Changes in extreme precipitation events over the Hindu Kush Himalayan region during 1961–2012

Abstract

Based on a new multi-source dataset (GLDP-V1.0) recently developed in China Meteorological Administration, we employed precipitation indices including percentile-based indices of light (below the 50th percentile), moderate (between the 50th and 90th percentile), and intense (above the 90th percentile) precipitation, maximum 1-day, 3-day, and 5-day precipitation amounts (RX1DAY, RX3DAY, and RX5DAY, respectively), and consecutive wet and dry days (CWDs and CDDs) to analyze variations in extreme precipitation events in the Hindu Kush Himalayan (HKH) during 1961–2012. The main results are presented as follows. Firstly, there was a significant increase in the amount of light and moderate precipitation and number of associated days over various parts of India and northern Tibetan Plateau during 1961–2012; but the intensity of light precipitation decreased significantly in the Hindu Kush and central India, and the regional average intensity also decreased. Secondly, the amount and frequency of intense precipitation mostly increased significantly on the Tibetan Plateau, but there was a heterogeneous change over the remainder of the HKH, and regional average annual intense precipitation amount and frequency significantly increased over the HKH during 1961–2012. Thirdly, regional average RX1DAY, RX3DAY, and RX5DAY all showed significant upward trends during 1961–2012, and there was a significant increased tendency of consecutive wet-days in most parts of the study region; however, trends of consecutive dry-days were mostly opposite to those of consecutive wet-days, with regional averaged consecutive dry-days showing no noticeable trend.