An Assessment of MWHTS Onboard FY-3C/D Over Quasi-Stable Scenes

Radiation characteristics of brightness temperatures over the PUER rain forest observed by the FY-3C/D Microwave humidity and temperature sounder (MWHTS) oxygen absorbing channels are studied. To demonstrate the characteristics of the data over PUER rain forest site, time series of monthly averages of the brightness temperatures are constructed for August from 2013 to 2020. The measured uncertainty distributions of brightness temperatures with frequencies centered at 118.75 GHz are investigated in terms of angular-dependent cohesive noise mitigation. Observations data used in this study are collected from April 2019 to March 2020 every orbit for FY-3C/D satellites. Such a close resemblance and stable pattern of uncertainty distributions from the two satellites with different equator crossing times are potentially useful for post launch calibration of future microwave radiometers. Results show that there are cohesive distributions in measurements during PUER observing from each satellite. Therefore these measurements provide a practical approach to obtain the calibrated model of inter-satellite data.