HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

The Saharan heat low and moisture transport pathways in the central Sahara-Multiaircraft observations and Africa-LAM evaluation

Abstract : We present a characterization of the Saharan heat low (SHL) based on dropsonde observations made on 22 June 2011 by two simultaneously flying aircraft during the Fennec project. The observations are used to identify moisture transport pathways and to validate the UK Met Office limited area model for northern Africa (Africa-LAM). The observations capture the SHL, harmattan, and monsoon surge. The SHL has a northeast-southwest orientated elongated shape centered over northern Mauritania. The SHL core is associated with a 950 hPa temperature minimum (36.4°C) in the morning caused by the monsoon surge and a maximum (42.6°C) in the afternoon. The monsoon surge east of the SHL core splits into two transport pathways: (a) curving around the SHL core in the north, especially pronounced in a morning near-surface layer, and (b) northeastward transport within the ~2 km deep monsoon surge (afternoon observations only). In the morning the model forecasts the harmattan, monsoon surge, and the SHL geographic location and northeast-southwest orientation well but the model represents the SHL flatter and more spatially extended and overestimates the convective boundary layer (CBL) by up to ~0.3 km. The simulated afternoon SHL location appears shifted westward by up to ~1°. The model overestimates the shallow afternoon monsoon surge CBL depth of ~1.8 km by >2 km resulting in southwestward transport of vertically mixed moisture above ~2.5 km contrasting observed northeastward-only transport at lower levels. This moisture distribution model error is likely to have consequences for simulations of Saharan thermodynamics and dust emissions caused by convection-driven cold pools.
Document type :
Journal articles
Complete list of metadata

Cited literature [48 references]  Display  Hide  Download

Contributor : Catherine Cardon Connect in order to contact the contributor
Submitted on : Thursday, April 7, 2016 - 2:18:05 PM
Last modification on : Tuesday, November 16, 2021 - 4:04:57 AM
Long-term archiving on: : Monday, November 14, 2016 - 8:30:33 PM


Publication funded by an institution


Distributed under a Creative Commons Attribution 4.0 International License



Sebastien Engelstaedter, Richard Washington, Cyrille Flamant, Doug J. Parker, C. J. T. Allen, et al.. The Saharan heat low and moisture transport pathways in the central Sahara-Multiaircraft observations and Africa-LAM evaluation. Journal of Geophysical Research: Atmospheres, American Geophysical Union, 2015, 120 (10), pp.4417-4442. ⟨10.1002/2015JD023123⟩. ⟨insu-01183105⟩



Record views


Files downloads