Integrating satellite and model data to explore spatial-temporal changes in aerosol optical properties and their meteorological relationships in northwest India.

This study aims to analyze the temporal and spatial distribution of Aerosol Optical Properties across Northwest India using aerosol data from MODIS (Moderate Resolution Imaging Spectroradiometer) and OMI (Ozone Monitoring Instrument) sensors from 2003 to 2022. Therefore, this study investigated the decadal, interannual, and seasonal changes in aerosol optical properties, vegetation index, and meteorological parameters in the northwest Indian region (8 boxes). Using GIOVANNI (Goddard Earth Sciences Data and Information Services Center (GES DISC) Online Visualization and Analysis Infrastructure), we retrieved daily and monthly Aqua and Terra MODIS products of aerosol optical depth (AOD), Angstrom exponent (AE), normalized difference vegetation index (NDVI), and OMI aerosol index (AI) to examine the spatiotemporal variations by using statistical approaches. The results demonstrated that the decadal averages of aerosol properties showed values of AOD 0.35 (Aqua) and 0.34 (Terra) and AE 1.20 (Aqua) and 1.10 (Terra) with the highest levels during the post-monsoon. Notably, the mean interannual concentrations of AOD and NDVI consistently surpass 0.3, and AE and AI exceed 1 in most locations, underscoring the persistence of high aerosol loading. Also, the study revealed a negative decadal change in AOD of about -8.24 %, while AE, AI, and NDVI showed positive decadal changes of about 9.24 %, 15.09 %, and 12.67 %, respectively. In addition, aerosol optical properties and local meteorology strongly correlated (-0.8 to +0.8). Principal Component Analysis (PCA) identifies meteorological parameters as significant drivers, with the first three components explaining over 70 % of the variation in aerosol optical properties. The NOAA HYSPLIT trajectory model suggests that the long-distance dust transport from the Arabian Peninsula frequently penetrates Gujarat province and then to northwest India. The results contributed to air quality management strategies and provided valuable insights into regional climate and air quality with the influence of meteorology.

Dynamics of land, ocean, and atmospheric parameters associated with Tauktae cyclone.

During the pre- and post-monsoon season, the eastern and western coasts are highly vulnerable to cyclones. The tropical cyclone "Tauktae" formed in the Arabian Sea on 14 May 2021 and moved along the west coast of India, and landfall occurred on 17 May 2021. During the cyclone, the maximum wind speed was 220 km/h with a pressure of 935 mb affecting meteorological, atmospheric parameters, and weather conditions of the northern and central parts of India causing devastating damage. Analysis of satellite, Argo, and ground data show pronounced changes in the oceanic, atmospheric, and meteorological parameters associated during the formation and landfall of the cyclone. During cyclone generation (before landfall), the air temperature (AT) was maximum (30.51 °C), and winds (220 km/h) were strong with negative omega values (0.3). The relative humidity (RH) and rainfall (RF) were observed to be higher at the location of the cyclone formation in the ocean and over the landfall location, with an average value of 81.28% and 21.45 mm/day, respectively. The concentration of total column ozone (TCO), CO volume mixing ratio (COVMR), H2O mass mixing ratio (H2O MMR), aerosol parameters (AOD, AE) and air quality parameter (PM) was increased over land and along the cyclone track, leading to a deterioration in the air quality. The strong wind mixes the air mass from the surroundings to the local anthropogenic emissions, and causing strong mixing of the aerosols. The detailed results show a pronounced change in the ocean, land, meteorological, and atmospheric parameters showing a strong land-ocean-atmosphere coupling associated with the cyclone.

A bibliometric and visualization analysis of the aerosol research on the Himalayan glaciers.

This research focuses on a bibliometric analysis of research on aerosols' impact on the glaciers in the Himalayan glacier region published in journals from all subject categories based on the Science Citation Index Expanded, collected from the Web of Science and Scopus database between January 2002 and April 2022. The indexing phrases like "aerosol," "glacier," and "snow" are commonly used terms and have been utilized to collect the related publications for this investigation. The document selections were based on years of publication, authorship, the scientific output of authors, distribution of publication by country, categories of the subjects, and names of journals in which scholarly papers were published. The number of articles on aerosols accelerating the melting of glaciers shows a notable increase in recent years, along with more glacier melting results from countries involved in climate science research. People's Republic of China (382) was the country with the highest publication output on aerosols impacting the melting of glaciers. The USA (367) was the most cited country, with about 17,500 total citations and 80.40 average citations per year from January 2002 to April 2022. The results reveal that research trends in the glaciers on aerosols' impact on the glaciers have been attractive in recent years, and the number of articles in this field keeps increasing fast. This study offers opportunities to track research trends, identify collaboration prospects, and inform climate policy. Integrating data sources and engaging the public will further enhance the impact and relevance of this critical research field.

The global scenario of hydrogeochemical research on glacier meltwater: a bibliometric and visualization analysis.

