A Bare Soil Moisture Content Inversion Method Based on Dual Polarization-like Emissivity

Abstract

The invention relates to the field of microwave remote sensing, and discloses a method for inversion of bare soil water content based on dual polarized emissivity, comprising the steps of: simulating the microwave radiation brightness temperature under different observation conditions and soil conditions; Convert them into emissivity-like rates respectively to obtain the microwave radiation brightness temperature class emissivity data set; obtain the dual-polarization class emissivity weighted variables according to the dual-polarization class emissivity weighting equation; establish the dual-polarization class emissivity weighting variables and the bare soil content. The relationship between the water content, and the bare soil water content is inverted according to the bipolar emissivity-like weighted variable. The invention defines the emissivity-like rate, avoids the error caused by the temperature data to the inversion process of soil water content, and improves the inversion accuracy. The invention eliminates the influence of the surface roughness on the microwave radiation signal through the weighting of the emissivity-like rate of dual polarization. At the same time, it avoids the inversion error of bare soil water content caused by the use of empirical roughness parameters for different surface conditions in the traditional inversion method.

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

Images