关键词: 气候变化, 蒸发皿蒸发量, 变化特征, 影响因素, 蒸发悖论, 安徽

Abstract:

Annual and seasonal variations analyzed by linear tendency estimate and MannKendall test of 20 cmpan evaporation of 32 meteorological stations over the YangtzeHuaihe River in Anhui Province from 1963 to 2007 indicated a significant negative trend (-65.3 mm/10 a，confidence level of 001).The jump point of the evaporation happened in 1976,and the obvious variation in 1982.The most remarkable decrease happened in summer.The evaporation had a significant negative trend of 24 stations and a positive trend (confidence level of 005) of only 1 station,which shows a spatial declining trend of more in North and less in South.Combining with other research on the impact climate factors of pan evaporation (7 factors:temperature，sunshine duration，daily temperature rang,wind speed，relative humidity，precipitation and lowcloud),the main result indicated as follows:(1)the annual temperature increased and pan evaporation decreased,therefore the “pan evaporation paradox” actually existed in Anhui Province,but the correlation between temperature and pan evaporation was not significant;(2)the pan evaporation had significant negative correlation with the sunlight，daily temperature range and wind speed，meanwhile the lowcloud cover,precipitation and relative humidity may also play an important role in an unknown mechanism.

Key words: climatic change, pan evaporation, features of variation, impact factors, pan evaporation paradox, Anhui Province