Amongst the many important products for predicting these events are remotely sensed estimates of Total Precipitable Water from polar orbiting satellites. When something is remotely sensed, it means it is acquired without direct contact. Precipitation estimates from radar are remotely sensed. Satellite images on the nightly news are remotely sensed. On Star Trek, Mr. Spock uses remote sensing to infer the composition and habitability of new planets being visited by the Starship Enterprise.
|Paramount Home Entertainment|
|Even Mr. Spock would envy the remote sensing capabilities provided |
by instruments aboard the NASA A-Train satellite constellation (Image: NASA)
Atmospheric TPW is estimated using observations of microwave radiation from three polar orbiting satellites, including one from the A-Train above (Aqua). The gory details are summarized here. Polar orbiting satellites circle the Earth in a path that nearly passes over the poles, with the satellite scanning a new swath of the Earth each orbit.
Today, thanks to government satellites and the Space Science and Engineering Center at the University of Wisconsin-Madison, you can be Mr. Spock and examine the water vapor loop for the eastern Pacific Ocean, which shows very nicely the large-scale transition that is underway. Note the low TPW values and inferred large-scale northwesterly flow early in the loop and the slug of moisture moving toward California in southwesterly flow late in the loop.
|Image Loop: SSEC, University of Wisconsin-Madison|