To conclude this material, we should always remember several points listed below:
- present operational weather satellites (with passive instruments) do not show the internal structure of convective storms, what we see in satellite imagery is the result (a "record") of the previous and present storm activity and its internal processes;
- satellite images do not forecast/nowcast the storm severity, but they show a result of the previous evolution and momentary state of the storm;
- based on proper interpretation of the satellite imagery it is possible to assess the storm activity, evolution phase, and possible severity, and possibly issue warnings (based on the next anticipated storm evolution and motion).
Also, we should always remember that not every large storm as seen in the satellite imagery has to be a severe one - it is not only its size, but all the details of storm top features which can provide us with some hint about the storm structure, its activity and possible severity. For this reason, when monitoring the individual convective storms, we should always try to use the satellite imagery at its full pixel resolution, to see as many details as possible.
We should also keep in our minds that what we see in our satellite data is limited by the satellite's image resolution (pixel size), that the real storm top structure can be much more complex than what we see in our satellite imagery. Below is an example of this - the storm above Nigeria (the same one which we have used so many times within this material), but shown at much higher pixel resolution than what the present MSG satellites are capable of - captured by the MODIS instrument of Aqua satellite, with visible band (MODIS band 1) at 250 m resolution, and thermal IR band (MODIS band 31) at 1 km resolution.
We should also keep in our minds that what we see in our satellite data is limited by the satellite's image resolution (pixel size), that the real storm top structure can be much more complex than what we see in our satellite imagery. Below is an example of this - the storm above Nigeria (the same one which we have used so many times within this material), but shown at much higher pixel resolution than what the present MSG satellites are capable of - captured by the MODIS instrument of Aqua satellite, with visible band (MODIS band 1) at 250 m resolution, and thermal IR band (MODIS band 31) at 1 km resolution.
For a full size view, click on the image
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| Figure 17. High-resolution image of the storm above Nigeria, captured by the Aqua satellite on 2013-05-18 at 13:09 UTC, shown as sandwich product of MODIS bands 1 and 31 (BT 190K-230K). |
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This material was prepared for EUMETSAT by Martin Setvák (setvak@chmi.cz), Satellite Department of the Czech Hydrometeorological Institute, Praha, Czech Republic, 2013.
