Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 9 7 2009 10.5194/acp-9-2301-2009 http://www.atmos-chem-phys.net/9/2301/2009/ http://www.atmos-chem-phys.net/9/2301/2009/acp-9-2301-2009.html http://www.atmos-chem-phys.net/9/2301/2009/acp-9-2301-2009.pdf 2301 2318 2009-04-01 Chemistry and transport of pollution over the Gulf of Mexico and the Pacific: spring 2006 INTEX-B campaign overview and first results H. B. Singh hanwant.b.singh@nasa.gov W. H. Brune J. H. Crawford F. Flocke D. J. Jacob NASA Ames Research Center, Moffett Field, CA 94035, USA Pennsylvania State University, Dept. of Meteorology, PA 16902, USA NASA Langley Research Center, Hampton, VA 23665, USA National Center for Atmospheric Research, Boulder, CO 80301, USA Harvard University, Dept. of Earth and Planetary Science, MA 02138, USA Intercontinental Chemical Transport Experiment-B (INTEX-B) was a major NASA (Acronyms are provided in Appendix A.) led multi-partner atmospheric field campaign completed in the spring of 2006 (<a href="http://cloud1.arc.nasa.gov/intex-b/"target="_blank">http://cloud1.arc.nasa.gov/intex-b/</a>). Its major objectives aimed at (i) investigating the extent and persistence of the outflow of pollution from Mexico; (ii) understanding transport and evolution of Asian pollution and implications for air quality and climate across western North America; and (iii) validating space-borne observations of tropospheric composition. INTEX-B was performed in two phases. In its first phase (1–21 March), INTEX-B operated as part of the MILAGRO campaign with a focus on observations over Mexico and the Gulf of Mexico. In the second phase (17 April–15 May), the main INTEX-B focus was on trans-Pacific Asian pollution transport. Multiple airborne platforms carrying state of the art chemistry and radiation payloads were flown in concert with satellites and ground stations during the two phases of INTEX-B. Validation of Aura satellite instruments (TES, OMI, MLS, HIRDLS) was a key objective within INTEX-B. Satellite products along with meteorological and 3-D chemical transport model forecasts were integrated into the flight planning process to allow targeted sampling of air parcels. Inter-comparisons were performed among and between aircraft payloads to quantify the accuracy of data and to create a unified data set. Pollution plumes were sampled over the Gulf of Mexico and the Pacific several days after downwind transport from source regions. Signatures of Asian pollution were routinely detected by INTEX-B aircraft, providing a valuable data set on gas and aerosol composition to test models and evaluate pathways of pollution transport and their impact on air quality and climate. This overview provides details about campaign implementation and a context within which the present and future INTEX-B/MILAGRO publications can be understood. A. F. Arellano Jr., , Raeder, K., Anderson, J. L., Hess, P. G., Emmons, L. K., Edwards, D. P., Pfister, G. G., Campos, T. L., and Sachse, G. W.: Evaluating model performance of an ensemble-based chemical data assimilation system during INTEX-B field mission, Atmos. Chem. Phys., 7, 5695–5710, 2007. Beer, R., Glavich, T. A., and Rider, D. M.: Tropospheric emission spectrometer for the Earth Observing System's Aura satellite, Appl. Optics, 40(15), 2356–2367, 2001. Boersma, K. F., Jacob, D. J., Bucsela, E. 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