Satellite Data
Satellite images are well known. But with the new generation of European Meteorological satellites (MSG - Metosat Second Generation) many more products are available which are special products for forecasters. Here not the whole variety of satellite products will be presented. There is a lot of literature like for instance the "MSG Interpretation Guide" and later on in this Nowcasting exercise there will be a module about the nowcasting SAF. Here we refer to the basic channels of IR and VIS.
The characteristics for an observation network are:
- Space resolution: depends on the geographical latitude and the channel. Pixels of IR images represent in 48 N an area of 4 - 5 kilometers; those of an high resolution VIS image 1,8 kilometers at this latitude
- Time resolution: 15 minutes
- Forecast period: observations; are the input for nowcasting models and systems; give also hints for the quality of the global numerical models
"Satellite images especially in form of loops are very impressive. When non meteorologists critisise wrong forecasts I hear quite often: Now you have satellites and you are still not in a position to make correct forecasts. Can you give me some ideas how to argue in such cases?"
"Well, there is no doubt that satellite images are an unavoidable data source, but they show only restricted qualitites of the atmosphere. Thunderstorm cells for instance are impressive but in the IR image you get the only information about the cloud top temperatures. So for example very white areas represent the coldest part of a cloud cell but not necessarily the most weather active one. If you forget this and let you be guided by what you see optically you could be forced to make wrong forecasts Again you have to combine this material with its content with other data sources!"
"The final set of data to be introduced are lightning reports. Follow
this link
to learn more!"