<?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>7</volume_number>
		<issue_number>12</issue_number>
		<publication_year>2007</publication_year>
	</journal>
	<doi>10.5194/acp-7-3211-2007</doi>
	<article_url>http://www.atmos-chem-phys.net/7/3211/2007/</article_url>
	<abstract_html>http://www.atmos-chem-phys.net/7/3211/2007/acp-7-3211-2007.html</abstract_html>
	<fulltext_pdf>http://www.atmos-chem-phys.net/7/3211/2007/acp-7-3211-2007.pdf</fulltext_pdf>
	<start_page>3211</start_page>
	<end_page>3229</end_page>
	<publication_date>2007-06-25</publication_date>
	<article_title content_type="html">Modelling the direct effect of aerosols in the solar near-infrared on a planetary scale</article_title>
	<authors>
		<author numeration="1" affiliations="1,2">
			<name>N. Hatzianastassiou</name>
			<email>nhatzian@cc.uoi.gr</email>
		</author>
		<author numeration="2" affiliations="2,3">
			<name>C. Matsoukas</name>
		</author>
		<author numeration="3" affiliations="2,4">
			<name>A. Fotiadi</name>
		</author>
		<author numeration="4" affiliations="5">
			<name>P. W. Stackhouse Jr.</name>
		</author>
		<author numeration="5" affiliations="6">
			<name>P. Koepke</name>
		</author>
		<author numeration="6" affiliations="2,7">
			<name>K. G. Pavlakis</name>
		</author>
		<author numeration="7" affiliations="2,4">
			<name>I. Vardavas</name>
		</author>
	</authors>
	<affiliations>
		<affiliation numeration="1" content_type="html">Laboratory of Meteorology, Department of Physics, University of Ioannina, 45110 Ioannina, Greece</affiliation>
		<affiliation numeration="2" content_type="html">Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece</affiliation>
		<affiliation numeration="3" content_type="html">Department of Environment, University of the Aegean, Mytilene, Greece</affiliation>
		<affiliation numeration="4" content_type="html">Department of Physics, University of Crete, Crete, Greece</affiliation>
		<affiliation numeration="5" content_type="html">Atmospheric Sciences, NASA Langley Research Center, Hampton, Virginia, USA</affiliation>
		<affiliation numeration="6" content_type="html">Meteorological Institute, University of Munich, Munich, Germany</affiliation>
		<affiliation numeration="7" content_type="html">Department of General Applied Science, Technological Educational Institute of Crete, Greece</affiliation>
	</affiliations>
	<abstract content_type="html">We used a spectral radiative transfer model to compute the direct radiative
effect (DRE) of natural plus anthropogenic aerosols in the solar
near-infrared (IR), between 0.85&amp;ndash;10 μm, namely, their effect on the
outgoing near-IR radiation at the top of atmosphere (TOA, &amp;Delta;F&lt;sub&gt;TOA&lt;/sub&gt;),
on the atmospheric absorption of near-IR radiation (&amp;Delta;F&lt;sub&gt;atmab&lt;/sub&gt;)
and on the surface downward and absorbed near-IR radiation
(&amp;Delta;F&lt;sub&gt;surf&lt;/sub&gt;, and &amp;Delta;F&lt;sub&gt;surfnet&lt;/sub&gt;, respectively). The
computations were performed on a global scale (over land and ocean) under
all-sky conditions, using detailed spectral aerosol optical properties taken
from the Global Aerosol Data Set (GADS) supplemented by realistic data for
the rest of surface and atmospheric parameters. The computed aerosol DRE,
averaged over the 12-year period 1984&amp;ndash;1995 for January and July, shows that
on a global mean basis aerosols produce a planetary cooling by increasing
the scattered near-IR radiation back to space by 0.48 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;, they warm
the atmosphere by 0.37 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; and cool the surface by decreasing
the downward and absorbed near-IR radiation at surface by 1.03 and 0.85 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;,
respectively. The magnitude of the near-IR aerosol DRE is smaller
than that of the combined ultraviolet (UV) and visible DRE, but it is still
energetically important, since it contributes to the total shortwave (SW)
DRE by 22&amp;ndash;31%. The aerosol-produced near-IR surface cooling combined with
the atmospheric warming, may affect the thermal dynamics of the
Earth-atmosphere system, by increasing the atmospheric stability, decreasing
thus cloud formation, and precipitation, especially over desertification
threatened regions such as the Mediterranean basin. This, together with the
