空间网格分辨率为9 km的SMAP（Soil Moisture Active and Passive）、0.1D（Degree）的ASCAT（The Advanced Scatterometer）、 25 km的FY-3B以及25 km ESA-CCI（European Space Agency -Climate Change Initiative）是较为广泛应用的卫星遥感土壤水分产品，对数据质量的评价是进一步应用于旱情监测、蒸散发估算等研究的前提。本研究基于2018年9月在闪电河流域内蒙古农牧交错带区域开展的碳、水循环与能量平衡遥感综合试验，采用近似同步的两种尺度观测数据即点尺度地面实测土壤水分数据以及面尺度（1 km×1 km）机载土壤水分数据，利用RMSE（Root Mean Square Error）， MAE（Mean Absolute Error），R（Correlation Coefficient），Bias以及ubRMSE（unbiased Root Mean Square Error）等评价指标分别对SMAP， ASCAT， FY-3B， ESA-CCI土壤水分卫星遥感产品进行了评价。本研究利用机载土壤水分数据作为桥梁，实现了从点尺度地面实测土壤水分数据、至面尺度（1 km×1 km）机载土壤水分数据、再至粗格网面尺度（9 km×9 km、0.1 D×0.1 D、25 km×25 km）卫星遥感土壤水分产品的对比分析过程。利用地面观测值对机载观测土壤水分开展评价分析，发现在裸土区域，机载土壤水分数据与地面实测数据较为一致，RMSE， MAE， Bias， ubRMSE 以及R值分别为0.033 cm³/cm³， 0.030 cm³/cm³， -0.004 cm³/cm³， 0.033 cm³/cm³， 0.474。对卫星土壤水分产品的评价结果显示，SMAP的9 km土壤水分卫星产品与地面观测更为一致，其RMSE，MAE，Bias，ubRMSE以及R值分别为0.037 cm³/cm³，0.032 cm³/cm³，-0.008 cm³/cm³， 0.036 cm³/cm³， 0.507。SMAP， ASCAT， FY-3B以及ESA-CCI与机载土壤水分数据有更高的相关性，R值分别为0.735， 0.558， 0.558， 0.575。综上，闪电河流域实验区内的4种卫星遥感土壤水分产品中，SMAP产品与地面土壤水分、机载土壤水分数据均较为一致，其次是FY-3B与ESA-CCI。

SMAP (Soil Moisture Active and Passive) with a grid resolution of 9 km, ASCAT (Advanced Scatterometer) with a grid resolution of 0.1D (Degree), FY-3B and ESA-CCI (European Space Agency-Climate Change Initiative) with a grid resolution of 25 km, these satellite soil moisture (SM) products were widely used in drought monitoring, evapotranspiration estimation etc. applications. It is very important to evaluate these satellite SM products before using them. In this study, the approximate synchronous in-situ SM measurements (point-scale) and airborne observation-based soil moisture data (area-scale airborne SM with a grid resolution of 1 km) from the Comprehensive Remote Sensing Experiment of Water Cycle and Energy Balance in the Shandian river basin of Inner Mongolia in September, 2018 were used to evaluate the SMAP, ASCAT, FY-3B, ESA-CCI satellite SM products using RMSE (Mean Square Root Error), R (Correlation Coefficient), MAE (Mean Absolute Error), Bias and ubRMSE (unbiased Mean Square Root Error) etc. evaluation indexes. This study achieved the evaluation process from the point-scale in-situ SM measurements to the area-scale (1 km×1 km) airborne SM data to the area-scale (9 km×9 km, 0.1 D×0.1 D, 25 km×25 km) satellite SM products using airborne SM as the bridge between in-situ SM measurements and satellite SM products. The results dedicated that in bare soil area the airborne SM was more consistent with the in-situ SM measurements, the RMSE, MAE, Bias and ubRMSE and R values were 0.033 cm³/cm³, 0.030 cm³/cm³, -0.004 cm³/cm³, 0.033 cm³/cm³ and 0.474 respectively. Comparing with ASCAT, FY-3B and ESA-CCI satellite SM products, the SMAP satellite SM product were more consistent with in-situ SM measurements, RMSE, MAE, Bias, ubRMSE and R values were 0.037 cm³/cm³, 0.032 cm³/cm³, -0.008 cm³/cm³, 0.036 cm³/cm³ and 0.507 respectively. In addition, the R values between the satellite SM products (SMAP, ASCAT, FY-3B and ESA-CCI) and airborne SM data were higher, 0.735, 0.558, 0.558 and 0.575 respectively. Overall, the SMAP satellite SM product was more consistent with in-situ SM measurements and airborne SM in Shandian river basin area, then FY-3B and ESA-CCI SM products.