Sensitivity of a regional indicator to Models-3 results at two spatial resolutions

EPA Region III is developing a Decision Consequence Model for strategic planning. The Decision Consequence Model evaluates alternative strategies in terms of the region-wide relative impact on predetermined sensitive indicators. A critical component of developing the indicators is the calculation of pollutant concentrations and depositions using Models-3. This paper examines the sensitivity of an indicator to the resolution of the computation. Indicator values developed with a 36-kilometer resolution are compared with values developed with a 12-kilometer resolution. The working hypothesis is that sufficient accuracy of the Region III indicators for the Decision Consequence Model can be derived from the 36-kilometer calculations. If accepted, this hypothesis eliminates a time and labor consuming step in the Decision Consequence Modeling process.