|Title||Assessment of FY-3A and FY-3B MWHS observations|
|Publication Type||Technical memorandum|
|Secondary Title||ECMWF Technical Memorandum|
|Authors||Chen, K, English, SJ, Bormann, N, Zhu, J|
The FY-3 series began in May 2008 with the launch of the FY-3A satellite. The Microwave Humidity Sounders (MWHS) provide vertical information about water vapour, which is important for numerical weather prediction (NWP). The Noise Equivalent Delta Temperature (NEDT) of the MWHS is higher than that of the Microwave Humidity Sounder (MHS) instrument (e.g. on MetOp-B) but lower than that of the older AMSU-B instruments (on NOAA-15, 16 and 17). Assimilation of MWHS observations into the ECMWF Integrated Forecasting System (IFS) improved the fit of short-range forecasts to other observations, notably MHS, and also slightly improved the longer-range forecast scores verified against analysis. Also, assimilating both the MWHS/FY-3A and the MWHS/FY-3B gave a larger impact than either instrument alone. Although some minor negative impacts were found, originating in the Tropics, the quality control appears to be adequate for a successful assimilation of MWHS. Substitution trials indicate that MWHS/FY-3 series data can recover a large proportion of the impact of a similar number of MHS data. These encouraging results suggest that the FY-3 series MWHS data has the quality required for use in NWP assimilation systems and can be implemented at ECMWF.