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Introducing Subgrid-scale convective cloud and aerosol interactions to the WRF-CMAQ integrated modeling system
Citation:
Alapaty, Kiran, S. Yu, G. Zhang, X. Song, Chris Nolte, Jon Pleim, R. Mathur, AND David-C Wong. Introducing Subgrid-scale convective cloud and aerosol interactions to the WRF-CMAQ integrated modeling system. Presented at AGU Fall Meeting, San Francisco, CA, December 09 - 13, 2013.
Impact/Purpose:
The National Exposure Research Laboratory (NERL) Atmospheric Modeling and Analysis Division (AMAD) conducts research in support of EPA mission to protect human health and the environment. AMAD research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
Description:
Many regional and global climate models include aerosol indirect effects (AIE) on grid-scale/resolved clouds. However, the interaction between aerosols and convective clouds remains highly uncertain, as noted in the IPCC AR4 report. The objective of this work is to help fill in this scientific gap by including aerosol indirect effects on parameterized deep convection in the WRF-CMAQ integrated regional modeling system. This is accomplished by first incorporating a convective cloud microphysical scheme directly into a deep convection parameterization, and linking that microphysical scheme with aerosols predicted by the air quality model, CMAQ. To study the relative magnitudes of aerosol indirect forcing by grid- and subgrid-scale clouds, three numerical simulations (one with AIE on resolved clouds only, one with AIE on subgrid-scale clouds only, and one with AIE on both resolved and subgrid-scale clouds) are performed for the summer months (June, July, and August) of 2006 covering the continental US using 12 km grids. These results along with the comparisons of the simulated cloud micro- and macro-physical and radiation parameters as well as other meteorological parameters with observations and reanalysis products will be presented.