Understanding the linkages between spatio-temporal urban land system changes and land surface temperature in Srinagar City, India, using image archives from Google Earth Engine.

Land-use and land-cover (LULC) is an important component for sustainable natural resource management, and there are considerable impacts of the rapid anthropogenic LULC changes on environment, ecosystem services, and land surface processes. One of the significant adverse implications of the rapidly changing urban LULC is the increase in the Land Surface Temperature (LST) resulting in the urban heat island effect. In this study, we used a time series of Landsat satellite images from 1992 to 2020 in the Srinagar city of the Kashmir valley, North-western Himalaya, India to understand the linkages between LULC dynamics and LST, derived from the archived images using the Google Earth Engine (GEE). Furthermore, the relationship between LST, urban heat island (UHI), and biophysical indices, i.e., Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI), was also analysed. LULC change detection analysis from 1992 to 2020 revealed that the built-up area has increased significantly from 12% in 1992 to 40% in 2020, while the extent of water bodies has decreased from 6% in 1992 to 4% in 2020. The area under plantations has decreased from 26% in 1992 to 17% in 2020, and forests have decreased from 4 to 2% during the same period. Urban sprawl of Srinagar city has resulted in the depletion of natural land covers, modification of natural drainage, and loss of green and blue spaces over the past four decades. The study revealed that the maximum LST in the city has increased by 11°C between 1992 and 2020. During the same period of time, the minimum LST in the city has increased by 5°C, indicating the impact of urbanization on the city environment, which is reflected by the observed changes in various environmental indices. UHI impact in the city is quite evident with the maximum LST at the city centre having increased from 13.03°C in 1992 to 22.01°C in 2020. The findings shall serve as a vital source of knowledge for urban planners and decision-makers in developing sustainable urban environmental management strategies for Srinagar city.

Towards understanding various influences on mass balance of the Hoksar Glacier in the Upper Indus Basin using observations.

Mass balance is a good indicator of glacier health and sensitivity to climate change. The debris-covered Hoksar Glacier (HG) in the Upper Indus Basin (UIB) was studied using direct and geodetic mass balances. During the 5-year period from 2013 to 2018, the glacier's mean in situ mass balance (MB) was - 0.95 ± 0.39 m w.e. a-1. Similarly, the glacier's mean geodetic MB from 2000 to 2012 was - 1.20 ± 0.35 m w.e. a-1. The continuously negative MB observations indicated that the HG is losing mass at a higher rate than several other Himalayan glaciers. The glacier showed increased mass loss with increasing altitude, in contrast to the typical decreasing MB with increasing elevation, due to the existence of thick debris cover in the ablation zone, which thins out regularly towards the accumulation zone. Rising temperatures, depleting snowfall and increasing black carbon concentration in the region, indicators of climatic change, have all contributed to the increased mass loss of the HG. During the lean period, when glacier melt contributes significantly to streamflow, the mass loss of glaciers has had a considerable impact on streamflow. Water availability for food, energy, and other essential economic sectors would be adversely affected, if, glaciers in the region continued to lose mass due to climatic change. However, long-term MB and hydro-meteorological observations are required to gain a better understanding of glacier recession in the region as climate changes in the UIB.

Anthropogenic climate change drives melting of glaciers in the Himalaya.

