PNNL

Abstract

Vertical distribution of radiative heating in the atmosphere is an important driver of atmospheric circulation, especially in the tropics. Evaluation of model simulations of the Earth's radiation balance typically focus on performance at the top of the atmosphere or at the surface. This study compares the vertical distribution of clouds 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). There are significant differences between the model vertical profiles of cloud properties and radiative heating and those calculated from the ARM observations. The MMF simulation results in better representation of the observed variability in ice cloud condensed water content and resulting upper tropospheric radiative heating rates than the CAM; more realistic diurnal variability in the radiative heating profiles; and a significantly lower level of zero net radiative heating.