Daily Earth Maps from Space from the Atmospheric Infrared Sounder
Global Water Vapor, High Altitude
Today's Near-Real-Time Satellite Feed
Last 3 Days Combined
Water Vapor in units of millimeters (mm) at 500-700 millibar atmospheric pressure
(500-700 millibar atmospheric pressure = approximately 10,000-18,000 feet / 3,000-5,500 meters / 1.6-3.5 miles altitude)
Why does this map show water vapor at this high altitude level?
AIRS, can look at distinct levels of the atmosphere, and AIRS is the first instrument with the ability to isolate water vapor content to layers of the atmosphere. While the concentration of high altitude water vapor is less than at the surface, water vapor at this altitude plays a large role in climate.
The atmosphere can hold very little water vapor at extremely cold temperatures, which results in the strong correspondence between dry areas in this map and cold areas in the temperature maps. The large area of maximum water vapor in the neighborhood of the equator is the Intertropical Convergence Zone or ITCZ, a region of strong convection and powerful thunderstorms.
What do the colors mean?
The color bar is the key to reading the map. The bar will tell you the lightest beige color in the map shows where water vapor amounts are close to 0 mm. Green is approximately 10 mm, and dark blue tops out at 20 mm.
Why are there "stripes" of color in the real-time map?
The AIRS instrument on the Aqua satellite orbits Earth from pole to pole. Imagine if you held a beach ball and tried wrapping a ribbon around the ball, going from top to bottom then bottom to top. Depending on the width of the ribbon, it can take many loops to cover the entire ball. AIRS orbits Earth 15 times a day--not enough orbits for AIRS to completely cover the globe. The black areas between the colored stripes show where AIRS has not yet retrieved data. We call these areas "gores". The stripes in the map shows where AIRS collected data in it's orbital path. We call this stripe a "swath".
> View an Aqua satellite orbit animation
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What do the black areas in the map signify?
In addition to the gores explained in the paragraph above, note that AIRS was designed to retrieve data in clear skies or skies with speckled or thin clouds. So black areas can also show where dense clouds have collected.
View Today's Data Granule Maps
AIRS data is sectioned into pieces called "granules".
DID YOU KNOW?
The warmer the air, the more moisture it can hold.