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Conceptual model of diurnal cycle of low-level stratiform clouds over southern West Africa

Lohou, Fabienne; Kalthoff, Norbert; Adler, Bianca; Babić, Karmen; Dione, Cheikh; Lothon, Marie; Pedruzo-Bagazgoitia, Xabier; Zouzoua, Maurin

Abstract:
The DACCIWA (Dynamics Aerosol Chemistry Cloud Interactions in West Africa) project and the associated ground-based field experiment, which took place during summer 2016, provided a comprehensive dataset on the low-level stratiform clouds (LLSCs), which develop almost every night over southern West Africa. The LLSCs, inaccurately represented in climate and weather forecasts, form in the monsoon flow during the night and break up during the following morning or afternoon, affecting considerably the radiation budget. Several published studies give an overview of the measurements during the campaign, analyse the dynamical features in which the LLSCs develop, and quantify the processes involved in the LLSC formation. Based on the main results of these studies and new analyses, we propose in this paper a conceptual model of the diurnal cycle of the LLSCs over southern West Africa. Four main phases compose the diurnal cycle of the LLSC. The stable and the jet phases are the two steps during which the relative humidity increases, due to cooling of the air, until the air is saturated and the LLSCs form. Horizontal advection of cold air from the Guinean coast by the maritime inflow and the nocturnal low-level jet (NLLJ) represents 50% of the local total cooling. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000117565
Veröffentlicht am 06.03.2020
Originalveröffentlichung
DOI: 10.5194/acp-20-2263-2020
Scopus
Zitationen: 1
Web of Science
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung - Forschungsbereich Troposphäre (IMK-TRO)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 1680-7324
KITopen-ID: 1000117565
HGF-Programm 12.01.02 (POF III, LK 01)
Proc.res.f.multisc.predictab.of weather
Erschienen in Atmospheric chemistry and physics
Band 20
Heft 4
Seiten 2263–2275
Vorab online veröffentlicht am 26.02.2020
Nachgewiesen in Web of Science
Scopus
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