climate Technologies       (Followers: 4) Environmental Dynamics and Global Climate Change       (Followers: 8) Frontiers in Climate       (Followers: 3) GeoHazards       (Followers: 2) Global Meteorology       (Followers: 17) International Journal of Atmospheric Sciences       (Followers: 22) International Journal of Biometeorology       (Followers: 1) International Journal of Climate Change Strategies and Management       (Followers: 22) International Journal of Climatology       (Followers: 31) International Journal of Environment and Climate Change       (Followers: 5) International Journal of Image and Data Fusion       (Followers: 2) Journal of Agricultural Meteorology Journal of Applied Meteorology and Climatology       (Followers: 35) Journal of Atmospheric and Oceanic Technology       (Followers: 34) Journal of Atmospheric and Solar-Terrestrial Physics       (Followers: 197) Journal of Atmospheric Chemistry       (Followers: 21) Journal of Climate       (Followers: 54) Journal of Climate Change       (Followers: 3) Journal of Climatology       (Followers: 3) Journal of Hydrology and Meteorology       (Followers: 29) Journal of Hydrometeorology       (Followers: 11) Journal of Integrative Environmental Sciences       (Followers: 4) Journal of Meteorological Research       (Followers: 1) Journal of Meteorology and Climate Science       (Followers: 14) Journal of Space Weather and Space Climate       (Followers: 27) Journal of the Atmospheric Sciences       (Followers: 81) Journal of the Meteorological Society of Japan       (Followers: 6) Journal of Weather Modification       (Followers: 2) Large Marine Ecosystems       (Followers: 1) Mathematics of Climate and Weather Forecasting       (Followers: 6) Mediterranean Marine Science       (Followers: 1) Meteorologica       (Followers: 2) Meteorological Applications       (Followers: 4) Meteorological Monographs       (Followers: 2) Meteorologische Zeitschrift       (Followers: 3) Meteorology and Atmospheric Physics       (Followers: 26) Mètode Science Studies Journal : Annual Review Michigan Journal of Sustainability       (Followers: 1) Modeling Earth Systems and Environment       (Followers: 1) Monthly Notices of the Royal Astronomical Society       (Followers: 13) Monthly Weather Review       (Followers: 34) Nature Climate Change       (Followers: 134) Nature Reports Climate Change       (Followers: 37) Nīvār npj Climate and Atmospheric Science       (Followers: 3) Open Atmospheric Science Journal       (Followers: 2) Open Journal of Modern Hydrology       (Followers: 6) Revista Brasileira de Meteorologia Revista Iberoamericana de Bioeconomía y Cambio Climático Russian Meteorology and Hydrology       (Followers: 3) Space Weather       (Followers: 25) Studia Geophysica et Geodaetica Tellus A       (Followers: 22) Tellus B       (Followers: 21) The Cryosphere (TC)       (Followers: 5) The Cryosphere Discussions (TCD)       (Followers: 4) The Quarterly Journal of the Royal Meteorological Society       (Followers: 27) Theoretical and Applied Climatology       (Followers: 13) Tropical Cyclone Research and Review       (Followers: 1) Urban Climate       (Followers: 4) Weather       (Followers: 19) Weather and Climate Dynamics Weather and Climate Extremes       (Followers: 16) Weather and Forecasting       (Followers: 28) Weatherwise       (Followers: 4) 气候与环境研究       (Followers: 1)
Similar Journals
 Meteorology and Atmospheric PhysicsJournal Prestige (SJR): 0.543 Citation Impact (citeScore): 1Number of Followers: 26      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1436-5065 - ISSN (Online) 0177-7971 Published by Springer-Verlag  [2656 journals]
• Assessment of near-surface air pollutants at an urban station over the
central Indo-Gangetic Basin: Role of pollution transport pathways
• 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: 2021-04-26

