Inline coupling of simple and complex chemistry modules within the global weather forecast model FIM (FIM-Chem v1)

[摘要] The global Flow-following finite-volume Icosahedral Model (FIM), which was developed in the Global Systems Laboratory (GSL) of NOAA, has beencoupled inline with aerosol and gas-phase chemistry schemes of different complexity using the chemistry and aerosol packages from WRF-Chem v3.7,named FIM-Chem v1. The three chemistry schemes include (1) the simple aerosol modules from the Goddard Chemistry Aerosol Radiation and Transportmodel that includes only simplified sulfur chemistry, black carbon (BC), organic carbon (OC), and sectional dust and sea salt modules (GOCART);(2) the photochemical gas phase of the Regional AtmosphericChemistry Mechanism (RACM) coupled to GOCART to determine the impact of more realistic gas-phase chemistry on the GOCARTaerosol simulations (RACM_GOCART); and (3) a further sophistication within the aerosol modules by replacing GOCART with a modal aerosol schemethat includes secondary organic aerosols (SOAs) based on the volatility basis set (VBS) approach (RACM_SOA_VBS). FIM-Chem is able to simulate aerosol, gas-phase chemicalspecies, and SOA at various spatial resolutions with different levels of complexity and quantify the impact of aerosol on numerical weatherprediction (NWP). We compare the results of RACM_GOCART and GOCART schemes which use the default climatological model fields for OH , H 2 O 2 , and NO 3 . We find significant reductions of sulfate that are on the order of 40 % to 80 % over the eastern USand are up to 40 % near the Beijing region over China when using the RACM_GOCART scheme. We also evaluate the model performance by comparing itwith the Atmospheric Tomography Mission (ATom-1) aircraft measurements in the summer of 2016. FIM-Chem shows good performance in capturing the aerosol andgas-phase tracers. The model-predicted vertical profiles of biomass burning plumes and dust plumes off western Africa are also reproducedreasonably well.

[学科分类] 土木及结构工程学