<?xml version="1.0" encoding="utf-8" standalone="no"?>
<!DOCTYPE article SYSTEM "http://www.atmos-chem-phys.net/inc/acp/copernicus.dtd">
<article language="en">
	<journal>
		<journal_title>Atmospheric Chemistry and Physics</journal_title>
		<journal_url>www.atmos-chem-phys.net</journal_url>
		<issn>1680-7316</issn>
		<eissn>1680-7324</eissn>
		<volume_number>8</volume_number>
		<issue_number>23</issue_number>
		<publication_year>2008</publication_year>
	</journal>
	<doi>10.5194/acp-8-6995-2008</doi>
	<article_url>http://www.atmos-chem-phys.net/8/6995/2008/</article_url>
	<abstract_html>http://www.atmos-chem-phys.net/8/6995/2008/acp-8-6995-2008.html</abstract_html>
	<fulltext_pdf>http://www.atmos-chem-phys.net/8/6995/2008/acp-8-6995-2008.pdf</fulltext_pdf>
	<start_page>6995</start_page>
	<end_page>7014</end_page>
	<publication_date>2008-12-04</publication_date>
	<article_title content_type="html">Monthly-averaged anthropogenic aerosol direct radiative forcing over the Mediterranean based on AERONET aerosol properties</article_title>
	<authors>
		<author numeration="1" affiliations="1">
			<name>A. Bergamo</name>
		</author>
		<author numeration="2" affiliations="1">
			<name>A. M. Tafuro</name>
		</author>
		<author numeration="3" affiliations="2">
			<name>S. Kinne</name>
		</author>
		<author numeration="4" affiliations="1">
			<name>F. De Tomasi</name>
		</author>
		<author numeration="5" affiliations="1">
			<name>M. R. Perrone</name>
			<email>perrone@le.infn.it</email>
		</author>
	</authors>
	<affiliations>
		<affiliation numeration="1" content_type="html">CNISM, Physics Department, University of Salento, Italy</affiliation>
		<affiliation numeration="2" content_type="html">Max Planck Institute für Meteorologie, Hamburg, Germany</affiliation>
	</affiliations>
	<abstract content_type="html">The all-sky direct radiative effect by anthropogenic aerosol (DRE&lt;sub&gt;a&lt;/sub&gt;) is
calculated in the solar (0.3–4 μm) and infrared (4–200 μm)
spectral ranges for six Mediterranean sites. The sites are differently
affected by pollution and together reflect typical aerosol impacts that are
expected over land and coastal sites of the central Mediterranean basin.
Central to the simulations are aerosol optical properties from AERONET
sun-/sky-photometer statistics for the year 2003. A discussion on the
variability of the overall (natural + anthropogenic) aerosol properties with
site location is provided. Supplementary data include MODIS satellite sensor
based solar surface albedos, ISCCP products for high- mid- and low cloud
cover and estimates for the anthropogenic aerosol fraction from global
aerosol models. Since anthropogenic aerosol particles are considered to be
smaller than 1 μm in size, mainly the solar radiation transfer is
affected with impacts only during sun-light hours. At all sites the (daily
average) solar DRE&lt;sub&gt;a&lt;/sub&gt; is negative all year round at the top of the
atmosphere (ToA). Hence, anthropogenic particles produce over coastal and
land sites of the central Mediterranean a significant cooling effect.
Monthly DRE&lt;sub&gt;a&lt;/sub&gt; values vary from site to site and are seasonally dependent
as a consequence of the seasonal dependence of available sun-light and
microphysical aerosol properties. At the ToA the monthly average DRE&lt;sub&gt;a&lt;/sub&gt;
is &amp;minus;(4&amp;plusmn;1) W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; during spring-summer (SS, April–September) and
&amp;minus;(2&amp;plusmn;1) W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; during autumn-winter (AW, October–March) at the
polluted sites. In contrast, it varies between &amp;minus;(3&amp;plusmn;1) W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; and
&amp;minus;(1&amp;plusmn;1) W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; on SS and AW, respectively at the less polluted site.
