Enhanced Impacts of Indian Ocean Sea Surface Temperature on the Dry/Wet Variations Over Northwest China. Issue 11 (9th June 2022)

• Record Type: Journal Article
• Authors: Wang, Shanshan; Huang, Jianping; Huang, Gang; Luo, Fu; Ren, Yulong; He, Yongli
• Is Part Of: Journal of geophysical research. Volume 127:Issue 11(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-09
• Subjects: Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2022JD036533
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Most western Northwest China (WNWC) has experienced notable wetting in recent decades. Despite the widespread attention of scientific community, the causes of such climate shift are still not well‐understood. In this study, we find that the dominant mode of Indian Ocean sea surface temperature variability — Indian Ocean Basin mode (IOBM) plays a crucial role in the precipitation over WNWC. Nonetheless, such a close lagged relationship is unstable, and varies with Pacific Decadal Oscillation (PDO). When the PDO is in its warm phase, there is no robust lagged relationship between April‐June WNWC precipitation variations and January‐March IOBM. When the PDO is in its cold phase, the warm phase of the IOBM inspires a wavetrain across the Eurasian continent in the next April‐June, with an uncommon low pressure around Lake Baikal, thereby enhancing the westerlies and thus more moisture into the WNWC region. This enables the IOBM‐based statistical rainfall prediction scheme to estimate the precipitation in the WNWC region with some confidence. This remarkable contrast in the influence of IOBM between the two phases of the PDO highlights exciting new avenues for improving climate predictions over the WNWC. Plain Language Summary: The preceeding January‐March Indian Ocean Basin mode (IOBM) plays a crucial role on early summer precipitation in WNWC. But such high lagged‐relationship is not stable and varies with the Pacific Decadal Oscillation (PDO). When the PDO is in warm phase, there is no robust lagged‐relationship between April‐June WNWC precipitation variations and January‐March IOBM. While the PDO is in cold phase, the warm IOBM inspires a wavetrain across Eurasian in next April‐June, with an anomalous low pressure around Lake Baikal, thereby enhancing the westerlies and thus more moisture into WNWC region. So is the success of an IOBM‐based statistical rainfall prediction scheme on WNWC. Key Points: Indian Ocean Basin mode (IOBM) in preceding Jan‐Mar plays a crucial role on the Apr‐Jun precipitation in western Northwest China (WNWC) The close lagged relationship between IOBM and WNWC precipitation is unstable, and varies with Pacific Decadal Oscillation (PDO) The IOBM‐based statistical rainfall prediction scheme on WNWC has a high predictability during the cold phase of PDO