Water vapor is a small but significant constituent of the atmosphere, warming the planet due to the greenhouse effect and condensing to form clouds which both warm and cool the Earth in different circumstances. Warm, moisture-laden air moving out from the tropics brings rainfall to the temperate zones. This animation shows the atmospheric water vapor for the whole globe from September 1, 2004, through September 5, 2004, during the period of Hurricane Frances in the western Atlantic Ocean and Typhoon Songda in the western Pacific Ocean. The band of water vapor over the tropics is the intertropical convergence zone, where converging trade winds and high temperatures force large amounts of water high into the atmosphere. Both Hurricane Frances and Typhoon Songda exhibit significant spiral bands of high water vapor.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 22.214.171.124.0