基于 SMOS 卫星和 GNSS-MET 地面土壤水分监测数据, 采用皮尔逊相关、滑动平均、反距离权重法等方法,评估 SMOS 土壤水分数据在三江源地区的适用性, 分析土壤水分的变化特征及其影响因素。结果表明: (1) SMOS土壤水分数据能反应研究区( 4 月- 10 月) 基本规律, 其值略低于地面实测值; (2) SMOS 卫星升轨土壤水分值大于降轨土壤水分值, 6 月- 8 月 SMOS 土壤水分值高于其它月份; 土壤水分季节性差异明显, 夏季显著高于春季; (3)三江源区土壤水分空间分布差异较大, 空间格局明显, 总体上澜沧江源区相对湿润, 长江源区相对干旱。

In this paper, the Pearson correlation, overlapping averages method, and inverse distance weighting ( IDW ) were used to make a corresponding analysis based on the SM data from SMOS ( Soil Moisture and Ocean Salinity ) satellite and in-situ GNSS-MET ( Global Navigation Satellite System-Meteorology) . We evaluated the applicability of SMOS SM data and analyzed the variety of SM and its influencing factors. The results showed that: ( 1) the general dynamic trend of soil water movement in the study area ( April to October) could be demonstrated by the SMOS SM data, how ever the SM from SMOS was slightly lower than that from the in-situ measured; ( 2) The SM from SMOS satellite in the ascending orbit were higher than those in the descending orbit. The SM from SMOS during the period from June to August were higher than those in the other months. The seasonal variation in soil water was obvious, and the SM in summer was significantly higher than that in spring; ( 3) T he spatial SM was greatly different in the Three-River Headwater s region. Generally , the soil was relatively wet in the source area of Lantsang River, while it was relatively dry in the source area of the Yangtze River .

“十三五”国家重点研发计划( 2017YFC0403600) ; 国家自然科学基金( 91847302)