Based on pan evaporation (PE) observations at 1302 weather stations in China for 1961-2013, in this paper, we present our analysis of the temporal and spatial characteristics and their impact on the climate factors of PE. The results indicate that both the annual and seasonal mean PE values from all stations show a significant downward trend, with an abrupt change occurring in 1978. The stations with a significant downward PE trend are mainly located in the North China Plain, Xinjiang, Guangdong, Guangxi, and Hainan provinces, whereas PE shows a significantly increasing trend in Fujian, Zhejiang, and Guizhou provinces. We performed empirical orthogonal function (EOF) analyses of the annual PE anomalies. For the first mode (EOF1), the time coefficient changes from positive to negative in 1981, and the variation of the EOF1 spatial pattern is similar as that of PE magnitude. The EOF2 mode presents opposite patterns in South and North China and after 2002, the PE decreased in North China, but increased in South China. Additionally, we calculated the partial correlation coefficients between PE and five climate elements, including precipitation, temperature, surface wind speed, relative humidity, and sunshine duration. The results show that except for precipitation, the other four variables are very well correlated with PE. The correlation between wind speed and PE is significantly positive, and the regions with the highest correlation are consistent with those with the largest EOF1 variability. The correlation between humidity and PE is significantly negative. The correlation between temperature and PE are positive overall, with the largest values appearing in areas where PE increases. The correlation coefficients between the sunshine duration and PE are greater than 0.6 in three seasons but not in spring. Moreover, we found that the linear trends of both wind speed and sunshine duration greatly impact their relationships with PE. Thus, we conclude that a decreasing trend in PE is largely because of decreasing wind speed and sunshine duration. Furthermore, when drought occurs, PE increases significantly, and the changes in precipitation, temperature, relative humidity, and sunshine duration also significantly contribute to the increases in PE. As such, PE could be a good indicator of drought.
谢睿恒,王爱慧,华维.2020.1961～2013年中国蒸发皿蒸发量时空分布特征及其影响因素[J].气候与环境研究,25(5):483-498. XIE Ruiheng, WANG Aihui, HUA Wei.2020. Temporal and Spatial Distribution Characteristics and Influencing Factors of Pan Evaporation in China from 1961 to 2013[J]. Climatic and Environmental Research (in Chinese],25(5):483-498.Copy