Tropical Cloud Heating Profiles: Analysis from KWAJEX

Abstract

Diabatic heating (or Q1) profiles associated with specific cloud types are produced by matching synoptic cloud observations with a sounding budget analysis during the Tropical Rainfall Measuring Mission (TRMM) Kwajalein Experiment (KWAJEX), which took place in the Marshall Islands from late July through mid-September 1999. Fair-weather cumulus clouds produce up to 1 K day?1 of heating below 850 hPa and are associated with cooling throughout much of the rest of the troposphere. Cumulus congestus clouds produce heating on the order of 1 K day?1 up to 575 hPa and cooling in the mid- to upper troposphere. Cumulonimbus clouds produce heating through the depth of the troposphere, with a maximum of 3.7 K day?1 near 550 hPa. Cloud types indicating widespread rain (stratus or cumulus fractus of bad weather at low levels and nimbostratus at midlevels) have the largest and most elevated heating, with values >10 K day?1 above 600 hPa. Other mid- and high-level cloud types are shown to be consistent with area-averaged rain rates and Q1 profiles. Profiles of the divergence and apparent moisture sink (or Q2) for convective clouds are also analyzed and are shown to be consistent with the physics of the heating profiles just described.