Impact of Southern Oscillation and Indian Ocean Dipole on rainfall variability over India: trends and interlinkages during 1871–2017

Todmal, Rahul S. and Koteswara Rao, Kundeti and Ingle, Sandip and Korade, Mahendra S. (2022) Impact of Southern Oscillation and Indian Ocean Dipole on rainfall variability over India: trends and interlinkages during 1871–2017. Meteorology and Atmospheric Physics, 134 (6). ISSN 0177-7971

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Abstract

This investigation highlights changes and various facets of inter-connections between rainfall over India and its prominent drivers such as Southern Oscillation (SO) and Indian Ocean Dipole (IOD). As the monsoon rainfall over majority of sub-divisions from Northeast India (NEI) and Central Northeast India regions (53% area) exhibits declining trend, which are reflected in annual rainfall (AR) as well. On the contrary, during the post-1971 period, the post-monsoon rainfall is observed to be decreasing over all the regions, except Peninsular India (PI). Moreover, the contradictory trends in monsoon and post-monsoon rainfall are registered over the PI, Northwest India (NWI) and West Central India regions. The significant increase in IOD (warming over Arabian Sea) is observed with a swift rise after 1960. Under changing climate conditions, a decline in rainfall and an increase in IOD Index (IODI) may aggravate the water scarcity challenge in semi-arid regions. More than 70% of sub-divisions has positive and negative relationship of SO with monsoon and post-monsoon rainfall, respectively. This contradiction is particularly observed over PI Region, which led to weaker SO-AR relationship. As compared to SO-rainfall relationship, almost opposite picture is observed in the case of sub-divisional and regional rainfall (monsoon and post-monsoon)-IOD relationship. The SO-AR relationship displays epochs of weak (1941–1970 and 1995–2016) and strong (1871–1941 and 1970–1995) connections. Interestingly, the strengthening of the IOD-AR relationship is responsible for the weakening of SO-AR and vice-versa, especially during the post-1970 period. It is evident that the strengthening of SO-IOD relationship results in good rainfall over India, as it shows a significant positive relationship and explains about 6 to 38% variations in regional and All-India annual rainfall.

Item Type:	Article
Authors:	Todmal, Rahul S. and Koteswara Rao, Kundeti and Ingle, Sandip and Korade, Mahendra S.
Document Language:	Language English
Subjects:	Natural Sciences > Earth sciences > Geology, hydrology, meteorology Natural Sciences > Earth sciences > Geology, hydrology, meteorology > Climatology and weather
Divisions:	Azim Premji University - Bengaluru > Research Centre > Centre for Climate Change and Sustainability
Full Text Status:	Public
URI:	http://publications.azimpremjiuniversity.edu.in/id/eprint/7098
Publisher URL:	https://doi.org/10.1007/s00703-022-00936-z

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