The MACPEX website will be undergoing a major upgrade beginning Friday, October 11th at 5:00 PM PDT. The new upgraded site will be available no later than Monday, October 21st. Please plan to complete any critical activities before or after this time.

 

Disclaimer: This material is being kept online for historical purposes. Though accurate at the time of publication, it is no longer being updated. The page may contain broken links or outdated information, and parts may not function in current web browsers. Visit https://espo.nasa.gov for information about our current projects.

 

Underestimation of deep convective cloud tops by thermal imagery

Sherwood, S. C., J. Chae, P. Minnis, and M. McGill (2004), Underestimation of deep convective cloud tops by thermal imagery, Geophys. Res. Lett., 31, L11102, doi:10.1029/2004GL019699.
Abstract: 

The most common method of ascertaining cloud heights from space is from thermal brightness temperatures. Deep convective clouds of high water content are expected to radiate as black bodies. Here, thermal cloud top estimates from GOES-8 are compared with direct estimates of where the top should be sensed, based on colocated Goddard Cloud Physics Lidar (CPL) observations collected during the Cirrus Regional Study of Tropical Anvils and Florida Area Cirrus Experiment (CRYSTAL-FACE). GOES-8 cloud top heights are consistently ~1 km lower than the ‘‘visible’’ cloud top estimates from the lidar, even though the latter take into account the finite visible opacity of the clouds and any overlying thin cirrus layers, and are often far below the position of highest detected cloud. The low bias in thermal estimates appears to get worse for the tallest clouds, perhaps by an additional kilometer, and depends little on cloud albedo. The consistency of the bias over multiple satellites suggests that cloud retrievals are affected by an unexpected radiative transfer issue.

PDF of Publication: 
Download from publisher's website.
Research Program: 
Radiation Science Program (RSP)
Mission: 
CRYSTAL FACE