Bare soil water content inversion method based on dual-polarization emissivity

Abstract

The invention relates to the field of microwave remote sensing, and discloses a bare soil water content inversion method based on dual-polarization emissivity, which comprises the following steps: simulating microwave radiation brightness temperatures under different observation conditions and soil conditions; converting the microwave radiation brightness temperature into emissivity-like emissivity respectively to obtain a microwave radiation brightness temperature emissivity-like emissivity data set; obtaining a dual-polarization emissivity weighting variable according to the dual-polarization emissivity weighting equation; and establishing a relational expression between the dual-polarization emissivity weighted variable and the bare soil water content, and inverting the bare soil watercontent according to the dual-polarization emissivity weighted variable. According to the invention, the class emissivity is defined; errors caused by temperature data to a soil water content inversion process are avoided, and the inversion precison is improved. According to the method, the influence of the surface roughness on the microwave radiation signals is eliminated through dual-polarization emissivity weighting, and meanwhile, the problem of bare soil water content inversion errors caused by the adoption of empirical roughness parameters under different surface conditions in a traditional inversion method is avoided.

Description

technical field [0001] The invention relates to the field of microwave remote sensing, in particular to a method for retrieving bare soil water content based on dual-polarization emissivity. Background technique [0002] Soil water content is the most active element in the exchange of energy and water between the land surface and the atmosphere, and is one of the key parameters affecting hydrological, ecological, and biogeochemical processes. With the increasing demand for long-term and large-scale soil water content data in agriculture, water conservancy, disasters and other fields, traditional ground measurement methods can no longer meet the application needs of various fields. Passive microwave remote sensing has the characteristics of being able to work all-weather and all-weather, and has a certain penetrating ability to land surface vegetation and soil, and has gradually become an effective tool for monitoring regional and global soil moisture content. [0003] In ge...

AI Technical Summary

Problems solved by technology

There are generally two ways to obtain temperature data. One is to establish the empirical relationship between remote sensing brightness temperature and soil temperature by means of thermal infrared remote sensing. The soil temperature calculated by this method is the indicated temperature, which corresponds to the temperature mechanism corresponding to the penetration of microwave remote sensing into the soil layer. It does not match, and is affected by cloud occlusion and weather, sometimes it is impossible to obtain valid data; the second is to obtain it through ground measurement of temperature measuring instruments. information matches

Both methods will lead to the introduction of new errors and reduce the accuracy of soil water content inversion; 2) Since the roughness affects the microwave brightness temperature, the inversion process requires the input of surface roughness information to correct the influence of roughness, but due to Surface roughness is difficult to obtain, so empirical values ​​are generally used in the inversion algorithm. This method cannot be applied to complex surface conditions in reality

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