Radiative heating of the ISCCP upper level cloud regimes and its impact on the large-scale tropical circulation Academic Article uri icon


  • Radiative heating profiles of the International Satellite Cloud Climatology Project (ISCCP) cloud regimes (or weather states) were estimated by matching ISCCP observations with radiative properties derived from cloud radar and lidar measurements from the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) sites at Manus, Papua New Guinea, and Darwin, Australia. Focus was placed on the ISCCP cloud regimes containing the majority of upper level clouds in the tropics, i.e., mesoscale convective systems (MCSs), deep cumulonimbus with cirrus, mixed shallow and deep convection, and thin cirrus. At upper levels, these regimes have average maximum cloud occurrences ranging from 30% to 55% near 12km with variations depending on the location and cloud regime. The resulting radiative heating profiles have maxima of approximately 1K/day near 12km, with equal heating contributions from the longwave and shortwave components. Upper level minima occur near 15km, with the MCS regime showing the strongest cooling of 0.2K/day and the thin cirrus showing no cooling. The gradient of upper level heating ranges from 0.2 to 0.4K/(daykm), with the most convectively active regimes (i.e., MCSs and deep cumulonimbus with cirrus) having the largest gradient. When the above heating profiles were applied to the 25year ISCCP data set, the tropicswide average profile has a radiative heating maximum of 0.45Kday1 near 250hPa. Columnintegrated radiative heating of upper level cloud accounts for about 20% of the latent heating estimated by the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). The ISCCP radiative heating of tropical upper level cloud only slightly modifies the response of an idealized primitive equation model forced with the tropicswide TRMM PR latent heating, which suggests that the impact of upper level cloud is more important to largescale tropical circulation variations because of convective feedbacks rather than direct forcing by the cloud radiative heating profiles. However, the height of the radiative heating maxima and gradient of the heating profiles are important to determine the sign and patterns of the horizontal circulation anomaly driven by radiative heating at upper levels.

published proceedings


author list (cited authors)

  • Li, W., Schumacher, C., & McFarlane, S. A.

citation count

  • 17

complete list of authors

  • Li, Wei||Schumacher, Courtney||McFarlane, Sally A

publication date

  • January 2013