ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-11-10449-2011 Aerosol Climatology over Nile Delta based on MODIS, MISR and OMI satellite data Marey H. S. 1 2 Gille J. C. 1 El-Askary H. M. 3 4 5 Shalaby E. A. 2 El-Raey M. E. 2 National Center for Atmospheric Research (NCAR), Boulder, CO, USA Institute of Graduate Studies and Research (IGSR), Alexandria University, Egypt School of Earth and Environmental Sciences, Schmid College of Science, Chapman University, Orange, CA, USA Center of Excellence in Earth Observing, Chapman University, Orange, CA 92866, USA Department of Environmental Sciences, Faculty of Science, Alexandria University, Moharem Bek, Alexandria, 21522, Egypt 04 04 2011 11 4 10449 10484 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/11/10449/2011/acpd-11-10449-2011.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/11/10449/2011/acpd-11-10449-2011.pdf

Since 1999 Cairo and the Nile delta region have suffered from air pollution episodes called the "black cloud" during the fall season. These have been attributed to either burning of agriculture waste or long-range transport of desert dust. Here we present a detailed analysis of the optical and microphysical aerosol properties, based on satellite data. Monthly mean values of Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) at 550 nm were examined for the 10 yr 2000–2009. Significant monthly variability is observed with maxima in April or May (~0.5) and October (~0.45), and a minimum in December and January (~0.2). Monthly mean values of UV Aerosol Index (UVAI) retrieved by the Ozone Monitoring Instrument (OMI) for 4 yr (2005–2008) exhibit the same AOD pattern. The carbonaceous aerosols during the black cloud periods are confined to the planetary boundary layer (PBL), while dust aerosols exist over a wider range of altitudes, as shown by Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) aerosol profiles. The monthly climatology of Multi-angle Imaging SpectroRadiometer (MISR) data show that the aerosols during the black cloud periods are spherical with a higher percentage of small and medium size particles, whereas the spring aerosols are mostly large non-spherical particles. All of the results show that the air quality in Cairo and the Nile delta region is subject to a complex mixture of air pollution types, especially in the fall season, when biomass burning contributes to a background of urban pollution and desert dust.

 References Abu-Allaban, M., Gertler, A. W., and Lowenthal, D. H. : A preliminary apportionment of the sources of ambient PM10, PM2.5, and VOCs in Cairo, Atmos. Env., 36 (35), 5549–5557, 2002. Abu-Allaban, M., Lowenthal, D. H., Gertler, A. W., and Labib, M.: Sources of PM$_10$ and PM$_2.5$ in Cairo's ambient air, Environ. Monit. Assess., $133$(1-3), 417–425, http://dx.doi.org/10.1007/s10661-006-9596-8doi:10.1007/s10661-006-9596-8, 2007. Alfaro, S. C. and Wahab, M. A.: Extreme variability of aerosol optical properties: The Cairo aerosol characterization experiment case study, Remote Sensing of the Atmosphere For Environmental Security, 285–299, 2006. Ahmad, S. P., Torres, O., Bhartia, P. K., Leptoukh, G. G., and Kempler, S. J.: Aerosol Index from TOMS and OMI Measurements, 14th Joint Conference on the Applications of Air Pollution Meteorology with the Air and Waste Management Assoc., 2006. Barnaba, F. and Gobbi, G. P.: Aerosol seasonal variability over the Mediterranean region and relative impact of maritime, continental and Saharan dust particles over the basin from MODIS data in the year 2001, Atmos. Chem. Phys., 4, 2367–2391, http://dx.doi.org/10.5194/acp-4-2367-2004doi:10.5194/acp-4-2367-2004, 