fact that the sign of near-IR aerosol DRE is sometimes opposite to that of
UV-visible DRE, demonstrates the importance of performing detailed spectral
computations to provide estimates of the climatic role of aerosols for the
Earth-atmosphere system. This was demonstrated by sensitivity tests
revealing very large differences (up to 300%) between aerosol DREs
computed using detailed spectral and spectrally-averaged aerosol optical
properties. Our model results indicate thus that the aerosol direct
radiative effect on the near-IR radiation is very sensitive to the treatment
of the spectral dependence of aerosol optical properties and solar
radiation.</abstract>
	<references>
		<reference numeration="1" content_type="text"> Allison, I.: East Antarctic sea ice: Albedo, thickness distribution, and snow cover, J. Geophys. Res., 98, 12 417&amp;ndash;12 429, 1993. </reference>
		<reference numeration="2" content_type="text"> Bellouin, N., Boucher, O., Haywood, J., and Reddy, M. S.: Global estimate of aerosol direct radiative forcing from satellite measurements, Nature, 438, 1138&amp;ndash;1141, 2005. </reference>
		<reference numeration="3" content_type="text"> Bush, B. C. and Valero, F. P. J.: Surface aerosol radative forcing at GOSAN during the ACE-Asia campaign, J. Geophys. Res., 108(D23), 8660, doi:10.1029/2002JD003233, 2003. </reference>
		<reference numeration="4" content_type="text"> Carlson, T. N. and Benjamin, S. G.: Radiative heating rates for Saharan dust, J. Atmos. Sci., 37, 193&amp;ndash;213, 1980. </reference>
		<reference numeration="5" content_type="text"> 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.: Tropospheric aerosol optical thickness from the GOCART model and comparisons with satellite and Sun photometer measurements, J. Atmos. Sci., 59, 461&amp;ndash;483, 2002. </reference>
		<reference numeration="6" content_type="text"> Christopher, S. A. and Zhang, J.: Shortwave aerosol radiative forcing from MODIS and CERES observations over the oceans, Geophys. Res. Lett., 29, 1859, doi:10.1029/2002GL014803, 2002. </reference>
		<reference numeration="7" content_type="text"> D&apos;Almeida, G. A., Koepke, P., and Shettle, E. P.: Atmospheric aerosols: Global climatology and radiative characteristics, 560 pp., A. Deepak Publishing, Hampton, Virginia, USA, 1991. </reference>
		<reference numeration="8" content_type="text"> Formenti P., Elbert, W., Maenhaut, W., Haywood, J., and Andreae, M. O.: Chemical composition of mineral dust aerosol during the Saharan Dust Experiment (SHADE) airborne campaign in the Cape Verde region, September 2000, J. Geophys. Res., 108(D18), 8576, doi:10.1029/2002JD002648, 2003. </reference>
		<reference numeration="9" content_type="text"> Hansen, J., Russell, G., Rind, D., Stone, P., Lacis, A., Lebedeff, S., Ruedy, R., and Travis, L.: Efficient three-dimensional global models for climate: Models I and II, Mon. Wea. Rev., 111, 609&amp;ndash;662, 1983. </reference>
		<reference numeration="10" content_type="text"> Hartmann, D. L.: Global Physical Climatology, Academic Press, 411 pp, 1994. </reference>
		<reference numeration="11" content_type="text"> Hatzianastassiou, N., Katsoulis, B., and Vardavas, I.: Global distribution of aerosol direct radiative forcing in the ultraviolet and visible arising under clear skies, Tellus, 56B, 51&amp;ndash;71, 2004a. </reference>
		<reference numeration="12" content_type="text"> Hatzianastassiou, N., Katsoulis, B., and Vardavas, I.: Sensitivity analysis of aerosol direct radiative forcings in the ultraviolet &amp;ndash; visible wavelengths and consequences for the heat budget, Tellus, 56B, 368&amp;ndash;381, 2004b. </reference>
		<reference numeration="13" content_type="text"> Hatzianastassiou, N., Fotiadi, A., Matsoukas, C., Drakakis, E., Pavlakis, K. G., Hatzidimitriou, D., and Vardavas, I.: A 17-year global distribution of Earth&apos;s surface shortwave radiation budget, Atmos. Chem. Phys., 5, 2847&amp;ndash;2867, 2005. </reference>
		<reference numeration="14" content_type="text"> Haywood, J. M. and Shine, K. P.: Multi-spectral calculations of the radiative forcing of tropospheric sulphate and soot aerosols using a column model, Quart. J. Roy. Meteorol. Soc., 123, 1907&amp;ndash;1930, 1997. </reference>
		<reference numeration="15" content_type="text"> Haywood, J. M. and Ramaswamy, V.: Global sensitivity studies of the direct radiative forcing due to anthropogenic sulfate and black carbon aerosols, J. Geophys. Res., 103, 6043&amp;ndash;6058, 1998. </reference>
