University of Sussex
Browse

File(s) not publicly available

Meteorological and dust aerosol conditions over the western Saharan region observed at Fennec Supersite-2 during the intensive observation period in June 2011

journal contribution
posted on 2023-06-08, 19:35 authored by Martin ToddMartin Todd, C J T Allen, M Bart, M Bechir, J Bentefouet, B J Brooks, C Cavazos-Guerra, T Clovis, S Deyane, M Dieh, S Engelstaedter, C Flamant, L Garcia-Carreras, A Gandega, M Gascoyne, M Hobby, C Kocha, C Lavaysse, J H Marsham, J V Martins, J B McQuaid, J B Ngamini, D J Parker, T Podvin, A Rocha-Lima, S Traore, Yi WangYi Wang, R Washington
1] The climate of the Sahara is relatively poorly observed and understood, leading to errors in forecast model simulations. We describe observations from the Fennec Supersite-2 (SS2) at Zouerate, Mauritania during the June 2011 Fennec Intensive Observation Period. These provide an improved basis for understanding and evaluating processes, models, and remote sensing. Conditions during June 2011 show a marked distinction between: (i) a “Maritime phase” during the early part of the month when the western sector of the Sahara experienced cool northwesterly maritime flow throughout the lower troposphere with shallow daytime boundary layers, very little dust uplift/transport or cloud cover. (ii) A subsequent “heat low” phase which coincided with a marked and rapid westward shift in the Saharan heat low towards its mid-summer climatological position and advection of a deep hot, dusty air layer from the central Sahara (the “Saharan residual layer”). This transition affected the entire western-central Sahara. Dust advected over SS2 was primarily from episodic low-level jet (LLJ)-generated emission in the northeasterly flow around surface troughs. Unlike Fennec SS1, SS2 does not often experience cold pools from moist convection and associated dust emissions. The diurnal evolution at SS2 is strongly influenced by the Atlantic inflow (AI), a northwesterly flow of shallow, cool and moist air propagating overnight from coastal West Africa to reach SS2 in the early hours. The AI cools and moistens the western Saharan and weakens the nocturnal LLJ, limiting its dust-raising potential. We quantify the ventilation and moistening of the western flank of the Sahara by (i) the large-scale flow and (ii) the regular nocturnal AI and LLJ mesoscale processes.

Funding

Fennec - The Saharan Climate System; G0400; NERC-NATURAL ENVIRONMENT RESEARCH COUNCIL; NE/G01826X/1

History

Publication status

  • Published

Journal

Journal of Geophysical Research: Atmospheres

ISSN

2169-897X

Publisher

Wiley

Issue

15

Volume

118

Page range

8426-8447

Department affiliated with

  • Geography Publications

Notes

Article first published online: 15 AUG 2013

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2015-01-15

Usage metrics

    University of Sussex (Publications)

    Categories

    No categories selected

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC