微波遥感监测土壤水分的研究初探

A Study on Soil Moisture Monitoring by Using Microwave Remote Sensing

在ＧＰＳ定位的基础上，同步测量土壤水分、土壤后向散射系数，和同步获取的ｘ波段、ＨＨ极化ＳＡＲ图像进行了土壤水分监测的微波遥感试验研究。结果表明，Ｘ波段ＳＡＲ图像的灰度与表层土壤（０～１０ｃｍ）水分有较好的相关性，３５°ＨＨ极化的土壤后向散射系数与ＳＡＲ图像灰度和土壤水分也有较好的相关性，由ＳＡＲ图像及土壤的后向散射系数估算的土壤水分精度相近，相对误差均为１２％左右，因而利用Ｘ波段、ＨＨ极化的机载ＳＡＲ图像监测土壤水分是可行的。雷达图像的穿透力一般在１０ｃｍ以内，因此探讨了由表层土壤水分推求剖面土壤水分的可能性。

Based on the GPS location in this paper,a study on soil moisture monitoring by usingairborne X-band SAR image data for HH polarization has been done with the help of soilmoisture and soil backscatter coefficient measured synchronously.The results showed thatthe gray level value of the SAR image has good relationship with the surface soil moisture(soil depth from 0 to 10cm).The soil backscatter coefficient for HH polarization at 35 de-gree pitch has good relationship not only with the SAR image data but also with surfacesoil moisture.And the soil backscatter coefficient for VV polarization at 65 degree pitchhas good relation with surface soil moisture.The average relative errors were less than12%from SAR image data and backscatter coefficient to evaluate soil moisture.Analysisresults indicated that radar image has great potential for monitoring soil moisture.Becausethe penetrative depth of radar is less than 10cm,the possibility for inquiring into sectionsoil moisture from surface soil moisture is discussed in the paper.And a new method formeasuring soil moisture with a apparatus is provided to improve measuring precision and speed.