• Annual displacement and appropriate index to determine ITCZ position in
East Africa and the Indian Ocean regions
• Abstract: Preliminary studies on ITCZ show that the displacement of this system can play an undeniable role in the climate of tropical regions as well as in surrounding areas. The purpose of this study is to investigate the annual ITCZ movement in the Indian Ocean and East Africa region and to select the appropriate and reliable index for ITCZ positioning. To conduct this research, the ERA-interim reanalysis gridded data from the European Centre for Medium-Range Weather Forecasts (ECMWF) was used to determine the location and spatial displacement of the ITCZ. The results showed that the HCC index is the appropriate index to detect the annual ITCZ displacement in all months of the year. The SH and P indices were in second place in terms of importance and accuracy in identifying the behavior and spatial displacement of the ITCZ system. The TCWV index has been a weak index to detect the ITCZ annual location and displacement. During the three months of winter, the ITCZ bends off the east coast of Africa to the southern latitudes and enters the waters of the Indian Ocean along the northwest-southeast. In the other words, the average ITCZ position on land is about 5˚–6˚ north latitude over the waters of the Indian Ocean. On the contrary, from April to the end of September, in the range of 30˚–50˚ E (Sudan), the ITCZ bends and extends to the northeast. During the summer months, this northward movement sometimes reaches up to 20˚.
PubDate: 2021-04-20

• Spatio-temporal analysis of rainfall pattern in the Western Ghats region
of India
• Abstract: This paper investigates the rainfall pattern and its distribution, which is one of the key drivers for the water availability in the Western Ghats region of India. The daily precipitation data from 1901 to 2014 were investigated to understand the rainfall pattern and its variability. The study area has been divided as southern, coastal, central, and northern regions and rainfall amount into 0.2–10 mm, 10–20 mm, and > 50 mm classes. The trends in the annual rainfall, number of rainy days, and various classes within these regions have been investigated. The mean annual rainfall varies between 4000 mm in the coastal areas and greater than 6000 mm at the mountain crest. The Mann–Kendall test indicates significant decrease of annual rainfall, at 5% significance level in central and coastal region. On Contrary, the coastal region recorded significant decrease in the number of rainy days at 5% significance level. An increasing trend in the number of rainy days has been observed in the northern region. No significant trends have been detected in the southern region. A decreasing trend has been detected in the number of rainy days in the rainfall class with 10–20 mm in coastal region. Similarly a significant decrease of rainy days was observed in > 50 mm rainfall class both in the southern and northern regions. The change point probability and homogeneity test indicates that there is a significant increase in rainfall in few stations under the northern region and similarly decrease in the rainfall in central region during the decade of 1970 and normally the rainfall has been homogeneous in the study area. From the precipitation concentration analysis found that Mysore, Kodagu, and adjoining areas are influenced by the bi-modal rainfall, receiving the rainfall during both south–west and north–east monsoons. This analysis helps to understand the spatial variability of rainfall in the Western Ghats of India, which depict mixed trends in the quantum of rainfall and decreasing trend of rainy days across various rainfall classes. These changes detected in the historical rainfall, both in its occurrence and quantum will have significant bearing on the water availability scenario in the Western Ghats region.
PubDate: 2021-04-09

• Historical extreme rainfall over the Bangalore city, India, on 14 and 15
August 2017: skill of sub-kilometer forecasts from WRF model
• Abstract: Urban extreme rainfall events (UEREs) are one of the weather hazards where modelers continue to struggle for accurate advance prediction despite recent advances in forecasting techniques. Bangalore, one of the prominent IT hubs in India, witnessed many urban flash floods in the recent past; a number of such events happened on 14 and 15 of August 2017, where overnight heavy rains brought several parts of the city to a standstill. In this study, the skill of sub-kilometer resolution forecasts from Weather Research and Forecasting (WRF) model in simulating these UEREs is examined. This study also compared the model performance for forecasts initialized from different forecast cycles in a day. Our examination for two UERE cases showed that forecast initialized at 0600 UTC yielded best results in terms of forecasting spatial distribution and intensity of rainfall. Our analysis also indicated that increasing model resolution further in convection-permitting resolution (< 3 km) has only marginal impact on spatial distribution of rainfall while model skill in simulating rainfall intensity slightly improved with increasing resolution. As expected, simulation by not deploying a cumulus scheme at cloud-resolving resolution do not make a significant difference in spatial distribution; however, inclusion of cumulus scheme improved quantitative precipitation forecast skill. The inferences from this study are useful for modelers working on improving operational forecast skill of UEREs using mesoscale model.
PubDate: 2021-04-08

