Meteorology and Atmospheric Physics

, Volume 90, Issue 3–4, pp 215–224 | Cite as

Squall lines and rainfall over Western Africa during summer 1986 and 87

  • A. Gaye
  • A. Viltard
  • P. de Félice


Using digitized IR images from the European satellite Meteosat, 153 squall lines (SLs) were observed over Western Africa during July, August and September 1986 and 87. The SL mean rainfall volume was computed using the daily rainfall amounts of more than 800 raingauges: 15 km3 in 1986 and 22.5 km3 in 1987. A mean amount of 15 mm was collected per rainy episode at a given station, however, as only about half of the stations situated under a SL experienced a rainy episode, the rainfall amount averaged along the total SL’s swath was 6.8 mm.

With the help of the 8 daily Meteosat slots the SL’s area daily variation could be estimated: namely a minimum around noon and a maximum around midnight. Using the SLs displacements (east–west) one had access to the daily variation of the rainfall volume, a minimum in the morning and a maximum toward the end of the afternoon, as already found by several authors who used Meteosat images.


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  1. ASECNA1975Analyse des lignes de grains dans la boucle du Niger.La Météorologie (VIème série)6183189Google Scholar
  2. Aspliden, CI, Toure, Y, Sabine, JB 1976Some climatological aspects of West African disturbance lines during GATE.Mon Wea Rev10410291035CrossRefGoogle Scholar
  3. D’Amato, N, Lebel, T 1998On the characteristics of the rainfall events in the Sahel with a view to the analysis of climatic variability.Int J Climatol18955974CrossRefGoogle Scholar
  4. Desbois, M, Kayiranga, T, Gnamien, B, Guessous, S, Picon, L 1993Characterization of some elements of the Sahelian climate and their interannual variations for July 1983, 1984 and 1985 from the analysis of Meteosat ISCCP data.J Climate9867904Google Scholar
  5. Desbois, M, Kayiranga, T, Gnamien, B 1989Diurnal cycle of convective cloudiness over tropical Africa observed from Meteosat: Geographic characterization and interannual variations.Ann Geophys7395404Google Scholar
  6. Diongue, A, Lafore, JP, Redelsperger, JL, Roca, R 2002Numerical study of a Sahelian synoptic weather system: Initiation and mature stages of convection and its interactions with the large-scale dynamics.Q J Roy Meteor Soc12818991927CrossRefGoogle Scholar
  7. Duvel, JP 1989Convection over tropical Africa and the Atlantic ocean during the northern summer. Part I: Interannual and diurnal variations.Mon Wea Rev11727822799CrossRefGoogle Scholar
  8. Fink AH, Reiner A (2003) Spatio-temporal variability of the relation between African Easterly waves and West African squall lines in 1998 and 1999. J Geophys Res 108: O. D11, 4332 (DOI: 10.1029/2002JD002816)Google Scholar
  9. Hamilton, RA, Archbold, JW 1945Meteorology of Nigeria and adjacent territory.Q J Roy Meteor Soc71231264Google Scholar
  10. Houze, RA 1977Structure and dynamics of a tropical squall-line system.Mon Wea Rev10515401567CrossRefGoogle Scholar
  11. Houze, RA,Jr, Betts, AK 1981Convection in GATE.Rev Geophys Space Phys19541576Google Scholar
  12. Houze, RA,Jr, Hobbs, PV 1982Organization and structure of precipitating cloud systems.Adv Geophys24225315Academic PressGoogle Scholar
  13. Laing, AG, Fritsch, JM 1993Mesoscale convective complexes in Africa.Mon Wea Rev12122542263CrossRefGoogle Scholar
  14. Laing, AG, Fritsch, JM, Negri, AJ 1999Contribution of mesoscale convective complexes to rainfall in Sahelian Africa: estimates from geostationary infrared and passive microwave data.J Appl Meteor38957964CrossRefGoogle Scholar
  15. Laurent, H, d’Amato, N, Lebel, T 1998How important is the contribution of the mesoscale convective complexes to the Sahelian rainfall?Phys Chem Earth23629633CrossRefGoogle Scholar
  16. Mathon, V, Laurent, H 2001Life cycle of Sahelian mesoscale convective cloud systems.Q J Roy Meteor Soc127377406CrossRefGoogle Scholar
  17. Mathon, V, Laurent, H, Lebel, T 2002Mesoscale convective system rainfall in the Sahel.J Appl Meteor4110811092CrossRefGoogle Scholar
  18. McCollum, JR, Gruber, A, Ba, MB 2000Discrepancy between gauges and satellite estimates of rainfall in Equatorial Africa.J Appl Meteor39666679Google Scholar
  19. Mohr, KI, Famiglietti, JS, Zipser, EJ 1999The contribution to tropical rainfall with respect to convective system type, size, and intensity estimated from the 85-GHz ice-scattering signature.J Appl Meteor38596606CrossRefGoogle Scholar
  20. Nicholson SE, Kim J, Hoopingarner J (1988) Atlas of African rainfall and its interannual variability. Dept. Meteorology, Florida State University, Tallahassee, 237 pGoogle Scholar
  21. Rickenbach, TM 2004Nocturnal cloud systems and the diurnal variation of clouds and rainfall in southwestern Amazonia.Mon Wea Rev13212011219CrossRefGoogle Scholar
  22. Ropelewski, CF, Lamb, PJ, Portis, DH 1993Seasonal climate summary.J Climate621882212CrossRefGoogle Scholar
  23. Roux, F 1993The West African squall line observed on 23 June during COPT81: Kinematics and thermodynamics on the convective region.J Atmos Sci45406426CrossRefGoogle Scholar
  24. Rowell, DP, Millford, JR 1993On the generation of African squall lines.J Climate611811193CrossRefGoogle Scholar

Copyright information

© Springer-Verlag/Wien 2005

Authors and Affiliations

  • A. Gaye
    • 1
  • A. Viltard
    • 2
  • P. de Félice
    • 2
  1. 1.LPASF, Ecole Supérieure PolytechniqueDakar-FannSénégal
  2. 2.LMD/IPSL, Ecole PolytechniquePalaiseau cédexFrance

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