In recent years, there has been a rapid increase in scientific research into hydrogeochemical research on glacier meltwater. Nevertheless, systematic and quantitative analyses are lacking to investigate how this research field has developed over the years. As a result, this study is aimed at examining and evaluating recent research trends and frontiers in hydrogeochemical research on glacier meltwater throughout the previous 20 years (2002-2022) and at locating collaboration networks. This is the first global-scale study, and visualization of the key hotspots and trends in hydrogeochemical research has been presented here. The Web of Science Core Collection (WoSCC) database aided in the retrieval of research publications related to hydrogeochemical research of glacier meltwater published between 2002 and 2022. From the beginning of 2002 till July 2022, 6035 publications on the hydrogeochemical study of glacier meltwater were compiled. The result revealed that the number of published papers on the hydrogeochemical study of glacier meltwater at higher altitudes had grown exponentially, with USA and China being the main research countries. The number of publications produced from the USA and China accounts for about half (50%) of all publications from the top 10 countries. Kang SC, Schwikowski M, and Tranter M are highly influential authors in hydrogeochemical research of glacier meltwater. However, the research from developed nations, particularly the United States, emphasizes hydrogeochemical research more than those from developing countries. In addition, the research on glacier meltwater's role in streamflow components is limited, particularly in the high-altitude regions and needs to be enhanced.

Assessing the geochemical processes controlling groundwater quality and their possible effect on human health in Patna, Bihar.

This research was conducted in the urban area of Patna region, the capital and largest city of Bihar, which is part of the Indo-Gangetic alluvium plain. This study aims to identify the sources and processes controlling groundwater's hydrochemical evolution in the Patna region's urban area. In this research, we evaluated the interplay between several measures of groundwater quality, the various possible causes of groundwater pollution, and the resulting health risks. Twenty groundwater samples were taken from various locations and examined to determine the water quality. The average EC of the groundwater in the investigated area was 728 ± 331.84 µS/cm, with a range of around 300-1700 µS/cm. Positive loadings were seen for total dissolved solids (TDS), electrical conductivity (EC), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), chloride (Cl-), and sulphate (SO42-) in principal component analysis (PCA), demonstrating that these variables accounted for 61.78% of the total variance. In the groundwater samples, the following main cations are the most prevalent such as Na+ > Ca2+ > Mg2+ > K+, while the dominant anions are HCO3- > Cl- > SO42-. The elevated HCO3- and Na+ ions indicate that carbonate mineral dissolution might affect the study area. The result demonstrated that 90% of samples fall into the Ca-Na-HCO3 type, remaining in the mixing zone. The presence of the NaHCO3 kind of water is suggestive of shallow meteoric water, which may have originated from the river Ganga that is located nearby. The results show that a multivariate statistical analysis and graphical plots successfully identify the parameters controlling groundwater quality. In accordance with guidelines for safe drinking water, the electrical conductivity and potassium ion concentrations in the groundwater samples are 5% higher than acceptable levels. People who take large amounts of salt replacements report feeling tight in the chest, vomiting, having diarrhoea, developing hyperkalaemia, having trouble breathing, and even experiencing heart failure.

Chemometric approach to evaluate the chemical behavior of rainwater at high altitude in Shaune Garang catchment, Western Himalaya.

The present research has been performed to analyze the chemical behavior of rainwater of the Shaune Garang catchment (32.19° N, 78.20° E) in the Baspa basin, located at a high elevation (4221 m above mean sea level) in the Himachal Himalaya, India. During the study period, sixteen rainwater samples were collected from the Shaune Garang catchment at five different sites. The volume-weighted mean (VWM) pH value of rainwater ranged between 4.59 and 6.73, with an average value of 5.47 ± 0.69, indicating the alkaline nature of rainfall. The total ionic strength in the rainwater ranged from 113.4 to 263.3 µeq/l with an average value of 169.1 ± 40.4 µeq/l. The major dominant cations were Ca2+ (43.10%) and Na+ (31.97%) and anions were Cl- (37.68%), SO42- (28.71%) and NO3- (23.85%) in rainwater. The ionic ratios were calculated among all the ions. The fraction of (NO3- +Cl-) with SO42- was measured as 2.3, which specifies sour faces of rainwater due to HNO3, H2SO4, and HCl. A multivariate statistical assessment of rainwater chemistry through Principal Component Analysis (PCA) shows the significance of four factors controlling 78.37% of the total variance, including four-component (PC1 explained 27.89%, PC2 explained 24.98%, PC3 explained 14.64%, PC4 explained 10.85%). However, the individual contribution of Factor 1(PC1) explains 27.89% of the total variance (78.37%) and displays a strong optimistic loading for Ca2+ and Cl-. Further, high loading of Ca2+ and NO3- and moderate loading of SO42- signify the contribution of burning fossil fuel and soil dust. Anthropogenic and natural pollutants influence the composition of rainwater in the pristine Himalayas due to local and long-distance transportation. The study area receives precipitation from the West and North-West, transporting dust and fossil fuel emissions from the Thar Desert and Northwestern countries.

Surface mass balance analysis at Naradu Glacier, Western Himalaya, India.

In the present study, we analyze a field-based seven-year data series of surface mass-balance measurements collected during 2011/12 to 2017/18 on Naradu Glacier, western Himalaya, India. The average annual specific mass balance for the said period is - 0.85 m w.e. with the maximum ablation of - 1.15 m w.e. The analysis shows that the topographic features, south and southeast aspects and slopes between 7 to 24 degrees are the reasons behind the maximum ablation from a particular zone. The causes of surface mass balance variability have been analyzed through multiple linear regression analyses (MLRA) by taking temperature and precipitation as predictors. The MLRA demonstrates that 71% of the observed surface mass balance variance can be explained by temperature and precipitation. It clearly illustrates the importance of summer temperature, which alone explains 64% variance of surface mass balance. The seasonal analysis shows that most of the surface mass balance variability is described by summer temperature and winter precipitation as two predictor variables. Among monthly combinations, surface mass balance variance is best characterized by June temperature and September precipitation.