• \
    Start Submission Become a Reviewer

    Reading: Saharan dust flux and deposition rate near the Gulf of Guinea

    Download

     A- A+
    Alt. Display

    Original Research Papers

    Saharan dust flux and deposition rate near the Gulf of Guinea

    Authors:

    F. Resch ,

    Laboratoire LSEET-LEPI, Université du Sud Toulon-Var, 83162 La Valette Cedex, FR
    X close

    A. Sunnu,

    Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, GH
    X close

    G. Afeti

    Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, GH
    X close

    Abstract

    It has been estimated that 240 ± 80 Tg of Saharan dust are transported annually from Africa over the Atlantic Ocean to far away places such as the Amazon Basin and the Caribbean during the summer months of June to August. There are, however, few direct measurements of the dust transport towards the Gulf of Guinea (5°N) during the winter months of December–March. In this study, the Saharan dust flux and deposition to the Gulf of Guinea during the Harmattan (winter) season are estimated using the geographical area of Ghana (lying between latitudes 5° and 12°N) as the reference location. The flux and deposition rates were determined during the Harmattan dust episodes of 2002 and 2005 by measuring surface dust concentrations concurrently at two locations in northern and central Ghana. The average particle number concentration in 2002 was 21 cm-3 while in 2005, it was 30 cm-3 (although a few daily mean values were as high as 60 cm-3). The corresponding mean mass concentrations were 543 μg m-3 and 1383 μg m-3 in 2002 and 2005, respectively. The deposition rates for the two winter seasons were estimated at 13 and 31 t km-2 yr-1, respectively, corresponding to a dust deposition thickness of 5 μm in 2002 and 12 μm in 2005. The transit time for the dust aerosol to travel a distance of 320 km between the two measurement sites in a north–south direction was determined experimentally to be of the order of 1 d, a result which could serve as an early warning indicator for severe dust outbreaks travelling from higher to lower latitudes in the region. The results of this study may also be compared with any future simulation of the African dust plume towards the Gulf of Guinea.

    How to Cite: Resch, F., Sunnu, A. and Afeti, G., 2008. Saharan dust flux and deposition rate near the Gulf of Guinea. Tellus B: Chemical and Physical Meteorology, 60(1), pp.98–105. DOI: http://doi.org/10.1111/j.1600-0889.2007.00286.x
      Published on 01 Jan 2008
    Peer Reviewed
     CC BY 4.0
     Accepted on 23 Mar 2007            Submitted on 13 Jul 2006

    Reference

    1. Afeti , G. M. and Resch , F. J . 2000 . Physical characteristics of Saharan dust near the Gulf of Guinea . Atmos. Environ . 34 , 1273 – 1279 .  

    2. Bertrand , J. , Baudet , J. and Drochon , A . 1974 . Importance des aerosols naturels en Afrique de 1' Quest . Journal de Recherche Atmospherique 8 , 845 – 860 .  

    3. Carruthers , D. J. and Choularton , T. C . 1986 . The micro-structure of hill cap clouds . Q. J. R. Met. Soc . 112 , 113 – 129 .  

    4. Chiapello , I. and Moulin , C . 2002 . TOMS and METEOSAT satellite records of the variability of Saharan dust transport over the Atlantic during the last two decades (1979-1997) . Geophys. Res. Lett . 29 ( 8 ), https://doi.org/10.1029/2001GL013767 .  

    5. Chiapello , I. , Bergametti , G. , Gomes , L. , Chatnet , B. , Dulac , F. and co-authors. 1995. An additional low layer transport of Sahalian and Saharan dust over the North-Eastern Tropical Atlantic. Geophys. Res. Lett . 22 , 3191 – 3194 .  

    6. Chiapello , I. , Moulin , C. and Prospero , J. M . 2005 . Understanding the long-term variability of African dust transport across the Atlantic as recorded in both Barbados surface concentrations and large-scale Total Ozone Mapping Spectrometer (TOMS) optical thickness . J. Geophys. Res . 110 , D18510 ,  

    7. Chin , M. , Ginoux , R , Kinne , S. , Tones , O. , Holbeb , B. and co-authors. 2002. Tropospheric aerosol optical thickness from the GOCART model and comparisons with satellite and sun photometer measurements. J. Atmos. Phys . 59 , 461 – 483 .  