2004. Barnes, W. L., Pagano, T. S., Salomonson, V. V., Directorate, E. S., Center, N., and Greenbelt, M. D.: Prelaunch characteristics of the moderate resolution imaging Spectroradiometer (MODIS) on EOS-AM1, IEEE T. Geosci Remote, 36(4), 1088–1100, 1998. Braak, R., de Laat, J., Torres, O., Veihelmann, B., Veefkind, J. P., Kroon, M., and Levelt, P. F.: OMI UV Absorbing Aerosol Index as a Tracer of Australian Biomass Burning Aerosols, Poster: EGU General Assembly, April 16–22, 2997, 16–22 April 2007, Vienna, Austria, EGU, 2007. Borai E. H. and Soliman, A. A.: Monitoring and statistical evaluation of heavy metals in airborne particulates in Cairo, Egypt, Journal of Chromatography A, 920, 261–269, 2001. Bull, M., Matthews, J., McDonald, D., Moroney, C., Paradise, S., and Smyth, M.: MISR Data Products Specifications, JPL, available at: http://eosweb.larc.nasa.gov/PRODOCS/misr/DPS/DPS_v43_RevQ.pdf, 2008. Dey, S. and Di Girolamo, L.: A climatology of aerosol optical and microphysical properties over the Indian subcontinent from 9 years (2000–2008) of Multiangle Imaging Spectroradiometer (MISR) data, J. Geophys. Res., 115, D15204, http://dx.doi.org/10.1029/2009JD013395doi:10.1029/2009JD013395, 2010. Diner, D. J., Beckert, J. C., Reilly, T. H., Bruegge, C. J., Conel, J. E., Kahn, R. A., Martonchik, R. A., Ackerman, T. P., Davies, R., Gerstl, S., Gordon, H. R., Muller, J.-P., Myneni, R., Sellers, P., Pinty, B., and Verstraete, M.: Multi-angle Imaging Spectro Radiometer (MISR) instrument description and experiment overview, IEEE T. Geosci. Remote, 36(4), 1072–1087, 1998. Diner, D. J., Abdou, W. A., Bruegge, C. J., Conel, J. E., Crean, K. A., Gaitley, B. J., Helmlinger, M. C., Kahn, R. A., Martonchik, J. V., Pilorz, S. H., and Holben, B. N.: MISR aerosol optical depth retrievals over southern Africa during the SAFARI-2000 dry season campaign, Geophys. Res. Lett., 28, (16), 3127–3130, 2001b. Diner, D. J., Abdou, W., Ackerman, T., Crean, K., Gordon, H., Kahn, R., Martonchik, J., McMuldroch, S., Paradise, S., Pinty, B., Verstrete, M., Wang, M., and West, R.: MISR Level 2 Aerosol Retrieval Algorithm Theoretical Basis, JPL- D11400, 2001a. Draxler, R. R. and Hess, G. D.: Description of the HYSPLIT 4 modeling system, NOAA Tech. Memo., ERL ARL-224, 24, 1997. Draxler, R., Draxler, R., Stunder, B., Rolph, G., Stein, A., and Taylor, A.: HYSPLIT4 User's Guide version 4.9, available at: http://www.arl.noaa.gov/documents/reports/hysplit_user_guide.pdf, 2009. Dubovik, O. and King, M. D.: A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurements, J. Geophys. Res., 105(D16), 20673–20696, 2000. DWUA (Demographia World Urban Areas) & Population Projections: 6th Comprehensive Edition (Revised March 2010), available at: http://www.demographia.com/db-worldua.pdf, 2010. El-Metwally, M., Alfaro, S. C., Abdel Wahab, M., and Chatenet, B.: Aerosol characteristics over urban Cairo: Seasonal variations as retrieved from Sunphotomete measurements, J. Geophys. Res., $113$, D14219, http://dx.doi.org/10.1029/2008JD009834doi:10.1029/2008JD009834, 2008. El-Metwally, M., Alfaro, S. C., Abdel Wahab, M. M., Favez, O., Mohamed, Z., and Chatenet, B.: Aerosol properties and associated radiative effects over Cairo (Egypt), Atmos. Res., 9(2), 263–276, 2011. El-Askary, H. and Kafatos, M.: Dust storm and black cloud influence on aerosol optical properties over Cairo and the greater delta region, Egypt, Int. J. Remote Sensing, 29(24), 7199–7211, 2008. El-Askary, H., Farouk, R., Ichoku, C., and Kafatos, M.: Transport of dust and anthropogenic aerosols across Alexandria, Egypt, Ann. Geophys., 27, 