		<reference numeration="16" content_type="text"> Hess, M., Koepke, P., and Schult, I.: Optical properties of aerosols and clouds: The software package OPAC, Bull. Am. Meteorol. Soc., 79, 831&amp;ndash;844, 1998. </reference>
		<reference numeration="17" content_type="text"> Intergovernmental Panel on Climate Change (IPCC): Climate Change 2001, The Scientific Basis, 881 pp., edited by: Houghton J. T., Ding, Y., Griggs, D. J., et al., Cambridge Univ. Press, New York, 2001. </reference>
		<reference numeration="18" content_type="text"> Jacobson, M. Z.: Global direct radiative forcing due to multicomponent anthropogenic and natural aerosols, J. Geophys. Res., 106, 1551&amp;ndash;1568, 2001. </reference>
		<reference numeration="19" content_type="text"> Jaenicke, R.: Tropospheric aerosols, in: Aerosol-Cloud-Climate Interactions, edited by: P. Hobbs, pp. 1&amp;ndash;31, Academic, San Diego, Calif., 1993. </reference>
		<reference numeration="20" content_type="text"> Joseph, J. H., Wiscombe, W. J., and Weinmann, J. A.: The Delta-Eddington approximation of radiative flux transfer, J. Atmos. Sci., 33, 2452&amp;ndash;2459, 1976. </reference>
		<reference numeration="21" content_type="text"> Kaufman, Y. J., Tanré, D., Dubovik, O., Karnieli, A., and Remer, L. A.: Absorption of sunlight by dust as inferred from satellite and ground-based measurements, Geophys. Res. Lett., 28, 1479&amp;ndash;1482, 2001. </reference>
		<reference numeration="22" content_type="text"> Kaufmann, Y. J., Tanré, D., and Boucher, O.: A satellite view of aerosols in the climate system, Nature, 419, 215&amp;ndash;223, 2002. </reference>
		<reference numeration="23" content_type="text"> Keil, A. and Haywood, J.: Solar radiative forcing by biomass burning aerosol particles during SAFARI-2000: A case study based on measured aerosol and cloud properties, J. Geophys. Res., 108(D13), 8467, doi:10.1029/2002JD002315, 2003. </reference>
		<reference numeration="24" content_type="text"> King, M. D., Kaufmann, Y. J., Tanré, D., and Nakajima, T.: Remote sensing of tropospheric aerosols from space: Past, present, and future, Bull. Am. Meteorol. Sos., 80, 2229&amp;ndash;2259, 1999. </reference>
		<reference numeration="25" content_type="text"> Kinne, S., Lohmann, U., Feichter, J., Schulz, M., et al.: Monthly averages of aerosol properties: A global comparison among models, satellite data, and AERONET ground data, J. Geophys. Res., 108(D20), 4634, doi:10.1029/2001JD001253, 2003. </reference>
		<reference numeration="26" content_type="text"> Koepke, P., Hess, M., Schult, I., and Shettle, E. P.: Global aerosol data set. Rep. No 243, Max-Planck Institut für Meteorologie, 44 pp., Hamburg, Germany, 1997. </reference>
		<reference numeration="27" content_type="text"> Lelieveld, L., Berresheim, H., Borrmann, S., et al.: Global air pollution crossroads over the Mediterranean, Science, 298, 794&amp;ndash;799, 2002. </reference>
		<reference numeration="28" content_type="text"> Liao, H., Seinfeld, J. H., Adams, P. J., and Mickley, L. J.: Global radiative forcing of coupled tropospheric ozone and aerosols in a unified general circulation model, J. Geophys. Res., 109, D16207, doi:10.1029/2003JD004456, 2004. </reference>
		<reference numeration="29" content_type="text"> Ming, Y., Ramaswamy, V., Ginoux, P. A., and Horowitz, L. H.: Direct radiative forcing of anthropogenic organic aerosols, J. Geophys. Res., 110, D20208, doi:10.1029/2004JD005573, 2005. </reference>
		<reference numeration="30" content_type="text"> Morcrette, J.-J.: The surface downward longwave radiation in the ECMWF forecast system, J. Climate, 15, 1875&amp;ndash;1992, 2002. </reference>
		<reference numeration="31" content_type="text"> Nishizawa, T., Asano, S., Uchiyama, A., and Yamazaki, A.: Seasonal variation of aerosol direct radiative forcing and optical properties estimated from ground-based solar radiation measurements, J. Atmos. Sci., 61, 57&amp;ndash;72, doi:10.1175/1520-0469(2004)061, 2004. </reference>
		<reference numeration="32" content_type="text"> Reddy, M. S., Boucher, O., Bellouin, N., Schulz, M., Balkanski, Y., Dufresne, J.-L., and Pham, M.: Estimates of global multicomponent aerosol optical depth and direct radiative perturbation in the Laboratoire de Météorologie Dynamique general circulation model, J. Geophys. Res., 110, D10S16, doi:10.1029/2004JD004757, 2005. </reference>
