References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-11-2145-2011

Three-year ground based measurements of aerosol optical depth over the Eastern Mediterranean: the urban environment of Athens

Gerasopoulos

¹ Amiridis

² Kazadzis

¹ Kokkalis

³ Eleftheratos

⁴ ⁵ Andreae

M. O.

⁶ Andreae

T. W.

⁶ El-Askary

⁷ ⁸ Zerefos

C. S.

⁴ ⁵

Institute for Environmental Research and Sustainable Development, National Observatory of Athens, I. Metaxa and Vas. Pavlou, 15236, P. Penteli, Athens, Greece

Insitute for Space Applications and Remote Sensing, National Observatory of Athens, P. Penteli, Athens, Greece

National Technical University of Athens, Laboratory of Lasers and Applications, Athens, Greece

National Kapodistrian University of Athens, Geology Department, Athens, Greece

Biomedical Research Foundation, Academy of Athens, Athens, Greece

Biogeochemistry Department, Max Planck Institute for Chemistry, 55020 Mainz, Germany

School of Earth and Environmental Sciences, Schmid College of Science, Chapman University, Orange, CA, USA

Department of Environmental Sciences, Faculty of Science, Alexandria University, Egypt

10 03 2011

11 5 2145 2159

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.net/11/2145/2011/acp-11-2145-2011.html

The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/2145/2011/acp-11-2145-2011.pdf

Three years (2006–2008) of ground-based observations of the Aerosol Optical Depth (AOD) in the urban environment of Athens, in the Eastern Mediterranean, are analysed in this work. Measurements were acquired with a Multi-Filter Rotating Shadowband Radiometer at five wavelengths. The daily average AOD at 500 nm is 0.23, and the mean Ångström coefficient calculated between 415 and 867 nm is 1.41. The annual variability of AOD has a spring maximum dominated by coarse dust particles from the Sahara (AOD 0.34–0.42), while the diurnal pattern is typical for urban sites, with AOD steadily increasing throughout the day. The greatest contribution to the annually averaged AOD, accounting for almost 40%, comes from regional and local sources (namely the Istanbul metropolitan area, the extended areas of biomass burning around the north coast of the Black Sea, power plants spread throughout the Balkans and the industrial area in the Po valley, with average daily AOD in the range of 0.25–0.35). An additional important contribution (23%) is dust from Africa, whereas the rest of Europe contributes another 22%. The geographical distribution of the above sources in conjunction with the prevailing synoptic situation and contribution of local sources, lead to mixed types of aerosols over Athens, with highly variable contribution of fine and coarse particles to AOD in the range 10%–90%. This is the first long-term, ground based data set available for Athens, and it has also been used for the validation of satellite derived AOD by MODIS, showing good agreement on an annual basis, but with an overestimation of satellite AODs in the warm period.

References 1

Amiridis, V., Balis, D. S., Kazadzis, S., Bais, A., Giannakaki, E., Papayannis, A., and Zerefos, C.: Four-year aerosol observations with a Raman lidar at Thessaloniki, Greece, in the framework of EARLINET, J. Geophys. Res., 110, D21203, http://dx.doi.org/10.1029/2005JD006190doi:10.1029/2005JD006190, 2005.

Amiridis, V., Kafatos, M., Perez, C., Kazadzis, S., Gerasopoulos, E., Mamouri, R. E., Papayannis, A., Kokkalis, P., Giannakaki, E., Basart, S., Daglis, I., and Zerefos, C.: The potential of the synergistic use of passive and active remote sensing measurements for the validation of a regional dust model, Ann. Geophys., 27, 3155–3164, http://dx.doi.org/10.5194/angeo-27-3155-2009doi:10.5194/angeo-27-3155-2009, 2009.

Andreae, T. W., Andreae, M. O., Ichoku, C., Maenhaut, W., Cafmeyer, J., Karnieli, A., and Orlovsky, L., Light scattering by dust and anthropogenic aerosol at a remote site in the Negev desert, Israel, J. Geophys. Res., 107, 4008, http://dx.doi.org/10.1029/2001JD900252doi:10.1029/2001JD900252, 2002.

Ångström, A.: On the atmospheric transmission of sun radiation and on dust in the air, Geogr. Ann. 12, 130–159, 1929.

Balis, D., Amiridis, V., Zerefos, C., Gerasopoulos, E., Andreae, M. O., Zanis, P., Kazantzidis, A., Kazadzis S., and Papayannis, A.: Raman lidar and sunphotometric measurements of aerosol optical properties over Thessaloniki, Greece during a biomass burning episode, Atmos. Environ., 37, 4529–2538, 2003.

