A Guide to Understanding Satellite Images of Hurricanes
[NOAA] On the morning of September 2, 2019, as a devastating Hurricane Dorian made landfall over three islands in the Bahamas, delivering torrential rain and sustained winds of 185 miles per hour, the VIIRS instruments on the NOAA-20 and NASA-NOAA Suomi-NPP (S-NPP) satellites captured infrared pictures from above. These images, caught at 2:13 am ET and 3:03 am ET respectively, showed a circular eye inside a nearly perfectly symmetrical Category-5 storm.
The world watched that week as Dorian slammed into the Bahamas and then stalled for more than 36 hours, leaving at least 61 people dead and 70,000 homeless. It was the strongest storm on record to hit the island nation.
During a hurricane, instruments on NOAA-20 and S-NPP capture data twice a day. These data are converted into brightly colored pictures that reveal the structure, intensity and temperature of a storm, along with other features, such as lightning and gravity waves.
NOAA’s GOES East and West satellites also show the storm’s evolution by measuring infrared and visible radiation from the atmosphere and surface in real-time. These measurements tell us about wind at various levels in the atmosphere, sea surface temperatures and cloud properties.