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Nighttime Imagery of Hurricane Katrina

Nighttime Change Image

Power Outages = Red, Lights = Yellow and Green, Clouds = Blue

2004 Annual Composite vs August 30, 2005 local time on the left
2004 Annual Composite vs Sept. 11th local time on the right

(Click here to view the high resolution image)                            (Click here to view the high resolution image)
Hurricane Image
Nighttime Satellite image showing areas of the Gulf Coast without power (shown in red) following the passage of Hurricane Katrina, versus areas with normal lights (yellow). This nighttime change image is made by comparing an annual composite against data from one night. The composite is produced using cloud-free portions of low-light imaging data acquired by the U.S. Air Force Defense Meteorological Satellite Program (DMSP) over one year. In this case the composite is made using data from 2004 and it is compared with data from August 30, 2005. To make the image an RGB(Red, Green, Blue) is created with the 2004 composite in red, the visible band data from August 30 in green, and the thermal band data from August 30 in blue. This creates an image in which red represents lights that were seen in 2004, but not on August 30, 2005, which suggests a power outage. Lights from both time periods show up in yellow and lights from just August 30, 2005 show up in green. The clouds are displayed in blue. As power is restored the areas in red should revert to yellow. Thin streaks of light near in the vicinity of clouds are lightning strikes.