An experimental research on how to measure the surface soil moisture on pixial scale

Passive microwave remote sensing provide soil moisture product. The problem of validation of soil moisture products is that the true soil moisture of such a large pixel is difficult to estimate. This paper is a preliminary research on how to measure the true soil moisture of a 30m×30m quadrat. The results suggest that 20 measurement in such a quadrat should gave a reliable estimation of the soil moisture of the quadrat. This could be used as a thumb rule in designing the validation plan of remote sensing soil moisture product. And also could be used to estimate the soil moisture distribution within a space-born microwave radiometer footprint.