SMAP L3 Radiometer Global and Northern Hemisphere Daily 36 km EASE-Grid Freeze/Thaw State, Version 3

This Level-3 (L3) product provides a daily composite of landscape freeze/thaw conditions retrieved by the Soil Moisture Active Passive (SMAP) radiometer from 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. SMAP L-band brightness temperatures are used to derive freeze/thaw state and transition data, which are then resampled to both an Earth-fixed, Northern Hemisphere azimuthal 36 km Equal-Area Scalable Earth Grid (EASE-Grid 2.0), and to an Earth-fixed global 36 km EASE-Grid 2.0.本三级（L3）产品提供了由土壤湿度主动被动（Soil Moisture Active Passive, SMAP）辐射计，通过每日上午6时降轨半轨过境与下午6时升轨半轨过境的观测数据反演得到的地表冻融条件日合成数据集。研究团队利用SMAP的L波段亮温数据反演得到冻融状态与相变数据，随后将上述数据重采样至两类地固坐标系网格：其一为北半球方位投影36公里等面积可缩放地球网格（Equal-Area Scalable Earth Grid, EASE-Grid 2.0），其二为全球36公里EASE-Grid 2.0网格。