Reexamining the Indian Summer Monsoon Rainfall–ENSO Relationship From Its Recovery in the 21^st Century: Role of the Indian Ocean SST Anomaly Associated With Types of ENSO Evolution

Abstract

Over the 21 st century, the ISMR-ENSO relationship has strengthened and almost recovered to its pre-1980 level. 2. On interannual and decadal timescales, the tropical Indian Ocean warming (cooling) indicates a stronger (weaker) ISMR-ENSO relationship. 3. The Indian Ocean basin-wide SST anomaly in summer is related to different types of temporal evolution of ENSO.

Effect of Interdecadal Variation in Southern Indian Ocean SST on the Relationship Between ENSO and Summer Precipitation in the Asian‐Pacific Monsoon Region

“…Previous studies have shown that the relationship between ENSO and the Asian climate can be modulated by Pacific, Atlantic and Indian Ocean signals, such as the Atlantic Multidecadal Oscillation (AMO), tropical Indian Ocean SST, and Pacific Multidecadal Oscillation (Chen et al, 2018;Xu et al, 2021;Yu et al, 2021). Xu et al (2021) pointed out that in the negative phase of the AMO, the ENSO-East Asian early summer monsoon relationship is strong; however, in the positive phase, the relationship disappears.…”

“…In addition, the relationship between Indian summer monsoon rainfall and ENSO exhibits interdecadal variation. After the 1970s, the relationship of the Indian summer monsoon with the ENSO weakened but has recovered since 2001 (Krishna Kumar et al, 1999;Yu et al, 2021). Yu et al (2021) pointed out that this linkage is intimately related to the summer tropical Indian Ocean SST, with a stronger (weaker) relationship present under tropical Indian Ocean warming (cooling).…”

Editorial: The Asian Monsoon

“…Most of them focus on the summer monsoon and discuss the role of air-sea interactions in the monsoon variability on the interannual timescale. The El Nino-Southern Oscillation (ENSO) is an essential driver for the Indian summer monsoon (ISM) precipitation (Ju and Slingo, 1995;Gadgil, 2003), and its relationship with the ISM underwent decadal weakening in the late 1970s (Kumar et al, 1999) and recovered recently (Yang and Huang, 2021;Yu et al, 2021). Bódai et al revisit the unstable ENSO-ISM relationship and the underlying mechanism with the help of large-ensemble simulations and discuss its nonlinearity and nonergodicity.…”

Modulation of Indian Summer Monsoon Rainfall response to ENSO in the recent decades and its large-scale dynamics

“…ISMR is well known to have a negative correlation with the simultaneous central-equatorial Paci c (Niño 3.4 region i.e. area over 5 °S-5 °N and 170 °W-120 °W) Sea Surface Temperature (SST) anomalies, as the development of the La Niña (El Niño) event can enhance (weaken) the ISMR through the displacement of the Walker circulation (Sikka, 1980;Webster and Yang, 1992;Yu et al, 2021). It has been postulated that during warm phase (El Niño) of ENSO, the eastward shift of the Walker cell results in the enhancement of the lower-level convergence over the equatorial Indian ocean, which drives an anomalous Hadley cell with a descending branch over the Indian landmass causing weaker than normal monsoon and below normal rainfall over the Indian subcontinent (Goswami, 1998;Seetha et al, 2020).…”