Dr Marek Wlasak Research Scientist Met Office, FitzRoy Road, Exeter, Devon, EX1 3PB, UK http://www.metoffice.gov.uk/    Marek is a Research Scientist at the United Kingdom's Met Office which he joined in 2002. At the MetOffice he has worked on the development of four dimensional variational data assimilation 4DVAR in the numerical prediction of short-range weather forecasts. This has included working on the implementation of the assimilation of visibility with a 4DVAR context and on the setup of a limited-area 4DVAR. Marek's current interests have returned to those of his PhD, namely research and implementation of the background error covariance matrix for 4DVAR.