• Sanjay K Jain

      Articles written in Journal of Earth System Science

    • Statistical analysis of long term spatial and temporal trends of temperature parameters over Sutlej river basin, India

      Dharmaveer Singh R D Glupta Sanjay K Jain

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      The annual and seasonal trend analysis of different surface temperature parameters (average, maximum, minimum and diurnal temperature range) has been done for historical (1971–2005) and future periods (2011–2099) in the middle catchment of Sutlej river basin, India. The future time series of temperature data has been generated through statistical downscaling from large scale predictors of CGCM3 and HadCM3 models under A2 scenario. Modified Mann–Kendall test and Cumulative Sum (CUSUM) chart have been used for detecting trend and sequential shift in time series of temperature parameters. The results of annual trend analysis for period of 1971–2005 show increasing as well as decreasing trends in average ($T_{\text{Mean}}$), maximum ($T_{\text{Max}}$), minimum ($T_{\text{Min}}$) temperature and increasing trends in Diurnal Temperature Range (DTR) at different stations. But the annual trend analysis of downscaled data has revealed statistically significant (95% confidence level) rising trends in $T_{\text{Mean}}$, $T_{\text{Max}}$, $T_{\text{Min}}$ and falling trend in DTR for the period 2011–2099. The decreasing trend in DTR is due to higher rate of increase in $T_{\text{Min}}$ compared to $T_{\text{Max}}$.

    • Decline in snowfall in response to temperature in Satluj basin, western Himalaya

      Riyaz Ahmad Mir Sanjay K Jain Arun K Saraf Ajanta Goswami

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      Snow is an essential resource present in the Himalaya. Therefore, monitoring of the snowfall changes over a time period is important for hydrological and climatological purposes. In this study, variability of snowfall from 1976–2008 were analysed and compared with variability in temperature ($T$max and $T$min) from 1984–2008 using simple linear regression analysis and Mann–Kendall test in the Satluj Basin. The annual, seasonal, and monthly analyses of average values of snowfall and temperature ($T$max and $T$min) have been carried out. The study also consists an analysis of average values of annual snowfall and temperature over six elevation zones (<1500 to >4000 m amsl). During the study, it was observed that the snowfall exhibited declining trends in the basin. The snowfall trends are more sensitive to the climate change below an elevation of 4000 m amsl. Over the elevation zones of 3000–3500 and 4000–4500 m amsl, positive trends of mean annual values of snowfall were observed that may be due to higher precipitation as snowfall at these higher elevations. Although, both negative and positive snowfall trends were statistically insignificant, however, if this decreasing trend in snowfall continues, it may result in significant however, changes in future. Furthermore, the $T$min is also increasing with statistically significant positive trend at 95% confidence level for November, winter season, annually as well as for the elevation zones of 2500–3000, 3000–3500, and 3500–4000 m amsl. There are dominantly increasing trends in $T$max with negative trends for February, June–September, monsoon season, and for elevation zone <1500 m amls. It is important to state that in the present basin, during the months of winter season, most of the precipitation is produced as snowfall by the westerly weather disturbances. Thus, the declining nature in snowfall is concurrent with the positive trends in temperature particularly $T$min, therefore, reflecting that the positive trends in $T$min may be the dominant factor besides $T$max in controlling the snowfall trends. The snowfall data were also compared with SCA and this showed a highly positive correlation of 0.95% which validates the utilisation of time series of snowfall for the trend analysis.

    • Statistical downscaling and projection of future temperature and precipitation change in middle catchment of Sutlej River Basin, India

      Dharmaveer Singh Sanjay K Jain R D Gupta

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      Ensembles of two Global Climate Models (GCMs), CGCM3 and HadCM3, are used to project future maximum temperature ($T$Max), minimum temperature ($T$Min) and precipitation in a part of Sutlej River Basin, northwestern Himalayan region, India. Large scale atmospheric variables of CGCM3 and HadCM3 under different emission scenarios and the National Centre for Environmental Prediction/National Centre for Atmospheric Research reanalysis datasets are downscaled using Statistical Downscaling Model (SDSM). Variability and changes in $T$Max, $T$Min and precipitation under scenarios A1B and A2 of CGCM3 model and A2 and B2 of HadCM3 model are presented for future periods: 2020s, 2050s and 2080s. The study reveals rise in annual average $T$Max, $T$Min and precipitation under scenarios A1B and A2 for CGCM3 model as well as under A2 and B2 scenarios for HadCM3 model in 2020s, 2050s and 2080s. Increase in mean monthly $T$Min is also observed for all months of the year under all scenarios of both the models. This is followed by decrease in $T$Max during June, July August and September. However, the model projects rise in precipitation in months of July, August and September under A1B and A2 scenarios of CGCM3 model and A2 and B2 of HadCM3 model for future periods.

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