Hydrological modeling to simulate stream flow under changing climate conditions in Jhelum catchment, western Himalaya

The changes in maximum and minimum temperature, potential evapotranspiration (PET) and precipitation of future bi-decades, i.e., 2020-2040, 2040-2060, 2060-2080 and 2080-2100 with the corresponding observed baseline datasets (1991-2016) were analyzed for the Jhelum catchment, western Himalayas, using Representative Concentration Pathways (RCPs) 4.5 and 8.5 of Regional Climate Model version 4 (RegCM4). Maximum and minimum temperature projections indicated a rise of 1.18 degrees C to 3.29 degrees C and 1.30 degrees C to 2.92 degrees C under RCP 4.5, and 3.58 degrees C to 7.22 degrees C and 3.38 degrees C to 6.92 degrees C under RCP 8.5, respectively, relative to the baseline period. Precipitation shows a decline of 14.34 mm, 9.60 mm, 4.19 mm and 15.62 mm under RCP 4.5, whereas RCP 8.5 shows an incline of 7.45 mm, 12.37 mm, 22.19 mm, and 6.86 mm during 2040s, 2060s, 2080s and 2100s, respectively, as compared to the baseline period. For the months of May to September, both the RCPs indicated a decrease in PET values. Snow cover area (SCA) computed from MODIS Snow Cover 8-Day L3 Global 500 m Grid (MOD10A2) datasets over a period of 2002 to 2016, depicted a negative relationship with river runoff, with strong negative coefficient of -0.88 for the year 2012. The impact of these climate change projections were computed on the hydrology of Jhelum catchment using Variable Infiltration Capacity (VIC) model. Comparison among the future bi-decades, show increasing trend of precipitation under both the RCPs from 2020 to 2080, then slightly decreases during 2080-2100. Similar trend was exhibited by runoff projections, viz. runoff increases till 2080 and decreases afterwards under both the RCP emission scenarios. Temperature and runoff shows relatively higher values under RCP 8.5, than RCP 4.5. Overall, results indicated a strong influence of precipitation projections on runoff of Jhelum catchment.

Automated summary

The study analyzed the changes in temperature, precipitation, potential evapotranspiration, and snow cover area in the Jhelum catchment area in the Western Himalayas for future bi-decades using different emission scenarios. The results showed an overall increase in temperature, with a decrease in precipitation under RCP 4.5 and an increase under RCP 8.5. The snow cover area exhibited a negative relationship with river runoff.