1980—2018年中国极端高温事件时空格局演变特征

基于全国2 419个气象站1980—2018年逐日气象观测资料，利用Mann-Kendall突变检验、滑动t检验、空间自相关及标准差椭圆等方法，选取4个典型的极端高温指数，分析了中国极端高温事件时空格局演变特征。结果表明：① 中国近40 a来夏天日数、热夜日数、暖夜日数和暖昼日数均呈显著的上升趋势，4个指数均在20世纪80、90年代偏少，2000年以后逐渐增加，4个极端高温指数均在2000年左右发生显著变化。② 4种极端高温指数的空间自相关主要是以高?高和低?低2种空间聚集形态为主，夏天日数和热夜日数的聚集性较强，近40 a来暖夜日数和暖昼日数的空间聚集性先增强后减弱，且空间聚集性分布格局由高?高包围低?低转变为低?低包围高?高。③ 4个指数变化率最大的站点均位于南方地区，其中夏天日数变化率最大的站点呈东西向分布格局，其余3个指数变化率最大的站点呈南北向分布格局，西南、西北地区交界地带夏天日数和暖昼日数在近40 a来变化率均显著高于全国其他地区，华东沿海地区暖夜日数的变化趋势方向性分布最明显，且变化趋势高于全国其他地区。

Spatio-temporal Variations of Extreme High Temperature Event in China From 1980 to 2018

Extreme high temperature is extremely destructive and influential, and characterizing its change over time and space can provide help to guide future efforts to mitigate impacts of climate change. Based on the daily scale observation data of 2419 meteorological stations in China, the trend analysis, the time-lapse analysis and Mann Kendall mutation test were used to study the change characteristics of extreme high temperature with time in China in the past 40 years. The trend change and distribution pattern (direction feature) of the extreme high temperature distribution pattern in the corresponding years were explored by using Moran index and standard deviation ellipse respectively. The results show that: 1) The number of summer days, hot night days, warm night days and warm days in China showed a significant upward trend. The four indexes were less in the 1980s and 1990s, and gradually increased after 2000 and commonly changed significantly circa 2000;2) The spatial autocorrelation of the four extreme temperature indices was mainly high-high and low-low. The summer days and hot night days had strong aggregation, while the spatial aggregation of warm night days and warm days first increased and then decreased in past 40 years, and the spatial distribution pattern of warm night days and warm days changed from high-high surrounding low-low to low-low surrounding high-high; 3) The most obvious points of directional distribution of change trend of Summer days, warm days and hot night days are in the north. The stations of summer days and warm days showed the southeast-northwest distribution pattern, while the stations of hot night days showed the East-West distribution pattern. The stations with the largest change trend of summer days are East-West distribution pattern, while the stations with the largest change trend of hot night days, warm night days and warm days are north-south distribution pattern. The most significant changes of the four extreme temperature indices are in southern China. The change rates of summer days and warm days in the border areas of Gansu, Sichuan, Shaanxi and Chongqing in past 40 years are higher than those in other regions of China. The directional distribution of change trend of warm night days in Zhejiang and Fujian is the most obvious, and the change trend is higher than that in other areas of China. Our results provide meaningful information for a deeper understanding of the spatiotemporal variations in temperature extremes across the mainland China.