Impact of ENSO, Global Warming, and Land Surface Elevation on Extreme Precipitation in India

Abstract

The linkages of precipitation extremes with large-scale global climatic phenomenon such as global warming, the El Niño–Southern Oscillation (ENSO), and the land surface elevation were explored across India. Temporally, the annual average precipitation on rainy days (PRCPTOT) was found to exhibit decreasing trends for a larger part of India; however, most of the extreme precipitation indexes (EPIs) had increasing trends (except cumulative wet days) for a larger part of India. In addition, most EPIs exhibited a positive and statistically significant correlation of high magnitude with the land surface elevation for the elevation band above 1,500 m. Parts of northern, north-central, and northeastern India had a decrease in precipitation extremes with an increase in the global temperature, whereas an increase in EPIs per degree Celsius increase in the average global temperature was found for the eastern coastal regions and most parts of southern India. A spatial heterogeneity of teleconnections between precipitation extremes and the large-scale climatic indexes was found. The Southern Oscillation Index (SOI) and the Northern Oscillation Index (NOI) had similar spatial patterns of correlation with the analyzed EPIs. Most EPIs except consecutive dry days (CDD) and consecutive wet days (CWD) had higher positive association with extreme events in the contiguous region of Rajasthan, Madhya Pradesh, Uttar Pradesh, and West Bengal. The NINO3 and NINO3.4 sea surface temperature (SST) indexes had patches of higher correlation over south-central India. Moreover, teleconnections of ENSO with CDD were strongest with stronger correlation values and higher percentage of area with significant correlation compared with other indexes.