Monday, November 13, 2006 - 3:20 PM
46-6
Land Surface / Vegetation Considerations for Agricultural Air Quality Studies.
We discuss the significance of vegetation (particularly the treatment of canopy resistance and seasonality of vegetation density) and land surface representation including soil moisture variability on the estimation and analysis of deposition velocity for agricultural air quality studies. An overview of the land – atmosphere coupling and the evolution in representing the land surface/vegetation will be discussed. Using specific examples, we will illustrate the implication of the surface representations on meteorological forecasts at various scales. We will then focus on the impact of different methods to represent vegetation in the coupled weather/land-surface model on the dry deposition modeling and the need for considering detailed photosynthesis-based canopy schemes for reducing the uncertainty with deposition estimation. Recent developments with a dry deposition modeling approach that includes vegetation-atmosphere interactions through photosynthesis/carbon assimilation in a coupled soil-vegetation-atmosphere transfer (SVAT) model, together with various methods to specify the seasonal variation of vegetation density, will be presented. Results from the coupled model studies to estimate observed deposition velocity estimates for ozone over agricultural fields, and the enhancements needed to model the bi-directional exchange for ammonia deposition near an animal agricultural facility will be presented. The presentation will conclude with specific recommendations regarding various land surface/vegetation parameterizations for agricultural air quality models.
Recorded presentation