Experimental Study On The Impact Of The Soil Pore For The Microwave Radiation Characteristics

Microwave remote sensing technology has most potential for detecting and monitoring soil property.Currently,most studies focused on the retrieval of soil moisture and temperature without considering the influence from the soil pore.Also,few studies have done experiment research to indicate the characteristic of soil pore within microwave radiation.This paper analyzes the passive microwave remote sensing data,research situation of soil surface parameters retrieval and the dielectric properties of soil in previous related theory and method based on the study.Based on the microwave radiation characteristics of soil,through the double band(C,K)microwave radiometer for different porosity,different size of pore of microwave radiation properties of soil by experiments and analysis the relation between the soil porosity and soil microwave emission rate,soil porosity and microwave remote sensing index MPDI,the pore size and the microwave brightness temperature,the pore size and the microwave emission rate.The results show that:1)Porosity has a significant impact on the microwave radiation characteristics ofdry soil.There is a fine linear positive correlation relation between microwave emissivity and porosity in horizontal polarization.The correlation coefficient between microwave emissivity and porosity is above 0.99 at 550of horizontal polarization in band C,which can be considered as the optimal observation condition to retrieve the properties ofsoil porosity.2)Microwave polarization different index(MPDI)has a linear negative correlation to porosity in the same polarization mode.The correlation coefficient between MPDI and porosity is above 0.97 at observing angle 55°,band C.It showed that the strength of the depolarization effect is larger for the large porosity.3)With the soil pore size increasing,the microwave emission rate increased at first,than decreased in band C.There is a quadratic curve relationship between microwave emissivity and pore size,and the quadratic correlation is better in band C,horizontal polarization.The microwave emission rate dropped quickly under band K when the soil pore size increased from 2mm to 10mm.The microwave emission rate decreased at first,than increased with the soil pore size increasing.Overall,our results by taking lots of trial and error can provide the technical reference and support for the study of microwave remote sensing on soil properties.