2869–2879, http://dx.doi.org/10.5194/angeo-27-2869-2009doi:10.5194/angeo-27-2869-2009, 2009. Favez, O., Cachier, H., Sciare, J., Alfaro, S. C., El-Araby, T. M., Harhash, M. A., and Abdelwahab, M. M.: Seasonality of major aerosol species and their transformations in Cairo megacity, Atmos. Environ., 42, 1503–1516, 2008. Fleishman, J.: EGYPT Cairo's hovering "black cloud", can be found online at: http://latimesblogs.latimes.com/babylonbeyond/2009/10/fires-burn-in-the-provinces-and-mornings-break-smoky-in-the-cityits-harvest-time-the-rice-has-been-gathered-and-farmers.html http://latimesblogs.latimes.com/babylonbeyond/2009/10/fires-burn-in-the-provinces-and-mornings-break-smoky-in-the-cityits-harvest-time-the-rice-has-been-gathered-and-farmers.html, 2009. Haywood, J. M., Ramaswamy, V., and Soden, B. J.: Tropospheric Aerosol climate forcing in clear-sky satellite observations over the oceans, Science, 283, 1299–1303, http://dx.doi.org/10.1126/science.283.5406.1299doi:10.1126/science.283.5406.1299, 1999. Heinrich, J. and Slama, R.: Fine particles, a major threat to children, International Journal of Hygiene and Environmental Health, 210(5), 617–622, 2007. Herman, J. R. and Celarier, E.: Earth's surface reflectivity climatology at 340–380 nm from TOMS data, J. Geophys. Res., 102(28), 28003–28011, http://dx.doi.org/10.1029/97JD02074doi:10.1029/97JD02074, 1997. Holben, B. N., Slutsker, I., Tanre', D., Buis, J. P., Setzer, A., Vermote, E., Reagan, J. A., Kaufman, Y. J., Nakajima, T., Lavenu, F., Jankowiak, I., and Smirnov, A.: AERONET – A federated instrument network and data archive for aerosol characterization, Remote Sens. Environ., $66$(1), 1–16, 1998. Horvath, H., Alados Arboledas, L., Olmo, F. J., Jovanović, O., Gangl, M., Kaller, W., Sánchez, C., Sauerzopf, H., and Seidl, S.: Optical characteristics of the aerosol in Spain and Austria and its effect on radiative forcing, J. Geophys. Res., 107(D19), 4386, http://dx.doi.org/10.1029/2001JD001472doi:10.1029/2001JD001472, 2002. Hsu, N. C., Tsay, S. C., King, M. D., and Herman, J. R.: Aerosol properties over bright-reflecting source regions, IEEE T. Geosci. Remote, 42, 557–569, http://dx.doi.org/10.1109/TGRS.2004.824067doi:10.1109/TGRS.2004.824067, 2004. Hsu, N. C., Tsay, S., King, M. D., and Herman, J. R.: Deep Blue Retrievals of Asian Aerosol Properties During ACE-Asia, IEEE T. Geosci. Remote, ISSN 0196-2892 CODEN IGRSD2, 44(11), 3180–3195, http://dx.doi.org/10.1109/TGRS.2006.879540doi:10.1109/TGRS.2006.879540, 2006. Hossny, E., Mokhtar, G., El-Awady, M., Ali, I., Morsy, M., and Dawood, A.: Environmental exposure of the pediatric age groups in Cairo city and its suburbs to cadmium pollution, Sci. Total Environ., 273, 135–146, 2001. Kaufman, Y. J., Tanre', D., Remer, L. A., Vermote, E. F., Chu, A., and Holben, B. N.: Operational remote sensing of tropospheric aerosol over land from EOS moderate resolution imaging spectroradiometer, J. Geophys. Res., 102(17), 17–51, 1997a. Kaufman, Y. J., Wald, A. E., Remer, L. A., Gao, B.-C., Li, R.-R., and Flynn, L.: The MODIS 2.1-mm channel-correlation with visible reflectance for use in remote sensing of aerosol, IEEE T. Geosci. Remote, 355, 1286–1298, http://dx.doi.org/10.1109/36.628795doi:10.1109/36.628795, 1997b. Labonne, M., Br\'êon, F.-M., and Chevallier, F.: Injection height of biomass burning aerosols as seen from a spaceborne lidar, Geophys. Res.Lett., 34, L11806, http://dx.doi.org/10.1029/2007GL029311doi:10.1029/2007GL029311, 2007. Liu, Z., Vaughan, M. A., Winker, D. M., Hostetler, C. A., Poole, L. R., Hlavka, D., Hart, W., and McGill, M.: Use of probability distribution functions for discriminating between cloud and aerosol in lidar backscatter data, J. Geophys. Res., 109, D15202, http://dx.doi.org/10.1029/2004JD004732doi:10.1029/2004JD004732, 2004. Mahmoud, K. F., Alfaro, S. C., Favez, O., Abdel Wahab, M. M.: Origin of black carbon concentration peaks in Cairo (Egypt), Atmos. Res., 89, 161–169, 2008. Mahowald, N. M. and Dufresne, J.