		<reference numeration="33" content_type="text"> Remer, L. A. and Kaufman, Y. J.: Aerosol direct radiative effect at the top of the atmosphere over cloud free ocean derived from four years of MODIS data, Atmos. Chem. Phys., 6, 237&amp;ndash;253, 2006. </reference>
		<reference numeration="34" content_type="text"> Roesch, A., Wild, M., Pinker, R., and Ohmura, A.: Comparison of surface spectral albedos and their impact on the general circulation model estimated surface climate, J. Geophys. Res., 107(D14), ACL 13-1&amp;ndash;ACL 13-8, doi:10.1029/2001JD000809, 2002. </reference>
		<reference numeration="35" content_type="text"> Rossow, W. B., Walker, A. W., Beuschel, D. E., and Roiter, M. D.: International Satellite Cloud Climatology Project (ISCCP). Documentation of new cloud datasets, 115 pp., Wold Meteorol. Org. Geneva, 1996. </reference>
		<reference numeration="36" content_type="text"> Shettle, E. P. and Weinmann, J. A.: The transfer of solar irradiance through inhomogeneous turbid atmospheres evaluated by Eddington&apos;s approximation, J. Atmos. Sci., 27, 1048&amp;ndash;1055, 1970. </reference>
		<reference numeration="37" content_type="text"> Sokolik, I. N., Andronova, A., and Johnson, T. C.: Complex refractive index of atmospheric dust aerosols, Atmos. Environ., 27A(16), 2495&amp;ndash;2502, 1993. </reference>
		<reference numeration="38" content_type="text"> Sokolik, I. N. and Toon, O. B.: Incorporation of mineralogical composition into models of the radiative properties of mineral aerosol from UV to IR wavelengths, J. Geophys. Res., 104(D8), 9423&amp;ndash;9999, 1999. </reference>
		<reference numeration="39" content_type="text"> Stackhouse, P. W., Gupta, S. K., Cox, S. J., Mikowitz, C., and Chiacchio, M.: New results from the NASA/GEWEX Surface Radiation Budget project: Evaluating El Nino effects at different scales, 11th American Meteorological Society Conference on Atmospheric Radiation, Ogden, UT, USA, P.3.6, 2002. </reference>
		<reference numeration="40" content_type="text"> Takemura, T., Nakajima, T., Dubovik, O., Holben, B. N., and Kinne, S.: Single-scattering albedo and radiative forcing of various aerosol species with a global three-dimensional model, J. Climate, 15, 333&amp;ndash;352, 2005. </reference>
		<reference numeration="41" content_type="text"> Thekaekara, M. P. and Drummond, A. J.: Standard values for the solar constant and its spectral components, Nature Phys. Sci., 229, 6&amp;ndash;9, 1971. </reference>
		<reference numeration="42" content_type="text"> Valero, F. P. J., Bush, B. C., Pope, S. K., Marsden, D. C., and Leitner, A. S.: Aerosol forcing during INDOEX and ACE-Asia as determined from aircraft and ground measurements, Geophys. Res. Abstr., 5, 01607, 2003. </reference>
		<reference numeration="43" content_type="text"> Vardavas, I. and Carver, J. H.: Solar and terrestrial parameterizations for radiative convective models, Planet. Space Sci., 32, 1307&amp;ndash;1325, 1984. </reference>
		<reference numeration="44" content_type="text"> Vardavas, I. and Koutoulaki, K.: A model for the solar radiation budget of the northern hemisphere: Comparison with Earth Radiation Budget Experiment data, J. Geophys. Res., 100, 7303&amp;ndash;7314, 1995. </reference>
		<reference numeration="45" content_type="text"> Willson, R. C.: Total solar irradiance trend during solar cycles 21 and 22, Science, 277, 1963&amp;ndash;1965, 1997. </reference>
		<reference numeration="46" content_type="text"> 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 assessment of aerosol direct radiative effect and forcing, J. Geophys. Res., 109, D03206, doi:10.1029/2003JD003914, 2006. </reference>
		<reference numeration="47" content_type="text"> Zhang, J., Christopher, S. A., Remer, L. A., and Kaufman, Y. J.: Shortwave aerosol cloud-free radiative forcing from Terra, II: Seasonal and global distributions, J. Geophys. Res., 110, D10S24, doi:10.1029/2004JD005009, 2005. </reference>
		<reference numeration="48" content_type="text"> Zhao, T. X.-P., Laszlo, I., Minnis, P., and Remer, L.: Comparison and analysis of two aerosol retrievals over the ocean in the Terra/Clouds and the Earth&apos;s Radiant Energy System-Moderate Resolution Imaging Spectroradiometer single scanner footprint data: 1. Global evaluation, J. Geophys. Res., 110, D21208, doi:10.1029/2005JD005851, 2005. </reference>
	</references>
</article>

