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Keywords:

  • satellite data assimilation;
  • calibration;
  • validation;
  • MWTS;
  • MWHS;
  • IRAS;
  • MWRI

Abstract

FY-3A, launched in May 2008, is the first in a series of seven polar-orbiting meteorological satellites due to be launched by China's Meteorological Administration in the period leading up to 2020. The FY-3A payload includes four instruments of particular interest for numerical weather prediction (NWP): microwave temperature and humidity sounders, a microwave imager, and an infrared sounder. The main features of these instruments are described. Data from the calibration–validation phase of the FY-3A mission were introduced into the ECMWF Integrated Forecasting System in order to assess the data quality and the influence of the data on analyses and forecasts. An analysis of first-guess departures has shown the data to be of good quality overall. Several issues with instrument performance and ground segment processing have been identified. The most serious of these are: uncertainties in the temperature sounder passbands on-orbit, orbital biases in the infrared instrument affecting the highest peaking channels, and scan biases in the microwave humidity sounder. Variational bias correction partially corrects for these errors, but more work remains to be done to correct the problems before the full benefit of the data is realised. In observing system experiments, the FY-3A instruments, both individually and as a package, show considerable skill when added to observation depleted control experiments. When added to a full observing system, the impacts are neutral to slightly positive, as expected. These initial results are encouraging and build confidence that the following series of FY-3 instruments will be widely used in NWP data assimilation systems. Copyright © 2011 Royal Meteorological Society