AtmosphericPollutionResearch1(2010)102Ͳ111 Atmospheric Pollution Research www.atmospolres.com MethodologicalguideforimplementationoftheAERMODsystem withincompletelocaldata LeonorMariaTurtosCarbonell,MadeleineSanchezGacita,JosedeJesusRiveroOliva, LarisaCurbeloGarea,NorbertoDiazRivero,EliezaMenesesRuiz CUBAENERG7A,Calle20#4111%18Ay47,Playa,11300,CiudaddelaHabana,Cuba ABSTRACT The stateͲofͲtheͲart air quality modelling system AERMOD includes an updated treatment of turbulence and Keywords: dispersionintheplanetaryboundarylayerforflowovertheflatandcomplexterrain,scalingconcepts,andsurface AERMOD andelevatedsources.However,thedatarequirementsarehigherthanforthescreeningandtheISCST3models,in Airpollution particularmeteorological,topographyandlandusedataforthemodellingdomain. Dispersionmodelling Mixingheight This work presents a methodology for implementation of the AERMOD modelling system when local data is Gaussianmodels incompleteandisnotintheformatrequiredbythemodel,whichisatypicalsituationinmanycountries,particularly indevelopingones.Inaddition,themaincomputationaltoolsdevelopedtoachievethisobjectivewerepresented: ArticleHistory: LandUse.xls, which takes the place of AERSURFACE; AERMET+, a version of AERMET that runs without upper air Received:06January2010 soundingmeteorologicaldata;andSD_Aermet,whichconvertsthesurfacemeteorologicaldatatoaformataccepted Revised:22March2010 byAERMET. Accepted:24March2010 Threerepresentativecasestudieswerealsopresented,andthemodellingresultsofacasestudywerecomparedto CorrespondingAuthor: measurementdata.TheworkconcludeswithadiscussionofthepossibilityofusingtheAERMODmodelinCubaand LeonorMariaTurtosCarbonell in other countries, even when some input data is absent and climatological conditions differ from the medium Tel:+537Ͳ206Ͳ2065 latitudesforwhichthemodelwasdevelopedfor. Fax:+537Ͳ204Ͳ1188 EͲmail:[email protected] ©Author(s)2010.ThisworkisdistributedundertheCreativeCommonsAttribution3.0License. doi:10.5094/APR.2010.013 1.Introduction dispersion in the planetary boundary layer for flow over the flat andcomplexterrain. Air quality assessment by integrating measurement techͲ niques and modelling tools is a crucial element in pollution AERMOD adopts the ISCST3’s input/output architecture, mitigation.However,inmanycountriessystematicmeasurements ensuringthatthesourcesandatmosphericprocessesmodelledby for monitoring and evaluation of air quality are not available, the ISCST3 can still be handled. Therefore, all the work done to mainlyduetolackofresources. implementISCST3(Turtosetal.,2007a)isastartingpointforthe implementationofAERMOD. Additionally, modelling works are not an effective manageͲ ment tools in many countries due to lack of regulations. In AERMOD, like its predecessor ISCST3, is open–source developingcountrieslikeCuba,theregulatoryframeworkisbased software.Thesourcecode,usermanuals,modelformulation,and on screening models, which are many years behind the stateͲofͲ test cases are available for public access as anonymous user at theͲart dispersion models and they generally yield inaccurate http://www.epa.gov/scram001/dispersion_prefrec.htm and diͲ predictions. spersion_alt.htmrespectively.Beingopen–sourcehasfacilitatedits steadyimprovementandensuredthatitcanbeusedindeveloping The implementation of high–resolution models at the local countries at no additional cost, after making the necessary scale, such as AERMOD (American Meteorological Society–AMS/ adjustments. Environmental Protection Agency–EPA Regulatory MODel), improvestheaccuracyofpredictions,whichtranslatesdirectlyinto 2.Methodology a better understanding of the risks at involved receptors and an improved assessment of compliance with air quality standards, The AERMOD modelling system includes the AERMOD enablingmoreinformeddecisions.However,datarequirementfor dispersionmodel(EPA,2004a)andtwoinputdataprocessorsthat high–resolution models is higher than for screening models, are regulatory components: AERMET (EPA, 2004b), a thereforetheiruseislimitedindevelopingcountries. meteorological data processor, and AERMAP (EPA, 2004c), a terrain data processor. Other non–regulatory components of this TheU.S.EPAestablishedAERMODastheregulatorymodelin system are AERSURFACE (EPA, 2008), a surface characteristics 2005 (EPA, 2005), to replace ISCST3 (Industrial Source Complex processor,andBPIP–PRIME(EPA,2004d)forprocessingdatafrom modelforShortTerms,version3).AERMODisanadvancedplume buildings and obstacles near emission points to determine their model that incorporates updated treatments of turbulence and Turtosetal.