三江源区温性草原蒸散量与主要影响因子的相关分析

以小型自动气象站观测资料为基础,采用FAO Penman-Monteith方法估算三江源温性草原参考作物蒸散量,并结合FAO-56的推荐值进行了草地实际蒸散量的计测。结果表明,蒸散量季节动态呈单峰曲线变化趋势,在8月中旬达到年度最高值,平均为1.94 mm\5d-1,年蒸散总量达到 275.36 mm,暖季日蒸散量明显大于冷季。对实际蒸散量与各个主要环境因子的相关性进行了分析,结果可按照相关系数排序:空气温度（T）＞太阳辐射（Ra）＞空气相对湿度（RH）＞风速（u2）。辐射量与实际蒸散量具有较高的线性相关。根据蒸散量与相关环境因子关系分析的结果,建立了适合三江源区域温性草原的蒸散量简化计测公式。

Correlation between Evapotranspiration and Climate Factors in Warm Steppe in Source Region of Yangtze,Yellow and Yalu Tsangpo Rivers

Based on the meteorological data of HOBO Weather Station(U.S.A), the reference evapotranspiration of crop in warm steppe in source region of Yangtze, Yellow and Yalu Tsangpo rivers was calculated by the FAO Penman-Monteith equation, by which in combination with FAO-56 recommended value the actual evapotranspiration was calculated. The results show that: there is obviously seasonal variation of the actual evapotranspiration and its curve is unimodal type with the largest 1.94 mm·d~(-1) in middle-August;the annual evapotranspiration is up to 275.36 mm and the daily evapotranspiration in warm season is lager than that in cold season. Analyzing result of correlation between actual evapotranspiration and climate factors suggests that the significance from larger to smaller are as: air temperature>solar radiation>air relative humidity>wind speed. Based on the results of correlation analysis, a simplified calculation equation was establish to calculate the evapotranspiration of in warm steppe in source region of Yangtze, Yellow and Yalu Tsangpo rivers.