Using WRF for Parameterization Development: The Making of ECPP for MMF Models

The Weather Research and Forecasting (WRF) model (Skamarock et al. 2005) is a powerful tool for model parameterization development. The ability to easily vary grid resolution and alter the domain size makes WRF particularly attractive because one is not limited to parameterizations solely suited for mesoscale grid sizes; one can also work with coarser, global climate model-like spacing. With relatively easy modifications WRF can also be converted to work as a single column model, which allows parameterizations developed in 3-D to be tested in varying frameworks. Additionally, the chemistry features in WRF account for both cloud processing of aerosols and the effect of aerosols on cloud properties, which allows researchers to focus on parameterizations addressing some of the key uncertainties hampering climate change modeling. One example of how these features have been utilized in WRF is the development of the ExplicitCloud Parameterized-Pollutant (ECPP) parameterization (Gustafson et al. 2008) that is intended for use with Multiscale Modeling Framework (MMF) models (Grabowski 2001; Randall et al. 2003).