• Are ocean-moored buoys redundant for prediction of Indian monsoon'
• Abstract: The Tropical Atmosphere Ocean (TAO) and Triangle Trans-Ocean Buoy Network (TRITON) buoys deployed in the tropical Pacific play a significant role in monitoring tropical Pacific conditions such as El-Niño/La-Niña in real-time. Earlier studies have illustrated the importance as well as irrelevance of moored buoy observations towards the prediction of sea surface temperature in the tropical Pacific Ocean. With the advent of Argo floats, have these moored buoy observations become redundant' In the present study, we address this question in the context of Indian summer monsoon rainfall (ISMR) prediction. The extreme monsoon year of 2018 was selected to test the above hypothesis. Without moored buoy observations being assimilated, the oceanic initial conditions and the seasonal forecasts had large oceanic temperature errors and forecasted a normal monsoon instead of a below-normal monsoon during 2018. Therefore, moored buoy observations are essential and should be assimilated to get realistic Pacific sea surface temperature (SST) and accurate ISMR predictions.
PubDate: 2021-04-08

• Trend tests on maximum rainfall series by a novel approach in the Aegean
region, Turkey
• Abstract: This study aims to analyse the annual maximum (i.e., outlier or extreme) rainfall datasets, and also to detect potential trends and assess their significance for the Aegean region, Turkey. These datasets were analysed using the parametric Student’s t-test, the nonparametric Mann–Kendall (MK) trend test, the Şen trend test, and a novel proposed approach in this present study. Moreover, a homogeneity test was applied to the datasets. The analyses were based on 60-year [1960–2019, except for Uşak (1960–2015)] records at the eight meteorological stations. In this context, the findings showed that there was no statistically significant trend according to the Student’s t-test and the MK test except for Afyonkarahisar. Şen test provided some different results from the Student’s t-test and the MK trend test except for Kütahya, Manisa, Muğla, and Uşak provinces. The novel approach provided some different results from the Student’s t-test, Mann–Kendall (MK) trend test, and the Şen trend test. For example, there was a statistically significant increasing trend in the Student’s t-test, Mann–Kendall (MK) trend test, and the Şen trend test for Afyonkarahisar. There was a statistically insignificant increasing trend in the newly developed approach at a 90% confidence interval with a two-tailed hypothesis test; therefore, this increasing trend especially for Afyonkarahisar should be considered in designing of the engineering and other related structures. In addition to these consequences, some advantages of the novel approach can be explained as follow: this novel approach (i) provides a good option to see the limits of the data on the plot because data visualisation is very important; (ii) has benefited both visually and mathematically in considering the extreme data, and (iii) can also be evaluated as a support test for other trend tests, such as MK and Şen.
PubDate: 2021-04-04

