Role of land–atmosphere coupling in persistent extreme climate events in eastern China in summer 2022

In 2022, eastern China was wet in the north and dry in the south, and characterized particularly by a persistent compound extreme event with high temperatures, low precipitation, and dry soil during the warm season. Here, the authors investigate the evolution and possible underlying mechanism of this compound extreme event. From May to September in eastern China, there was a clear climate pattern transition from north to south, with noticeable intraseasonal changes in temperature, precipitation, and soil moisture. Different from the long-term climatology of 1940–2022, an enhanced influence of soil moisture on evaporation occurred in the Yangtze River Valley and Southeast China in 2022. These regions, however, are typically where evapotranspiration is limited by the land-surface available energy. Strong feedback between soil moisture and climate elements may have played a crucial role in the evolution and persistence of extreme climate events during the warm season in 2022.

摘要

2022年暖季, 中国东部地区遭受持续性高温, 少雨和土壤干旱的复合极端事件. 特征分析指出, 在研究时段内, 中国东部地区的气温, 降水和土壤湿度呈现明显的季节内变化和南北差异. 由1940–2022年的气候态可知, 长江流域和东南地区的土壤含水充足, 蒸散主要受限于陆面有效能量. 然而, 潜在机制研究指出, 2022年土壤湿度对蒸散的限制作用在上述区域异常偏强. 土壤湿度与气候要素之间的强反馈可能在2022年复合极端事件的演变和持续中发挥了关键作用.