Figure 1
This image shows average temperatures in April, 2003, observed by AIRS at
an infrared wavelength that senses either the Earth's surface or any
intervening cloud. Similar to a photograph of the planet taken with the
camera shutter held open for a month, stationary features are captured
while those obscured by moving clouds are blurred. Many continental
features stand out boldly, such as our planet's vast deserts, and India,
now at the end of its long, clear dry season. Also obvious are the high,
cold Tibetan plateau to the north of India, and the mountains of North
America. The band of yellow encircling the planet's equator is the
Intertropical Convergence Zone (ITCZ), a region of persistent
thunderstorms and associated high, cold clouds. The ITCZ merges with the
monsoon systems of Africa and South America. Higher latitudes are
increasingly obscured by clouds, though some features like the Great
Lakes, the British Isles and Korea are apparent. The highest latitudes of
Europe and Eurasia are completely obscured by clouds, while Antarctica
stands out cold and clear at the bottom of the image.
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.