Balis, D. S., Amiridis, V., Zerefos, C., Kazantzidis, A., Kazadzis, S., Bais, A. F., Meleti, C., Gerasopoulos, E., Papayannis, A., Matthias, V., Dier, H., and Andreae, M. O.: Study of the effect of different type of aerosols on UV-B radiation from measurements during EARLINET, Atmos. Chem. Phys., 4, 307–321, http://dx.doi.org/10.5194/acp-4-307-2004doi:10.5194/acp-4-307-2004, 2004.

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.

Basart, S., Pérez, C., Cuevas, E., Baldasano, J. M., and Gobbi, G. P.: Aerosol characterization in Northern Africa, Northeastern Atlantic, Mediterranean Basin and Middle East from direct-sun AERONET observations, Atmos. Chem. Phys., 9, 8265–8282, http://dx.doi.org/10.5194/acp-9-8265-2009doi:10.5194/acp-9-8265-2009, 2009.

Chu, D. A., Kaufman, Y. J., Ichoku, C., Remer, L. A., Tanré, D., and Holben, B. N.: Validation of MODIS aerosol optical depth retrieval over land, Geophys. Res. Lett., 29(12), 8007, http://dx.doi.org/10.1029/2001GL013205doi:10.1029/2001GL013205, 2002.

Dorling, S. R., Davies, T. D., and Pierce, C. E.: Cluster analysis: a technique for estimating the synoptic meteorological controls on air and precipitation chemistry – method and applications, Atmos. Environ. 26A, 2575–2581, 1992.

Draxler, R. R. and Hess, G. D.: An overview of the HYSPLIT_4 modeling system for trajectories, dispersion and deposition, Aust. Meteorol. Mag., 47, 295–308, 1998.

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. of Rem. Sens., 29(24), 7199–7211, 2008.

El-Askary, H., Sarkar, S., Kafatos, K., and El-Ghazawi, T. A.: A multisensor approach to dust storm monitoring over the Nile delta, IEEE T. Geosci. Remote, 41(10), 2386–2391, 2003.

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.

Elias, T., Silva, A. M., Belo, N., Pereira, S., Formenti, P., Helas, G., and Wagner, F.: Aerosol extinction in a remote continental region of the Iberian Peninsula during summer, J. Geophys. Res., 111(D14), D14204, http://dx.doi.org/10.1029/2005JD006610doi:10.1029/2005JD006610, 2006.

El-Metwally, M., Alfaro, S. C., Abdel Wahab, M. M., Zakey, A. S., and Chatenet, B.: Seasonal and inter-annual variability of the aerosol content in Cairo (Egypt) as deduced from the comparison of MODIS aerosol retrievals with direct AERONET measurements, Atmos. Res., 97, 14–25, http://dx.doi.org/10.1016/j.atmosres.2010.03.003doi:10.1016/j.atmosres.2010.03.003, 2010.

Engel-Cox, J. A., Holloman, C. H., Coutant, B. W., and Hoff, R. M.: Qualitative and quantitative evaluation of MODIS satellite sensor data for regional and urban scale air quality, Atmos. Environ., 38, 2495–2509, 2004.

Engelstaedter, S. and Washington, R.: Atmospheric controls on the annual cycle of North African dust, J. Geophys. Res., 112, D03103, http://dx.doi.org/10.1029/2006JD007195doi:10.1029/2006JD007195, 2007.

Formenti, P., Andreae, M. O., Andreae, T. W., Galani, E., Vasaras, A., Zerefos, C., Amiridis, V., Orlovsky, L., Karnieli, A., Wendisch, M., Wex, H., Holben, B. N., Maenhaut, W., and Lelieveld, J.: Aerosol optical properties and large scale transport of air masses: Observations at a coastal and a semiarid site in the eastern Mediterranean during summer 1998, J. Geophys. Res., 106, 9807–9826, 2001.

Fotiadi, A., Hatzianastassiou, N., Drakakis, E., Matsoukas, C., Pavlakis, K. G., Hatzidimitriou, D., Gerasopoulos, E., Mihalopoulos, N., and Vardavas, I.: Aerosol physical and optical properties in the Eastern Mediterranean Basin, Crete, from Aerosol Robotic Network data, Atmos. Chem. Phys., 6, 5399–5413, http://dx.doi.org/10.5194/acp-6-5399-2006doi:10.5194/acp-6-5399-2006, 2006.

