关键词: 高温日数, 时空变化, 高温过程, 华北地区

Abstract:

Based on the daily maximum air temperature data from 90 meteorological stations in the period 1960-2009, the climatic characteristics and the spatio-temporal variation of high temperature days (HTDs) in North China were analyzed by using the statistical methods including trend analysis. The results show that the HTDs are more in the south and less in the north on conditions that 800-meters elevation contour serves the boundary. There exist two high value centers, which is located in the south of Hebei Province and the regions from southwest of Shanxi Province to Zhengzhou and Xuchang of Henan Province respectively. The most annual mean HTDs reach 25.7d, which occurs in Yuncheng of Shanxi Province. The HTDs are mainly on the decrease in the south of North China and on the increase in the north. The most obvious decrease in HTDs occurs in Kaifeng of Henan Province and the linear trend is -2.8d/10a. The most obvious increase in HTDs occurs in Hequ of Shanxi Province and the linear trend is 1.51d/10a. The HTDs in recent 50 years has a distinct decadal evolution of increasing-decreasing-increasing. The high temperature mainly occurs during May to August, especially in June and July. Compared with the HTDs in the 1960s, those in the 2000s are slightly on the increase during July and on the decrease during May and August. The accumulated high temperature process (HTP) is on the detectable decrease, while the moderate HTP is on the detectable increase. As far as the HTP lasting day number more than 5 days is concerned, the number in Beijing is less than Erenhot and the number in Zhengzhou is 3.3 times as many as that in Beijing. There exist some difference in the era and month of HTP between the south and the north .

Key words: high temperature day, spatio-temporal variation, high temperature process, North China