Chemistry and Biological Meteorology
Chemical and Biological Meteorology research aims to advance knowledge of the underlying processes involved in transport, dispersion and transformation of atmospheric pollutants, particulates and chemical constituents across a wide range of scales, from microscale to mesoscale.
Influence of the surface on the distribution of chemical constituents: Complex terrain creates drainage flow at night that transports CO2 and affects ecosystem-atmosphere exchange. Mountain circulations can also delay the daytime convective mixing. Understanding coupled forest-atmosphere-land-surface interactions in mountain terrain is now being pursued as part of the BEACHON (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen) project, which is an interdisciplinary project involving scientists from MMM, ACD, EOL, and RAL. Contributions from MMM scientists will be to improve understanding and prediction of the role of complex terrain on the water cycle and convective-cloud initiation using WRF combined with the new LES capacity to handle terrain, to investigate complex-terrain issues through analyzing existing small-area datasets, and to analyze aerosol-cloud-precipitation interactions over the Manitou Forest Observatory.
The Canopy Horizontal Array Turbulence Study (CHATS) field program took place in Spring 2007 to understand the impact of tall vegetation on boundary-layer structure, to enable testing of models of within-canopy turbulence, and to guide efforts to improve LES simulations of canopy-modified turbulent flow.
Related Links: CHATS, BEACHON http://www.tiimes.ucar.edu/beachon/
Understanding effects of boundary-layer dynamics and clouds on chemistry: Large-Eddy Simulation studies of the effect of boundary-layer dynamics and clouds on chemical-species concentrations and distributions have shown that the segregation between isoprene and hydroxyl radical (two species that play an important role in ozone production) is increased in the presence of shallow cumulus due to the enhanced vertical transport, the aqueous-phase chemistry, and the scattering of radiation affecting the photochemistry.
Related Link: Workshop on Boundary Layer Processes http://www.atm.helsinki.fi/ILEAPS/surface-processes/
Wildland fires: Wildland fires have been investigated to understand the dynamics of fires for improving fire meteorology prediction and in a collaborative effort with ACD for assessing their impact on air quality. A WRF-Fire version of WRF is now part of the WRF community model suite.
Related Link: WRF http://www.mmm.ucar.edu/wrf/users/
Thunderstorms and Chemistry: The effect of thunderstorms on the distribution of chemical constituents in the troposphere is being investigated with numerical modeling using the WRF-Chem model and through planning a field campaign on Deep Convective Clouds and Chemistry (DC3).
The Deep Convective Clouds and Chemistry (DC3) field campaign will investigate the impact of deep, midlatitude continental convective clouds, including their dynamical, physical, and lightning processes, on upper tropospheric (UT) composition and chemistry. The campaign will make use of extensively instrumented aircraft platforms and ground-based observations.
Using the WRF-Chem model, a convective-system resolving simulation is being conducted to simulation the chemistry of gaseous chemical constituents and aerosols during the 2006 North American Monsoon. Results from this simulation are being examined to understand the generation and dissipation of the upper troposphere ozone maximum, including assessment of the relation between ozone sources/sinks on photolysis rates and convective storm replenishment of ozone precursors, and to understand the influence of surface-heat waves and wild fires on air quality.
Related links: DC3 http://utls.tiimes.ucar.edu/science/dc3.html ; WRF-Chem http://www.acd.ucar.edu/wrf-chem/ ; NAM-Chemistry Simulation http://acd.ucar.edu/~barthm/namcase.html
