Analysis on temporal and spatial distribution of reference evapotranspiration and its possible influencing factors in Yunnan Province.

This article was based on the climate data of 125 meteorological stations from 1982 to 2011 in Yunnan Province, the daily basis <italic>ET</italic>0 was calculated with Penman-Monteith equation recommended by <italic>FAO</italic> in 1998. Then the Kriging interpolation method and related methods of climate statistical diagnosis analysis were used to analyze the features. The main results showed that the highest value of annual <italic>ET</italic>0 of Yunnan Province was the joint parts of Dali, Lijiang and Chuxiong, and also the north of Chuxiong and Kunming, while the least value was the northeast and northwest of Yunnan Province. The <italic>ET</italic>0 was showed rising trend, the speed was about 5.9mm/10a, but the rising trend was not significant. The <italic>ET</italic>0 of spring was highest, and the <italic>ET</italic>0 of summer and autumn was taken the second place, the <italic>ET</italic>0 of winter was last. The <italic>ET</italic>0 of spring, summer, autumn, winter was account for 33.35 per cent, 28.91 per cent, 20.36, per cent, 17.39 per cent of annual <italic>ET</italic>0 respectively. The <italic>ET</italic>0 of May was highest and December was least in annual. <italic>ET</italic>0 was closely related to wind speed, relative humidity, hours of sunshine and the daily maximum temperature. The correlation between wind speed, hours of sunshine, the daily maximum temperature and <italic>ET</italic>0 was very significantly positive, while the correlation between relative humidity and <italic>ET</italic>0 was very significantly negative. [ABSTRACT FROM AUTHOR]