References

ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-9-22539-2009

Aerosol direct radiative forcing during Sahara dust intrusions in the central Mediterranean

Perrone

M. R.

¹ Bergamo

¹ Bellantone

CNISM, Dipartimento di Fisica, Università del Salento, Lecce, Italy

23 10 2009

9 5 22539 22579

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/9/22539/2009/acpd-9-22539-2009.html

The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/9/22539/2009/acpd-9-22539-2009.pdf

The clear-sky, instantaneous Direct Radiative Effect (DRE) by all and anthropogenic particles is calculated during Sahara dust intrusions in the Mediterranean basin, to evaluate the role of anthropogenic particle's radiative effects and to get a better estimate of the DRE by desert dust. The clear-sky aerosol DRE is calculated by a two stream radiative transfer model in the solar (0.3–4 μm) and infrared (4–200 μm) spectral range, at the top of the atmosphere (ToA) and at the Earth's surface (sfc). Aerosol optical properties by AERONET sun-sky photometer measurements and aerosol vertical profiles by EARLINET lidar measurements, both performed at Lecce (40.33° N, 18.10° E) during Sahara dust intrusions occurred from 2003 to 2006 year, are used to initialize radiative transfer simulations. Instantaneous values at 0.44 μm of the real (n) and imaginary (k) refractive index and of the of aerosol optical depth (AOD) vary within the 1.33–1.55, 0.0037–0.014, and 0.2–0.7 range, respectively during the analyzed dust outbreaks. Fine mode particles contribute from 34% to 85% to the AOD by all particles. The complex atmospheric chemistry of the Mediterranean basin that is also influenced by regional and long-range transported emissions from continental Europe and the dependence of dust optical properties on soil properties of source regions and transport pathways are responsible for the high variability of n, k, and AOD values and of the fine mode particle contribution. Instantaneous net (solar+infrared) DREs that are negative as a consequence of the cooling effect by aerosol particles, span the – (32–10) W m−2 and the – (44–20) W m−2 range at the ToA and surface, respectively. The instantaneous net DRE by anthropogenic particles that is negative, varies within −(13–8) W m−2 and −(17–11) W m−2 at the ToA and surface, respectively. It represents from 41 up to 89% and from 36 up to 67% of the net DRE by all particles at the ToA and surface, respectively. A linear relationship to calculate the DRE by natural particles in the solar and infrared spectral range is provided.

References 1

Balkanski,~Y., Schulz,~M., Claquin,~T., and Guibert,~S.: Reevaluation of Mineral aerosol radiative forcings suggests a better agreement with satellite and AERONET data, Atmos. Chem. Phys., 7, 81–95, 2007.

Bates,~T S., Anderson,~T L., Baynard,~T., Bond,~T., Boucher,~O., Carmichael,~G., Clarke,~A., Erlick,~C., Guo,~H., Horowitz,~L., Howell,~S., Kulkarni,~S., Maring,~H., McComiskey,~A., Middlebrook,~A., Noone,~K., O'Dowd,~C D., Ogren,~J., Penner,~J., Quinn,~P K., Ravishankara,~A R., Savoie,~D L., Schwartz,~S E., Shinozuka,~Y., Tang,~Y., Weber,~R J., and Wu,~Y.: Aerosol direct radiative effects over the northwest Atlantic, northwest Pacific, and North Indian Oceans: estimates based on in-situ chemical and optical measurements and chemical transport modeling, Atmos. Chem. Phys., 6, 1657–1732, 2006.

Bergamo,~A., Tafuro,~A M., Kinne,~S., De Tomasi,~F., and Perrone,~M R.: Monthly-averaged anthropogenic aerosol direct radiative forcing over the Mediterranean based on AERONET aerosol properties, Atmos. Chem. Phys., 8, 6995–7014, 2008.

Bergamo,~A., De~Tomasi,~F., and Perrone,~M R.: Direct radiative effects by anthropogenic particles at a~polluted site: Rome (Italy), Il Nuovo Cimento, 31C, 513–526, doi:10.1393/ncc/i2009–10320–1, 2008b.

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.-P., 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.

De~Tomasi,~F., Blanco,~A., and Perrone,~M R.: Raman lidar monitoring of extinction and backscattering of Africa dust layers and dust characterization, Appl. Optics, 42, 1699–1709, 2003.

