Future changes in sub‐seasonal variability of Indian winter precipitation

Abstract

AbstractThe winter precipitation over north India is due to the passage of synoptic systems known as Western Disturbances (WDs), which are embedded in large‐scale subtropical westerly jet (SWJ). The winter (December, January, February [DJF]) precipitation is vital to maintaining glaciers, sustenance of rivers, replenishing downstream springs, and agriculture. Any change in winter precipitation has a profound impact on agriculture, socio‐economic status, and water security of the nation. Thus, a close understanding of future changes in winter precipitation is critical to the country. The present study evaluates the future changes in sub‐seasonal variability of winter precipitation over north India using ICHEC‐EC‐EARTH‐SMHI‐RCA4 CORDEX‐SA experiment. Wet bias in precipitation and cold bias in temperature are observed in model. Almost all days in the winter season witnessed a shift towards a warm‐wet climate in a future warming scenario. A large amount of precipitation is observed in February in model as well as observation. A 10‐day interval scale spanning during DJF is considered to evaluate these changes. Future changes in winter precipitation are analysed under RCP4.5 and 8.5 scenarios. The percentage change in winter precipitation shows a maximum increase during the first fortnight of December and the first week of February. Precipitation intensity weakens during January. Two hundred hectopascal wind, 850 hPa wind, and moisture flux influence the increase in precipitation over the region.