Interesting Satellite Image

This morning as I was looking at the infrared satellite loop at 2:30 AM (yep, that’s normal for a morning weather guy!), I noticed a dark patch of water down in the Gulf that I hadn’t seen before. It’s been there all along, but sometimes we overlook small details of images like these and forget how cool some of the big weather toys are! The image below is from 5:45 AM. The few patchy white spots are clouds, but the darkest area represents where sea surface temperatures are about 5 to 10 F warmer than the surrounding water in an area known as the Loop Current:

Here’s a map of current estimated sea surface temperatures:

The Loop Current is a stream of warm water that bulges up into the southern Gulf of Mexico. After our unusually cold winter, the Loop Current is one of the few spots in the Gulf where temperatures are near or slightly above normal.

(Click here for a map of how current sea surface temperatures compare to the climate “normals.”)

So why is it visible on the satellite image? Well, satellites don’t just look for clouds. The “IR” (infrared) satellite measures outgoing longwave radiation emitted by the earth, clouds, and oceans. Cold things like clouds, snow cover, or very cold ground emit much less longwave radiation than warmer land masses or oceans. On IR satellite images, cold things show up brighter and warm things show up darker. (More on how satellites work from UCAR here)

You can learn a lot staring at a computer early in the morning! That, or the sunny weather has just given me too much time to play with! Enjoy the day!

Jason
Follow me on Twitter! I am @simpson3340

Category: Pre-November 2010 Posts