Premium
Interplay Between Subseasonal Rainfall and Global Predictors in Modulating Interannual to Multidecadal Predictability of the ISMR
Author(s) -
Saha Subodh Kumar,
Konwar Mahen,
Pokhrel Samir,
Hazra Anupam,
Chaudhari Hemantkumar S.,
Rai Archana
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl091458
Subject(s) - predictability , climatology , environmental science , madden–julian oscillation , meteorology , geology , geography , convection , physics , quantum mechanics
Skillful prediction of the Indian Summer Monsoon Rainfall (ISMR) has been a bottleneck problem for more than 100 years. The low seasonal predictability is attributed primarily to the chaotic nature of the subseasonal variability. Here, we show that these subseasonal variabilities rather have significant predictable contributions to the seasonal ISMR, varying on the interannual to multidecadal timescale. The subseasonal modes being the building blocks of the monsoon, their net linear contribution may approximate the predictability limit of the ISMR. It is estimated that an average of about 76% ( R ∼ 0.87) of the ISMR variance predictable around the 1960s is decreased to about 64% ( R ∼ 0.79) in the recent past four decades. It is suggested that improvements in the simulation of subseasonal, particularly the synoptic variability will be key to further improve the seasonal ISMR forecast skill.