1750—2020年中国东北地区极端洪涝事件重建及驱动机制分析^*

Reconstruction and driving mechanism analysis of extreme flood events in Northeast China in 1750-2020

摘要

全球变暖背景下区域极端气候事件的发生规律与归因是气候变化研究的重点领域。利用历史文献记载和现代降水数据识别了公元1750—2020年中国东北地区发生概率10%的极端洪涝事件,并分析了其发生特征及驱动机制。结果表明: (1)1750—2020年共识别出东北极端洪涝事件29年(次),显示出波动变化的特征,1871—1930年是过去270年间东北极端洪涝发生频率最高的时段; (2)中国和东北地区的增温显著增大了东北极端洪涝的发生频率; (3)多百年尺度上东亚夏季风强度变化引起的季风雨带异常是导致东北极端洪涝事件发生的主要原因。在东亚夏季风偏强、雨带位置偏北的时段,极端洪涝事件的发生概率会显著上升; (4)在多百年尺度上,印太暖池和热带中、东太平洋海温异常通过影响东亚夏季风的位置和水汽输送,引发东北极端洪涝事件的发生。其中,La Niña事件发生时的水汽输送正异常对于极端洪涝的发生至关重要,也是东北极端洪涝事件可靠的预报因子。

Abstract

The study of incidence and attributes of regional extreme climatic events under the background of global change is a frontier of climate change research. This paper reconstructs the extreme flooding events with a probability of 10% in the Northeast China in 1750-2020 using historical documentary records and precipitation data,and then analyzes its incidence characteristics and driving mechanism. The main conclusions include: (1)In 1750-2020,29 extreme flooding events were identified in the Northeast China,exhibiting fluctuating patterns,with 1871 to 1930 marking the period of highest frequency over the past 270 years;(2)The global and regional warming significantly enhanced the frequency of extreme flooding events in the Northeast China;(3)The anomaly of the monsoon rain belt caused by the change of the East Asian summer monsoon is the direct cause of the occurrence of extreme flooding events in the Northeast China. Particularly,periods with a stronger monsoon and a northward shift in the rain belt significantly raise the likelihood of such events;(4)The Indo-Pacific warm pool and the sea surface temperature anomalies in the tropical central and eastern Pacific caused the incidence of extreme floods events in northeast China by affecting the location of the East Asian summer monsoon and the water vapor transport. The positive anomaly of water vapor transport at the time of La Niña years is crucial for the occurrence of extreme flooding,and is a reliable predictor of extreme flooding events in the Northeast China.

关键词

极端洪涝事件 / 全球变暖 / 东亚夏季风 / 海温异常

Key words

extreme floods events / global warming / East Asian summer monsoon / sea surface temperature anomaly

基金资助

*国家社科基金重大项目(编号: 22 & ZD223)资助