Experimental Study On Soil Moisture Retrieval From Passive Microwave Remote Sensing

Soil moisture plays an important role in the global climate change. Passive microwave remote sensing is not limited by illumination conditions, it is capable to work all-weather, and it can penetrate the vegetation and has a certain capability to penetrate the soil, which makes it the most effective method to monitor soil moisture. But now the soil surface roughness in under the influence of soil moisture determination is not fully mature the need for further research.This paper analyzes the passive microwave remote sensing data, research situation of soil moisture in previous related theory and method based on the study. Based on the microwave radiation characteristics of soil, through the double band (C, Ku) microwave radiometer for different water, different surface roughness of microwave radiation properties of soil by experiments and analysis the soil moisture and soil microwave emission rate, soil roughness and microwave remote sensing index the quantitative relation between soil humidity and, a microwave emission rate, roughness and microwave remote sensing experience model between index. The experiment results show that:①in the soil surface level off, soil humidity and soil microwave emission rate is linear negative correlation, in the other words, with the increase of soil moisture, soil microwave emission rate decreased.②In the incident angle between30°～50°, whether the vertical or horizontal polarization, the soil moisture measuring sensitivity of microwave is largest in30°angle. It shows that the effect of microwave inversion soil moisture is the best under horizontal polarization in30°angle.③With the increase of soil surface roughness, both the value of microwave polarization index (MPDI) and microwave emission rate polarization difference Δe have the trend of drop quickly, and then stabilize, and then raise slowly, present quadratic curves relationship with the roughness change.The results for the satellite passive microwave remote sensing data and the establishment of the soil moisture passive microwave remote sensing data of soil water model offers some experimental theory basis.