Hamtah and Chhota Shigri are two nearby,well monitored glaciers of western Himalaya,lying in the same climatic zone and driven by the same climatic conditions.In this study,topographical characteristics of both the gl...Hamtah and Chhota Shigri are two nearby,well monitored glaciers of western Himalaya,lying in the same climatic zone and driven by the same climatic conditions.In this study,topographical characteristics of both the glacier have been explored to understand the role of topography in controlling the glacier response.Further,their topographical characteristics and possible response towards climatic variations have been compared with each other and also with that of the other glaciers in the basin to find out the suitability of these two glaciers to be considered as representative of the region.Multi sensor and multi temporal remote sensing data have been used to carry out to fulfill the objectives.It is found that being in the same climatic zone,the mean accumulation area ratio of Chhota Shigri is 54%and Hamtah is 11%between 1980 and 2014.In comparison to Hamtah,Chhota Shigri glacier has a small upslope area,low compactness ratio indicating the ability of the glacier to receive direct precipitation and solar radiation.The analysis revealed that the Chhota Shigri glacier has a closer resemblance with the other glaciers in the region than Hamtah glacier.Also,the topographical settings of Chhota Shigri glacier are suitable for recording and reflecting year-to-year climatic variations.展开更多
Present study shows suspended sediment dynamics in the meltwater of Chhota Shigri glacier,Himachal Pradesh,India for different melt seasons during the period 2011-2014.Maximum suspended sediment concentration in the m...Present study shows suspended sediment dynamics in the meltwater of Chhota Shigri glacier,Himachal Pradesh,India for different melt seasons during the period 2011-2014.Maximum suspended sediment concentration in the meltwater was found during the month of July 2011,2012 and 2014 constituting to 55.2%,48.3% and 46.9%,respectively.Whereas in 2013,maximum suspended sediment concentration was observed in August accounting for46.1% of the total.On the other hand,maximum suspended sediment load was monitored in the month of July 2011,2012 and 2014 constituting 59.5%,63% and 55.7% of the total,respectively.Whereas in2013,maximum suspended sediment load was observed in the month of August accounting for 49.8% of the total suspended sediment load.Annual distribution of suspended sediment concentration(SSC)and suspended sediment load(SSL)in the Chhota Shigri glacier shows higher value of SSC and SSL during the study period 2012 and 2013,which may be due to the presence of high glacial runoff and negative mass balance of the studied area during these time periods.Marked diurnal variation has been observed in the SSC of meltwater.Strong correlation was observed between SSC and SSL with discharge.On the other hand,SSC and SSL also showed strong exponential correlation with air temperature of the studied area.Sediment yield from the catchment of Chhota Shigri glacier is high during the peak melt season(July and August)and low during the late melt season(September and October).The average value of erosion rate for Chhota Shigri glacier basin during the study period 2011-2014 was calculated to be 1.1mm/yr,which is lower than the average erosion rate of other Himalayan glaciers such as Rakiot,Chorabari and Gangotri glaciers,which may be caused by its geological setting containing high erosion resistant rocks such as granite,granite gneiss and porphyritic granite.展开更多
The hydro-geochemistry and isotopic variations in groundwater,coupled with sediment geochemistry,were investigated in the Middle Gangetic Plain,India,to better understand the aquifer dynamics that influence the arseni...The hydro-geochemistry and isotopic variations in groundwater,coupled with sediment geochemistry,were investigated in the Middle Gangetic Plain,India,to better understand the aquifer dynamics that influence the arsenic(As)evolution and mobilization.Eighty-four groundwater samples,thirteen River water samples,and two sediment cores(33 mbgl)were studied.The samples were analyzed for major ions and trace metals,including As and stable isotopic variability(δ^(2)H,δ^(18)O,andδ^(13)C).The study area was categorized into older and younger alluvium based on existing geomorphological differences.Younger alluvium exhibits higher As enrichment in sediment and groundwater,ranging of 2.59–31.52 mg/kg and bdl to 0.62 mg/L.Groundwater samples were thermodynamically more stable with As(OH)_(3)species ranging from 88.5%to 91.4%and FeOOH from 69%to 81%,respectively.PHREEQC and mineralogical analysis suggested goethite and siderite act as a source and sink for As.However,statistical analysis suggested reductive dissolution as the primary mechanism for As mobilization in the study area.Spatio-temporal analysis revealed elevated concentrations of As in the central and northeastern regions of the study area.Stable isotope(δ^(2)H andδ^(18)O)analysis inferred active recharge conditions primarily driven by precipitation.The depleted d-excess value and enrichedδ^(18)O in the groundwater of younger alluvium indicate the effect of groundwater recharge with significant evaporation enrichment.Groundwater recharge potentially decreased the quantity of arsenic in groundwater,whereas evaporation enrichment increased it.Rainwater infiltration during recharge introduces oxygenated water into the aquifer,leading to changes in the redox conditions and facilitating biogeochemical reactions.The carbon isotope(δ^(13)C)results suggest that high microbial activity in younger alluvium promotes As leaching from sediment into the groundwater.展开更多
文摘Hamtah and Chhota Shigri are two nearby,well monitored glaciers of western Himalaya,lying in the same climatic zone and driven by the same climatic conditions.In this study,topographical characteristics of both the glacier have been explored to understand the role of topography in controlling the glacier response.Further,their topographical characteristics and possible response towards climatic variations have been compared with each other and also with that of the other glaciers in the basin to find out the suitability of these two glaciers to be considered as representative of the region.Multi sensor and multi temporal remote sensing data have been used to carry out to fulfill the objectives.It is found that being in the same climatic zone,the mean accumulation area ratio of Chhota Shigri is 54%and Hamtah is 11%between 1980 and 2014.In comparison to Hamtah,Chhota Shigri glacier has a small upslope area,low compactness ratio indicating the ability of the glacier to receive direct precipitation and solar radiation.The analysis revealed that the Chhota Shigri glacier has a closer resemblance with the other glaciers in the region than Hamtah glacier.Also,the topographical settings of Chhota Shigri glacier are suitable for recording and reflecting year-to-year climatic variations.