Gerasopoulos, E., Andreae, M. O., Zerefos, C. S., Andreae, T. W., Balis, D., Formenti, P., Merlet, P., Amiridis, V., and Papastefanou, C.: Climatological aspects of aerosol optical properties in Northern Greece, Atmos. Chem. Phys., 3, 2025–2041, http://dx.doi.org/10.5194/acp-3-2025-2003doi:10.5194/acp-3-2025-2003, 2003.

Gerasopoulos, E., Kouvarakis, G., Babasakalis, P., Vrekoussis, M., Putaud, J.-P., Mihalopoulos, N.: Origin and variability of particulate matter (PM$_10$) mass concentrations over the Eastern Mediterranean, Atmos. Environ., 40(25), 4679–4690, 2006.

Gerasopoulos, E., Koulouri, E., Kalivitis, N., Kouvarakis, G., Saarikoski, S., Mäkelä, T., Hillamo, R., and Mihalopoulos, N.: Size-segregated mass distributions of aerosols over Eastern Mediterranean: seasonal variability and comparison with AERONET columnar size-distributions, Atmos. Chem. Phys., 7, 2551–2561, http://dx.doi.org/10.5194/acp-7-2551-2007doi:10.5194/acp-7-2551-2007, 2007.

Gerasopoulos, E., Kokkalis, P., Amiridis, V., Liakakou, E., Perez, C., Haustein, K., Eleftheratos, K., Andreae, M. O., Andreae, T. W., and Zerefos, C. S.: Dust specific extinction cross-sections over the Eastern Mediterranean using the BSC-DREAM model and sun photometer data: the case of urban environments, Ann. Geophys., 27, 2903–2912, http://dx.doi.org/10.5194/angeo-27-2903-2009doi:10.5194/angeo-27-2903-2009, 2009.

Giannakaki, E., Balis, D. S., Amiridis, V., and Zerefos, C.: Optical properties of different aerosol types: seven years of combined Raman-elastic backscatter lidar measurements in Thessaloniki, Greece, Atmos. Meas. Tech., 3, 569–578, http://dx.doi.org/10.5194/amt-3-569-2010doi:10.5194/amt-3-569-2010, 2010.

Giavis, G. M., Kambezidis, H. D., Sifakis, N., Toth, Z., Adamopoulos, A. D., and Zevgolis, D.: Diurnal variation of the aerosol optical depth for two distinct cases in the Athens area, Greece, Atmos. Res., 78(1-2), 79–92, http://dx.doi.org/10.1016/j.atmosres.2005.03.003doi:10.1016/j.atmosres.2005.03.003, 2005.

Gobbi, G. P., Kaufman, Y. J., Koren, I., and Eck, T. F.: Classification of aerosol properties derived from AERONET direct sun data, Atmos. Chem. Phys., 7, 453–458, http://dx.doi.org/10.5194/acp-7-453-2007doi:10.5194/acp-7-453-2007, 2007.

Griffin, D. W., Kubilay, N., Kocak, M., Gray, M. A., Borden, T. C., and Shinn, E. A.: Airborne desert dust and aeromicrobiology over the Turkish Mediterranean coastline, Atmos. Environ., 41, 4050–4062, http://dx.doi.org/10.1016/j.atmosenv.2007.01.023doi:10.1016/j.atmosenv.2007.01.023, 2007.

Harrison, L. and Michalsky, J.: Objective algorithms for the retrieval of optical depths from ground-based measurements, Appl. Optics, 33, 5126–5132, 1994.

Harrison, L., Michalsky, J., and Berndt, J.: Automated multifilter rotating shadow-band radiometer: an instrument for optical depth and radiation measurements, Appl. Optics, 33, 5118–5125, 1994.

Hatzianastassiou, N., Gkikas, A., Mihalopoulos, N., Torres, O., and Katsoulis, B. D.: Natural versus anthropogenic aerosols in the eastern Mediterranean basin derived from multiyear TOMS and MODIS satellite data, J. Geophys. Res., 114, D24202, http://dx.doi.org/10.1029/2009JD011982doi:10.1029/2009JD011982, 2009.

IPCC: Intergovernmental Panel on Climate Change, Climate Change 2001: The Scientific Basis, in: Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate, edited by: Houghton, J.T., Ding, Y., Griggs, D. J., Noguer, M., van der Linden, P. J., Dai, X., Maskell, K., and Johnson, C. A., Cambridge Univ. Press, New York, 2001.

