The Impact of Changing Surface Transportation on Northeast US Chemical Weather and Chemical Climate

Using the modeled behavior of surface freight shippers and carriers in the Northeast US from a recently developed dynamic commodity-flow model (Chen and Donaghy, in prep., Donaghy and Chen, in prep.), we analyze the impact of surface freight transportation in the Northeastern US using the Community Earth System Model (CESM) Community Atmosphere Model, Version 5 (CAM5) with the Modal Aerosol Model (MAM3). The commodity-flow model simulates the county-level independent behaviors of producers (shippers) and carriers along with their associated emissions for 13 states in the Northeastern US and the rest of the US among 13 industries. We both diagnose the model output for a known historical period, 1977 - 2007, and examine potential future scenarios for the 2050s. The historical simulation will provide constraints on future regional air quality simulations as well as allow for verification and calibration of the model configuration. The future simulations are still under development, and will be presented as preliminary results. Currently, these scenarios include: (1) a business-as-usual scenario extrapolating current trends; (2) a severe emission reduction promulgation scenario; and (3) a significant technological “magic-bullet” scenario. The output from this model is gridded and converted to surface emissions for major air quality pollutants, which are then used in simulations of air quality and climate in the CESM CAM5 MAM3 global climate-chemistry model. Particular attention is given to black carbon as it is a pollutant whose regional emissions are subject significant uncertainties. The resulting gridded emissions will be made available to the larger scientific community, and results of the simulations will provide information for local, regional, and national decision makers concerned with air quality, chemical weather, and chemical climate.