Due to atmospheric absorption the DRE&lt;sub&gt;a&lt;/sub&gt; at the surface is larger than at
the ToA. At the surface the monthly average DRE&lt;sub&gt;a&lt;/sub&gt; varies between the
most and the least polluted site between &amp;minus;(7&amp;plusmn;1) W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; and
&amp;minus;(4&amp;plusmn;1) W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; during SS, and between &amp;minus;(4&amp;plusmn;3) W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; and &amp;minus;(1&amp;plusmn;1) W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;
during AW. The DRE&lt;sub&gt;a&lt;/sub&gt; at infrared wavelengths is positive but
negligible, especially at the ToA (&amp;lt;0.3 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;). The average of
DRE&lt;sub&gt;a&lt;/sub&gt; monthly-means referring to all sites has allowed getting a ToA-
and sfc-DRE&lt;sub&gt;a&lt;/sub&gt; yearly-mean value of &amp;minus;(3&amp;plusmn;2) and &amp;minus;(5&amp;plusmn;3) W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;,
respectively at solar wavelengths. Last data, even if refer to a
particular year, indicate that the radiative energy-balance of Central
Mediterranean land and coastal sites is quite affected by anthropogenic
particles.</abstract>
	<references>
		<reference numeration="1" content_type="text"> % vor jede Referenz 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(D2), 4008, doi:10.1029/2001JD900252, 2002. </reference>
		<reference numeration="2" content_type="text"> % vor jede Referenz Bellouin, N., Boucher, O., Haywood, J., and Reddy, M. S.: Global estimate of aerosol direct radiative forcing from satellite measurements, Nature, 438, 1138–1141, 2005. </reference>
		<reference numeration="3" content_type="text"> % vor jede Referenz Chin, M., Ginoux, P., Kinne, S., Torres, O., Holben, B. N., Duncan, B. N., Martin, R. V., Logan, J. A., Higurashi, A., and Nakajima, T.: Troposheric aerosol optical thickness from the GOCART model and comparison with satellite and sun photometer measurements, J. Atmos. Sci., 59, 461–483, 2002. </reference>
		<reference numeration="4" content_type="text"> % vor jede Referenz Chung, C. E., Ramanathan, V., Kim, D., and Podgorny, I. A.: Global anthropogenic aerosol direct forcing derived from satellite and groundbased observations, J. Geophys. Res., 110, D24207, doi:10.1029/2005JD006356, 2005. </reference>
		<reference numeration="5" content_type="text"> % vor jede Referenz Collins, W. J., Derwent, R. G., Johnson, C. E., and Stevenson, D. S.: The oxidation of organic compounds in the troposphere and their global warming potentials, Clim. Change, 52, 453–479, 2002. </reference>
		<reference numeration="6" content_type="text"> % vor jede Referenz Dentener, F., Kinne, S., Bond, T., Boucher, O., Cofala, J., Generoso, S., Ginoux, P., Gong, S., Hoelzemann, J. J., Ito, A., Marelli, L., Penner, J. E., Putaud, J.-E., Textor, C., Schulz, M., van der Werf, G. R., and Wilson, J.: Emissions of primary aerosol and precursor gases in the years 2000 and 1750 prescribed data-sets for Aerocom, Atmos. Chem. Phys., 6, 4321–4344, 2006. </reference>
		<reference numeration="7" content_type="text"> % vor jede Referenz 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, 20 673–20 696, 2000. </reference>
		<reference numeration="8" content_type="text"> % vor jede Referenz Dubovik, O., Smirnov, A., Holben, B. N., King, M. D., Kaufman, Y. J., Eck, T. F, and Slutsker, I: Accuracy assessments of aerosol optical properties retrieved from Aerosol Robotic Network (AERONET) Sun and sky radiance measurements, J. Geophys. Res, 105(D8), 9791–9806, 2000. </reference>
		<reference numeration="9" content_type="text"> % vor jede Referenz Dubovik, O., Holben, B. N., Lapyonok, T., Sinyuk, A., Mishchenko, M. I., Yang, P., and Slutsker, I.: Non-spherical aerosol retrieval method employing light scattering by spheroids, Geophys. Res. Lett., 29(10), 541–544, 2002. </reference>
