Elevation-dependent precipitation in the Indian Himalayan Region

Abstract

The linkage between elevation and precipitation in the mountainous regions across the world including the Indian Himalayan Region (IHR) is very complex. Various meteorological parameters, viz., albedo, shortwave and longwave radiations, humidity, and mass-energy balance, play a major role in the physical processes occurring in these places. The present study examines the changes in precipitation across the IHR. The precipitation patterns act differently from east to west, and north to south due to the varying elevation. The study employed high-resolution observational gridded precipitation analyses (CHELSA) for the period 1980–2018 and the GTOPO 30 DEM for the analyses. The two major precipitating seasons over the IHR such as the monsoon (JJAS) and winter (DJF) precipitation are considered. Characteristics of the precipitation with altitude over subregions of IHR such as Shivalik’s IHR (SH), Lesser IHR (LH) and Higher IHR (HH) are presented. In addition, longitudinal variations over western IHR (WH), central IHR (CH) and eastern IHR (EH) are presented. Further, a non-parametric Mann–Kendall method has been used for trend analysis of precipitation, while the Pettitt test is used for change point detection. A positive precipitation trend is observed over HH and the western part of SH whereas a negative trend is found over the eastern part of SH. In most of the regions in SH, change in mean precipitation is observed during the recent time (1999–2018). However, HH located in the east of CH and west of EH shows a change in mean precipitation quite early (1979–1998).