SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 1

This Level-2 (L2) soil moisture product provides gridded estimates of global land surface conditions retrieved by the Soil Moisture Active Passive (SMAP) passive microwave radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. Input SMAP L-band brightness temperature data used to derive soil moisture are resampled to an Earth-fixed, global, cylindrical 36 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0). A variety of ancillary data are also used as input, such as soil texture and vegetation opacity. Note: These data are Beta-release quality, meaning that they have not undergone full validation and may still contain significant errors. Currently, in this Beta release, 6:00 p.m. ascending half-orbit granules are not considered by the SPL2SMP processing software; however, that inclusion is expected after further analysis. In addition, the data fields that indicate retrieval quality, called retrieval qual flag and retrieval qual flag option[1-5], were found to contain incorrect information. Users are advised to ignore these data fields in Version 1 of this product.本二级（L2）土壤湿度产品提供全球陆面状况的网格化估算值，数据由土壤湿度主动被动（Soil Moisture Active Passive, SMAP）被动微波辐射计在早6点降轨半轨道与晚6点升轨半轨道的过境时段获取。用于反演土壤湿度的SMAP L波段亮温数据，已被重采样至地球固定、全球圆柱投影式的36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）。此外还辅以多种辅助数据作为输入，例如土壤质地与植被光学厚度。 注意：本数据为Beta测试版质量，即尚未经过完整验证，仍可能存在显著误差。当前该Beta版本中，SPL2SMP处理软件未纳入晚6点升轨半轨道数据粒，但预计在后续分析完成后将其纳入。此外，用于指示反演质量的数据字段（即反演质量标记（retrieval qual flag）与反演质量标记选项[1-5]）被发现存在信息错误，建议用户在该产品的V1版本中忽略此类数据字段。