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關(guān)鍵詞: 寒潮, 強度指數, 氣候特征, 華南

Abstract: Based on the daily minimum and mean temperature data of 192 stations in South China (Guangdong, Guangxi, and Hainan provinces) from 1 January 1961 to 31 December 2008, climatic characteristics and variations of cold wave frequency in South China were first analyzed. An intensity index of cold wave was defined and intensity changes of cold wave activities in South China were analyzed. The results of climatic analysis show that there were 221 times cold wave processes in South China in the last 48 years. The cold waves might occur in the period from October to April of the next year, and 88.7 % of them concentrated in December, January, February and March. It has been found that the mean annual frequency and mean temperature reduction of cold wave processes of single station gradually reduced but the mean minimum temperature gradually increased from north to south and from inland to coast in South China in the past 48 years. The mean maximum temperature reduction of cold wave processes of single station ranged from 11.5 to 16.0℃. In the last 48 years, cold wave activities in South China showed a generally declining trend, but its frequency and intensity still exhibited monthly, yearly and decadal variabilities. The ratios of strong and medium cold waves have gradually decreased since the 1980s, however the ratio of weak cold waves has significantly increased, and the strongest cold wave in the last 48 years occurred in South China in 2008.

Key words: cold wave, intensity index, climatic characteristics, South China