This image of tropical storm Bonnie was captured on August 11 at 1:30am
CDT. Located in the Gulf of Mexico, the center of the storm is positioned
about 280 miles south-southwest of the mouth of the Mississippi River.
Bonnie is a small tropical storm with wind speeds sustained at 45 mph and
extending 30 miles from the storm center. It is moving northward at 5 mph.
About the Movies
The major contribution to radiation (infrared light) that AIRS infrared
channels sense comes from different levels in the atmosphere, depending
upon the channel wavelength. To create the movies, a set of AIRS infrared
channels were selected which probe the atmosphere at progressively deeper
levels. If there were no clouds, the color in each frame would be nearly
uniform until the Earth's surface is encountered. The tropospheric air
temperature warms at a rate of 6 K (about 11 F) for each kilometer of
descent toward the surface. Thus the colors would gradually change from
cold to warm as the movie progresses.
Clouds block the infrared radiation. Thus wherever there are clouds we can
penetrate no deeper in infrared. The color remains fixed as the movie
progresses, for that area of the image is "stuck" to the cloud top
temperature. The coldest temperatures around 220 K (about -65 F) come
from altitudes of about 10 miles.
We therefore see in a 'surface channel' at the end of the movie, signals
from clouds as cold as 220 K and from Earth's surface at 310 K (about 100
F). The very coldest clouds are seen in deep convection thunderstorms over
land.
Images
August 11, 2004
Infrared image.
August 10, 2004
Daylight snapshot from AIRS visible/near-infrared sensor.
August 11, 2004
At this time, Bonnie is a small tropical storm with wind speeds sustained at 50
mph (85 km/h), and it moving northward at 6 mph.
August 10, 2004
Infrared image. (Larger image not currently available.)
Movies
Slice down the atmosphere with the AIRS infrared sensor.
August 10, 2004, 1:30pm ET (Movie not currently available.)
August 10, 2004, 1:30am ET
August 9, 2004, 1:30pm ET
The Atmospheric Infrared Sounder Experiment, with its visible, infrared,
and microwave detectors, provides a three-dimensional look at Earth's
weather. Working in tandem, the three 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 and provides information on clouds, greenhouse
gases, and many other atmospheric phenomena. The AIRS Infrared Sounder
Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's
Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL
is a division of the California Institute of Technology in Pasadena.
