Frequency of tropical precipitating clouds as observed by the Tropical Rainfall Measuring Mission Precipitation Radar and ICESat/Geoscience Laser Altimeter System Academic Article uri icon


  • Convective clouds in the tropics can be grouped into three categories: shallow clouds with cloud top heights near 2 km above the surface, midlevel congestus clouds with tops near the 0C level, and deep convective clouds capped by the tropopause. This trimodal distribution is visible in cloud data from the Geoscience Laser Altimeter System (GLAS), carried aboard the Ice, Cloud, and land Elevation Satellite (ICESat), as well as in precipitation data from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). Fractional areal coverage (FAC) data is calculated at each of the three levels to describe how often optically thick clouds or precipitation are seen at each level. By dividing the FAC of TRMM PR-observed precipitation by the FAC of thick GLAS/ICESat-observed clouds, we derive the fraction of clouds that are precipitating. We find that the tropical mean precipitating cloud fraction is low: 3.7% for shallow clouds, 6.5% for midlevel clouds, and 24.1% for deep clouds. Copyright 2007 by the American Geophysical Union.

published proceedings

  • Journal of Geophysical Research

author list (cited authors)

  • Casey, S., Dessler, A. E., & Schumacher, C.

publication date

  • January 1, 2007 11:11 AM