ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-9-21199-2009 Saharan dust infrared optical depth and altitude retrieved from AIRS: a focus over North Atlantic – comparison to MODIS and CALIPSO Peyridieu S. 1 Chédin A. 1 Tanré D. 2 Capelle V. 1 Pierangelo C. 3 Lamquin N. 1 Armante R. 1 Laboratoire de Météorologie Dynamique, CNRS/IPSL, Ecole Polytechnique, Palaiseau, France Laboratoire d'Optique Atmosphérique, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France Centre National d'Etudes Spatiales, Toulouse, France 08 10 2009 9 5 21199 21235 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/9/21199/2009/acpd-9-21199-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/9/21199/2009/acpd-9-21199-2009.pdf

Monthly mean infrared (10 μm) dust layer aerosol optical depth (AOD) and mean altitude are simultaneously retrieved over the tropics (30° S–30° N) from six years of Atmospheric Infrared Sounder (AIRS) observations covering the period January 2003 to December 2008. The method developed relies on the construction of Look-up-Tables computed for a large selection of atmospheric situations and follows two main steps: first, determination of the observed atmospheric thermodynamic situation and, second, determination of the dust properties. A very good agreement is found between AIRS-retrieved AODs and visible optical depths from the Moderate resolution Imaging Spectroradiometer (MODIS/Aqua) during the main (summer) dust season, in particular for three regions of the tropical North Atlantic and one region of the north-western Indian Ocean. Outside this season, differences are mostly due to the sensitivity of MODIS to aerosol species other than dust and to the more specific sensitivity of AIRS to the dust coarse mode. AIRS-retrieved dust layer mean altitudes are compared to the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP/CALIPSO) aerosol mean layer altitude for the period June 2006 to December 2008. Results for a region of the north tropical Atlantic downwind of the Sahara show a good agreement between the two products (σ≈370 m). Differences observed in the peak-to-trough seasonal amplitude, smaller from AIRS, are principally attributed to the large difference in spatial sampling of the two instruments. They also come from the intrinsic limit in sensitivity of the passive infrared sounders at low altitudes. These results however demonstrate the capability of high resolution infrared sounders to measure not only dust aerosol AOD but also the mean dust layer altitude.

 References Alpert, P., Kishcha, P., Shtivelman, A., Krichak, S., and Joseph, J.: Vertical distribution of Saharan dust based on 2.5-year model predictions, Atmos. Res., 70, 109–130, doi:10.1016/j.atmosres.2003.11.001, 2004. Carlson, T.: Atmospheric turbidity in Saharan dust outbreaks as determined by analyses of satellite brightness data, Mon. Weather Rev., 107, 322–335, 1979. Chédin, A., Scott, N A., Wahiche, C., and Moulinier, P.: The Improved Initialization Inversion Method: A~high resolution physical method for temperature retrievals from satellites of the TIROS-N series, J. Clim. Appl. Meteorol., 24, 128–143, 1985. Chevallier, F., Cheruy, F., Scott, N A., and Chédin, A.: A~neural network approach for a fast and accurate computation of a longwave radiative budget, J. Appl. Meteorol., 37, 1385–1397, 1998. Chiapello, I., Bergametti, G., Gomes, L., Chatenet, B., Dulac, F., Pimenta, J., and Santos Soares, E.: An additional low layer transport of Sahelian and Saharan dust over the North-Eastern Tropical Atlantic, Geophys. Res. Lett., 22, 3191–3194, doi:0094-8534/95/95GL-0.3313, 