On the proper use of the satellite imagery for the manual synoptic

Although satellite images were extensively used for the manual synoptic work since they became available, and a lot of rules and conceptual models were developed in order to allow a physical correct interpretation of these data, there are also in the time being analyses distributed by Met Centres which are obviously based on a over-simplified use of the imagery. That refers especially to surface fronts which are often analyzed according to band-like structures in the imagery only and neglecting the typical signatures in the fields of temperature, pressure and wind by which fronts are physically correct defined. And there is still (or again) the tendency to argue with the satellite imagery alone when diagnosing synoptic features not only in upper levels, but also in the surface field. That is dangerous or even misleading since the baroclinic waves in the upper current which are mainly responsible for the cloud coverage in middle and high levels, often are not connected with surface features for a longer time, but show a distinct relative motion with respect to these features, approaching them, but also overtaking them and moving away. All this is reflected by the changing position of the cloud in the imagery, but cannot be recognized when applying too simple and rigid conceptual models of the relationship between clouds and synoptic systems. In the paper the described facts will be discussed with the aid of some typical examples. The right way to use the satellite imagery in the synoptic analysis and diagnosis is therefore a continuous comparison of the images with all the other observations and the analyses or forecasts of the dynamically relevant parameters. In doing so, the imagery may provide the proof for the results of the diagnosis made with the aid of the other data, but can give also important hints with respect to inaccurate or even wrong analyses or forecasts.