• Spectral and synoptic analysis of Haboob in Tehran, Iran
• Abstract: On 2 June 2014, a Haboob dust storm occurred in Tehran, which lasted less than 2 h, caused severe damages to the properties and involved loss of human life. This paper describes the behavior of this Haboob dust storm, by analyzing of metrological satellites data, as well as assessing the mesoscale and microscale patterns that led to the occurrence of the dust. A dust detection scheme was developed to monitor the dust formation using the Infrared (IR) channels of the Spinning-Enhanced Visible and Infrared Imager (SEVIRI), carried on board MSG satellites. Restrictive thresholds were placed on the individual components to maximize detection success, and to minimize the misidentification of dust. The results indicated cold and strong downdrafts along with the cold front activity during the maximum temperature over the central hot desert caused a strengthened and intensified wind velocity that led to a strong Haboob in Tehran province. The synoptic analysis indicated that a low-pressure system stretching from the southeast of Iran to the northwest of Iran and Iraq was the dominant feature, despite the presence of a weak high-pressure in the center of Iran. The satellite analysis indicates an extreme dustiness discernible in the southwest of Tehran following the formation of a convective storm; however, uncertainty in dust identification increases as the IR dust signal weakens because of underlying dust cloud beneath the thick convective clouds. The analysis of could physical properties reveals the formation of a convective storm after dramatically decrease in cloud top temperature (CTT) and cloud top pressure (CTP), and increasing the cloud optical depth (COT) which led to development of an overshooting cold cloud over Tehran province before dust formation.
PubDate: 2021-04-03

• Prediction of dominant daily modes of the Indian summer monsoon in the
NCEP GFS model
• 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: 2021-04-02

• Assessment of physical parameterization schemes in WRF over national
capital region of India
• Abstract: Increase in the extreme weather events around the world has necessitated application of numerical weather prediction (NWP) models to forecast these events and minimize consequences. Application of NWP models requires appropriate selection of physics parameterization options for close representation of atmospheric processes. In this study, the WRF model performance was evaluated for varying physical parameterization of surface processes in simulating meteorology with respect to varying (i) shortwave and longwave radiation schemes, (ii) planetary boundary layer (PBL) and corresponding surface layer (SL) schemes over Delhi NCR. A total of 11 simulation sets were curated with 7 PBL schemes (ACM2, GBM, UW, MYJ, SH, TEMF and BouLac), 4 surface layer schemes (Pleim-Xiu, Revised MM5, Eta and TEMF), 3 shortwave radiation schemes (Dudhia, New Goddard and RRTMG), 3 longwave radiation schemes (RRTM, New Goddard and RRTMG) and 2 land surface models (LSM) (Pleim-Xiu and Noah). Sensitivity experiments are performed at a fine resolution (1 km) with updated LULC input. Based on the sensitivity analysis, it is inferred that the simulation set which works best for the region is TEMF PBL, TEMF SL, Dudhia shortwave radiation, RRTM longwave radiation and Noah LSM schemes. The TEMF PBL scheme is designed as hybrid (local–nonlocal) scheme and thereby, with consideration of both local and nonlocal viewpoints it is noted that the near-surface meteorological parameters are depicted with greater accuracy. To further address the model biases it is important to refine the physical parameterizations schemes in the WRF model or using different bias correction and data assimilation techniques.
PubDate: 2021-04-01

• Characteristics of pre-monsoon convective systems over south peninsular
India and neighborhood using tropical rainfall measuring mission's
• Abstract: Ten-year climatology of physical properties of convective echoes during pre-monsoon season over south peninsular India and neighborhood are studied using Precipitation Radar dataset onboard Tropical Rainfall Measuring Mission satellite. Attenuation corrected radar reflectivity (Ze) is used to define an intense convective echo (ICE) which is a group of two or more contiguous convective pixels with Ze exceeding 30 dBZ. Height distribution of ICE is right skewed, single modal with mean and median as 7.8 and 7.3 kms. The ICE with area in range of more than 102 to 103 km2 (C) are most frequent (58.5%) followed by smallest scale (D) having area ≤ 102 km2 (37.2%). Large ICE’s (B/C scale) are less frequent (4.2%). Mean areas of ICE’s in D, C and B/C scales are 72.7, 279 and 1932 km2, respectively. The relation between height and area is linear indicating that taller ICE’s are broader. The mean top heights of D, C and B/C scales are 5.5, 8.7 and 14.2 km, respectively. Frequency distributions of the height of 30 and 40 dBZ show single peaks at 5.5 and 4.75 km. Mean heights of 30 dBZ and 40 dBZ are 5.7 and 4.8 km while median heights are 5.5 and 4.7 km. Their cumulative frequency distribution shows that 6 and 3% of ICE cross 10 km height. Reflectivity structures of ICE show that systems over land are intense compared to that over ocean.
PubDate: 2021-04-01

