SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 4

This enhanced Level-2 (L2) product contains calibrated, geolocated, brightness temperatures acquired by the Soil Moisture Active Passive (SMAP) radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. This product is derived from SMAP Level-1B (L1B) interpolated antenna 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 [available as the SPl1CTB_E product]. These 9-km brightness temperatures are then used to retrieve surface soil moisture posted on the 9-km grid [this SPL2SMP_E product].

本增强型二级（Level-2, L2）产品包含土壤湿度主动被动（Soil Moisture Active Passive, SMAP）辐射计在上午6时下行半轨道过境与下午6时上行半轨道过境期间获取的经定标、地理定位的亮温数据。本产品由SMAP一级B（Level-1B, L1B）插值天线温度数据衍生而来。研究采用Backus-Gilbert最优插值技术，从SMAP天线温度数据中提取最大有效信息并将其转换为亮温数据，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（Equal-Area Scalable Earth Grid Version 2.0, EASE-Grid 2.0）[该数据集以SPL1CTB_E产品形式提供]。后续，上述9公里分辨率的亮温数据被用于反演发布于9公里网格上的表层土壤湿度[即本SPL2SMP_E产品]。