IPCC: Intergovernmental Panel on Climate Change 2007: Climate Change 2007: The Physical Science Basis, Summary for Policymakers, Paris, February 2007.

Israelevich, P. L., Levin, Z., Joseph, J. H., and Ganor, E.: Desert aerosol transport in the Mediterranean region as inferred from the TOMS aerosol index, J. Geophys. Res., 107(D21), 4572, http://dx.doi.org/10.1029/2001JD002011doi:10.1029/2001JD002011, 2002.

Jacovides, C. P., Kaltsounides, N. A., Asimakopoulos, D. N., and Kaskaoutis, D. G.: Spectral aerosol optical depth and Ångström parameters in the polluted Athens atmosphere, Theor. Appl. Climatol., 81, 161–167, http://dx.doi.org/10.1007/s00704-004-0110-3doi:10.1007/s00704-004-0110-3, 2005.

Kazadzis, S., Bais, A., Amiridis, V., Balis, D., Meleti, C., Kouremeti, N., Zerefos, C. S., Rapsomanikis, S., Petrakakis, M., Kelesis, A., Tzoumaka, P., and Kelektsoglou, K.: Nine years of UV aerosol optical depth measurements at Thessaloniki, Greece, Atmos. Chem. Phys., 7, 2091–2101, http://dx.doi.org/10.5194/acp-7-2091-2007doi:10.5194/acp-7-2091-2007, 2007.

Kalabokas, P. D., Adamopoulos, A. D., and Viras L. G.: Atmospheric PM$_10$ particle concentration measurements at central and peripherals urban sites in Athens and Thessaloniki, Greece, Global NEST Journal, 12(1), 71–83, 2010.

Kalivitis, N., Gerasopoulos, E., Vrekoussis, M., Kouvarakis, G., Kubilay, N., Hatzianastassiou, N., Vardavas, I., and Mihalopoulos, N.: Dust transport over the Eastern Mediterranean from TOMS, AERONET and surface measurements, J. Geophys. Res., 112, D03202, http://dx.doi.org/10.1029/2006JD007510doi:10.1029/2006JD007510, 2007.

Kanakidou, M., Mihalopoulos, N., Kindap, T., Im, U., Vrekoussis, M., Dermitzaki, E., Gerasopoulos, E. , Unal, A., Koçak, M., Markakis, K., Melas, D., Youssef, A. F., and Moubasher, H.: Megacities as hot spots of air pollution in the East Mediterranean, http://dx.doi:10.1016/j.atmosenv.2010.11.048doi:10.1016/j.atmosenv.2010.11.048, 2010.

Karnieli, A., Derimian, Y., Indoitu, R., Panov, N., Levy, R. C., Remer, L. A., Maenhaut, W., and Holben, B. N.: Temporal trend in anthropogenic sulfur aerosol transport from central and eastern Europe to Israel, J. Geophys. Res., 114, D00D19, http://dx.doi.org/10.1029/2009JD011870doi:10.1029/2009JD011870, 2009.

Kaskaoutis, D. G., Kosmopoulos, P., Kambezidis, H. D., and Nastos, P. T.: Aerosol climatology and discrimination of different types over Athens, Greece, based on MODIS data, Atmos. Environ., 41, 7315–7329, http://dx.doi.org/10.1016/j.atmosenv.2007.05.017doi:10.1016/j.atmosenv.2007.05.017, 2007.

Kosmopoulos, P. G., Kaskaoutis, D. G., Nastos, P. T., and Kambezidis, H. D.: Seasonal variation of columnar aerosol optical properties over Athens, Greece, based on MODIS data, Remote Sens. Environ., 112, 2354–2366, http://dx.doi.org/10.1016/j.rse.2007.11.006doi:10.1016/j.rse.2007.11.006, 2008.

Kaufman, Y. J., Herring, D. D., Ranson, K. J., and Collatz, G. J.: Earth Observing System AM1 mission to Earth, IEEE T. Geosci. Remote, 36(4), 1045–1055, 1998.

Koukouli, M. E., Kazadzis, S., Amiridis, V., Ichoku, C., Balis, D. S., and Bais, A. F.: Signs of a negative trend in the MODIS aerosol optical depth over the Southern Balkans, Atmos. Environ., 44 1219–1228, 2010.