• Characterizing mesoscale variability in low-level jet simulations for
CBLAST-LOW 2001 campaign
• Abstract: A low-level jet (LLJ) event observed during a frontal passage in the 2001 Coupled Boundary Layers and Air–Sea Transfer Experiment in Low Winds campaign was simulated using the Weather Research and Forecasting model (WRF). The sensitivity of the modeled LLJ characteristics, such as formation time, height and the strength of the LLJ core, to the choice of initial and boundary conditions, planetary boundary layer (PBL) schemes and vertical resolution was evaluated with a suite of diagnostic tools. The model simulations were compared against available soundings from the campaign observations as well as with surface observations from the Automated Surface Observing Systems. The simulation initialized with ERA-interim reanalysis and using the Mellor–Yamada–Nakanishi–Niino PBL scheme gave the best mix of diagnostic scores for surface temperature and wind speed predictions. The choice of boundary conditions introduced a stronger variability in the LLJ characteristics than the changes in PBL schemes or vertical resolution. The variability emerged primarily due to the timing of the frontal passage in the boundary condition datasets.
PubDate: 2021-04-01

• Radar characteristics of summer thunderstorms in the Kanto Plain of Japan
with and without cloud-to-ground lightning
• Abstract: The elucidation of characteristics of cumulonimbus clouds that cause lightning is important for predicting thunderstorm development. These characteristics, with and without lightning, were observed during a day (in 2010) of severe thunderstorms and lightning in Japan and statistically analyzed using radar observations with cell tracking. Observed cells were categorized into a cell including cloud-to-ground lightning (CG) and intra-cloud lightning (CGIC), a cell containing only intra-cloud lightning (IC), and a cell without lightning (NoL). These cells were compared to the average and temporal evolution of radar observations. Out of the 265 cells generated, 103 were CGIC cells, 30 were IC cells, and 132 were NoL cells. Significant differences were detected between the averaged values of lifetime, size, echo top, vertically integrated liquid (VIL), maximum radar reflectivity, and radar reflectivity of each cell category, when the − 10 °C isotherm height was considered. The temporal evolution of CGIC cell characteristics revealed changes in radar reflectivity at 0 °C and − 10 °C that were synchronized with lightning activity. The VIL value was elevated only for CGIC cells and had the tendency to decrease with time as lightning activity. CGIC cells produced the highest echo top and maintained their height during their lifetime. To predict CG within 20 min using 35 dBZ radar reflectivity at − 30 °C as the criterion, a critical success index (CSI) of 0.82 and false alarm rate (FAR) of 0.64 were found to have the best prediction scores.
PubDate: 2021-04-01

• Estimation of solar radiation using stepwise multiple linear regression
with principal component analysis in Algeria
• Abstract: For the modelling of solar systems, reliable and complete time series of solar radiation are required. However, solar radiation data from ground measurements or satellite images may be available only for limited time periods and often have data quality issues or/and data gaps. It is possible to get reasonably accurate radiation estimates of solar radiation from meteorological parameters, which can complement or extend existing data. In this paper, a model based on eight meteorological parameters (evaporation, temperature, wind speed, visibility, cloud cover, sunshine duration, sunshine ratio and global solar radiation) is developed to predict the global solar radiation using 29-year (1986–2014) data from Oran radiometric station in Algeria. Two versions of the multiple regression analysis are used: the first with original observation variables (called as manifest variables) and the second by PCs called as latent variables or (common) factors. Separate analyses have been carried out for two scenarios: overall and partial study. The first scenario uses all climatic dataset, but the last scenario uses three subsets which are sunny, partly cloudy and cloudy days. This classification has been obtained using certain statistical properties that we have considered as thresholds. Stepwise multiple linear regression analysis is used to fit global solar radiation data using meteorological variables as predictors. A variable selection method based on PCA technique are used to obtain the subsets of predictors to be included in the regression model of global solar radiation data. Hence, the proposed relationships may be considered useful for predicting global solar radiation rate in other sites of Algeria that have climatic conditions similar to the study area.
PubDate: 2021-04-01

