关键词: 青藏高原, 不同下垫面, 实际蒸散发量, 气象因子, 相关性

Abstract:  Based on eddy correlation instrument observation data at 5 observation stations with different underlying surfaces (The underlying surfaces of A’li station, Zhufeng station and Mushitage station are gravel and sparse short grass, and the underlying surfaces of Naqu station and A’rou station are alpine meadow and alpine grassland, respectively.) in the Tibetan plateau in 2013, the actual evaporations were caculated and the correlation between the daily actual evapotranspiration and meteorological factors (net radiation flux,  soil humidity, soil surface temperature, air temperature, wind speed and saturated water vapor pressure difference) were analyzed. The results are as follows: (1) The variation trend of daily actual evapotranspiration on different underlying surfaces was roughly the same, but the variation range was different. The daily actual evapotranspiration and monthly actual evapotranspiration on the underlying surface of the alpine grassland were the most, followed by the underlying surface of the alpine meadow, and on the underlying surface of the gravel sparse short grass it was the least. (2) The variation trends of ground temperature, air temperature and net radiation of different underlying surfaces in the Tibetan plateau were roughly the same, and the daily actual evapotranspirations of the different underlying surfaces were significantly correlated with ground temperature, air temperature and net radiation, while the correlation between wind speed and daily actual evapotranspiration was relatively small. (3) Thermal factors and water supply conditions had a greater impact on the daily actual evapotranspiration of the Tibetan plateau, while dynamic factor had little influence on the actual daily evapotranspiration.

Key words:  Tibetan plateau, different underlying land surfaces, actual evapotranspiration, meteorological factors, correlation