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AN IMPROVED MODEL FOR ESTIMATING EMISSIONS OF VOLATILE ORGANICCOMPOUNDS FROM FORESTS IN THE EASTERN UNITED STATES
Citation:
Geron, C., A. Guenther, AND T. Pierce. AN IMPROVED MODEL FOR ESTIMATING EMISSIONS OF VOLATILE ORGANICCOMPOUNDS FROM FORESTS IN THE EASTERN UNITED STATES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/272.
Description:
Regional estimates of biogenic volatile organic compound (BVOC) emissions are important inputs for models of atmospheric chemistry and carbon budgets. ince forests are the primary emitters of BVOCs, it is important to develop reliable estimates of their areal coverage and BVOC emission rate. ew system is developed to estimate these emissions for specific tree genera at hourly and county level resolution. he U.S. Department of Agriculture, Forest Service Forest Inventory and Analysis Eastwide Database is used to describe the areal extent, species composition, and tree diameter distributions of United States forests. orizontal canopy occupancy by genera is then estimated as a function of diameter at breast height. rowing season peak foliar masses are derived from the empirical literature for canopies of deciduous and coniferous genera. imple canopy model is used to adjust photosynthetically active solar radiation at five vertical levels in the canopy. eaf temperature and photosynthetically active radiation derived from ambient conditions above the forest canopy are then used to drive empirical equations to estimate genus level emission rates of BVOCs vertically through forest canopies. hese genera level estimates are then aggregated to regional levels for comparison with the regulatory model currently used and for input into air quality models. he proposed model yields isoprene emission rate estimates for specific countries that are 5 to 10 times higher (and total BVOC emission rates that are 3 to 5 times higher) than the Environmental Protection Agency BVOC emission rate model currently used. mission estimates of isoprene and monoterpenes from the new system compare favorably with rates measured at various forested sites in the United States.