ASCAT Surface Soil Moisture DR2017 time series 12.5 km sampling - Metop

Time series available on a discrete global grid (DGG) with a spatial resolution of 25 km (grid spacing 12.5 km) of the Surface Soil Moisture representing the water content in the upper soil layer (< 2 cm) in relative units between totally dry conditions (0%) and total water capacity (100%), retrieved from the radar backscattering coefficients measured by the ASCAT (Advanced scatterometer) instrument on board the MetOp satellites. The temporal sampling rate is irregular (every 1-2 days) and depends on the latitude. Each surface soil moisture estimate has an associated noise value, indicating the uncertainty.

本数据集为基于空间分辨率25 km（格点间距12.5 km）的离散全球格网（Discrete Global Grid, DGG）的时间序列数据，核心变量为地表土壤湿度（Surface Soil Moisture）：该指标以相对单位表征地表0~2 cm土层的含水量，取值范围覆盖完全干燥状态（0%）至饱和持水量（100%）；数据由搭载于MetOp卫星上的ASCAT（高级散射计，Advanced Scatterometer）仪器测得的雷达后向散射系数反演得到。该数据集的时间采样频率不固定，间隔为1~2天，且采样间隔随纬度变化。每一条地表土壤湿度估算结果均附带对应的噪声值，用以表征其不确定性。