Bias Correction in Monthly Records of Satellite Soil Moisture Using Nonuniform CDFs

Table 1

A brief introduction of three satellites.

Satellite	Nation	Resolution	Function	Characteristics
FY3B [7]	China (2010)	25 km	FY3B is the second satellite of the FY3 series, and it is the first in the series to carry a microwave imager (MWRI) for observing the Earth’s surface in 10 microwave channels.	The FY3B satellite has 5 frequencies (10.65, 18.7, 23.8, 36.5, and 89 GHz) and dual polarization (vertical and horizontal polarization) mode
SMOS [8, 9]	Europe (2009)	25 km	SMOS is the only satellite in the world that can observe changes in soil moisture and sea salinity.	The SMOS satellite which emits the microwave signals at 1.4 GHz frequency (L band) can penetrate the soil to a depth of 5 cm.
WindSat [10]	America (2003)	25 km	Besides providing the sea surface wind vector measurement for the Navy, WindSat also observed other sea surface environmental parameters and was also used to measure soil moisture and sea ice.	The WindSat discrete frequency band is 6.8, 10.7, 18.7, 23.8, and 37 GHz, of which 10.7, 18.7, and 37 GHz are all polarization mode and 6.8 and 23.8 GHz are dual polarization mode