Hygroscopic properties of aerosols in the Sahel: preliminary results

Mouhamadou Bedou (1) , Abdourahamane Konare (1) , Ibrah Seidou-Sanda (2) , Paul Assamoi (1) , Arona Diedhiou (3)

1 LPA-MF - Laboratoire de Physique de l'Atmosphère et de Mécanique des Fluides
2 UAM - Abdou Moumouni University of Niamey = Université Abdou Moumouni de Niamey
3 INRAN Niamey - Institut National de Recherches Agronomiques du Niger [Niamey]

Approximately three years of sunphotometric measurements carried out in the locality of Bidi (13.36°N; 2.30°W) in Burkina Faso (West Africa) from October 1986 to January 1989 were used to estimate the atmospheric precipitable water vapour (APW) and the Angstrom exponent values a. A study of the relationship between these two parameters on a seasonal time scale shows that an increase of water vapour in the Sahel is associated with a decrease of a values, indicating hygroscopic growth of aerosol particles. This result shows that the Sahel aerosol particles may grow in size through water vapour absorption due to hygroscopic properties.

Mots clés: Aerosol; optical depth; angstrom coefficient; atmospheric water content and hygroscopic growth

Domaines: Hydrologie

Mouhamadou Bedou, Abdourahamane Konare, Ibrah Seidou-Sanda, Paul Assamoi, Arona Diedhiou. Hygroscopic properties of aerosols in the Sahel: preliminary results. Scientific Research and Essays, 2007, 2 (6), pp.177 à 183. ⟨insu-00386664⟩