		<reference numeration="10" content_type="text"> % vor jede Referenz Dubovik, O., Sinyuk, A., Lapyonok, T., Holben, B. N., Mishchenko, M., Yang, P., Eck, T. F., Volten, H., Muñoz, O., Veihelmann, B., Van Der Zande, W. J., Leon, J. F., Sorokin, M., and Slutsker, I.: Application of spheroid models to account for aerosol particle nonsphericity in remote sensing of desert dust, J. Geophys. Res., 111, D11208, doi:10.1029/2005JD006619, 2006. </reference>
		<reference numeration="11" content_type="text"> % vor jede Referenz 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, 2006. </reference>
		<reference numeration="12" content_type="text"> % vor jede Referenz Giorgi, F., Bi, X. Q., and Qian, Y.: Direct radiative forcing and regional climatic effects of anthropogenic aerosols over East Asia: A regional coupled climate-chemistry/aerosol model study, J. Geophys. Res., 107, 4439, doi:10.1029/2001JD001066, 2002. </reference>
		<reference numeration="13" content_type="text"> % vor jede Referenz Giorgi, F.: Climate change hot-spots, J. Geophys. Res., 33, L08707, doi:10.1029/2006GL025734, 2006. </reference>
		<reference numeration="14" content_type="text"> % vor jede Referenz Guibert, S., Matthias, V., Schulz, M., Bösenberg, J., Eixmann, R., Mattis, I., Pappalardo, G., Perrone, M. R. , Spinelli, N., and Vaughan, G.: The vertical distribution of aerosol over Europe – synthesis of one year of EARLINET aerosol lidar measurements and aerosol transport modeling with LMDzT–INCA, Atmos. Environ., 39, 2933–2943, 2005. </reference>
		<reference numeration="15" content_type="text"> % vor jede Referenz Haywood, J. and Boucher, O.: Estimates of the direct and indirect radiative forcing due to tropospheric aerosols: a review, Rev. Geophys., 38, 4, 513–543, 2000. </reference>
		<reference numeration="16" content_type="text"> % vor jede Referenz Holben, B. N., Eck, T. F., Slutsker, I., Tanré, D., Buis, J. P., Setzer, A., Vermote, E., Reagan, J. A., Kaufman, Y., Nakajima, T., Lavenu, F., Jankowiak, I., and Smirnov, A.: AERONET – A federated instrument network and data archive for aerosol characterization, Remote Sens. Environ., 6, 1–16, 1998. </reference>
		<reference numeration="17" content_type="text"> % vor jede Referenz Holben, B. N., Tanré, D., Smirnov, A., Eck, T. F., Slutsker, I., Abuhassan, N., Newcomb, W. W., Shafer, J., Chatenet, B., Lavenue, F., Kaufman, Y. J., Vande Castel, J., Setzer, A., Markham, B., Clark, D., Frouin, R., Halthore, R., Karnieli, A., O&apos;Neill, N. T., Pietras, C., Pinker, R. T., Voss, K., and Zibordi, G.: An emerging ground-based aerosol climatology: Aerosol optical depth from AERONET, J. Geophys. Res, 106, 12 067–12 097, 2001. </reference>
		<reference numeration="18" content_type="text"> % vor jede Referenz Intergovermental Panel on Climate Change (IPCC): Climate change 2007, The Physical Science Basis – Summary for Policymakers, http://www.ipcc.ch/ipccreports/ar4-wg1.htm, 2007. </reference>
		<reference numeration="19" content_type="text"> % vor jede Referenz Kaufman, Y. J., Smirnov, A., Holben, B. N., and Dubovik, O.: Baseline maritime aerosol: methodology to derive the optical thickness and scattering properties, J. Geophys. Res. Lett., 28, 17, 3251–3254, 2001. </reference>
		<reference numeration="20" content_type="text"> % vor jede Referenz Kaufman, Y. J., Tanré, D., and Boucher, O.: A satellite view of aerosols in the climate system, Nature, 419, 215–223, 2002. </reference>
		<reference numeration="21" content_type="text"> % vor jede Referenz Kaufman, Y. J., Boucher, O., Tanré, D., Chin, M., Remer, L. A., and Takemura, T.: Aerosol anthropogenic component estimated from satellite data, Geophys. Res. Lett., 32, L17804, doi:10.1029/2005GL023125, 2005. </reference>
		<reference numeration="22" content_type="text"> % vor jede Referenz King, M. D., Kaufman, Y. J., Menzel, W. P., and Tanré, D.: Remote Sensing of Cloud, Aerosol, and Water Vapor Properties from the Moderate Resolution Imaging Spectrometer (MODIS), IEEE T. Geosci. Remote, 30, 1–27, 1992. </reference>
