Regional perspectives in Eurasian snow - Indian monsoon relationship: An observational study

• Published in: Polar Science
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Eurasian snow; Indian summer monsoon; Pacific SST; snow-monsoon relationship; Pacific; Indian; North Atlantic; North Atlantic oscillation; Polar Science
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=16890; http://id.nii.ac.jp/1291/00016759/

Relationship between Indian summer monsoon rainfall and Eurasian snow in the preceding seasons is studied extensively. However, the spatial structures of this snow-monsoon relation have rarely been investigated. The present study is aimed at diagnosing nature of observed linkage between Eurasian winter snow and spatial distribution of following summer monsoon rainfall over India. Eurasian snow association with spatial distribution of rainfall over India features a tri-polar pattern of significant negative-positive-negative correlations over the northern, east-central and peninsular regions of India respectively. The physical mechanism underlying snow-monsoon connection is envisaged through two pathways. One of the channels is through Eurasian winter snow directly affecting the monsoon by modulating large scale circulation, while the other way is indirectly through Tropical Eastern Pacific (TEP) Sea Surface Temperatures (SSTs). Enhanced Eurasian wintertime snow is associated with warm TEP SSTs from preceding winter through to the following summer, leading to anomalous large scale zonal circulation during summer monsoon season, thereby affecting rainfall over India. The spatial facets of snow-monsoon relationship remain unaltered by Indian Ocean Dipole and North Atlantic Oscillation modes.