烟台市蒸发量变化趋势及影响因子

利用烟台市1971—2010年蒸发量、气温、日照、降水和总云量资料，采用线性回归、相关分析、小波分析、逐步回归方法，对蒸发量变化趋势及其影响因子进行分析。结果表明，烟台年蒸发量存在2～3年的主周期和4～8、8～12年的次周期变化，春季、夏季、秋季和冬季蒸发量分别存在3～5、5～7、7～11和2～4年的周期变化。平均相对湿度的增加和日照时数的减少是蒸发量减少的主要原因，而影响各季节蒸发量变化的气象因子各有不同。日照时数和总云量是影响夏秋季节蒸发量变化的最主要因子，秋冬季节的蒸发量主要受平均相对湿度、日照时数和总云量的共同影响。

Variation Tendency of Evaporation in Yantai and Its Influencing Factors

With the pan evaporation data, temperature, sunlight, precipitation, and some other meteorological data from 1971 to 2010 in Yantai, the changes in pan evaporation characteristics are analyzed. By using the linear regression, correlation analysis, wavelet analysis, and stepwise regression analysis methods, effects of meteorological factors on the changes of evaporation are analyzed. The results show that there existed periodic variation in annual evaporation with the main periods of 2 to 3 years and the periods of 4 to 8 and 8 to 12 years; there were periodic changes of 3 to 5, 5 to 7, 7 to 11, and 2 to 4 years, respectively, in evaporation in spring, summer, autumn, and winter. Increased average relative humidity and reduced sunshine duration brought about the reduction in annual evaporation, and factors influencing the changes of evaporation in different seasons were different. Sunshine duration and total cloud cover were the most important in summer and autumn. While in autumn and winter evaporation is mainly affected by average relative humidity, sunshine duration, and total cloud cover jointly.