1995. Claquin, T., Schulz, M., Balkanski, Y., and Boucher, O.: Uncertainties in assessing radiative forcing by mineral dust, Tellus, 50B, 491–505, 1998. Colarco, P., Toon, O., and Holben, B.: Saharan dust transport to the Caribbean during PRIDE: 1. Influence of dust sources and removal mechanisms on the timing and magnitude of downwind aerosol optical depth events from simulations of in situ and remote sensing observations, J. Geophys. Res., 108, 8589, doi:10.1029/2002JD002658, 2003a. Colarco, P., Toon, O., Reid, J., Livingston, J., Russel, P., Redemann, J., Schmid, B., Maring, H., Savoie, D., Welton, E., Campbell, J., Holben, B., and Levy, R.: Saharan dust transport to the Caribbean during PRIDE: 2. Transport, vertical profiles, and deposition in simulations of in situ and remote sensing observations, J. Geophys. Res., 108, 8590, doi:10.1029/2002JD002659, 2003b. d'Almeida, G., Koepke, P., and Shettle, E.: Atmospheric Aerosols: Global Climatology and Radiative Characteristics, A. Deepak Publishing, Hampton, Virginia 23666-1340, USA, 1991. Deschamps, P.-Y., Breon, F.-M., Leroy, M., Podaire, A., Bricaud, A., Buriez, J.-C., and Sèze, G.: The POLDER mission: Instrument characteristics and scientific objectives, IEEE T. Geosci. Remote, 32, 598–615, 1994. Forster, P., Ramaswamy, V., Artaxo, P., Bernsten, T., Betts, R., Fahey, D., Haywood, J., Lean, J., Lowe, D., Myhre, G., Nganga, J., Prinn, R., Raga, G., Schulz, M., and Van Dorland, R.: Changes in Atmospheric Constituents and in Radiative Forcing, in: Climate Change 2007: The Physical Science Basis. Contribution of the Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K., Tignor, M., and Miller, H., 129–234, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA., 2007. Giglio, L., Csiszar, I., and Justice, C.: Global distribution and seasonality of active fires as observed with the terra and aqua moderate resolution imaging spectroradiometer (MODIS) sensors, J. Geophys. Res., 111, G02016, doi:10.1029/2005JG000142, 2006. Goldberg, M., Qu, Y., McMillin, L., Wolf, W., Zhou, L., and Divakarla, M.: AIRS near-real-time products and algorithms in support of operational numerical weather prediction, IEEE T. Geosci. Remote, 41, 379–389, 2003. Herman, M., Deuzé, J.-L., Marchand, A., Roger, B., and Lallart, P.: Aerosol remote sensing from POLDER//ADEOS over the ocean: Improved retrieval using a~nonspherical particle model, J. Geophys. Res., 110, D10S02, doi:10.1029/2004JD004798, 2005. Hess, M., Koepke, P., and Schult, I.: Optical properties of aerosols and clouds: The software package OPAC, B. Am. Meteorol. Soc., 79, 831–844, 1998. Highwood, E., Haywood, J., Silverstone, M., Newman, S., and Taylor, J.: Radiative properties and direct effect of Saharan dust measured by the C-130 aircraft during Saharan Dust Experiment (SHADE): 2. Terrestrial spectrum, J. Geophys. Res., 108, 8578, doi:10.1029/2002JD002552, 2003. Karyampudi, V., Palm, S., Reagen, J., Fang, H., Grant, W., Hoff, R., Moulin, C., Pierce, H., Torres, O., Browell, E., and Melfi, S.: Validation of the Saharan dust plume conceptual model using Lidar, Meteosat, and ECMWF Data, B. Am. Meteorol. Soc., 80, 1045–1075, 1999. Kaufman, Y., Koren, I., Remer, L., Tanré, D., Ginoux, P., and Fan, S.: Dust transport and deposition observed from the terra-moderate resolution imaging spectroradiometer (MODIS) spacecraft over the Atlantic Ocean, J. Geophys. Res., 110, D10S12, doi:10.1029/2003JD004436, 2005. Kim, S.-W., Berthier, S., Chazette, P., Raut, J.-C., Dulac, F., and Yoon, S.