May 30, 2008
Journal Article

The Explicit-Cloud Parameterized-Pollutant Hybrid Approach for Aerosol-Cloud Interactions in Multiscale Modelling Framework Models: Tracer Transport Results

Abstract

All estimates of aerosol indirect effects on the global energy balance have either completely neglected the influence of aerosol on convective clouds or treated the influence in a highly parameterized manner. Embedding cloud-resolving models (CRMs) within each grid cell of a global model provides a multiscale modelling framework for treating both the influence of aerosols on convective as well as stratiform clouds and the influence of all clouds on the aerosol, but treating the interactions explicitly by simulating all aerosol processes in the CRM would be computationally prohibitive. An alternate approach is to use horizontal statistics (e.g., cloud mass flux, cloud fraction, and precipitation) from the CRM simulation to drive a single-column parameterization of cloud effects on the aerosol and then use the aerosol profile to simulate aerosol effects on clouds within the CRM. Here we test this concept for vertical transport by clouds, using a CRM with tracer transport simulated explicitly to serve as a benchmark. We show that this parameterization, driven by the CRM’s cloud mass fluxes, reproduces the tracer transport by the CRM significantly better than a single column model that uses a conventional convective cloud parameterization.

Revised: January 17, 2011 | Published: May 30, 2008

Citation

Gustafson W.I., L.K. Berg, R.C. Easter, and S.J. Ghan. 2008. The Explicit-Cloud Parameterized-Pollutant Hybrid Approach for Aerosol-Cloud Interactions in Multiscale Modelling Framework Models: Tracer Transport Results. Environmental Research Letters 3, no. 2:Art. No. 025005. PNNL-SA-58748. doi:10.1088/1748-9326/3/2/025005