Does the Dimension of Solar Radiative Transfer Calculations Influence Cloud System-resolving Model Simulations?
Category: Modeling Most, if not all, cloud system-resolving models (CSRMs) perform radiative transfer calculations with the Independent Column Approximation (ICA). Many studies have shown that there can be locally large instantaneous biases between radiative fluxes computed using three-dimensional (3D) transport methods and the, inherently one-dimensional (1D), ICA; especially at solar wavelengths. The purpose of the present study is to begin testing the hypothesis that CSRM simulations are not influenced by the ICA. In order to test this hypothesis, it was necessary to couple a 3D Monte Carlo solar radiative transfer model to the System for Atmospheric Modeling (SAM-version 6.5) CSRM. Several simulations were performed with SAM for the case of a large cyclic domain: 4096 km long (east-west) and either 1 cell wide (2D simulations) or 128 km in the north-south (3D simulations) with horizontal grid-spacing of 1 km. The lower boundary condition was a prescribed sinusoidal sea surface temp
