The FY-3C evaluation project: microwave sounder calibration and direct broadcast experiences

Since the launch of FY-3C in September 2013, there has been an international partnership between CMA/NMSC, the Met Office and ECMWF to evaluate the data for use in NWP. The main focus initially was on comparisons of observed brightness temperatures with NWP model simulations: these are reported in other presentations. More recently, a particular effort has been made to understand the details of the calibration process for the sounder instruments (mainly MWTS-2 and MWHS-2); the Met Office and CMA have been working closely together, through visiting scientist missions, to enable this. The paper presents the findings from these investigations, and discusses the relationship between pre-launch measurements of instrument characteristics (e.g. nonlinearity parameters and antenna pattern) and the operational calibration process. It is hoped that by understanding the FY-3C process clearly, and verifying the implementation, the way will be smoothed for a rapid implementation of data from FY-3D when that is launched.