基金DST (Department of Science and Technology), Govt. of India for financial support for this research projectSERB, DST, Government of India for awarding NPDF (National Postdoctoral Fellowship) (Reference No. PDF/2016/000286)the partial funding given to this project by GLACINDIA, CHARIS, INDICE, IFCPAR/CEFIPRA and SAC
文摘Present study shows suspended sediment dynamics in the meltwater of Chhota Shigri glacier,Himachal Pradesh,India for different melt seasons during the period 2011-2014.Maximum suspended sediment concentration in the meltwater was found during the month of July 2011,2012 and 2014 constituting to 55.2%,48.3% and 46.9%,respectively.Whereas in 2013,maximum suspended sediment concentration was observed in August accounting for46.1% of the total.On the other hand,maximum suspended sediment load was monitored in the month of July 2011,2012 and 2014 constituting 59.5%,63% and 55.7% of the total,respectively.Whereas in2013,maximum suspended sediment load was observed in the month of August accounting for 49.8% of the total suspended sediment load.Annual distribution of suspended sediment concentration(SSC)and suspended sediment load(SSL)in the Chhota Shigri glacier shows higher value of SSC and SSL during the study period 2012 and 2013,which may be due to the presence of high glacial runoff and negative mass balance of the studied area during these time periods.Marked diurnal variation has been observed in the SSC of meltwater.Strong correlation was observed between SSC and SSL with discharge.On the other hand,SSC and SSL also showed strong exponential correlation with air temperature of the studied area.Sediment yield from the catchment of Chhota Shigri glacier is high during the peak melt season(July and August)and low during the late melt season(September and October).The average value of erosion rate for Chhota Shigri glacier basin during the study period 2011-2014 was calculated to be 1.1mm/yr,which is lower than the average erosion rate of other Himalayan glaciers such as Rakiot,Chorabari and Gangotri glaciers,which may be caused by its geological setting containing high erosion resistant rocks such as granite,granite gneiss and porphyritic granite.
基金funded by the Ministry of Earth Sciences(MoES)under the Geochronology project[MoES/P.O.(Seismic)8(09)-Geochron/2012]。
文摘The hydro-geochemistry and isotopic variations in groundwater,coupled with sediment geochemistry,were investigated in the Middle Gangetic Plain,India,to better understand the aquifer dynamics that influence the arsenic(As)evolution and mobilization.Eighty-four groundwater samples,thirteen River water samples,and two sediment cores(33 mbgl)were studied.The samples were analyzed for major ions and trace metals,including As and stable isotopic variability(δ^(2)H,δ^(18)O,andδ^(13)C).The study area was categorized into older and younger alluvium based on existing geomorphological differences.Younger alluvium exhibits higher As enrichment in sediment and groundwater,ranging of 2.59–31.52 mg/kg and bdl to 0.62 mg/L.Groundwater samples were thermodynamically more stable with As(OH)_(3)species ranging from 88.5%to 91.4%and FeOOH from 69%to 81%,respectively.PHREEQC and mineralogical analysis suggested goethite and siderite act as a source and sink for As.However,statistical analysis suggested reductive dissolution as the primary mechanism for As mobilization in the study area.Spatio-temporal analysis revealed elevated concentrations of As in the central and northeastern regions of the study area.Stable isotope(δ^(2)H andδ^(18)O)analysis inferred active recharge conditions primarily driven by precipitation.The depleted d-excess value and enrichedδ^(18)O in the groundwater of younger alluvium indicate the effect of groundwater recharge with significant evaporation enrichment.Groundwater recharge potentially decreased the quantity of arsenic in groundwater,whereas evaporation enrichment increased it.Rainwater infiltration during recharge introduces oxygenated water into the aquifer,leading to changes in the redox conditions and facilitating biogeochemical reactions.The carbon isotope(δ^(13)C)results suggest that high microbial activity in younger alluvium promotes As leaching from sediment into the groundwater.