–AtmosphericPollutionResearch1(2010)102Ͳ111103 interferencewithplumeriseandtoestimatethevariablesneeded For Cuba, the following adjustments to the default values byAERMODtoevaluatebuildingdownwasheffect. definedbyAERMET’suserguidefordifferentseasons(definedby defaultformid–latitudecontinentalareas)areproposed: 2.1.AERMAP •ValuesinsummerequaltoAERMET’sdefaultsinsummer, One of the main limitations for the use of AERMAP in Cuba •ValuesinwinterequaltoAERMET’sdefaultsinautumn, and other developing countries is the availability of a digital • Values in autumn equal to the average of the AERMET’s elevation model (DEM) containing topographical data of the defaultvaluesforsummerandautumn, modelling domain with an adequate resolution that can be • Values in spring equal to the average of the AERMET’s acquired quickly and inexpensively. There are online free DEM defaultvaluesforspringandsummer. sourcesthatcanbeusedtorunAERMAPwhenalocaloneisnot available.Thefollowingdatasetswereevaluated: In all cases, the default values of the Bowen ratio must be usedforaveragemoistureconditions.Insomeareasofthecountry GTOPO30.ADEMwithsamplespacingof30arc–seconds(~900m) astheverydryregionsofGuantanamo,theseconsiderationsmay (GTOPO30,1996),usingtheLatitude/LongitudeWGS84projection. vary. InthecaseofCuba,CentralAmerica,MexicoandtheCaribbean, thefilesw100n40.demandw140n40.demarerequired. InCuba,asinmanyothercountries,thereisalackofupdated digital land use layers. In this case, the layer contained in the SRTM (Shuttle Radar Topography Mission). A DEM with sample International North America land cover database could be used. spacing of 3 arc–seconds (~90 m), using the Latitude/Longitude ThislayerispartoftheGlobalLandCoverCharacteristicsDatabase projection. Each file corresponds to one degree of latitude and (availableinhttp://LPDAAC.usgs.gov/glcc/glcc.asp)fromtheUSGS longitude. The largest local domain (100x100km) could require and includes all continents. Data share the same projections uptoninefiles.Thenamesofthefiles,e.g.N23W075.hgt,contain (Interrupted Goode Homolosine and Lambert Azimuthal Equal the latitude (North or South) and longitude (West or East) Areas)ataspatialresolutionof~1000m.Thedecisionwasmade correspondingtothelowerleftcornerofthegridsystem. tousethedataintheLambertAzimuthalEqualAreasprojection, whichissupporteddirectlyinmostGISapplications. SRTMisaninternationalprojectspearheadedbytheNational Geospatial–Intelligence Agency (NGA) and the National The data is presented as a raster image with the spatial AeronauticsandSpaceAdministration(NASA).Elevationdataona resolution of 1000m. A land use value corresponds to a 24– near–global scale was obtained to generate the most complete categorylanduseclassificationgiveninthefirstcolumninTable1. high–resolutiondigitaltopographicaldatabaseofEarth(Rodriguez Inaddition,Table1showsthecorrespondenceproposedbetween etal.,2005;Farretal.,2007). thecategoriesusedinthisdatabase,inAERMET,andAERMOD. The resolution of this data set is 10 times higher than Ifanothersourceofdataisused,thecorrespondencetothe GTOPO30.Recently,version2oftheSRTMwasreleased.Version2 categories established for AERMET and AERMOD should be istheresultofasubstantialeditingeffortbytheNGAandexhibits verified. well–defined water bodies and coastlines and the absence of spikes and wells (single pixel errors), although some areas of Table1.LandusecategoriesinUSGSandAERMET–AERMOD missing data (“voids”) are still present. Both are available using anonymousftpate0srp01u.ecs.nasa.gov/srtm. USGScategories AERMET AERMOD Urbanland, 2.2.Landuse UrbanandBuiltͲUpLand Urban no vegetation AERSURFACE, designed to aid in obtaining realistic and DryͲland,CroplandandPasture reproducible surface characteristic values for the AERMOD Agricultural modellingsystem,isavailablefromearly2008(version08009)and IrrigatedCroplandandPasture Cultivated land requires the input of land cover data from the U.S. Geological MixedDryͲland/IrrigatedCroplandandPasture Survey(USGS)NationalLandCoverData1992archives(NLCD92), Land Cropland/GrasslandMosaic ataspatialresolutionof30meters.Thisinformationisavailableat nochargeonlyforusersfromtheUnitedStates.Thismethodology Cropland/WoodlandMosaic Rangeland proposes to replace AERSURFACE combining the use of the Grassland Grassland followingtools: Desert Barrenland, ShrubͲland Shrubland mostlydesert 1)AGeographicalInformationSystem(GIS),fortheprocessing MixedShrubͲland/Grassland oftheavailablelanduselayerisusedtointegrateitwiththelayer Grassland Rangeland that represents the modelling domain in order to estimate the Savannas percentage corresponding to each land use category for each DeciduousBroadleafForest Deciduous sector. In order to satisfy both AERMET and AERMOD requireͲ DeciduousNeedleͲleafForest Forest ments, the modelling domain must be composed of 72 radial sectorsoffivedegreeseach. EvergreenBroadleafForest Forest Coniferous EvergreenNeedleͲleafForest Forest 2)TheMSExcelapplication,LandUse.xls,isusedtocalculatea