Abstract: Soil moisture is a primary factor influencing vegetation growth. In order to comprehensively investigate the growth status of grassland and evaluate its drought-disaster level, the data from the latest satellite of Sentinel-1 SAR radar and ground-based measurements were used to examine the relation between multi-temporal radar backscattering coefficient and soil moisture variation in the typical steppe in Xilinhot City. The results show that the backscattering coefficient inversed by multi-temporal Sentinel-1 SAR significantly correlated with soil moisture measured based on the ground-based experiments (R2=0.8). Under different ground roughness conditions, the correlation coefficient between the radar backscattering coefficient and the measured soil moisture was about 0.9. The results indicated that Sentinel-1 SAR inversion was highly sensitive to soil moisture in the typical steppe, it could monitor soil moisture dynamics quickly and accurately, and may become a new method for monitoring drought in grasslands.

Key words: soil moisture, synthetic aperture radar, remote sensing inversion, typical steppe

摘要： 土壤水分是影响植被生长发育的重要因子，为快速、有效了解典型草原植被生长状况及评估草原干旱灾害，以Sentinel-1合成孔径雷达(SAR)数据和地面实测数据为基础，利用雷达后向散射系数快速监测和反演锡林浩特市典型草原土壤水分并与地面实测数据进行对比。结果表明：SAR后向散射系数与实测土壤含水量存在显著相关关系，相关系数R2达0.8；在不同地面粗糙度条件下，雷达后向散射系数与实测土壤水分相关系数达0.9。说明利用Sentinel-1 SAR数据能够快速、准确地对研究区进行土壤水分动态监测，这也将可能成为一种新的典型草原干旱监测方法。

关键词: 土壤水分, 合成孔径雷达, 遥感反演, 典型草原