The ASAR data were in AP mode and VV/VH polarization combinations, and the overpass time was approximately at 23:04 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.
Simultaneous with the satellite overpass, numerous ground data were collected: the soil temperature , volumetric soil moisture (cm^3/cm^3), soil salinity (s/m), soil conductivity (s/m) by the Hydra probe, the surface radiative temperature by the handheld infrared thermometer, gravimetric soil moisture, volumetric soil moisture, and soil bulk density by drying soil samples from the cutting ring (100cm^3). Meanwhile, vegetation parameters as height, coverage and water content were also observed.
Those provide reliable ground data for the development and validation of soil moisture, soil freeze/thaw algorithms and the forward model from active remote sensing approaches.
Data Citation Jin Rui, Bai Yunjie, Cao Yongpan, Li Xin, Wang Weizhen, Wang Xufeng. WATER: Dataset of ground truth measurements synchronizing with Envisat ASAR in the Biandukou foci experimental area on Oct. 17, 2007 during the pre-observation period. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science. 2008. doi:10.3972/water973.0189.db
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