• Difference of total precipitation and snowfall in the Upper Yangtze River
basin under 1.5 °C and 2 °C global warming scenarios
• Abstract: The influence of climate change on regional-scale precipitation is becoming undeniable, and can lead to increased flood and drought risks in some regions. The study assessed the potential effect of global warming of 1.5 °C and 2 °C on total precipitation and snowfall in the Upper Yangtze River Basin (UYRB) based on General Circulation Models (GCMs). Seven total precipitation and six snowfall indices were employed in this analysis. The results show that the annual precipitation (PA) in the UYRB will increase by approximately 4.5–5% and 9–13% per 1.0 °C under the 1.5 °C and 2 °C warming, respectively. Spatially, the PA is shown to increase across the northern part of the basin, but decrease in the southern part. Relative to the baseline period (1986–2005), the frequency of trace and moderate precipitation days shows a decreasing trend, while that of heavy and intense precipitation days will increase under both 1.5 °C and 2 °C warming scenarios. Moreover, it varies among significance levels of trace, light, moderate, heavy and intense precipitation frequency under 1.5 °C and 2 °C warming for different Representative Concentration Pathways (RCPs). Unlike overall total precipitation, the annual snowfall (ASF) will decrease by approximately 2.5–8% per 1.0 °C under the 1.5 °C warming, and the 2–4% per 1.0 °C under the 2 °C warming. The ASF exhibits a decreasing trend in most of the UYRB except for the far northern part under all global warming scenarios. The date of first snowfall is modeled to be delayed and that of last snowfall will advance, which will lead to the decrease of snowfall days by about 15–20 days under different warming scenarios. In a warming world, total precipitation in the UYRB will increase and snowfall will decrease, which may increase the risk of flood in the future, and more attention should be paid.
PubDate: 2021-04-01

• Seasonal characteristics of sea breeze and thermal internal boundary layer
over Indian east coast region
• Abstract: Characteristics of the sea breeze and thermal internal boundary layer (TIBL) during different seasons are studied using mini micropulse lidar (MPL) at Kattankulathur (12.83° N, 80.04° E, 45 m) and radiosonde and surface meteorological observations at Meenambakkam (13.0° N, 80.06° E, 16 m) during the period January 2016–June 2018 over Chennai, in the Indian east coast region. Study of the sea breeze is important because it is one of the main factors responsible for most of the convective rainfall during summer monsoon season over Chennai. The sea breeze onset occurs from morning ~ 07:00 IST to late afternoon during winter and pre-monsoon seasons whereas it occurs from mid-morning ~ 09:00 IST to late evening ~ 19:00 IST during the summer monsoon and post-monsoon seasons. The cessation of the sea breeze lies between the late evening ~ 18:00 IST and early morning ~ 04:00 IST on the next day. Sea breeze prevails for the longest (shortest) duration during pre-monsoon (summer monsoon) season. The temperature, moisture, refractivity, and aerosol profiles show double mixed layer characteristics indicating TIBL as the first layer and convective boundary layer (CBL) or residual layer (RL) as the second layer. TIBL occurs throughout the year with maximum occurrence during pre-monsoon season. It varies from 0.2 to 0.8 km (0.4–1.0 km) with peak at 0.4 km (0.6 km) over Meenambakkam (Kattankulathur). TIBL height is found to be at altitude ~ 0.54 ± 0.16 km and 0.62 ± 0.13 km at Meenambakkam and Kattankulathur, respectively. TIBL shows a weak seasonal variation with maximum height during winter and minimum height during summer in contrast to the seasonal variation of the CBL.
PubDate: 2021-04-01

