This week’s Satellite Image of the Week was chosen early- otherwise I would have picked one of the massive winter storm. Instead, this week, I chose an infrared image over Minnesota to demonstrate an important concept about satellite imagery.
It was so cold over the Great Plains and the Midwest this past weekend that the infrared sensors were fooled into thinking the ground was a cloud top! The infrared sensor detects radiation in the infrared spectrum, and then translates that to a temperature. Based on our understanding of the atmosphere, that temperature can be used as a proxy to determine cloud top height.
The arctic air mass that we experienced this week was so cold that the infrared sensors recorded low temperatures, and assumed that there was uniform, cold cloud tops. In reality, there were clear skies on this day.
Also, notice that Lake Superior is pixelated. This is because the resolution of the sensor is only so large (1 square km or so), meaning that each square km is given a single temperature value.
Lots of fun things to see in this image! Enjoy.
Thank you for reading this post!
Source: College of DuPage – Meteorology