Unraveling Impact of North Indian Ocean on Tibetan Plateau Summer Precipitation From Its Pattern Diversity

Abstract

The sea surface temperature anomaly (SSTA) in the North Indian Ocean (NIO) region associated with Indian Ocean Basin Mode (IOBM) is well-known as a key factor in impacting the Tibetan Plateau summer precipitation (TPSP). However, either the commonly used IOBM index or the basin-mean index of SSTA in the NIO region captures only a small portion of TPSP variability, making it underrated in indicating the TPSP. In this study, we demonstrate a significant and predictable relationship between the NIO SSTA and TPSP, when further considering the NIO pattern diversity. This relationship can be depicted by two physics-based indices accounting for the diverse NIO patterns, which can effectively capture their distinct spatial features and associated impacts on the TPSP. Such an extended diversity view of NIO provides potential predictability of the TPSP.