Regional evapotranspiration calculation method based on remote sensing

Abstract

The invention provides a regional evapotranspiration calculation method based on remote sensing, which relates to the field of regional ecological environment evaluation, and comprises the following steps of: 1, acquiring related surface parameters by utilizing remote sensing data; 2, calculating earth surface net radiation flux Rn by utilizing the earth surface albedo alpha according to a solar radiation transmission theory; 3, calculating soil heat flux G by utilizing the earth surface net radiation flux Rn and the vegetation coverage fv; 4, calculating to obtain a momentum roughness length Z0m and a heat roughness length Z0h by utilizing a morphological model; 5, calculating sensible heat flux H by utilizing the momentum roughness length Z0m, the heat roughness length Z0h and an atmospheric transmission similarity theory; 6, calculating earth surface latent heat flux lambda E, and then calculating an evaporation ratio lambda; and 7, calculating the regional daily evapotranspiration Eday according to the evaporation ratio lambda. By means of the advantages of space continuity and time dynamic observation of the remote sensing technology, a remote sensing parameterization model of the surface momentum roughness and the zero-plane displacement height is improved based on a morphological method.

Description

technical field [0001] The invention relates to the field of regional ecological environment assessment, in particular to a method for calculating regional evapotranspiration based on remote sensing. Background technique [0002] Population expansion, shortage of resources and environmental pollution are the three major problems facing us human beings, among which the shortage of water resources is one of the main problems facing human beings. my country's per capita water resources are about 2200m 3 , which is less than 1 / 3 of the world's average level, is one of the 13 countries with severe water shortages in the world, and the distribution of time and space is extremely uneven. Therefore, the shortage of water resources is particularly prominent in our country and has become an important restrictive factor for social and economic development. In the increasingly serious situation of scarcity of water resources, we must rationally utilize and optimize the allocation of l...

AI Technical Summary

Problems solved by technology

With the deepening of people's understanding of the land surface process, the accuracy requirements for the description of the material and energy conversion process in the earth-atmosphere system are gradually increasing. The traditional method of estimating the distribution of regional characteristics from points and surfaces through limited Inherent disadvantages can no longer meet the requirements of research and application, and the cost of large-scale intensive observation is high and the cycle is long. In terms of current measurement technology, it is necessary to carry out daily monitoring of regional surface evapotranspiration and achieve application accuracy. Requirements are still difficult

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