Met office and ECMWF contribution to NPP and NPOESS cal/val effort

The use of numerical weather prediction (NWP) models m validating and characterizing satellite sounder data is described. The next generation U.S. polar-orbiter missions will be the NPOESS Preparatory Project (NPP) and the National Polar-orbiting Operational Environmental Satellite System (NPOESS). The Met Office and ECMWF will be participating in the calibration/validation activities for these missions, and the planned contributions are described. These contributions include both pre-processing expertise and the assessment of instrument bias and noise, using NWP models as a reference.