**AERMIC Update 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**• History of AERMIC • Reconstituted AERMIC** **• Summary of AERMIC Activities • Future plans for AERMOD – Overview** **• AMS/EPA Regulatory Model Improvement Committee initially formed in 1991; charged** **to develop replacement for ISCST based on state-of-the-science** **– AERMOD promulgated Dec. 2006 – Membership of “new” AERMIC committee:** **• Roger Brode, OAQPS, Co-chair • Jeff Weil, CIRES-NCAR, Co-chair** **• Akula Venkatram, UC-Riverside • Al Cimorelli, EPA Region 3** **• Bret Anderson, EPA Region 7 • Vlad Isakov, EPA/ORD/AMD** History of AERMIC**• New AERMIC committee has held two meetings in RTP (March and July 2008), with third meeting tentative** **ly planned for mid-November** **• AERMIC reviewed status of AERMOD modeling system a nd** **activities of AIWG at initial meeting • Key priority for AERMIC has been the Urban formula** **tion in AERMOD** **• However, AERMIC recognized significant overlap amo ng** **many issues, including Urban, Surface Characteristi cs and** **Met Data • AERMIC also recognized opportunities to address ma** **ny implementation issues by utilizing newly available** **data**Summary of AERMIC Activities**• AERMIC discussed issues associated with building d ownwash in** **AERMOD – Recommended incorporating building processing func** **tion within AERMOD – Eliminates need for separate BPIPPRM processor** **– Facilitates assessment of additional options for p rocessing building** **information for PRIME, including alternative criter ia for determining controlling** **structure; possibility of combining influences from multiple structures; and** **option for looping through all influencing structur es** **• AERMIC has developed an alternative implementation horizontal** **meander – Preserves centerline value from current implementa** **tion but eliminates upwind dispersion component** **– Could significantly optimize model runtime for som e applications, especially** **for short-term design values – May require additional guidance on applicability f** **or long-term averages – Considering implementation in AERMOD as a regulato** **ry option – This approach is still under assessment** Some AERMIC Recommendations**• AERMIC has discussed the use of gridded prognostic meteorological with AERMOD and will provide science** **support for the development and evaluation of optio ns** **related to this effort – Recommends implementing and testing approach of pr** **ocessing gridded met data as pseudo-observations through AER** **MET, in addition to approach currently implemented in MM5-A** **ERMOD Tool – Recommendation to invite experts in gridded meteor** **ological modeling community to next (or future) AERMIC meeti** **ng – Consideration of options to incorporate some non-s** **teady-state characteristics in AERMOD modeling system, possibly** **driven by gridded meteorological model inputs** Some AERMIC Recommendations**• Building on plans to enhance AERSURFACE by combining land cover and elevation data, AERMIC** **is developing an approach to address a wide range of issues by utilizing this data directly in the mo** **del • Land cover and elevation data (SRTM-NED) will be** **fed directly to AERMOD to develop source-specific meteorology accounting for land cover and obstacle** **heights around source and met tower • Meteorology adjustments will account for effect of** **urban canopy on wind profiles**AERMIC - Future Plans for AERMOD**• This approach could eliminate many implementation issues, especially related to urban applications** **– No distinction between “rural” and “urban” sources – No requirement to estimate “effective” population a** **s surrogate for urban influences** **– Spatial and temporal variability of urban heat isl and** **influence will be accounted for – Representativeness of met data will always be an i** **ssue, but influence of surface characteristic variability** **should be mitigated** **• Considerable work will be required to implement this plan, including performance evaluations** Future Plans for AERMOD (cont.)**• Incorporating fuller range of data directly into AERMOD may eliminate need for preprocessors,** **including AERMAP, AERMET, and AERSURFACE (as well as BPIPPRM)** **• Access to “raw” input data in AERMOD may allow additional enhancements, such as direction-specific** **“hill height scales” for terrain influences, current ly** **not practical to implement • New AERMOD structure will better accommodate** **future enhancements as new data sources emerge • Downside is that this plan is not likely to speed** **up AERMOD!** Future Plans for AERMOD (cont.)**Questions?**