Operational NWP assimilation of GPS radio occultation data

Abstract

Since 26 September 2006, refractivity profiles from the CHAMP and GRACE-A satellites have been assimilated in the Met Office operational global numerical weather prediction system. This article presents the results of two experiments, which aim to determine the potential impact on the forecast resulting from the assimilation of this new dataset, and goes on to describe the Met Office operational implementation. Despite the limited number of occultations available for assimilation, the experiments show a significant positive impact on upper troposphere and lower stratosphere temperature and geopotential height fields, mid-tropospheric geopotential heights and pressure at mean sea level in the Southern Hemisphere. © Crown 2008. Reproduced with permission of Controller of HMSO and Queen's Printer for Scotland.