The Himalayan glaciers provide water to a large population in south Asia for a variety of purposes and ecosystem services. As a result, regional monitoring of glacier melting and identification of the drivers are important for understanding and predicting future cryospheric melting trends. Using multi-date satellite images from 2000 to 2020, we investigated the shrinkage, snout retreat, thickness changes, mass loss and velocity changes of 77 glaciers in the Drass basin, western Himalaya, India. During this period, the total glacier cover has shrunk by 5.31 ± 0.33 km2. The snout retreat ranged from 30 to 430 m (mean 155 ± 9.58 m). Debris cover had a significant impact on glacier melting, with clean glaciers losing ~ 5% more than debris-covered glaciers (~ 2%). The average thickness change and mass loss of glacier have been - 1.27 ± 0.37 and - 1.08 ± 0.31 m w.e.a-1, respectively. Because of the continuous melting and the consequent mass loss, average glacier velocity has reduced from 21.35 ± 3.3 m a-1 in 2000 to 16.68 ± 1.9 m a-1 by 2020. During the observation period, the concentration of greenhouse gases (GHGs), black carbon (BC) and other pollutants from vehicular traffic near the glaciers increased significantly. Increasing temperatures, caused by a significant increase in GHGs, black carbon and other pollutants in the atmosphere, are driving glacier melting in the study area. If the current trend continues in the future, the Himalayan glaciers may disappear entirely, having a significant impact on regional water supplies, hydrological processes, ecosystem services and transboundary water sharing.

Hydrochemical characterization and pollution assessment of groundwater in Jammu Siwaliks, India.

Physico-chemical groundwater (GW) parameters were evaluated to understand the hydrogeochemical processes in the Siwalik plains of Jammu and Kashmir, India. During the 2012-2013 post-monsoon (POM) and pre-monsoon (PRM) seasons, GW samples (n = 207) from deep bore wells and shallow open wells were chemically analysed. Cations (Ca2+, Mg2+, Na+, K+ and Fe2+) and anions (HCO3-, Cl-, SO42- and F-) showed a wide spatio-temporal variation. Results suggest that weathering and dissolution of carbonates and silicate rocks is the main source of water mineralization. The major hydrochemical facies is characterized by Ca-Mg-HCO3 and Ca-HCO3 during the PRM and POM seasons respectively. The presence of sulphate-bearing water in a large number of the samples indicates a significant role of gypsum dissolution and anthropogenic contamination of the GW. Factor analysis (FA) and hierarchical cluster analysis (HCA) revealed that the variability of hydrochemistry is mainly related to rock-water interaction, dissolution of carbonates and other lithological units as well as the influence of anthropogenic activities in the area. Overall, it was found that the GW quality is within the limits of human consumption. The higher concentration of a few chemicals indicates an increasing trend of industrial contamination of the GW. For sustainable development of the portable GW in Siwaliks, it is necessary to minimize the adverse impacts of the anthropogenic and industrial contamination on the GW resources through best management practices and prevent its further contamination to a level that could make GW unsuitable for human uses.

Massive land system changes impact water quality of the Jhelum River in Kashmir Himalaya.

The pristine aquatic ecosystems in the Himalayas are facing an ever increasing threat from various anthropogenic pressures which necessitate better understanding of the spatial and temporal variability of pollutants, their sources, and possible remedies. This study demonstrates the multi-disciplinary approach utilizing the multivariate statistical techniques, data from remote sensing, lab, and field-based observations for assessing the impact of massive land system changes on water quality of the river Jhelum. Land system changes over a period of 38 years have been quantified using multi-spectral satellite data to delineate the extent of different anthropogenically driven land use types that are the main non-point sources of pollution. Fifteen water quality parameters, at 12 sampling sites distributed uniformly along the length of the Jhelum, have been assessed to identify the possible sources of pollution. Our analysis indicated that 18% of the forested area has degraded into sparse forest or scrublands from 1972 to 2010, and the areas under croplands have decreased by 24% as people shifted from irrigation-intensive agriculture to orchard farming while as settlements showed a 397% increase during the observation period. One-way ANOVA revealed that all the water quality parameters had significant spatio-temporal differences (p < 0.01). Cluster analysis (CA) helped us to classify all the sampling sites into three groups. Factor analysis revealed that 91.84% of the total variance was mainly explained by five factors. Drastic changes in water quality of the Jhelum since the past three decades are manifested by increases in nitrate-nitrogen, TDS, and electric conductivity. The especially high levels of nitrogen (858 ± 405 µgL(-1)) and phosphorus (273 ± 18 µgL(-1)) in the Jhelum could be attributed to the reckless application of fertilizers, pesticides, and unplanned urbanization in the area.