中国热浪时空变化特征分析

Spatial-Temporal Characteristics of Heat Waves in China

为有效应对新形势下高温热浪的潜在危害性,利用中国气象站1961-2017年日最高气温资料,采用相对高温阈值方法识别热浪事件,分析了热浪频次、高温日数的时空变化特征。研究结果表明:中国热浪频次、热浪累积日数大体呈“南高北低”的空间格局;全国热浪开始于4月,空间上由西南向东北延伸,再向长江中下游和西北地区发展,9月全国热浪基本结束;除淮河流域外,高温热浪年累积日数呈显著增加趋势,7月全国热浪的持续性增强,以北方和东南地区变化最为显著;全国高温热浪日数于1980年和1990年发生突变,西北、东北北部及黄河中下游于1980年前发生突变,云南、福建及江西的突变年份为2000年以后;高温热浪日数呈逐年代先减(1960年至1980年)后增(1990年起)的变化趋势。

In the context of global warming, extreme climate events such as heat waves become more frequent, which threaten the human health and social ecological environments. Using the daily gridded temperature data of 824 national meteorological stations during 1961-2017, heat waves in China were recognized with the relative high temperature threshold method, and the spatio-temporal characteristics of such events, along with high temperature days were analyzed. Results show that the frequency of heat waves and high temperature days present a similar spatial pattern with both values decreased from south to north. Starting from April, the affected areas of heat waves spatially migrate northeastward, and extend to the middle and lower reaches of Yangtze River and northwest regions in the following few months. Almost no heat waves occur in China in September. Except for the Huaihe River basin, annual high temperature days in most areas in China significantly increase. For seasonal patterns, July ranks first during the summer time in which the persistence of high temperature days overall lengthens across China, with significant changes in the north and southeast regions. Abrupt changes of high temperature days mainly occur in 1980s and 1990s. For northwest regions, northern parts of northeast, and middle and lower reaches of the Yellow River basin, the abrupt changes of high temperature days occur before 1980s, and after 2000 for Yunnan, Fujian, and Jiangxi. Decadal high temperature days gradually decrease from 1960s to 1980s, and significantly increase since 1990s.