De~Tomasi,~F., Tafuro,~A M., and Perrone,~M. R: Height and seasonal dependence of aerosol optical properties over south-east Italy, J Geophys. Res., 111, D10203, doi:10.1029/2005JD006779, 2006.

di Sarra,~A., Di Iorio,~T., Cacciani,~M., Fiocco,~G., and Fuá,~D.: Saharan dust profiles measured by lidar at Lampedusa, J Geophys. Res., 106, 10335–10347, 2001.

Haywood,~J., Francis,~P., Osborne,~S., Glew,~M., Loeb,~N., Highwood,~E., Tanré,~D., Myhre,~D., Formenti,~P., and Hirst,~E.: Radiative properties and direct radiative effect of Saharan dust measured by the C-130 aircraft during SHADE: 1. Solar spectrum, J Geophys. Res., 108(D18), 8577, doi:10.1029/2002JD002687, 2003.

Hamonou,~E., Chazette,~P., Balis,~D., Dulac,~F., Scheider,~X., Galani,~E., Ancellet,~G., and Papayannos,~A.: Characterization of the vertical structure of Saharan dust export to the Mediterranean basin, J Geophys. Res., 104, 22257–22270, 1999.

Holben,~B N., Eck,~T F., Slutsker,~I., Tanré,~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~federate instrument network and data archive for aerosol characterization, Remote Sens. Environ., 66, 1–16, 1998.

King,~M D., Kaufman,~Y J., Menzel,~W P., 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.

Matthias,~V., Balis,~D., Boesenberg,~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, J Geophys. Res., 109, D18201, doi:10.1029/2004JD004638, 2004.

Meloni,~D., di Sarra,~A., Di Iorio,~T., and Fiocco,~G., Junkermann,~W., and Pace,~G.: Tropospheric aerosols in the Mediterranean: 2. Radiative effects through model simulations and measurements, J Geophys. Res., 108(D10), 4317, doi:10.1029/2002JD002807, 2003.

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.

Meloni ,~D., di Sarra,~A., Biavati,~G., DeLuisi,~J J., Monteleone,~F., Pace,~G., Piacentino,~S., and Sferlazzo,~D M.: Seasonal behavior of Saharan dust events at the Mediterranean island of Lampedusa in the period 1999–2005, Atmos. Environ., 41, 3041–3056, 2007.

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.

Pavese,~G., De~Tomasi,~F., Calvello,~M., Esposito,~F., and, Perrone,~M R.: Detection of Sahara dust intrusions during mixed advection patterns over south-east Italy: a~case study, Atmos. Res., 92, 489–504, doi:10.1016/j.atmosres.2009.02.003, 2009.

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.

Santese,~M., De~Tomasi,~F., and Perrone,~M R.: Moderate Resolution Imaging Spectroradiometer (MODIS) and Aerosol Robotic Network (AERONET) retrievals during dust outbreaks over the Mediterranean, J Geophys. Res., 112, D18201, doi:10.1029/2007JD008482, 2007.

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.

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., Kirkevåg,~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.

Sokolik,~I N., Winker,~D., Bergametti,~G., Gillette,~D., Carmichael,~G., Kaufman,~Y., Gomes,~L., Schuetz,~L., and Penner,~J.: Introduction to special section on mineral dust: outstanding problems in quantifying the radiative impact of mineral dust, J Geophys. Res., 106, 18015–18027, 2001.

Stier,~P., Seinfeld,~J H., Kinne,~S., and Boucher,~O.: Aerosol absorption and radiative forcing, Atmos. Chem. Phys., 7, 5237–5261, 2007.

Tafuro,~A M., Banaba,~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.

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.

Tafuro,~A M., De~Tomasi,~F., and Perrone,~M R.: Remote Sensing of Aerosols by Sunphotometers and Lidar Techniques, chap 14, in: Advanced Environmental Monitoring, edited by: Kim,~Y J. and Platt,~U., Springer, ISBN 978–1-4020–6363–3, XXII, 179–189, 2008.

Tegen,~I.: Modeling the mineral dust aerosol cycle in the climate system, Quaternary Sci. Rev., 22, 1821–1834, 2003.