• Orographic effects on the propagation and rainfall modification associated
with the 2007–08 Madden–Julian oscillation (MJO) past the New Guinea
Highlands
• Abstract: Based on the tropical rainfall measuring mission (TRMM)-measured rainfall and estimated outgoing longwave radiation (OLR) fields, it is found that 2007–08 Madden–Julian Oscillation (MJO07-08) went through blocking, splitting, and merging stages when it passed over the New Guinea Highlands (NGH). The TRMM-estimated OLR fields fail to capture detailed TRMM rainfall field and thus is not suitable to serve as proxy for rainfall, as also found in previous studies. The mechanism of orographic blocking is explained by strong orographic blocking on the incoming, low-Froude number, and moist flow, which belonged to the flow-around regime. This is evidenced by estimating the Froude number by upstream soundings. The strong blocking forced the flow to go around the mountains on NGH, leading to the splitting of flow and MJO precipitating system and the merging at the southeast tip of New Guinea. Orographic, MJO, and cyclone clouds were shown in both observed and model-simulated results. The major differences of the model-simulated and TRMM-measured precipitation are as follows: (a) the model-simulated rainfall area is much larger than that covered by the observed rainfall and (b) even though they both show comparable maximum rainfall rate, the rainfall estimated by TRMM reveals more localized rainfall spots, which is unexpected since the WRF simulation uses a relatively fine resolution (5 km). In summary, during the blocking stage, the mountains have slowed down the MJO propagation and increased the rainfall amount upstream of the local mountains, while during the splitting and merging stages, the mountains have made significant impacts on the MJO rainfall distribution.
PubDate: 2021-04-01

• On observations of correlation functions and power spectra in rain:
• Abstract: Rain is often characterized using statistical approaches. Among the most common are temporal correlations and power (variance) spectra from time series measurements at a single location. Likewise, temporal observations over a network are used to deduce a radial distribution function and spatial power spectra. In such studies the potential effects of advection on the results are ignored. Moreover, observations involve filtering of the data. In time, this may involve sampling over a sufficiently long period so as to increase statistical confidence in the measurement. The same is also true for spatial observations over a network which must contain a sufficient number of instruments for a reliable characterization of the spatial variability. This also usually includes some form of averaging over time as well. Temporal averaging amounts to a low pass filter that attenuates contributions from higher frequencies. In contrast, the finite dimension of a network acts as a high-pass filter that tends to suppress the lower wavenumbers much larger than the dimension of the network. In this work the effects of both the advection of the rain and the observational filtering are considered for the simplest case of wide-sense statistically stationary and homogeneous rain along one-dimension for rain exponentially correlated in both space and time. It is found that advection and filtering can significantly shift the portrayal of the rain from the true structures. Consequently, rainfall characterizations from observations should not be over-generalized to other situations.
PubDate: 2021-04-01

