PREMAQ: A New Pre-Processor to CMAQ for Air Quality Forecasting Tanya L. Otte*, George Pouliot*, and Jonathan E. Pleim* Atmospheric Modeling Division U.S. EPA ORD National Exposure Research Laboratory Research Triangle Park, NC *On assignment from NOAA Air Resources Laboratory. Disclaimer: The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce’s National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their views or policies.

What is PREMAQ? PREMAQ = “Preprocessor to CMAQ” Part of National AQF System Currently processes Eta Model output Handles functionality of MCIP, parts of SMOKE, and parts of BCON in real time Currently a serial code

The Eta/CMAQ AQF System Eta-12 CMAQ Eta Post PRDGEN PREMAQ AQF Post Verification Tools Vertical interpolation from eta to sigma Horizontal interpolation to Lambert grid CMAQ-ready meteorology and emissions Gridded ozone files for users Chemistry model Meteorology model Performance feedback for users and developers

Practical and Technical Differences fewer (~22) layers terrain-following vert. northeast U.S. Lambert Conformal Arakawa-C P TOP = 100 hPa 60 layers step-mountain vert. continental rotated lat-lon Arakawa-E P TOP = 25 hPa EtaCMAQ

New in PREMAQ (vs. MCIP) GRIB reader (2-D slices vs. full 3-D fields, Arakawa-A) Grid geometry calculations –Different method of defining grids in GRIB –GRIB precision insufficient for lat/lon Modifications to use different suite of variables New dry deposition routine (EtaDry) Met-dependent emissions & LBCs included

166 grid cells 142 grid cells Lambert Conformal projection true at 46°N true at 36°N center at 40.5°N, 79.5°W central meridian 79.5°W I/O API Lower-Left Corner: , [meters from center]  x = 12 km  y = 12 km GRIB Lower-Left Corner: °N, °W Must use LLC lat-lon and projection info (including earth radius) to calculate center and distance from center to LLC!

Grid Gymnastics E dx u,v h i j j+1/2 j-1/2 i-1/2i+1/2 Eta A dx u,v,h j+1 j j-1 i-1ii+1 GRIB C dx j+1 j j-1 i-1ii+1 h u v CMAQ

Changes at NCEP for AQF Hourly post-processed Eta output Hydrostatic  -P structure to 100 hPa Additional forecast variables (PBL height, canopy conductance, plant canopy water) New GRIB grids for AQF

grid cells 259 grid cells Northeast Domain East “3x” Domain Forecast Domains (2004)

PREMAQ: Emission Processing PREMAQ contains a subset of the SMOKE modules PREMAQ contains Point Source and Biogenic Source processing from SMOKE Area Sources computed in SMOKE outside of PREMAQ Mobile Sources (nonlinear least squares approximation to SMOKE/Mobile6)

PREMAQ (part of SMOKE) LaypointMrggridSmkmerge Tmpbeis3

Area and Biogenic Sources Area Sources: 2001 NEI version 3 inventory used. (CAIR) No changes made to inventory. Computed outside of PREMAQ Biogenic Sources: BEIS3.12 included directly into PREMAQ. Canadian Inventory: 1995 used (no changes) Mexico Inventory: BRAVO 1999 used for point sources (3x domain only)

Mobile Sources SMOKE/MOBILE6 not efficient for real- time forecasting SMOKE/MOBILE6 used to create retrospective emissions for AQF grid –1999 VMT data used for input to Mobile 6 –2004 Vehicle Fleet used for input to Mobile 6

Mobile Sources Regression applied at each grid cell at each hour of the week for each species to create temperature/emission relationship Mobile Source emissions calculated in real-time using this derived temperature/emission relationship

NE Domain Mobile6 vs Regression 2003 retrospective SMOKE/MOBILE6 vs nonlinear approximation for NO (Nitric oxide) 8/4/03-9/29/03

NE Domain Mobile6 vs Regression 2003 retrospective SMOKE/MOBILE6 vs. nonlinear approximation for ALD2 (Acetaldehyde and higher aldehydes) 8/4/03-9/29/03

Point Sources 2001 NEIv3 inventory (from CAIR); modified EGU NOx emissions using DOE’s Annual Energy Outlook (Jan 2004) Calculated 2004/2001 NOx annual emission ratios on a regional basis (from DOE data) Applied NOx factors to 2001 base inventory for 2003 (retrospective) and 2004

EGU NOX adjustments 2004/2001 by region for Point Source Inventory Source: Department of Energy Annual Energy Outlook

AQF vs Reported NOx TVA Cumberland Plant

AQF vs Reported NOx TVA Shawnee Plant

PREMAQ Emissions Summary Area/Biogenic No major changes made Mobile Sources: Nonlinear regression used to create temperature/emissions relationship. Point Sources: EGU projections to 2003 and 2004 seem to capture the emission changes from the larger sources but not from smaller sources