基于SEBS模型的藏北那曲蒸散量研究

Study on Evapotranspiration in Northern Tibet based on SEBS Model

SEBS模型为研究高原非均匀地表区域蒸散量估算提供了一种新的方法,为高原气象台站稀少地区蒸散量变化研究提供一定的参考依据。应用SEBS模型,利用MODIS遥感数据反演所需的地表物理参数(如反照率、比辐射率、地表温度和植被覆盖度等),再结合气象站地面观测数据,包括温度、相对湿度、风速、气压等,对藏北那曲地表能量通量和蒸散量进行估算;最后分析了蒸散量与气象因子、NDVI之间的关系。结果表明:2010年藏北那曲蒸散量呈春夏季高,秋冬季低的变化趋势,蒸散量较大区域为研究区南部、东北部和区域内的水体;中部和西北部地区蒸散量较小。气温和地表温度对蒸散量的影响较明显,随着气温和地表温度的升高蒸散量不断增大,NDVI对蒸散量也有一定的影响。所以,SEBS模型在估算高原地区蒸散量方面具有一定的精度,可以满足区域日蒸散发估算的需要。

The SEBS model provides a new method for studying the plateau non-uniform surface regional e- vapotranspiration estimation and some vapotranspiration reference for the sparse areas of high altitude me- teorological stations. The evapotranspiration of Naqu county was estimated by using MODIS data and me- teorological observations based on SEBS model in 2010,and analyzed the evapotranspiration with relation- ship between the meteorological factors , and the NDVI. The results show that the evapotranspiration of Naqu county in spring and summer is high, autumn and winter is low,the south and the northeast water in the study area are large evapotranspiration,in central and the northwest evapotraspiration is smaller. The temperature and the surface temperature effect is obvious to evapotranspiration,the increasing of air tem- perature and surface temperature lead to evapotranspiration increase; and the NDVI has different season variations, NDVI and evapotranspiration change were the largest in summer, they are minimum in winter. The SEBS model is of adequate accuracy in estimating the evapotranspiration of Tibetan Plateau and can be applied to estimating the daily evapotranspiration on a regional scale.