**AERMOD Modeling System: Status and Updates** **Roger W. Brode U.S. EPA/OAQPS** **Air Quality Modeling Group 9** **th Conference on Air Quality Modeling** **October 9, 2008 Research Triangle Park, NC** **Outline • Recap of AERMOD status** **• Recent AERMOD developments – AERMOD dispersion model** **– AERMAP terrain preprocessor – AERMET meteorological preprocessor** **• Other AERMOD-related activities • Promulgated as EPA-preferred near-field model in F** **ederal Register notice dated November 9, 2005, with effect** **ive date of December 9, 2005, as version dated 04300** **• One-year grandfather period expired December 9, 20 06** **• Significant updates to all AERMOD components relea sed** **January 2007 (dated 06341), with limited update to AERMOD (dated 07026)** **– AERMOD model changes included enhancements to impr ove support for** **urban-scale applications • Additional options to vary emissions by month, hour-** **of-day and day-of-week (MHRDOW, MHRDOW7)** **• Multiple urban areas in single model run • Improved memory management** **– Updates to PM-2.5 processing in AERMOD – Beta-test options for capped/horizontal releases a** **nd for PVMRM PSD credit option** **AERMOD Status • AERMET v06341 updates included significant** **changes to processing of NWS Integrated Surface Hourly Data (ISHD) surface data (TD-3505)** **– Selection of which record to process for hours wit h** **multiple records – Processing of cloud cover codes** **– Identify “variable” winds as missing WD and non missing WS rather than calm** **• Several additional bug fixes in AERMET • Single AERMET executable** **AERMOD Status - AERMET • Significant changes in AERMAP v06341 related to** **horizontal datum (NAD) conversion process – Previous version did not account for shift due to** **UTM Lat/Lon conversion** **– Error typically about 200m in Northing coordinate – Incorporated NAD conversion for DOMAIN extent** **– Clarified and simplified treatment of DEM file gap s** **• Corrected bug with method to optimize hill height scale calculation by skipping adjacent DEM files** **• Enhanced debug output options, fixed several bugs, and incorporated additional optimizations** **AERMOD Status - AERMAP • Updates to all three AERMOD components** **completed (dated 08280): – To be released on SCRAM ASAP** **– Miscellaneous bug fixes and enhancements for all t hree** **AERMOD components (more details on following slides )** **– Improvements in code portability across compilers and** **platforms (Windows/Linux) for all components – Update to Intel Fortran Compiler for distributed** **executables (about 40% runtime improvement compared to Compaq Visual Fortran)** **– User’s Guides being updated to incorporate Addenda &** **other corrections Recent AERMOD Developments** **• Modified optional urban roughness length to treat values other than 1.0** **meter as non-DFAULT (per discussion in Section 5.3 of** **AERMOD Implementation Guide** **) • Added options to vary emissions by hour-of-day and** **day-of-week (HRDOW and HRDOW7)** **• Enhanced HOUREMIS option to allow specifying hourl y-varying release** **heights and initial dispersion coefficients for VOL UME and AREA** **sources • Corrected significant bug with use of OLMGROUP key** **word for OLM option; more details in Addendum to Model Change Bu** **lletin (MCB#3) • Corrected problems with processing of surface file** **header for screening meteorology, for interface with AERSCREEN** **• Improved efficiency of memory allocation (especial ly for AREAPOLY)** **• Use of DOUBLE PRECISION for nearly all non-integer variables** **– addresses some long-standing and recent issues with precision** **– also improves consistency of results across differe nt compilers, compiler options, and** **computing platforms Recent AERMOD Changes** **• Fixed problems with processing Alaska DEM files (1 -deg, 15-min** **and 7.5-min data; non-uniform longitude spacing of nodes)** **• Support for National Elevation Dataset (NED), avai lable from** **USGS Seamless Data Server in GeoTIFF format • Allow “mixed” DEM files (1-deg, 7.5-min, and 15-min** **for AK); can be used to fill gaps in 7.5-min coverage, such as o** **ver water grids; however, no** **support for mixed DEM & NED data • Domain keywords (DOMAINXY/DOMAINLL) are now option** **al; will use all available data if omitted** **• Support for INCLUDED keyword on RE and SO pathways • Modified to use standard convention of negative fo** **r West longitude – Simplifies code structure and inputs** **– Consistency with other tools (e.g., AERSURFACE) – Improves applicability beyond the U. S.** **• Allocatable array storage at runtime Recent AERMAP Changes** **• Corrected cosmetic bug with user-specified station elevation,** **incorrectly reported as 100m in Stage 3 report file s** **• Corrected problems with averaging of sub-hourly in puts for site** **specific data • Make broader use of station elevations from data f** **iles (ISHD & SAMSON) and/or user-specified elevations for SURFAC** **E data • Corrected problems with time zone adjustments for** **cases with surface and onsite stations in different zones** **• Added optional user-specified upper air sounding w indow,** **currently hardwired to 11-13Z • Incorporated changes to handle ISHD files with “pr** **oblem” addressed on interim basis by** **FIXISHD utility** **Recent AERMET Changes • Updating Air Pollution Training Institute (APTI) c** **ourse 423, “Dispersion of Air Pollution: Theory and Model App** **lication,” to reflect AERMOD model** **• Support for in-house applications of AERMOD, inclu ding:** **– Application for “Detroit MP Study” to model local-s cale impacts of CAPs and** **HAPs, combined with CMAQ results using “hybrid” appr oach** **– Model-to-monitor comparisons for Benzene emissions from Texas City** **refineries for RTR – Support to Alabama DEM for Birmingham Area Particu** **late Study (BAPS) (discussed this morning)** **– Exposure assessment for Atlanta area to support cu rrent NO** **2 NAAQS** **review (more on this tomorrow morning) – Common themes are meteorological data representati** **veness and processing, source characterization and emission un** **certainties, and model performance on a paired-in-space and/or time basis** **(more on this tomorrow morning)** **Other AERMOD-related Activities • Developing infrastructure to support more efficien** **t updates to AERMOD modeling system, with full assessment of** **the impact of model changes** **– Developing more effective procedures to challenge model changes** **prior to release, including more comprehensive test beds and** **testing across multiple compilers and computing pla tforms** **– Automating process of assessing impact of model ch anges through** **routine application of consequence analysis databas es and model** **evaluation field study databases – Developing procedures for notifying community of s** **ignificant bugs or other issues, with information on potential impa** **cts, work-around if any, and status of fixes** **– Provide clearer procedures and mechanism for repor ting problems** **with the AERMOD modeling system to EPA and tracking status of** **response/resolution Other AERMOD-related Activities** **• Assessing application issues related to AERMOD mod eling** **system and coordinating work of AIWG and AERMIC to address these issues** **– Modeling impacts from haul roads • Coordination with CRA and other stake-holders in a** **ssessing potential updates to AP-42 emission factors** **• Assessing source characterization issues to develo p “best practices”** **recommendations for modeling haul roads • Addressing consistency issues across Regions and S** **tates – Meteorological data representativeness and sensiti** **vity to surface characteristics** **• Conducted AERMOD sensitivity analysis study, prese nted at A&WMA** **Annual Conference in June 2008; plans to expand con ference paper to** **more complete EPA report • Activities of AIWG to develop better understanding** **of issue with goal of improving guidance; plans of AERMIC to enhance AER** **MOD formulation to mitigate this issue (discussed later in this ses** **sion) Other AERMOD-related Activities** **Questions?**