The use of data assimilation to augment the utility of satellite data

The assimilation of tropospheric satellite data into chemistry transport models was envisaged by TROPOSAT from the outset. Data assimilation combines both direct and indirect information about the state of the chemical system, whatever the source of information is: satellite data, other remote sensing data, in situ observations with models and climatologies. The measurement data are generally scattered in time and space and have various error characteristics as well as spatial and temporal representativity. The cost associated with this flexibility is given in terms of highly demanding mathematical and computational requirements.