The Envisat ASAR data were in AP mode and VV/VH polarization combinations, and the overpass time was approximately at 11:17 BJT. Both the quadrates were divided into 3×3 subsites, with each one spanning a 30×30 m2 plot. 25 sampling points were chosen, including centers and corners of each subsites.
Simultaneous with the satellite overpass, numerous ground data were collected, soil volumetric moisture, soil conductivity, the soil temperature, and the real part of soil complex permittivity by the WET soil moisture sensor; the surface radiative temperature by the hand-held infrared thermometer; soil gravimetric moisture, volumetric moisture, and soil bulk density after drying by the cutting ring (100cm^3). Meanwhile, vegetation parameters as height, coverage and water content were also observed. Surface roughness was detailed in the "WATER: Surface roughness dataset in the A'rou foci experimental area".
Those provide reliable ground data for retrieval and validation of soil moisture and freeze/thaw status from active remote sensing approaches.
Data Citation Jin Rui, Li Xin, Bai Yunjie, Hao Xiaohua, Li Hongyi, Li Zhe. WATER: Dataset of ground truth measurements synchronizing with Envisat ASAR in the A'rou foci experimental area on Oct. 18, 2007 during the pre-observation period. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science. 2008. doi:10.3972/water973.0003.db
The dataset is generated from the "Watershed Airborne Telemetry Experimental Research (WATER) “, the user must have a clear statement in the article of the original data source and adopt the reference style providing by the metadata in the References section.