Koulouri, E., Saarikoski, S., Theodosi, C., Markaki, Z., Gerasopoulos, E., Kouvarakis, G., Makela, T., Hillamo, R., and Mihalopoulos, N.: Chemical composition and sources of fine and coarse aerosol particles in the Eastern Mediterranean, Atmos. Environ., 42(26), 6542–6550, http://dx.doi.org/10.1016/j.atmosenv.2008.04.0102008doi:10.1016/j.atmosenv.2008.04.0102008, 2008.

Kouvarakis, G., Doukelis, Y., Mihalopoulos, N., Rapsomanikis, S., Sciare, J., and Blumthaler, M.: Chemical, physical and optical characterisation of aerosols during PAUR II experiment, J. Geophys. Res., 107(18), 8141, http://dx.doi.org/10.1029/2000JD000291doi:10.1029/2000JD000291, 2002.

Kubilay, N., Cokacar, T., and Oguz, T.: Optical properties of mineral dust outbreaks over the northeastern Mediterranean, J. Geophys. Res., 108(D21), 4666, http://dx.doi.org/10.1029/2003JD003798doi:10.1029/2003JD003798, 2003.

Ladstätter-Weissenmayer, A., Kanakidou, M., Meyer-Arnek, J., Dermitzaki, E. V., Richter, A., Vrekoussis, M., Wittrock, F., and Burrows, J. P.: Pollution events over the East Mediterranean: Synergistic use of GOME, ground-based and sonde observations and models, Atmos. Environ., 41, 7262–7273 http://dx.doi.org/10.1016/j.atmosenv.2007.05.031doi:10.1016/j.atmosenv.2007.05.031, 2007.

Lelieveld, J., Berresheim, H., Borrmann, S., Crutzen, P. J., Dentener, F. J., Fischer, H., Feichter, J., Flatau, P. J., Heland, J., Holzinger, R., Korrmann, R., Lawrence, M. G., Levin, Z., Markowicz, K. M., Mihalopoulos, N., Minikin, A., Ramanathan, V., de Reus, M., Roelofs, G. J., Scheeren, H. A., Sciare, J., Schlager, H., Schultz, M., Siegmund, P., Steil, B., Stephanou, E. G., Stier, P., Traub, M., Warneke, C., Williams, J., and Ziereis, H.: Global air pollution crossroads over the Mediterranean, Science 298, 794-799, 2002.

Liakakou, E., Bonsang, B., Williams, J., Kalivitis, N., Kanakidou, M., and Mihalopoulos, N.: C2–C8 NMHCs over the Eastern Mediterranean: Seasonal variation and impact on regional oxidation chemistry, Atmos. Environ., 43, 5611–5621, http://dx.doi.org/10.1016/j.atmosenv.2009.07.067doi:10.1016/j.atmosenv.2009.07.067, 2009.

Masuoka, E., Fleig, A., Wolfe, R. W., and Patt, F.: Key characteristics of the MODIS data products, IEEE T. Geosci. Remote, 36(4), 1313–1323, http://dx.doi.org/10.1109/36.701081doi:10.1109/36.701081, 1998.

Matthias, V., Balis, D., Bosenberg, J., Eixmann, R., Iarlori, M., Komguem, L., Mattis, I., Papayannis, A., Pappalardo, G., Perrone, M. R., and Wang, X.: Vertical aerosol distribution over Europe: Statistical analysis of Raman lidar data from 10 European Aerosol Research Lidar Network (EARLINET) stations, 109, D18201, http://dx.doi.org/10.1029/2004JD004638doi:10.1029/2004JD004638, 2004.

Melas, D., Kioutsioukis, I., and Lazaridis M.: The Impact of Sea Breeze on Air Quality in Athens Area, Advances in Air Pollution Modeling for Environmental Security, NATO Science Series, 54, 285–295, doi: 10.1007/1-4020-3351-6_26doi:10.1007/1-4020-3351-6_26, 2005.

Mitsakou, C., Kallos, G., Papantoniou, N., Spyrou, C., Solomos, S., Astitha, M., and Housiadas, C.: Saharan dust levels in Greece and received inhalation doses, Atmos. Chem. Phys., 8, 7181–7192, http://dx.doi.org/10.5194/acp-8-7181-2008doi:10.5194/acp-8-7181-2008, 2008.

Papadimas, C. D., Hatzianastassiou, N., Mihalopoulos, N., Kanakidou, M., Katsoulis, B. D., 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.

