发表机构
Ulsan National Institute of Science and Technology; Pohang University of Science and Technology; Yonsei University; Seoul National University（蔚山科学技术院; 浦项科技大学; 延世大学; 首尔大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过区域气候模式试验发现，2020年东亚夏季风极端降水并非由近期海表温度变暖驱动，暖SST会抑制副高扩张、减弱西南风，使EASM区域降水减少。
AI 中文摘要
本研究分析了近期海表温度（SST）变暖对2020年夏季异常东亚夏季风（EASM）降水的可能影响。通过区域气候模式试验，对比观测SST（暖SST）与去除22年SST趋势的冷SST，考察SST的动力和热力影响。结果显示，在暖SST存在时，低纬度地区降水增加，但EASM区域降水减少，这种偶极型降水变化模式与2020年夏季降水异常相反，表明2020年异常EASM降水不太可能由近期SST变暖驱动。暖SST会抑制西北太平洋副热带高压的扩张，减弱从南海吹向EASM区域的西南风；在大尺度大气环流方面，SST引起的风场变化会增强南海及菲律宾地区的局地沃克环流，以及EASM区域的局地哈得来环流。这些因素共同导致控制试验中EASM降水比冷SST试验减少，意味着在暖SST下，EASM区域因动力效应导致的降水减少可能超过热力效应带来的降水增加。
英文摘要
We analyzed the possible effects of recent sea surface temperature (SST) warming on the extraordinary East Asian summer monsoon (EASM) precipitation in 2020 summer. The dynamic and thermodynamic impacts of SST are examined by conducting regional climate model experiments with observed SST and cold SST where the 22-year SST trend is removed. In the presence of warm SST, precipitation increases in low latitudes but decreases in the EASM region. This dipolar precipitation change pattern opposes the precipitation anomalies in 2020 summer, indicating that the extraordinary 2020 EASM precipitation is not likely driven by recent SST warming. The warm SST suppresses the western North Pacific subtropical high expansion and weakens the southwesterly from the South China Sea toward the EASM region. In terms of large-scale atmospheric circulations, SST-induced wind changes strengthen the local Walker circulation in the South China Sea and the Philippines and the local Hadley circulation across the EASM region. These support the reduced EASM rainfall in the control experiment compared to the cold SST experiment and imply that the precipitation reduction by dynamical effects could exceed the precipitation increase by thermodynamic effects in the EASM region under warm SST.
CommentsPublished article with supplementary material appended. 14 pages: 9-page article (6 figures, 2 tables) and 5-page supplement (4 figures)
Journal refWeather and Climate Extremes 44, 100682 (2024)
DOI：10.1016/j.wace.2024.100682
