Spatial extent of concurrent extremes over India and its teleconnection
to climate indices
Abstract
Concurrent temperature and precipitation extremes during Indian summer
monsoon generally have signicant effects on agriculture, society and
ecosystems. Due to climate change, frequency and spatial extent of
concurrent extremes have changed, and there is a need to advance our
understanding in this domain. Quantication of individual extremes
(temperature and precipitation) during the summer monsoon season and its
teleconnections to climate indices have been studied comprehensively.
But, less attention is devoted to the quantication of concurrent
extremes and its teleconnections to climate indices. In this study,
concurrent extremes (dry/hot and wet/cold) based on mean monthly
temperature and total monthly precipitation during the Indian summer
season from 1951 to 2019 over the Indian mainland are investigated.
Next, the study uses wavelet coherence analysis to unravel the
teleconnections of the spatial extent of concurrent extremes to climate
indices (Nino 3.4, WEIO SST and SEEIO SST). Results show that the
frequency of wet/hot concurrent extremes has increased signicantly,
while the frequency of wet/cold concurrent has decreased for the time
window 1985 to 2019 relative to 1951-1984. Also, a statistically
signicant increase (decrease) in the spatial extent exists in concurrent
dry/hot (wet/cold) extremes during the July, August and September
months. The ndings of this study could advance our understanding of
changes in concurrent extremes during the Indian summer monsoon due to
climate change.