The Interdecadal Weakening of the Relationship Between Indian Ocean Sea Surface Temperature and Summer Precipitation in Central Asia

Abstract

Abstract The close relationship between the Indian Ocean Basin mode (IOBM) and summer precipitation in Central Asia (CA) has been documented in several studies. Nonetheless, this relationship has weakened since the 1990s and varies with the Atlantic Multi‐decadal Oscillation (AMO) phase transition. During the cold phase of the AMO (1970–1998), precipitation in CA was significantly positively correlated with the IOBM. Conversely, during the warm phase of the AMO (1999–2019), this correlation became insignificant. The decrease in the interannual variation in the IOBM resulted in the weakening of the atmospheric heat source variation over the North Indian continent and the south‐north movement of the subtropical westerly jet (SWJ). Along with the southerly SWJ, the IOBM exhibited only a weak positive correlation with precipitation in southern CA after the 1990s. This remarkable contrast in the impact of IOBM during different phases of the AMO offers intriguing possibilities for improving climate prediction in CA.

Keywords

• summer precipitation in Central Asia
• Indian Ocean sea surface temperature
• interdecadal variation of the impacts
• Atlantic Multi‐decadal Oscillation