Papayannis, A., Balis, D., Amiridis, V., Chourdakis, G., Tsaknakis, G., Zerefos, C., Castanho, A. D. A., Nickovic, S., Kazadzis, S., and Grabowski, J.: Measurements of Saharan dust aerosols over the Eastern Mediterranean using elastic backscatter-Raman lidar, spectrophotometric and satellite observations in the frame of the EARLINET project, Atmos. Chem. Phys., 5, 2065–2079, http://dx.doi.org/10.5194/acp-5-2065-2005doi:10.5194/acp-5-2065-2005, 2005.

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., http://dx.doi.org/10.1016/j.envpol.2010.07.035doi:10.1016/j.envpol.2010.07.035, in press, 2010.

Querol, X., Alastuey, A., Pey, J., Cusack, M., Pérez, N., Mihalopoulos, N., Theodosi, C., Gerasopoulos, E., Kubilay, N., and Koçak, M.: Variability in regional background aerosols within the Mediterranean, Atmos. Chem. Phys., 9, 4575–4591, http://dx.doi.org/10.5194/acp-9-4575-2009doi:10.5194/acp-9-4575-2009, 2009.

Remer, L. A., Kaufman, Y. J., Tanré, 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, http://dx.doi.org/10.1175/JAS3385.1doi:10.1175/JAS3385.1, 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, http://modis.gsfc.nasa.gov/data/atbd/atbd_mod02.pdf, 2006.

Remer, L. A., Kleidman, R. G., Levy, R. C., Kaufman, Y. J., Tanre, D., Mattoo, S., Martins, J. V., Ichoku C., Koren, I., Yu, H., and Brent N.: Holben Global aerosol climatology from the MODIS satellite sensors, J. Geophys. Res., 113, D14S07, http://dx.doi.org/10.1029/2007JD009661doi:10.1029/2007JD009661, 2008.

Sciare, J., Oikonomou, K., Cachier, H., Mihalopoulos, N., Andreae, M. O., Maenhaut, W., and Sarda-Estève, R.: Aerosol mass closure and reconstruction of the light scattering coefficient over the Eastern Mediterranean Sea during the MINOS campaign, Atmos. Chem. Phys., 5, 2253–2265, http://dx.doi.org/10.5194/acp-5-2253-2005doi:10.5194/acp-5-2253-2005, 2005.

Sciare, J., Oikonomou, K., Favez, O., Liakakou, E., Markaki, Z., Cachier, H., and Mihalopoulos, N.: Long-term measurements of carbonaceous aerosols in the Eastern Mediterranean: evidence of long-range transport of biomass burning, Atmos. Chem. Phys., 8, 5551–5563, http://dx.doi.org/10.5194/acp-8-5551-2008doi:10.5194/acp-8-5551-2008, 2008.

Smirnov, A., Holben, B. N., Eck, T. F., Slutsker, I., Chatenet, B., and Pinker, R. T.: Diurnal variability of aerosol optical depth observed at AERONET (Aerosol Robotic Network) sites, Geophys. Res. Lett., 29, 2115, http://dx.doi.org/10.1029/2002GL016305doi:10.1029/2002GL016305, 2002.

Washington, R., Todd, M.C., Engelstaedter, S., Mbainayel, S., and Mitchell, F.: Dust and the low-level circulation over the Bodele Depression, Chad: Observations from BoDEx 2005, J. Geophys. Res., 111, D03201, http://dx.doi.org/10.1029/2005JD006502doi:10.1029/2005JD006502, 2006.

Zerefos, C. S. and Eleftheratos, K.: The Atmospheric Environment Division of the Center of Environmental Health & Biophysics of the Biomedical Research Foundation of the Academy of Athens, in Bio Academy, A Quarterly Bulletin of the Biomedical Research Foundation, Academy of Athens, October–December~2007, Issue 1, 10–13, 2007.

Zerefos, C., Ganev, K., Kourtidis, K., Tzortziou, M., Vasaras, A., and Syrakov, E.: On the origin of SO<sub>2</sub> above Northern Greece, Geophys. Res. Lett., 27(3), 365–368, 2000.

Ziomas, I. C.: The Mediterranean campaign of photochemical tracers–transport and chemical evolution (MEDCAPHOT-TRACE): an outline, Atmos. Environ., 32(12), 2045-2-053, http://dx.doi.org/10.1016/S1352-2310(97)00413-5doi:10.1016/S1352-2310(97)00413-5, 1998.