-C.: Validation of aerosol and cloud layer structures from the space-borne lidar CALIOP using a ground-based lidar in Seoul, Korea, Atmos. Chem. Phys., 8, 3705–3720, http://www.atmos-chem-phys.net/8/3705/2008/, 2008. Kinne, S., Lohmann, U., Feichter, J., Schulz, M., Timmreck, C., Ghan, S., Easter, R., Chin, M., Ginoux, P., Takemura, T., Tegen, I., Koch, D., Herzog, M., Penner, J., Pitari, G., Holben, B., Eck, T., Smirnov, A., Dubovik, O., Slutsker, I., Tanré, D., Torres, O., Mishchenko, M., Geogdzhayev, I., Chu, D., and Kaufman, Y.: Monthly averages of aerosol properties: A global comparison among models, satellite data, and AERONET ground data, J. Geophys. Res., 108, 4634, doi:10.1029/2001JD001253, 2003. Koren, I., Kaufman, Y., Washington, R., Todd, M., Rudich, Y., Vanderlei Martins, J., and Rosenfeld, D.: The Bodélé depression: a single spot in the Sahara that provides most of the mineral dust to the Amazon forest, Environ. Res. Lett., 1, 014005, doi:10.1088/1748-9326/1/014005, 2006. Koven, C. and Fung, I.: Inferring dust composition from wavelength-dependent absorption in Aerosol Robotic Network (AERONET) data, J. Geophys. Res., 111, D14205, doi:10.1029/2005JD006678, 2006. Léon, J.-F. and Legrand, M.: Mineral dust sources in the surroundings of the north Indian Ocean, Geophys. Res. Lett., 30, 1309, doi:10.1029/2002GL016690, 2003. Levy, R., Remer, L., Tanré, D., Kaufman, Y., Ichoku, C., Holben, B., Livingston, J., Russell, P., and Maring, H.: Evaluation of the moderate-resolution imaging spectroradiometer (MODIS) retrievals of dust aerosol over the ocean during PRIDE, J. Geophys. Res., 108, 8594, doi:10.1029/2002JD002460, 2003. Li, F. and Ramanathan, V.: Winter to summer monsoon variation of aerosol optical depth over the tropical Indian Ocean, J. Geophys. Res., 107, 4284, doi:10.1029/2001JD000949, 2002. Liu, L. and Mishchenko, M.: Toward unified satellite climatology of aerosol properties: Direct comparisons of advanced level 2 aerosol products, J. Quant. Spectrosc. Ra., 109, 2376–2385, doi:10.1016/j.jqsrt.2008.05.003, 2008. Maring, H., Savoie, D., Izaguirre, M., and Custals, L.: Vertical distributions of dust and sea-salt aerosols over Puerto Rico during PRIDE measured from a~light aircraft, J. Geophys. Res., 108, 8587, doi:10.1029/2002JD002544, 2003a. Maring, H., Savoie, D., Izaguirre, M., Custals, L., and Reid, J.: Mineral dust aerosol size distribution change during atmospheric transport, J. Geophys. Res., 108, 8592, doi:10.1029/2002JD002536, 2003b. McConnell, C., Highwood, E., Coe, H., Formenti, P., Anderson, B., Osborne, S., Nava, S., Desboeufs, K., Chen, G., and Harrison, M.: Seasonal variations of the physical and optical characteristics of Saharan dust: Results from the Dust Outflow and Deposition to the Ocean (DODO) experiment, J. Geophys. Res., 113, D14S05, doi:10.1029/2007JD009606, 2008. Mona, L., Amodeo, A., Pandolfi, M., and Pappalardo, G.: Saharan dust intrusions in the Mediterranean area: Three years of Raman lidar measurements, J. Geophys. Res., 111, D16203, doi:10.1029/2005JD006569, 2006. Moulin, C. and Chiapello, I.: Evidence of the control of summer atmospheric transport of African dust over the Atlantic by Sahel sources from TOMS satellites (1979–2000), Geophys. Res. Lett., 31, L02107, doi:10.1029/2003GL018931, 2004. Papayannis, A., Amiridis, V., Mona, L., Tsaknakis, G., Balis, D., Bösenberg, J., Chaikovski, A., De Tomasi, F., Grigorov, I., Mattis, I., Mitev, V., Müller, D., Nickovic, S., Pérez, C., Pietruczuk, A., Pisani, G., Ravetta, F., Rizi, V., Sicard, M., Trickl, T., Wiegner, M., Gerding, M., Mamouri, R., D'Amico, G., and Pappalardo, G.: Systematic lidar observations of Saharan dust over Europe