The Chemistry of Atmosphere-Forest Exchange (CAFE) Model – Part 1: Model description and characterization G. M. Wolfe1,2 and J. A. Thornton2 1Department of Chemistry, University of Washington, Seattle, WA, USA 2Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA
Abstract. We present the Chemistry of Atmosphere-Forest Exchange (CAFE) model, a
vertically-resolved 1-D chemical transport model designed to probe the
details of near-surface reactive gas exchange. CAFE integrates all key
processes, including turbulent diffusion, emission, deposition and
chemistry, throughout the forest canopy and mixed layer. CAFE utilizes the
Master Chemical Mechanism (MCM) and is the first model of its kind to
incorporate a suite of reactions for the oxidation of monoterpenes and
sesquiterpenes, providing a more comprehensive description of the oxidative
chemistry occurring within and above the forest. We use CAFE to simulate a
young Ponderosa pine forest in the Sierra Nevada, CA. Utilizing
meteorological constraints from the BEARPEX-2007 field campaign, we assess
the sensitivity of modeled fluxes to parameterizations of diffusion, laminar
sublayer resistance and radiation extinction. To characterize the general
chemical environment of this forest, we also present modeled mixing ratio
profiles of biogenic hydrocarbons, hydrogen oxides and reactive nitrogen.
The vertical profiles of these species demonstrate a range of structures and
gradients that reflect the interplay of physical and chemical processes
within the forest canopy, which can influence net exchange.
Citation: Wolfe, G. M. and Thornton, J. A.: The Chemistry of Atmosphere-Forest Exchange (CAFE) Model – Part 1: Model description and characterization, Atmos. Chem. Phys., 11, 77-101, doi:10.5194/acp-11-77-2011, 2011.