Climatic Characteristics and Their Changing Law during Summer High- Temperature Times in East China
华东地区夏季高温期的气候特征及其变化规律

Based on the daily highest temperature data covering the period 1961-2005, temporal and spatial characteristics and their changing in mean annual and monthly high temperature days (HTDs) and the mean daily highest temperature (MDHT) during annual and monthly HTDs in East China were studied. The results show that the mean annual HTDs were 15.1 and the MDHT during annual HTDs was 36.3 oC in the past 45 years. Both the mean annual HTDs and the MDHT during annual HTDs were negative anomaly in the 1980s and positive anomaly in the other periods of time, oscillating with a cycle of about 12-15 years. The mean annual HTDs were more in the southern part, but less in the northern part of East China. The MDHT during annual HTDs was higher in Zhejiang, Anhui and Jiangxi provinces in the central and western parts of East China. The high temperature process (HTP) was more in the southwestern part, but less in the northeastern part of East China. Both the numbers of HTDs and HTP were most in July, and the MDHT during monthly HTDs was also the highest in July. In the first 5 years of the 21st century, the mean annual HTDs and the MDHT during annual HTDs increased at most of the stations, both the mean monthly HTDs and the MDHT during monthly HTDs were positive anomaly from April to October, the number of each type of HTP generally was the most and the MDHT in each type of HTP was also the highest.