Study on Spatiotemporal Distribution Characteristics of High Temperature and Heat Waves in Southwest China from 1979 to 2019

Abstract

In the context of global warming, extreme warming events occur frequently. In order to further study the spatial and temporal distribution characteristics of heat wave in southwest China, in this paper, linear trend analysis and Mann-Kendall test are used to study the spatial and temporal distribution of heat waves in southwest China. The 1979-2019 summer temperature data of European Centre for Medium-Range Weather Forecasts (ECMWF) are used. The following conclusions are drawn: Over the past 41 years, the frequency, duration and intensity of heat waves have shown a general trend of linear increase, with the rates of 0.09 times/10a, 0.37 d/10a and 0.44 ̊C∙d, respectively. From the mutation situation, before 2013, the frequency, duration and intensity of heat waves showed an increasing trend, but the increasing trend was not significant. After 2013, the frequency, duration and intensity of heat waves showed a significant increase trend. The spatial distribution of the frequency, duration and intensity of heat waves is more in the southeast and less in the northwest. The heat waves areas were concentrated in the central and eastern part of the study area, while the hot and heat wave events were rare in western Sichuan and southwestern Yunnan. Except for western Yunnan and western Sichuan, the frequency, duration and intensity of heat waves in the study area all showed an increasing trend. The central region of the study area had a larger increasing trend, and the regions that passed the 0.05 significance test were also concentrated in the central region.