What does the brightness of a cloud mean on the TV weather shows?
Below, the image to the left is an example of an infrared (IR) image. Infrared light is invisible to the human eye, but we can see it with specialized instruments, such as the radiometers flown on the GOES weather satellites. The image below is very typical of the images you see on TV weather shows. We’ve zoomed in on a piece of this image, which you can see below the larger satellite image. This zoomed in portion contains a cloud and some clear sky areas.
Use this simulator to create different conditions that change the appearance of this zoomed in portion. Change the cloud altitude and temperature by dragging the cloud and moving it up and down. You’ll notice from the scales on the sides of the simulation that the air temperature becomes colder the higher the cloud is in the atmosphere. You can change the ground temperature by dragging the black triangle to the right or left.
“What are those cloud images on TV?" WebApp Courtesy of the Cooperative Institute for Meteorological Satellite Studies (CIMSS), Copyright © 2008, 2011, 2013 by Tom Whittaker.
Questions:
- What happens to the image when you lower the cloud?
- What happens to the image when you decrease the ground temperature?
- Adjust the cloud altitude and ground temperature so that the cloud is no longer visible in the image. Can you think of a situation when this might occur?
Adjust the cloud and altitude and ground temperature so that the cloud appears darker than the ground. Can you think of a time of year and geographic region when this meteorological situation might occur?