Recent Developments in the Assimilation of Satellite Radiances at the UK Met Office

This paper summarises recent satellite upgrades to the Met Office global data assimilation system including: the evaluation and pre-operational testing of data from the Suomi NPP ATMS and CrIS instruments; improved handling of surface affected hyperspectral IR data; improved treatment of observation errors - including an explicit treatment of interchannel error correlations for IASI and a physically based error model for low peaking AMSU-A temperature sounding channels; improved handling of biases in data from the SSMIS instruments and the application of advanced adjoint techniques to data selection. The paper also reviews the performance of the current Met Office bias correction scheme, almost 10 years after it was first implemented, in light of the increasingly stringent requirements on data quality.