Interpreting Satellite Infrared and Visible Images.

How does the thickness of a cloud change the way it looks from the satellite?

The image to the left is an example of a visible image made from a radiometer flown on the GOES-8 satellite. This image is in the visible part of the spectrum, and measures the amount of solar energy reflected by objects. (Why aren't visible images shown on evening weather reports?) A piece of this image has been extracted and appears as a square below the larger satellite image. This portion of the image contains a cloud and some clear sky areas. You can change the appearance of this extracted image by changing the cloud thickness, which changes the amount of water suspended in the cloud, or the surface temperature. You do this by moving the sliding scales (scroll bars) accompanying the picture on the right.

You can modify the surface characteristics which will, in turn, alter the brightness of the cloud-free scene, by using the horizontal sliding scale.

Questions

• What happens to the image when you make the cloud thinner?
• What happens to the image when you make the cloud thicker?
• What happens to the image when you decrease the ground temperature?
• What happens to the brightness of the cloud when you change the ground temperature? Why?