-L.: Sensitivity of TOMS aerosol index to boundary layer height: Implications for detection of mineral aerosol sources, Geophys. Res. Lett., 31, L03103, http://dx.doi.org/10.1029/2003GL018865doi:10.1029/2003GL018865, 2004. Moorthy, K. K., Nair, V. S., Babu, S. S., and Satheesh, S. K.: Spatial and vertical heterogeneities in aerosol properties over oceanic regions around India: Implications for radiative forcing, Q. J. Roy. Meteorol. Soc., 135, 2131–2145, http://dx.doi.org/10.1002/qj.525doi:10.1002/qj.525, 2009. Mahowald, N. M. and Dufresne, J.-L.: Sensitivity of TOMS aerosol index to boundary layer height: Implications for detection of mineral aerosol sources, Geophys. Res. Lett., 31, L03103, http://dx.doi.org/10.1029/2003GL018865doi:10.1029/2003GL018865, 2004. Marey, H. S., Gille, J. C., El-Askary, H. M., Shalaby, E. A., and El-Raey, M. E.: Study of the formation of the "black cloud" and its dynamics over Cairo, Egypt, using MODIS and MISR sensors, J. Geophys. Res., 115, D21206, http://dx.doi.org/10.1029/2010JD014384doi:10.1029/2010JD014384, 2010. Martonchik, J. V., Diner, D. J., Crean, K. A., and Bull, M. A.: Regional aerosol retrieval results from MISR, IEEE T. Geosci. Remote, 40(7), 1520–1531, 2002. Martonchik, J. V., Diner, D. J., Kahn, R., Gaitley, B., and Holben, B. N.: Comparison of MISR and AERONET aerosol optical depths over desert sites, Geophys. Res. Lett., 31, L16102, http://dx.doi.org/10.1029/2004GL019807doi:10.1029/2004GL019807, 2004. McGill, M. J., Vaughan, M. A., Trepte, C. R., Hart, W. D., Hlavka, D. L., Winker, D. M., and Kuehn, R.: Airborne validation of spatial properties measured by the CALIPSO lidar, J. Geophys. Res., 112, D20201, http://dx.doi.org/10.1029/2007JD008768doi:10.1029/2007JD008768, 2007. Meloni, D., di Sarra, A., di Iorio, T., and Fiocco, G.: Influence of the vertical profile of Saharan dust on the visible direct radiative forcing, J. Quant. Spectrosc. Ra., 93, 347–413, 2005. Moroney, C., Davies, R., and Muller, J.-P.: Operational retrieval of cloud-top heights using MISR data, IEEE T. Geosci. Remote, 40(7), 1532–1540, 2002. Moulin, C., Lambert, C. E., Dayan, U., Masson, V., Ramonet, M., Bousquet, P., Legrand, M., Balkanski, Y. J., Guelle, W., Marticorena, B., Bergametti, G., and Dula, F.: Satellite climatology of African dust transport in the Mediterranean atmosphere, J. Geophys. Res., 103, 13137–13144, http://dx.doi.org/10.1029/98JD00171doi:10.1029/98JD00171, 1998. Muller, J., Mandanayake, A., Moroney, C., Davies, R., Diner, D. J., and Paradise, S.: MISR stereoscopic image matchers: Techniques and results, IEEE Trans. Geosci. Remote Sens., 40(7), 1547–1559, 2002. Nasralla, M. M.: Air pollution in greater Cairo, In: Proceeding of the Italian–Egyptian Study-days on the Environment, Cairo, Egypt, 88–100, 1994. Papadimas, C. D., Hatzianastassiou, N., Mihalopoulos, N., Querol, X., and Vardavas, I.: Spatial and temporal variability in aerosol properties over the Mediterranean basin based on 6-year (2000–2006) MODIS data, J. Geophys. Res., 113, D11205, http://dx.doi.org/10.1029/2007JD009189doi:10.1029/2007JD009189, 2008. Prasad A. K., El-Askary, H., and Kafatos, M.: Implications of high altitude desert dust transport from Western Sahara to Nile Delta during biomass burning season, Environ. Pollut., 158(11), 3385–3391, 