		<reference numeration="23" content_type="text"> % vor jede Referenz Kirkev&amp;aring;g, A. and Iversen, T.: Global direct radiative forcing by process-parameterized aerosol optical properties, J. Geophys. Res.-Atmos., 107(D20), 4433, doi:10.1029/2001JD000886, 2002. </reference>
		<reference numeration="24" content_type="text"> % vor jede Referenz Lelieveld, J., Berresheim, H., Borrman, 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., 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. </reference>
		<reference numeration="25" content_type="text"> % vor jede Referenz Le Truet, H., Forchon, M., Boucher, O., and Li, X.-Z.: Sulfate aerosol indirect effect and CO&lt;sub&gt;2&lt;/sub&gt; greenhouse forcing: equilibrium response of the LMD GCM and associated cloud feedbacks, J. Climate, 11, 1673–1684, 1998. </reference>
		<reference numeration="26" content_type="text"> % vor jede Referenz Meador, W. E and Weaver, W. R.: Two-stream approximation to radiative transfer in planetary atmospheres: a unified description of existing methods and new improvement, J. Atmos. Sci., 37, 630–643, 1980. </reference>
		<reference numeration="27" content_type="text"> % vor jede Referenz 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. </reference>
		<reference numeration="28" content_type="text"> % vor jede Referenz Pace, G., di Sarra, A., Meloni, D., Piacentino, S., and Chamard, P.: Aerosol optical properties at Lampedusa (Central Mediterranean). 1. Influence of transport and identification of different aerosol types, Atmos. Chem. Phys., 6, 697–713, 2006. </reference>
		<reference numeration="29" content_type="text"> % vor jede Referenz Pace, G., Meloni, D., and di Sarra, A.: Forest fire aerosol over the Mediterranean basin durin summer 2003, J. Geophys. Res., 110, D21202, doi:1029/2005JD005986. </reference>
		<reference numeration="30" content_type="text"> % vor jede Referenz Paltridge, G. W. and Platt, C. M. R.: Radiative Processes in Meteorology and Climatology, Elsevier Publishing, 1976. </reference>
		<reference numeration="31" content_type="text"> % vor jede Referenz Ramanathan V., Crutzen, P. J., Lelieveld, J., Mitra, A. P., Althausen, D., Anderson, J., Andreae, M. O., Cantrell, W., Cass, G. R., Chung, C. E., Clarke, A. D., Coakley, J. A., Collins, W. D., Conant, W. C., Dulac, F., Heintzenberg, J., Heymsfield, A. J., Holben, B., Howell, S., Hudson, J., Jayaraman, A., Kiehl, J. T., Krishnamurti, T. N., Lubin, D., McFarquhar, G., Novakov, T., Ogren, J. A., Podgorny, I. A., . Prather, K, Priestley, K., Prospero, J. M., Quinn, P. K., Rajeev, K., Rasch, P., Rupert, S., Sadourny, R., Satheesh, S. K., Shaw, G. E., Sheridan, P., and Valero, F. P. J.: Indian Ocean Experiment: an integrated analysis of the climate forcing and effects of the great Indo-Asian haze, J. Geophys. Res., 106, 28 371–28 398, 2001. </reference>
		<reference numeration="32" content_type="text"> % vor jede Referenz Reddy, M. S., Boucher, O., Balanski, Y., and Schulz, M.: Aerosol optical depths and direct radiative perturbations by species and source type, Geophys. Res. Lett., 32, L12803, doi:10.1029/2004GL021743, 2005. </reference>
		<reference numeration="33" content_type="text"> % vor jede Referenz Rossow, W. B. and Schiffer, R. A.: Advances in understanding clouds from ISCCP, Bull. Amer. Meteor. Soc., 80 , 2261–2287, 1999. </reference>
		<reference numeration="34" content_type="text"> % vor jede Referenz Russell, P. B., Livingston, J. M., Hignett, P., Kinne, S., Wong, J., Chien, A., Bergstrom, R., Durkee, P., and Hobbs, P. V.: Aerosol-induced radiative flux changes off the United States mid-Atlantic coast: Comparison of values calculated from Sun photometer and in situ data with those measured by airborne pyranometer, J. Geophys. Res., 104, 2289–2307, 1999. </reference>
