MOVES is the U.S. Environmental Protection Agency's (EPA) Motor Vehicle Emission Simulator. In the modeling process, the user specifies vehicle types, time periods, geographical areas, pollutants, vehicle operating characteristics, and road types to be modeled. The model then performs a series of calculations, which have been carefully developed to accurately reflect vehicle operating processes (such as cold start or extended idle) and provide estimates of bulk emissions or emission rates.
An important feature of MOVES is that it allows users to choose between (1) the Inventory calculation type, which provides emission rates in terms of total quantity of emissions for a given time period; and (2) Emission Rate calculation type, which gives emission rates in terms of grams/mile or grams/vehicle/hour. For large-scale emissions modeling such as that needed for regional- and national-scale air quality modeling projects, it is desirable to use the Emission Rate calculation type, which populates emission rate lookup tables that can then be applied to many times and places, thus reducing the total number of MOVES runs required.
To reduce the time and effort and to help the user obtain more accurate modeling results, users need to prepare and post-process MOVES runs for a reference county (See Section 2.8.4.6, “Reference Counties”) and reference fuel month (See Section 2.8.4.7, “Reference Fuel month”) This approach consists of a set of scripts that automate the proper use of the Emission Rate calculations for the purpose of estimating mobile-source emissions for air quality (AQ) modeling.
Integrating MOVES into SMOKE modeling system consists of three major parts:
1) Meteorological data processingThe meteorological data preprocessor program Met4moves prepares spatially and temporally averaged temperatures and relative humidity data to set up the meteorological input conditions for MOVES and SMOKE using the Meteorology-Chemistry Interface Processor (MCIP) output files.
With the specified reference county and reference fuel month approach for temperature and RH calculation for MOVES and SMOKE modeling systems, Met4moves uses hourly min/max temperatures and averaged RH over the spatial region that includes all of the inventory counties in a county group over the user-defined modeling period. Met4moves supports the averaging method (monthly or daily) to create min/max temperatures and averaged RH for all inventory counties in the county group(s). Met4moves determines the min/max grid cell temperatures and associated RH for both SMOKE and MOVES, and computes average 24-hour temperature profiles using Meteorology-Chemistry Interface Processor (MCIP) output files for use in MOVES. These Met4moves program is discussed in detail in Section 6.7, “Met4moves”.
The 24-hour temperature profiles are averaged over a user-specified time period and grid cells for all reference counties. For the MOVES Driver scripts, Met4moves outputs monthly average RH, min/max temperatures, and 24-hour temperature profiles in local time for all reference counties into one output file. For the SMOKE model, Met4moves outputs county-specific min/max temperatures and averaged RH values in local time for every inventory county and averaging period in the modeling inventory.