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This animation depicts changes in the temperature of Hurricane Isabel
as the storm moved across the Atlantic Ocean. The thermal structure
is visualized as three surfaces of equal temperature, or isotherms.
The temperature of each isotherm is represented by its color: red is
warmest at 62 F (17 C), orange is the freezing level of 32 F, or 0 C,
and yellow represents very cold temperatures of -10 F, or -23 C. The
animation tracks the hurricane from September 6, 2003 when Isabel formed
off the west coast of Africa, through September 18, 2003 when it made
landfall on the east coast of the United States. AIRS made 15
observations of the hurricane during this period. The storm maintains
a coherent shape throughout most of its life. This shape features a
distinct 'hump' in all three isotherm, corresponding to cooling of
air as it is uplifted in Isabel's thunderstorms. This hump undergoes
a distinct spreading as the storm moves westward, being much wider on
the 17th than on the 14th. The storm winds were significantly more
powerful on the 14th, but the winds were apparently concentrated over
a relatively smaller area. Also seen on the final day is the
beginning of the end of the storm. The hump in the -10 F isotherm has
disappeared in the last image, suggesting that Isabel's thunderstorms
have begun to weaken as the hurricane dissipates over land.
The Atmospheric Infrared Sounder (AIRS) in conjunction with the Advanced
Microwave Sounding Unit (AMSU) sense emitted infrared and microwave
radiation from the Earth to provide a three-dimensional look at Earth's
weather and climate. Working in tandem, the two instruments can make
simultaneous observations all the way down to the Earth's surface, even in
the presence of heavy clouds. With more than 2,000 channels sensing
different regions of the atmosphere, the system creates a global, 3-D map
of atmospheric temperature and humidity, cloud amounts and heights,
greenhouse gas concentrations, and many other atmospheric phenomena. The
AIRS and AMSU fly onboard NASA's Aqua spacecraft and are managed by the
Jet Propulsion Laboratory, Pasadena, California, under contract to NASA.
JPL is a division of the California Institute of Technology in Pasadena.
The AIRS Public Web site can be found at http://airs.jpl.nasa.gov.
