Click on the image for the
AIRS Storm Front Approaching California Animation
NASA's Atmospheric Infrared Sounder instrument is able to peel back cloud
cover to reveal 3-D structure of a storm's water vapor content, information
that can be used to improve weather forecast models.
In this animation the initial visible cloud image series shows a front moving
toward the West Coast of the United States as a low pressure area moves
into the Pacific Northwest. The "Pineapple Express," a stream of moisture
that originates in the tropics South of Hawaii and usually crosses Mexico
to enter New Mexico and Texas, has shifted Westward and is also visible
moving into Baja California. The area preceding the front appears to be
relatively clear in the visible images.
As the view shifts from the visible to the infrared wavelengths which
highlight water vapor, we see both cloud areas contain heavy burdens
of moisture. The area which appears clear in the visible images is seen
to contain water vapor near the coastline as well. The viewpoint then
rotates so that we can see the vertical cross section of the fronts. The
variability of the vertical extent of water vapor and the amount is now
clearly visible. The storm moving in from the Gulf of Alaska is more
heavily laden with water vapor than that moving in from the Southwest.
The moisture is concentrated in the lower atmosphere. The colors indicate
the amount of water vapor present. Blue areas denote low water vapor
content; green areas are medium water vapor content; red areas signify
high water vapor content. The vertical grid for the final frame ranges from
250 millibar pressure at the top to 1000 millibar pressure at the bottom.
The top is about 10 km (6.2 miles) above the surface of the Earth.
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.
