Growing operational use of FY-3 data in the ECMWF system

The paper reviews the data quality and impact of observations from the FY-3 satellite series used operationally in the ECMWF system. This includes data from passive microwave radiometers MWHS-1, MWHS-2, and MWRI, as well as observations from the radio occultation receiver GNOS. Evaluations against background equivalents show that the quality of the observations is broadly comparable to that of similar instruments on other polar-orbiting satellites, even though biases for the passive microwave observations can be somewhat larger and more complex for some channels. An observing system experiment shows that the FY-3 instruments jointly contribute significantly to the forecast skill in the ECMWF system. Positive impact of up to 2% is seen for most variables out to the day 2 forecasts over hemispheric scales, with significant benefits for total column water vapour or for temperature and wind in the stratosphere out to day 4.