    8. D' Almeida , G. A ., 1986 . A model for Saharan dust transport . J. Climatol. AppLMeteoroL 25 , 903 – 916 .  

    9. Fairall , C. W. , Larsen , S. E . 1984 . Dry deposition, surface production and dynamics of aerosols in the marine boundary layer . Atmos. Environ . 18 , 69 – 77 .  

    10. Ginoux , R , Chin , M. , Tegen , I. , Prospero , J. M. , Holben , B. and co-authors. 2001. Sources and distributions of dust aerosols simulated with the GOCART model. J. Geophys. Res . 106(D17), 20255 – 20273 .  

    11. Hasager , C. B. and Jensen , N. O . 1999 . Surface-flux aggregation in heterogeneous terrain . Q. J. R. Meteor Soc . 125 , 2075 – 2102 .  

    12. Kalu , A. E . 1979 . The African dust plume: Its characteristics and propagation across West Africa in Winter. In: Saharan Dust: Mobilization, Transport, Deposition (ed. C. Morales . Wiley, New York, pp. 95 – 118 .  

    13. Kaufman , Y. J. , Koren , I. , Remer , L. A. , Tanre , D. , Ginoux , P. and co-authors. 2005. Dust transport and deposition observed from the Terra-Moderate Resolution Imaging Spectroradiometer (MOD'S) spacecraft over the Atlantic Ocean. J. Geophys. Res. 110, D10512, https://doi.org/10.1029/2003JD004436 .  

    14. Martin , R. V. , Jacob , D. J. , Yantosca , R. M. , Chin , M. and Ginoux , P . 2003 . Global and regional decreases in tropospheric oxidants from photochemical effects of aerosols . J. Geophys. Res . 108 ( D3 ), 4097 , https://doi.org/10.1029/2002JD002622 .  

    15. McTainsh , G . 1980 . Harmattan dust deposition in northern Nigeria . Nature 286 , 587 – 588 .  

    16. McTainsh , G. H. and Walker , P. H . 1982 . Nature and distribution of Harmattan dust . Zeitschrift fuer Geomorphologie N. E 26 , 417 – 435 .  

    17. Prospero , J. M . 1999 . Long-term measurements of the transport of African mineral dust to the southern United States: implications for regional air quality . J. Geophys. Res . 104 ( D13 ), 15917 – 15927 .  

    18. Prospero , J. M. , Glaccum , R. A. and Nees , R. T . 1981 . Atmospheric transport of soil dust from Africa to South America . Nature 289 , 570 – 572 .  

    19. Prospero , J. M. , Ginoux , P. , Tones , O. , Nicholson , S. E. and Gill , T. E . 2002 . Environmental characterization of global sources of atmospheric soil dust identified with the NIMBUS 7 Total Ozone Mapping Spectrometer (TOMS) absorbing aerosol product . Rev. Geophys . 40 ( 1 ), 1002 , https://doi.org/10.1029/2000RG000095 .  

    20. Slinn , W. G. N . 1983 . Air-to-sea transfer of particles . In: Air-Sea Ex-change of Gases and Particles ( eds. P. S. Liss and W. G. N. Slinn ). D. Reidel Publishing Company , Holland , pp. 299 – 405 .  

    21. Smith , M. H. , Park , P. M. and Consterdine , I. E . 1991 . North Atlantic aerosol remote concentrations measured at a Hebridean coastal site . Atmos. Environ . 25A ( 3/4 ), 547 – 555 .  

    22. Tegen , I. , Werner , M. , Harrison , S. P. and Kohfeld , K. E . 2004 . Relative importance of climate and land use in determining present and future global soil dust emission . Geophys. Res. Lett . 31 , L05105 , https://doi.org/10.1029/2003GL019216 .  

    23. Zhang , X. Y. , Arimoto , R. , Zhu , G. H. , Chen , T. and Zhang , G. Y . 1998 . Concentration, size distribution and deposition of mineral aerosol over Chinese desert regions . Tellus 50B , 317 – 330  

    Jump to Discussions Related content
    comments powered by Disqus