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Asymmetry in the Indian Summer Monsoon Rainfall response to two types of La Niña evolution
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  • Satyaban B. Ratna,
  • Tanu Sharma,
  • Arti Bandgar,
  • O. P. Sreejith,
  • Sivananda Pai,
  • M. Rajeevan,
  • K S Hosalikar,
  • M Mohapatra
Satyaban B. Ratna
India Meteorological Department

Corresponding Author:[email protected]

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Tanu Sharma
India Meteorological Department
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Arti Bandgar
India Meteorological Department
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O. P. Sreejith
India Meteorological Department
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Sivananda Pai
office of Climate Reserach and Services
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M. Rajeevan
Ministry of Earth Sciences
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K S Hosalikar
India Meteorological Department
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M Mohapatra
India Meteorological Department
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Abstract

This study attempts to understand the asymmetry in the Indian Summer Monsoon Rainfall (ISMR) response to two types of La Niña whether they evolved from El Niño or La Niña in the previous boreal winter season. It was seen that nine La Niña years during the monsoon season were preceded by El Niño (hereafter ELLA) whereas eight were preceded by La Niña (hereafter LALA) during the period 1961-2021. India received more rainfall during the ELLA years as compared to the LALA years, linked to the difference in the Sea Surface Temperature (SST) and large-scale atmospheric circulation anomalies over the tropical Pacific and Indian oceans. Based on the strength and patterns of the cold SST anomaly and shift in the Walker circulation over the equatorial Pacific Ocean, the enhanced (weakened) convection over the Indian landmass during the ELLA (LALA) years, contributed to more (less) rainfall over India.
03 Mar 2023Submitted to ESS Open Archive
06 Mar 2023Published in ESS Open Archive