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Grid-scale Indirect Radiative Forcing of Climate due to aerosols over the northern hemisphere simulated by the integrated WRF-CMAQ model: Preliminary results
Yu, S., Kiran Alapaty, Jon Pleim, R. Mathur, David-C Wong, AND J. Xing. Grid-scale Indirect Radiative Forcing of Climate due to aerosols over the northern hemisphere simulated by the integrated WRF-CMAQ model: Preliminary results. Presented at CMAS Meeting, Chapel Hill, NC, October 30, 2013.
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.
In this study, indirect aerosol effects on grid-scale clouds were implemented in the integrated WRF3.3-CMAQ5.0 modeling system by including parameterizations for both cloud droplet and ice number concentrations calculated from the CMAQ-predicted aerosol particles. The resulting cloud droplet and ice number concentrations are provided to the Morrison double moment cloud microphysics scheme(mass and number concentrations for cloud water and ice),to estimate aerosol effects on cloud and ice optical depth and microphysical process rates for indirect aerosol radiative forcing (including first, second and glaciations indirect aerosol forcing). The cloud drop effective radius and cloud ice effective radius from the output of the Morrison cloud microphysics scheme are used in the RRTMG and CAM radiation schemes affecting the radiation fields. Evaluations of model performance on shortwave cloud forcing (SWCF), longwave cloud forcing (LWCF), cloud optical depth, cloud fraction, cloud effective radius, and PM2.5 are carried out over the northern hemisphere by comparing to satellite observation data such as CERES and MODIS and surface monitoring networks (AQS, IMPROVE, CASTNet, STN, and PRISM) over the continental U.S.