Dominant patterns of seasonal precipitation variability in association with hydrological extremes over the North-west Himalayas.

Abstract

The association of hydrological extremes to a specific season provides a perception that the extraction of dominant patterns of seasonal precipitation variability can be useful to identify the hidden pathways of oceanic-atmospheric mechanisms behind these extremes. The native objective of this study is to find the empirical orthogonal function (EOF) patterns of seasonal precipitation using daily gridded precipitation data over the study region. The spatio-temporal variability of monthly precipitation reveals that over the entire study region precipitation occurs throughout the year with less in November and more in August. We found two dominant EOF patterns of precipitation for summer (JJA) and fall (SON) that have captured all the observed floods from 1901 to 2018. The PC of the dominant pattern of summer season precipitation variability (EOF3) shows a significant negative correlation with the El Niño-Southern Oscillation (ENSO) index (Niño 3.4) depicting that global teleconnection influences the variability of JJA precipitation over this region, while the PC of the dominant pattern of SON season precipitation variability (EOF2) has captured the 2014 deadliest flood which is positively correlated with ENSO at < 5% significance level and can be considered a positive domain response of SON precipitation to the variability of SST over the tropical Pacific Ocean (ENSO). The study will find its applicability in predicting the response of hydrological extremes to global teleconnections and hence can be applied in disaster mitigation and decision-making for the water resource management over the study region.