Temporal Trends of Rainfall and Temperature over Two Sub-Divisions of Western Ghats

Abstract

Rainfall, along with temperature, is the major component of the hydrological cycle, and its spatiotemporal variability is essential from both scientific and practical perspectives. Due to the recent rise in temperatures all over the world, there are quite a number of conflicting trends in inter-annual variability in monsoon rainfall and temperature over the Western Ghats. The Western Ghats, next to the Himalayas, are the major watershed for the major south Indian rivers. In this study, an attempt has been made to understand the monthly, inter-seasonal, and inter-annual trends of rainfall and temperature over the two meteorological sub-divisions, namely Konkan Goa, and Coastal Karnataka. Monthly rainfall data for the period of 1977 to 2016 and temperature data from 1980 to 2016 are used. According to the analysis, maximum rainfall occurs during the summer, whereas the least rainfall occurs during the winter. The parametric, linear regression analysis and student t-test have been used to identify the existence of trends and to determine the changes in rainfall over the time period. An effort has been made to understand the relationship between ISMR (Indian Summer Monsoon Rainfall) and the ENSO phenomenon and to investigate whether the rainfall over WG is influenced by the ENSO phenomenon or not. Results reveal that although there is increased rainfall over Konkan and Goa, while declining over coastal Karnataka, the changes over both the sub-divisions were statistically significant. Considering rainfall in different seasons, there is a significant change during the monsoon season only. The study further reveals that there is increasing rainfall over Konkan and Goa and decreasing rainfall over Coastal Karnataka. Furthermore, no statistically significant trend (positive or negative) was evident in any of the seasons. All temperature trends were positive. The results of this study may prove useful in the preparation of climate change mitigation and adaptation strategies by understanding the patterns of rainfall over WG. Doi: 10.28991/HIJ-SP2022-03-03 Full Text: PDF