A31D-0092
Implementation and evaluation of the Modal Aerosol Model (MAM7) in GEOS-5
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Anton Darmenov, NASA Goddard Space Flight Center, Global Modeling and Assimilation Office, Greenbelt, MD, United States, Arlindo M da Silva Jr., NASA Goddard Space Flight Center, Greenbelt, MD, United States, Xiaohong Liu, University of Wyoming, Laramie, WY, United States, Richard C Easter, Battelle PNNL, Richland, WA, United States, Rahul A Zaveri, Pacific Northwest Natl Lab, Richland, WA, United States, Donifan Barahona, NASA GSFC, Greenbelt, MD, United States and Huisheng Bian, NASA Goddard Space Flight Ctr, Greenbelt, MD, United States
Abstract:
The online version of the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model [Chin et al., 2002; Colarco et al., 2010] is the current choice of aerosol model in the Goddard Earth Observing System Model, Version 5 (GEOS-5). The GOCART model belongs to the family of sectional aerosol models that use the mass of aerosol particles partitioned by their size, e.g., using fixed number of non-overlapping size bins. The discretization of the size distribution, however, imposes limits to the accuracy of this approach when using small number of bins. The simplified external mixture treatment of aerosols in GOCART and the use of mass tracers poses challenges for obtaining number concentration of aerosol particles and size resolved aerosol properties, which are important for modeling of aerosol activation properties and aerosol optical parameters. To further advance the GMAO's modeling capabilities a new aerosol component (MAMchem) was implemented in the Goddard Earth Observing System Model, Version 5 (GEOS-5). It predicts spatially and temporally varying aerosol size distribution and mixing state of sulfate, ammonium, black carbon, primary and secondary organic matter, sea salt and dust aerosols. The aerosol microphysics in the new aerosol component is the seven mode version of the modal aerosol model MAM7 [Liu et al., 2012] which was recently extended to include nitrate aerosols. MAMchem is coupled with the GEOS-5 radiation component and the two-moment cloud microphysics scheme enabling global and regional studies of aerosol-radiation-cloud interactions and feedbacks.
In this presentation, we discuss the implementation of MAM7 in GEOS-5 and show results from GEOS-5/MAM7, i.e. MAMchem, simulations including global aerosol simulations at mesoscale (~20km) resolution with such a detailed representation of aerosol processes. The aerosol and cloud fields simulated with MAMchem are evaluated and compared with observations and results from the GEOS-5 meteorological and aerosol reanalysis during the SEAC4RS field campaign.
