The Comparison of Distributed Hydrological Model and Remote Sensing Method for ET Calculation in Tianjin

摘要

This paper chooses Year 2002 to 2005 as the study period and calculates yearly average ET of different land use types and different regions in Tianjin by two methods, remote sensing inversion and SWAT model simulation. To compare the results of the two methods, we find that the two results of ET of different land use types are widely discrepant and the deviation is over 22%. The water body ET, beach land ET, swamp ET and paddy field ET of SWAT model simulation are larger than the counterpart ET results of remote sensing inversion, while the ET results of the rest land use types are lower. The ET results of different land use types which are simulated by SWAt model are widely different while the ET results of different land use types which are inversed by remote sensing data are nearly consistent. The comparison of the two results of different regions ET shows that the results got by the two methods are nearly consistent and the deviation is about 5%. Furthermore, this paper uses SWAT model to simulate the constitutions of ET of dominating crops in Tianjin and analyses water saving potential of agriculture. The result should be calibrated by experiments in Tianjin. This paper compares the two methods and proposes that GEF project which is carrying out in HaiHe basin should add some Et monitor stations for ET data calibration.