Analysis of emission databases for regional models

Abstract

General procedures for adapting emission inventories to regional models and for studying the impact of differences in inventories on model predictions are outlined. To illustrate the methods, analysis of two inventories which are still being validated is presented. The inventories together satisfy current requirements for the NCAR regional acid deposition model (RADM). These include anthropogenic emissions of SO 2, sulfate aerosol, NO, NO 2, NH 3 and volatile organic compounds (VOC) in 10 reactivity classes, from United States and Canadian point and area sources on 80-km grid resolutions, for weekend and weekday seasonally representative days on a diurnal basis during the 1980–1982 period. Application of checking procedures, designed by our group to screen for subtle anomalies not identified at previous stages of quality assurance employed by the inventory developers, resulted in adjustments primarily to VOC emissions. Comparisons of the modified inventories, which provide an indication of uncertainties in emissions due to variations in inventory development procedures, revealed differences in the eastern United States total daily emissions to be at most on the order of 5 % for SO x , and NO x , 20% for VOC and 85% for NH 3. Studies of the impact of inventory differences on predictions of RADM were conducted for the 22–24 April 1981 period, which was monitored as part of the Oxidation and Scavenging Characteristics of April Rains program. Event total wet sulfate deposition differed by 10% or less while midday O 3 concentrations differed by 1% or less for individual grids over the modeling domain.