CHANGE OF COOLING DEGREE DAY IN CHINA DURING 1960～2008

Using daily average temperature data during 1960～2008 from 531 weather stations in China,the characteristics of cooling degree day change were analyzed and the relationship between cooling degree day and cooling electricity load in summer was also investigated by taking Zhejiang province as an example in this paper.The results showed that the number of days with daily mean temperature above 26℃ were more than 10 days,and the stations with cooling requirements mostly distributed in Xinjiang,Sichuan,dry-hot valley in Yunnan and to the east of Taihang-Wushan-Xuefeng mountains.During the period of 1960～2008,June-September mean temperature of stations in northern China increased significantly after mid-1990s and resulted in the increase of cooling degree day in summer,while stations between south of the Yellow River and north of Nanlin Mountain showed little changing trend.The June-September mean temperature of stations to the south of Nanlin Mountains increased continuously and resulted in the significant increase of cooling degree day accordingly.In addition,there was a significant positive relationship between daily cooling degree days and daily cooling electricity load during summer in Zhejiang province,and the cooling degree day could be used to predicte cooling electricity consumption.