Variational data assimilation: How to extract more information from GOME total ozone data

Combining GOME total ozone measurements with an atmospheric circulation model by means of data assimilation leads to an improved description of the global ozone field. The model describes the time evolution of the instantaneous satellite observation, thereby filling in the large data voids and resulting in almost complete ozone field at any required instant in time. At the same time the forecast error statistics in the assimilation procedure provides a detailed and realistic estimate of the quality of the ozone field as a function of both position and time. This makes the assimilated fields useful for validation of the instruments, and climatological and case studies.