Abstract:

In order to find out the change rules of extreme climatic events in China and its different regions, the extreme weather and climate events ( short for “extreme events”) such as extreme high temperature, extreme low temperature, extreme precipitation, extreme drought and extreme typhoon were analyzed by using the daily observation data of 2 254 meteorological observation stations in China (except Hong Kong, Macao and Taiwan) over the past 60 years and in 2023. The results show that since 1961, the overall trend of extreme events in China has been decreasing, and the trend of decreasing from 1970 to the early 1990s was obvious, and the trend of increasing since the late 1990s was obvious. The extreme high temperature events showed a significant increasing trend, which was more obvious after entering the 21st century. Extreme low temperature events showed a decreasing trend. Extreme precipitation events showed an increasing trend in general. The extreme drought events showed a decreasing trend with obvious stage characteristics. In recent 60 years, the extreme wind speed and precipitation events affected by typhoons showed a decreasing trend, which was mainly caused by the decrease of extreme typhoon wind speed events, while the extreme typhoon precipitation events showed a slow increasing trend. The extreme events occurred frequently in 2023, with an average occurrence of 139 times per station, which was 28.3% more than the annual average from 1991 to 2020. Extreme high temperature events were 79 times per station, which was the most since 1961 and 76.8% more than normal average. Extreme low temperature events were 20 times per station, which was 23.8% less than normal average. Extreme precipitation events were 14 times per station, and extreme drought events were 26 times per station, both were close to the annual average values. Extreme typhoon events occurred 0.41 times on average in China, which was slightly more than normal average, and it was mainly dominated by extreme typhoon precipitation events. In 2023, extreme events mainly occurred in Southwest China, western areas of the south of the Yangtze River, western South China, central and northern Northwest China, western Inner Mongolia, and Beijing-Tianjin-Hebei and other places. Especially in eastern Sichuan, southern Guizhou, western Gansu, western Inner Mongolia, the extreme events were more than 200 times per station. Through the analysis of different types of extreme events in 2023, it was found that the increase of extreme events was mainly caused by more extreme high temperature and extreme drought events. According to the analysis of multiple extreme events composite risk index (MXCI), high risk areas were mainly located in the southern region of the mainland of China, especially in the southeast coastal region. In the past 60 years, the increase of MXCI was mainly located in the transition zone from Southwest China to south Northeast China. High risk areas in 2023 mainly appeared in the Southwest China and the central and northern parts of Northwest China. Through the study of the change rules of extreme events in different regions of China, it was helpful to improve the ability of disaster prevention and reduction and effectively cope with the risk of climate change.

Key words: the recent 60 years, 2023, China, regions, extreme weather and climate events

摘要：

对不同区域极端天气气候事件变化规律的研究，有助于提高我国防灾减灾能力和有效应对气候变化风险。利用我国均一化的2 254个气象观测站逐日观测资料，分析评估近60 a和2023年我国及其各区域（未包含港澳台地区）发生的极端高温、极端低温、极端干旱、极端降水和极端台风等极端天气气候事件（简称“极端事件”）的时空特征。结果表明，1961年以来，我国极端事件总体呈下降趋势，其中1970—1990年代初下降趋势明显，1990年代后期以来增加趋势明显；极端高温事件呈显著增加趋势，进入21世纪后增加趋势更加明显；极端低温事件呈减少趋势；极端降水事件总体呈增加趋势；极端干旱事件呈下降趋势且阶段性特征明显；近60 a来受台风影响出现的极端风速和降水事件呈减少趋势，主要由极端台风风速事件减少造成，而极端台风降水事件呈缓慢上升趋势。2023年我国极端事件每站平均发生139次，比气候平均值偏多28.3%。其中，极端高温事件平均发生79次（偏多76.8%），为1961年以来历史最多年；极端低温事件平均发生20次（偏少23.8%）；极端降水事件平均发生14次，极端干旱事件平均发生26次，都接近常年平均值；极端台风事件平均发生0.41次（偏多4.2%），主要以极端台风降水事件为主。2023年极端事件主要出现在西南地区、江南西部、华南西部、西北地区中部和北部、内蒙西部、京津冀等地，其中四川东部、贵州南部、甘肃西部、内蒙西部等地超过200次。极端事件增多的主要原因是极端高温事件和极端干旱事件增多。综合等级指数分析表明，极端事件高危险区域主要位于南方地区，特别是东南沿海地区，近60 a综合等级指数增加的区域主要位于西南地区到东北地区南部这个过渡带上。2023年高危险区域主要出现在西南地区和西北地区中北部。

关键词: 近60 a, 2023年, 中国, 区域, 极端天气气候事件