2010. Remer, L. A., Kaufman, Y. J., Tanre, D., Mattoo, S., Chu, D. A., Martins, J. V., Li, R. R., Ichoku, C., Levy, R. C., Kleidman, R. G., Eck, T. F., Vermote, E., and Holben, B. N.: The MODIS aerosol algorithm, products, and validation, J. Atmos. Sci., 62, 947–973, 2005. Remer, L. A., Tanré, D., and Kaufman, Y. J., Levy, R., and Mattoo, S.: Algorithm for remote sensing of tropospheric aerosols from MODIS, Collection 5, Product ID: MOD04/MYD04, last updated 11/01/2006, http://modis.gsfc.nasa.gov/data/atbd/atbd_mod02.pdf, 2006. Remer, L. A., Kleidman, R. G., Levy, R. C., Kaufman, Y. J., Tanré, D., Mattoo, S., Martins, J. V., Ichoku, C., Koren, I., Yu, H., and Holben, B. N.: Global aerosol climatology from the MODIS satellite sensors, J. Geophys. Res., 113 (D14S07), http://dx.doi.org/10.1029/2007JD009661doi:10.1029/2007JD009661, 2008. Rosenfeld, D.: Suppression of rain and snow by urban and industrial air pollution, Science, 287, 1793–1796, 2000. Robaa, S. M.: A study of ultraviolet solar radiation at Cairo urban area, Egypt, Solar Energy, 77, 251–259, 2004. Salomonson, V. V., Barnes, W. L., Maymon, P. W., Montgomery, H. E., and Ostrow, H.: MODIS: advanced facility instrument for studies of the Earth as a system, IEEE T. Geosci. Remote, 27(2), 145–153, 1989. Stammes, P. and Noordhoek, R.: "OMI Algorithm Theoretical Basis Document Volume III: Clouds, Aerosols, and Surface UV Irradiance", Tech. Rep. ATBD-OMI-03, Version 2.0, 2002. Stephens, G., Vane, D. G., Boain,~R. J., Mace,~G. G., Sassen,~K., Wang,~Z., Illingworth,~A. J., O'Connor,~E. J., Rossow,~W. B., Durden,~S. L., Miller,~S. D., Austin,~R. T., Benedetti,~A., and Mitrescu, C.: The CloudSat mission and the A-train, B. Am. Meteorol. Soc., 83(12), 1771–1790, 2002. Tanré, D., Kaufman, Y. J., Herman, M., and Mattoo, S.: Remote sensing of aerosol properties over oceans using the MODIS/EOS spectral radiances, J. Geophys. Res., 102(D14), 16971–16988, http://dx.doi.org/10.1029/96JD03437doi:10.1029/96JD03437, 1997. Tanskanen, A.: Aerosols from OMI, it can be found online at: http://www.fmi.fi/kuvat/WS_Aero-AerosolsfromOMI_Tanskanen.pdf, 2007. Torres, O., Bhartia, P. K., Herman, J. R., Ahmad, Z., and Gleason, J.: Derivation of aerosol properties from satellite measurements of backscattered ultraviolet radiation: theoretical basis, J. Geophys. Res., 103, 17099–17110, 1998. Torres, O., Bhartia, P. K., Sinyuk, A., Welton, E. J., and Holben, B.: Total Ozone Mapping Spectrometer measurements of aerosol absorption from space: Comparison to SAFARI 2000 ground-based observations, J. Geophys. Res., 110, D10S18, http://dx.doi.org/10.1029/2004JD004611doi:10.1029/2004JD004611, 2005. Torres, O., Tanskanen, A., Veihelmann, B., Ahn, C., Braak, R., Bhartia, P. K., Veefkind, P., and Levelt, P.: Aerosols and surface UV products from Ozone Monitoring Instrument observations: An overview, J. Geophys. Res., 112, D24S47, http://dx.doi.org/10.1029/2007JD008809doi:10.1029/2007JD008809, 2007. Winker, D. M., Pelon, J., and McCormick, M. P.: The CALIPSO mission: Spaceborne lidar for observation of aerosols and clouds, Proc. SPIE, 4893, 1–11, 2003. Winker, D. M., Hunt, W. H., and Hostetler, C. A.: Status and performance of the CALIOP lidar, Proc. SPIE Int. Soc. Opt. Eng., 5575, 8–15, 2004. Winker, D. M., Hostetler, C. A., Vaughan, M. A., and Omar, A. H.: CALIOP Algorithm Theoretical Basis Document, Part 1: CALIOP Instrument, and Algorithms Overview, available online at: http://www-calipso.larc.nasa.gov/resources/pdfs/PC-SCI-202.Part1_v2-Overview.pdf, 2006. Zakey, A. S., Abdelwahab, M. M., and Makar, P. A.: Atmospheric turbidity over Egypt, Atmos. Environ., 38, 1579–1591, 2004.