The good and bad of satellites

Satellite Picture of Hanna courtesy NOAA
Satellite Picture of Hanna courtesy NOAA

The cover photo above is today’s satellite shot of Tropical Storm Hanna, a familiar picture on TV and a vital tool in forecasting storms of all types, especially tropical storms.

I want to introduce you to another satellite, NASA’s Aqua satellite with MODIS instruments aboard. Our government loves acronyms, don’t they?

MODIS stands for Moderate Resolution Imaging Spectroradiometer, but the bottom line is that this satellite can measure temperatures of cloud tops and that is important in determining how strong thunderstorms are and, ergo how strong tropical systems are becoming. The reasoning is pretty simple: the colder the cloud tops of a thunderstorm, the higher that thunderstorm is growing into the atmosphere; and the higher up it is going, the stronger it is. The stronger storms can help hurricane forecasters determine that a depression is forming. That kind of info led the National Hurricane Center to upgrade the Gulf system to Tropical Depression 8 the other night (along with the invaluable and brave service of the Hurricane Hunters).

Look at the Aqua satellite below and notice the RED colors -- those are very cold cloud tops at -70° and that showed the NHC that Hanna was building strength.

Aqua Satellite Picture shows strong thunderstorm tops (in red) building around what is now Tropical Storm Hanna courtesy NOAA

So, weather satellites are not just all about pretty TV pictures. They are huge forecasting tools.

So what’s the downside?

More and more satellites are going into space for various reasons (your television entertainment being the least of them!) and we’ve watched launch after launch this year. All well and good until you’re trying to take a fabulous picture of Comet NEOWISE and then look what can happen:

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