		<reference numeration="35" content_type="text"> % vor jede Referenz Santese, M., De Tomasi, F., and Perrone, M. R.: Advection patterns and aerosol optical and microphysical properties by AERONET over south-east Italy in the central Mediterranean, Atmos. Chem. Phys., 8, 1881–1896, 2008. </reference>
		<reference numeration="36" content_type="text"> % vor jede Referenz Schaaf, C. B., Gao, F., Strahler, A. H., Lucht, W., Li, X., Tsang, T, Strugnell, N. C., Zhang, X., Jin, Y., Muller, J.-P., Lewis, P, Barnsley, M., Hobson, P., Disney, M., Roberts, G., Dunderdale, M., Doll, C., d&apos;Entremont, R. P., Hu, B., Liang, S., Privette, J., L., and Roy, D.: First operational BRDF, albedo nadir reflectance products from MODIS, Remote Sens. Environ., 83, 135–148, 2002. </reference>
		<reference numeration="37" content_type="text"> % vor jede Referenz Schulz, M., Textor, C., Kinne, S., Balkanski, Y., Bauer, S., Berntsen, T., Berglen, T., Boucher, O., Dentener, F., Guibert, S., Isaksen, I. S. A., Iversen, T., Koch, D., Kirkev&amp;aring;g, A., Liu, X., Montanaro, V., Myhre, G., Penner, J. E., Pitari, G., Reddy, S., Seland, Ø., Stier, P., and Takemura, T.: Radiative forcing by aerosols as derived from the AeroCom present-day and pre-industrial simulations, Atmos. Chem. Phys., 6, 5225–5246, 2006. </reference>
		<reference numeration="38" content_type="text"> % vor jede Referenz Stier, P., Feichter, J., Kinne, S., Kloster, S., Vignati, E., Wilson, J., Ganzeveld, L., Tegen, I., Werner, M., Balkanski, Y., Schulz, M., Boucher, O., Minikin, A., and Petzold, A.: The aerosol-climate model ECHAM5-HAM, Atmos. Chem. Phys., 5, 1125–1156, 2005. </reference>
		<reference numeration="39" content_type="text"> % vor jede Referenz Stier, P., Seinfeld, J. H., Kinne, S., and Boucher, O.: Aerosol absorption and radiative forcing, Atmos. Chem. Phys., 7, 5237–5261, 2007. </reference>
		<reference numeration="40" content_type="text"> % vor jede Referenz Tafuro, A. M., Barnaba, F., De Tomasi, F., Perrone, M. R., and Gobbi, G. P.: Saharan dust particle properties over the Central Mediterranean, Atmos. Res., 81, 67–93, 2006. </reference>
		<reference numeration="41" content_type="text"> % vor jede Referenz Tafuro, A. M., Kinne, S., De Tomasi, F., and Perrone, M. R.: Annual cycle of aerosol direct radiative effect over southeast Italy and sensitivity studies, J. Geophys. Res., 112, D20202, doi:10.1029/2006JD008265, 2007. </reference>
		<reference numeration="42" content_type="text"> % vor jede Referenz Tafuro, A. M., De Tomasi, F., and Perrone, M. R.: Remote Sensing of Aerosols by Sunphotometers and Lidar Techniques, Chapter 14, in: Advanced Environmental Monitoring, edited by: Kim, Y. J., Platt, U., Springer, ISBN 978-1-4020-6363-3, XXII, 179–189, 2008. </reference>
		<reference numeration="43" content_type="text"> % vor jede Referenz Takemura, T., Nozawa, T., Emori, S., Nakajima, T. Y., and Nakajima, T.: Simulation of climate response to aerosol direct and indirect effects with aerosol transport-radiation model, J. Geophys. Res.-Atmos., 110, D02202, doi:10.1029/2004JD005029, 2005. </reference>
		<reference numeration="44" content_type="text"> % vor jede Referenz Yu, H., Kaufman, Y. J., Chin, M., Feingold, G., Remer, L. A., Anderson, T. L., Balkanski, Y., Bellouin, N., Boucher, O., Christopher, S., DeCola, P., Kahn, R., Koch, D., Loeb, N., Reddy, M. S., Schulz, M., Takemura, T., and Zhou, M.: A review of measurement-based assessments of the aerosol direct radiative effect and forcing, Atmos. Chem. Phys., 6, 613–666, 2006. </reference>
		<reference numeration="45" content_type="text"> % vor jede Referenz Zhou, Mi, Yu, H., Dickinson, R.E., Dubovik, O., and Holben, B. N.: A normalized description of the direct effect of key aerosol types on solar radiation as estimated from Aerosol Robotic Network aerosols and Moderate Resolution Imagining Spectroradiometer albedos, J. Geophys. Res., 110, D19202, doi:10.1029/2005JD005909, 2005. </reference>
	</references>
</article>

