Wednesday, 12 February 2003: 8:45 AM
Soil moisture effects on gaseous exchanges between the atmosphere and the biosphere
The multi-layer biochemical dry deposition model (MLBC) was coupled with the community NOAH land-surface model (LSM) to investigate effects of soil type and soil moisture on gaseous exchanges between the atmosphere and the biosphere. The MLBC is a resistance model, an analog to Ohm's law. Some detailed bio-chemical processes that affect dry deposition are considered in the model. Parameterizations of aerodynamic, boundary layer, stomatal, cuticular and soil surface resistances are updated with new findings in recent research. The model is designed for use in nationwide dry deposition networks, e.g. the Clean Air Status And Trends Network (CASTNet); and in mesoscale air quality models. The NOAH LSM model computes the surface energy and water balances, and produces realistic soil moisture conditions. Almost, every resistance terms in the MLBC model, such as, aerodynamic resistance, stomatal resistance and soil surface resistance are strongly linked with available soil water content. Soil moisture saturation point, field capacity and wilting point vary with soil type, and so does the available soil water content. In this study, we modeled CO2, O3, SO2, NH3 and latent heat fluxes under wet, dry and normal soil moisture conditions with 11 soil types. The preliminary results show that soil moisture effect on the modeled fluxes is significant.