SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 1

This enhanced Level-3 (L3) soil moisture product provides a composite of daily estimates of global land surface conditions retrieved by the Soil Moisture Active Passive (SMAP) radiometer. This product is a daily composite of SMAP Level-2 (L2) soil moisture which is derived from SMAP Level-1C (L1C) interpolated brightness temperatures. Backus-Gilbert optimal interpolation techniques are used to extract maximum information from SMAP antenna temperatures and convert them to brightness temperatures, which are posted to the 9 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) in a global cylindrical projection.本增强型三级（L3）土壤湿度产品，系由土壤湿度主动被动（Soil Moisture Active Passive, SMAP）辐射计反演得到的全球陆面条件日估算值的合成数据集。该产品为基于SMAP一级C型（L1C）插值亮温衍生得到的SMAP二级（L2）土壤湿度日合成产品。研究采用巴克斯-吉尔伯特最优插值技术（Backus-Gilbert optimal interpolation），从SMAP天线温度中提取最大信息量并将其转换为亮温，随后将此类亮温数据发布至采用全球圆柱投影的9公里等面积可缩放地球网格2.0版（EASE-Grid 2.0）。