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List of Abstracts 132Contact: amir_hakami@carleton.caTransport of pollution across geopolitical borders may complicate effective implementation of regional ornationwide air pollution control strategies. The problem is further confounded for secondary pollutants thatcan be transported across a border as the pollutant or precursors. In such situations, source attribution fromvarious sources becomes an important and yet challenging task. Contributions from various local, regional,or global sources to air pollution at certain locations are usually evaluated using receptor- or source-basedmodels. However, various approaches can be taken for evaluation of source impacts. In this work we willexplore various approaches for source attribution that differ in terms of the impacted air quality metrics, aswell as attribution methodologies. In particular, we will look at three methods of source attribution in zerooutsimulations, adjoint contribution evaluation, and cross-border flux estimation. Zero-out and fluxsimulations are performed using the community multiscale air quality (CMAQ) model of the USEPA. Foradjoint calculations, we will employ the adjoint version of CMAQ. All simulations will be carried out for thesummer of 2007 and covering the main portion of the North American border between Canada and the US(excluding Alaska). We will explore deficiencies and strengths of each method while looking at the impacton concentrations and ozone exposure as two air quality metrics of concern.P-Transformation.19 ID:4231 10:30Spatial and Temporal Variability of Trace Gases over the United States Derived from Regional ModelOutputMelanie Follette-Cook 1 , Kenneth Pickering 2 , Yasuko Yoshida 3 , James Crawford 4 , Bryan Duncan 2 , ChrisLoughner 5 , Elena Yegorova 5 , Dale Allen 5 , Yongtao Hu 61 University of Maryland Baltimore County - Goddard Earth Sciences and Technology Center2 NASA Goddard Space Flight Center3 SSAI4 NASA Langley Research Center5 University of Maryland College Park6 Georgia Institute of TechnologyContact: melanie.cook@nasa.govThe determination of the spatial and temporal resolution needed by a geostationary instrument to adequatelyresolve trace gas species and aerosols associated with the emission and transport of air pollution will beexplored for several regions of the United States. WRF/Chem and CMAQ were used to generate 4-km and1.5 km horizontal resolution trace gas and aerosol fields, respectively, over the Eastern US for a high ozoneepisode that occurred on July 9, 2007. In addition, CMAQ was used, at a 4-km horizontal resolution, tomodel a pollution event over Los Angeles, CA on July 4, 2007. For each model run, O3, NO2, CO, HCHO,and SO2, and PM2.5 were analyzed. Using a spatial autocorrelation analysis, horizontal variability wascalculated as a function of separation distance in an attempt to quantify the resolution needed to capturevarious amounts of explained variance. This process was repeated for each species, all showing the decay ofthe autocorrelation with greater separation distance. For the Northeast US, autocorrelations of NO2 and SO2displayed the most rapid decay, whereas over Los Angeles, no particular species exhibited significantlyfaster decay than the others. In addition, a temporal correlation analysis was performed to determine theoptimal temporal resolution needed from a geostationary instrument. Results from spatial and temporalvariogram analyses will also be shown for several trace gas species. These variograms show how trace gasgradients in both space and time change with instrument resolution.iCACGP-IGAC 2010 14 July, 2010