• Dust induced radiative perturbations during an episode of long-range dust
transport over Delhi, India: a high-resolution regional NWP model study
• Abstract: Dust-induced modifications to the radiative fluxes/heating during a light-blocking haze episode over Delhi, India, 7–9th Nov 2017—triggered by long range transport from a severe Saudi Arabian dust storm—have been investigated with a regional NWP model, NCUM-R with prognostic dust-radiation feedbacks. The study employs ‘Double Radiation Calls’, wherein parallel runs of the radiation scheme ‘with’ (prognostic) and ‘without’ (diagnostic) dust radiative effects—while prognostic fields drive the forecast—isolate the dust-induced perturbations. The forecasted dust optical depth agreed spatially with the AOD from MODIS with Angstrom Exponent > 0.5, indicating that the dust was well mixed with the fine mode anthropogenic aerosols upwind. The ‘downward shortwave (SW) flux’ was diminished (upto − 12.9 Wm−2) in layers sampling (i) near-surface (L1Avg), (ii) well-mixed layer within the planetary boundary layer (PBL, L2Avg) and (iii) free-troposphere (FT, L3Avg). Dust-induced ‘Solar heating’ dominated in FT (upto 9.5 × 10–7 Ks−1) and the patches below (in L2Avg) exhibited a cooling, leading to thermal dipoles. The ‘upward longwave (LW) flux’ in FT was reduced and ‘LW heating’ prevailed in all levels—peak (2.5 × 10–6 Ks−1) in L2Avg—along with well-defined cooling zones in L1Avg. The dust–radiation interaction in turn influenced the boundary layer meteorology, manifested as (i) shallow PBLs that spatially correlate with dust-induced cooling of the boundary layer column, (ii) enhanced surface humidity and (iii) reduced visibility. The study is an instance of prognostic dust-radiation feedbacks improving the skill of NWP models in dust-laden regions.
PubDate: 2021-04-01

• Long-memory traces in $$\hbox {PM}_{10}$$ PM 10 time series in Athens,
Greece: investigation through DFA and R/S analysis
• Abstract: This paper investigates the existence of chaos in concentration dynamics of particulate matter with an aerodynamic diameter less than or equal to $$10\,\upmu \hbox {m}$$ ( $$\hbox {PM}_{10}$$ ) in the greater Athens area (GAA), Greece. It reports findings on three 16-year $$\hbox {PM}_{10}$$ time series recorded by three different air pollution monitoring stations located in GAA and examines if critical fractal epochs with long memory exist. Detrended Fluctuation Analysis (DFA) and Rescaled Range (R/S) Analysis were used via sliding windows of approximately 1-month duration. In all $$\hbox {PM}_{10}$$ time series, several segments were found with critical fractal behaviour and hidden long-memory patterns. All these segments exhibited Hurst exponents above 0.75 and DFA exponents above 1.75. Twelve $$\hbox {PM}_{10}$$ segments with fractality and long memory were commonly identified by both techniques. In one case, long memory was identified concurrently across all three air pollution monitoring stations and in another case, across two stations. The importance of the agreement between two different and independent chaos-analysis techniques is discussed in association with the proper selection of threshold values. This is the second time to address chaos in $$\hbox {PM}_{10}$$ data series in GAA, and the first time to combine two widely accepted techniques, DFA and R/S analysis.
PubDate: 2021-04-01

• Mapping snow cover using landsat data: toward a fine-resolution
water-resistant snow index
• Abstract: Snow cover is of significant importance to freshwater supplies and influences the hydrology of different altitudes in mountainous regions. The monitoring of snow cover over the Mediterranean region of Turkey is of high priority due to its rapid irregularities experienced during the past decades. These irregularities in snow cover might especially lead to severe risks for the local ecosystems, such as rivers, and irrigated agriculture. Water-Resistant Snow Index (WSI) is a new and powerful spectral index for mapping snow cover using Moderate Resolution Imaging Spectroradiometer (MODIS) data. There still exists a large knowledge gap about how to improve the finer resolution applications of WSI. This study aimed to explore the applicability of WSI using Landsat TM and OLI images with a better spatial resolution to a complex catchment in the eastern Mediterranean region of Turkey. The WSI maps derived from both MODIS/Terra-MOD09A1 and Landsat images from 2005 to 2018 were compared with the high-resolution Sentinel-2A data. The comparative analysis of the MODIS and Landsat WSI maps for the snowy areas was also presented with error distribution patterns. The baseline snow cover led to the coefficient of determination values of 0.77 with the MODIS data and 0.78 with the Landsat data. The results indicated that Landsat images offered a suitable spatial resolution for the snow cover mapping using the WSI approach in regional studies. A finer resolution mapping of snow cover with the Landsat data can provide essential insights into the spatiotemporal dynamics at the local and regional scales.
PubDate: 2021-04-01

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