Invisible Cirrus Clouds

high resolution images:
true color
cirrus detection channel

The Moderate-resolution Imaging Spectroradiometer’s (MODIS’) cloud detection capability is so sensitive that it can detect clouds that would be indistinguishable to the human eye. This pair ofimages highlights MODIS’ ability to detect what scientists call#147;sub-visible cirrus.” The image on top shows the scene using datacollected in the visible part of the electromagnetic spectrum—the partour eyes can see. Clouds are apparent in the center and lower right ofthe image, while the rest of the image appears to be relatively clear.However, data collected at 1.38µm (lower image) show that a thick layerof previously undetected cirrus clouds obscures the entire scene. Thesekinds of cirrus are called “sub-visible” because they can’t be detectedusing only visible light. MODIS’ 1.38µm channel detects electromagneticradiation in the infrared region of the spectrum. These images weremade from data collected on April 4, 2000.

References & Resources

Image courtesy Mark Gray, MODIS Atmosphere Team