Summary: Analysis of tropical radiative heating profiles: A
comparison of models and observations
Sally A. McFarlane,1
James H. Mather,1
and Thomas P. Ackerman1,2
Received 27 November 2006; revised 3 March 2007; accepted 29 May 2007; published 31 July 2007.
 The vertical distribution of radiative heating in the atmosphere is an important driver
of atmospheric circulation. Evaluation of model simulations of the Earth's radiation
budget typically focus only on performance at the top of the atmosphere or at the surface.
In this study, we compare the vertical distribution of cloud properties and radiative
heating rates calculated from observations at the Department of Energy's Atmospheric
Radiation Measurement (ARM) sites on the islands of Nauru and Manus to simulations
performed using the Multiscale Modeling Framework (MMF) and the Community
Atmosphere Model (CAM). Significant differences are found in the vertical profiles and
diurnal cycle of cloud amount, condensed water content, and cloud effect on heating
rates between the two models and between the models and the observations. The
differences in the heating rates between the models and ARM results depend partly on the
details of the parameterization of effective radius and absorption coefficients used and
partly on differences in cloud frequency, vertical location of clouds, and optical thickness.
Since the same radiative model is used in the CAM and MMF, differences in the effect of