in the frame of EARLINET (2000–2002), J. Geophys. Res., 113, D10204, doi:10.1029/2007JD009028, 2008. Péquignot, E., Chédin, A., and Scott, N A.: Infrared Continental Surface Emissivity Spectra Retrieved from AIRS Hyperspectral Sensor, J. Appl. Meteorol. Clim., 47, 1619–1633, doi:10.1175/2007JAMC1773.1, 2008. Pierangelo, C., Chédin, A., Heilliette, S., Jacquinet-Husson, N., and Armante, R.: Dust altitude and infrared optical depth from AIRS, Atmos. Chem. Phys., 4, 1813–1822, http://www.atmos-chem-phys.org/acp/4/1813/, 2004. Pierangelo, C., Mishchenko, M., Balkanski, Y., and Chédin, A.: Retrieving the effective radius of Saharan dust coarse mode from AIRS, Geophys. Res. Lett., 32, L20813, doi:10.1029/2005GL023425, 2005. Prospero, J.: Long-range transport of mineral dust in the global atmosphere: Impact of African dust on the environment of the southeastern United States, P. Natl. Acad. Sci. USA, 96, 3396–3403, 1999. Prospero, J. and Carlson, T.: Vertical and areal distribution of Saharan dust over the western equatorial North Atlantic Ocean, J. Geophys. Res., 77, 5255–5265, 1972. Prospero, J., Glaccum, R., and Nees, R.: Atmospheric transport of soil dust from Africa to South America, Nature, 289, 570–572, 1981. Prospero, J., Ginoux, P., Torres, O., Nicholson, S., and Gill, T.: Environmental characterization of global sources of atmospheric soil dust identified with the Nimbus-7 total ozone mapping spectrometer (TOMS) absorbing aerosols product, Rev. Geophys., 40(1), 1002, doi:10.1029/2000RG000095, 2002. Reid, J., Kinney, J., Westphal, D., Holben, B., Welton, E., Tsay, S.-C., Eleuterio, D., Campbell, J., Christopher, S., Colarco, P., Jonsson, H., Livingston, J., Maring, H., Meier, M., Pilewskie, P., Prospero, J., Reid, E., Remer, L., Russell, P., Savoie, D., Smirnov, A., and Tanré, D.: Analysis of measurements of Saharan dust by airborne and groundbased remote sensing methods during the Puerto Rico Dust Experiment (PRIDE), J. Geophys. Res., 108, 8586, doi:10.1029/2002JD002493, 2003. Remer, L., Tanré, D., Kaufman, Y., Ichoku, C., Mattoo, S., Levy, R., Chu, D., Holben, B., Dubovik, O., Smirnov, A., Martins, J., Li, R.-R., and Ahmad, Z.: Validation of MODIS aerosol retrieval over ocean, Geophys. Res. Lett., 29, 1618, doi:10.1029/2001GL013204, 2002. Remer, L., Kaufman, Y., Tanré, D., Mattoo, S., Chu, D., Martins, J., Li, R.-R., Ichoku, C., Levy, R., Kleidman, R., Eck, T., Vermote, E., and Holben, B.: The MODIS aerosol algorithm, products, and validation, J. Atm. Sci., 62, 947–973, doi:10.1175/JAS3385.1, 2005. Scott, N A. and Chédin, A.: A~fast line-by-line method for atmospheric absorption computations: the automatized atmospheric absorption atlas, J. Appl. Meteorol., 20, 802–812, 1981. Stamnes, K., Tsay, S.-C., Wiscombe, W., and Jayaweera, K.: Numerically stable algorithm for discrete ordinate-method radiative transfer in multiple scattering and emitting layered media, Appl. Optics, 27, 2502–2509, 1988. Vogelmann, A., Flatau, P., Szczodrak, M., Markowicz, K., and Minnett, P.: Observations of large aerosol infrared forcing at the surface, Geophys. Res. Lett., 30, 1655, doi:10.1029/2002GL016829, 2003. Volz, F.: Infrared optical constants of ammonium sulfate, Sahara dust, volcanic pumice, and flyash, Appl. Optics, 12, 564–568, 1973. Wald, A., Kaufman, Y., Tanré, D., and Gao, B.-C.: Daytime and nighttime detection of mineral dust over desert using infrared spectral contrast, J. Geophys. Res., 103, 32307–32313, 1998. Winker, D., Hunt, W., and McGill, M.: Initial performance assessment of CALIOP, Geophys. Res. Lett., 34, L19803, doi:10.1029/2007GL030135, 2007.