微波遥感裸露土壤和植被覆盖土壤含水量的研究

STUDY ON MICROWAVE REMOTE SENSING FOR BARE AND VEGETATION-COVERED SOIL MOISTURE

用X波段微波散射计研究了裸露土壤,有植被(红薯、大豆和花生)覆盖的土壤含水量与微波后向散射系数之间的关系,对X波段与C波段的结果做了分析对比。结果表明:在微波遥感裸露土壤含水量方面,入射角θ=6°时灵敏度S。最大;在θ=45°时,S_v=0;在θ>45°时,土壤含水量增大,而后向散射系数反而变小。在小入射角时,两个波段的精度相差不大。微波遥感在有植被覆盖的土壤含水量方面,X波段比C波段的灵敏度和精度要低,但是只要工作参数选择适当,就能达到一定的灵敏度和精度。应用本文提出的估算模型,X波段土壤含水量的估算误差大约为±25%左右。

In this paper, the relationship between the microwave backscattering coefficient and soil moisture of bare and vegetation (sweet potato, soybean and peanut)-covered fields is discussed, and the comparision between the results of X- and C-bands is made. The study results indicate that for microwave remote sensing of the soil moisture of bare fields, when incidence angle θ=6°, the sensitivity Sv is the maximum; when θ=45°, Sv=0; and while θ>45°, the backscattering coefficient is getting lower with the increase of soil moisture. At small incidence, X-and C-bands are quite similar in the accuracy. For microwave remote sensing vegetation-covered fields, the sensitivity and accuracy of X-band are lower than those of C-band, but X-band still has a certain sensitivity and accuracy as long as proper working parameters are selected. The prediction error of soil moisture which has been estimated by a simple model proposed in this paper is about ±25% at X-band.