Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations

C. L. Ryder; J. B. McQuaid; C. Flamant; P. D. Rosenberg; R. Washington; H. E. Brindley; E. J. Highwood; J. H. Marsham; D. J. Parker; M. C. Todd; J. R. Banks; J. K. Brooke; S. Engelstaedter; V. Estelles; P. Formenti; L. Garcia-Carreras; C. Kocha; F. Marenco; H. Sodemann; C. J. T. Allen; A. Bourdon; M. Bart; C. Cavazos-Guerra; S. Chevaillier; J. Crosier; E. Darbyshire; A. R. Dean; J. R. Dorsey; J. Kent; D. O'Sullivan; K. Schepanski; K. Szpek; J. Trembath; A. Woolley

doi:10.5194/acp-15-8479-2015

Atmospheric Chemistry and Physics (Jul 2015)

Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations

C. L. Ryder,
J. B. McQuaid,
C. Flamant,
P. D. Rosenberg,
R. Washington,
H. E. Brindley,
E. J. Highwood,
J. H. Marsham,
D. J. Parker,
M. C. Todd,
J. R. Banks,
J. K. Brooke,
S. Engelstaedter,
V. Estelles,
P. Formenti,
L. Garcia-Carreras,
C. Kocha,
F. Marenco,
H. Sodemann,
C. J. T. Allen,
A. Bourdon,
M. Bart,
C. Cavazos-Guerra,
S. Chevaillier,
J. Crosier,
E. Darbyshire,
A. R. Dean,
J. R. Dorsey,
J. Kent,
D. O'Sullivan,
K. Schepanski,
K. Szpek,
J. Trembath,
A. Woolley

Affiliations

C. L. Ryder: Department of Meteorology, University of Reading, Reading, RG6 6BB, UK
J. B. McQuaid: School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
C. Flamant: Sorbonne Universités, UPMC, Université Paris 06, CNRS & UVSQ, UMR 8190 LATMOS, Paris, France
P. D. Rosenberg: School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
R. Washington: School of Geography and the Environment, University of Oxford, Oxford, UK
H. E. Brindley: Space and Atmospheric Physics, Department of Physics, Imperial College London, London, UK
E. J. Highwood: Department of Meteorology, University of Reading, Reading, RG6 6BB, UK
J. H. Marsham: School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
D. J. Parker: School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
M. C. Todd: Department of Geography, University of Sussex, Brighton BN1 9QJ, UK
J. R. Banks: Space and Atmospheric Physics, Department of Physics, Imperial College London, London, UK
J. K. Brooke: School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
S. Engelstaedter: School of Geography and the Environment, University of Oxford, Oxford, UK
V. Estelles: Dept. Física Fundamental y Experimental, Electrónica y Sistemas, Universidad de La Laguna, San Cristóbal de La Laguna, Spain
P. Formenti: LISA, UMR CNRS 7583, Université Paris Est Créteil et Université Paris Diderot, Institut Pierre Simon Laplace, Créteil, France
L. Garcia-Carreras: School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
C. Kocha: Sorbonne Universités, UPMC, Université Paris 06, CNRS & UVSQ, UMR 8190 LATMOS, Paris, France
F. Marenco: Met Office, Exeter, EX1 3PB, UK
H. Sodemann: Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
C. J. T. Allen: School of Geography and the Environment, University of Oxford, Oxford, UK
A. Bourdon: SAFIRE, UMS CNRS-CNES-Météo-France, Francazal, France
M. Bart: School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
C. Cavazos-Guerra: Department of Geography, University of Sussex, Brighton BN1 9QJ, UK
S. Chevaillier: LISA, UMR CNRS 7583, Université Paris Est Créteil et Université Paris Diderot, Institut Pierre Simon Laplace, Créteil, France
J. Crosier: National Centre for Atmospheric Science, University of Manchester, Manchester, M13 9PL, UK
E. Darbyshire: Department of Meteorology, University of Reading, Reading, RG6 6BB, UK
A. R. Dean: Facility for Airborne Atmospheric Measurements, Cranfield, MK43 0AL, UK
J. R. Dorsey: National Centre for Atmospheric Science, University of Manchester, Manchester, M13 9PL, UK
J. Kent: Met Office, Exeter, EX1 3PB, UK
D. O'Sullivan: Met Office, Exeter, EX1 3PB, UK
K. Schepanski: School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
K. Szpek: Met Office, Exeter, EX1 3PB, UK
J. Trembath: Facility for Airborne Atmospheric Measurements, Cranfield, MK43 0AL, UK
A. Woolley: Facility for Airborne Atmospheric Measurements, Cranfield, MK43 0AL, UK

DOI: https://doi.org/10.5194/acp-15-8479-2015
Journal volume & issue: Vol. 15, no. 14
pp. 8479 – 8520

Abstract

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The Fennec climate programme aims to improve understanding of the Saharan climate system through a synergy of observations and modelling. We present a description of the Fennec airborne observations during 2011 and 2012 over the remote Sahara (Mauritania and Mali) and the advances in the understanding of mineral dust and boundary layer processes they have provided. Aircraft instrumentation aboard the UK FAAM BAe146 and French SAFIRE (Service des Avions Français Instrumentés pour la Recherche en Environnement) Falcon 20 is described, with specific focus on instrumentation specially developed for and relevant to Saharan meteorology and dust. Flight locations, aims and associated meteorology are described. Examples and applications of aircraft measurements from the Fennec flights are presented, highlighting new scientific results delivered using a synergy of different instruments and aircraft. These include (1) the first airborne measurement of dust particles sizes of up to 300 microns and associated dust fluxes in the Saharan atmospheric boundary layer (SABL), (2) dust uplift from the breakdown of the nocturnal low-level jet before becoming visible in SEVIRI (Spinning Enhanced Visible Infra-Red Imager) satellite imagery, (3) vertical profiles of the unique vertical structure of turbulent fluxes in the SABL, (4) in situ observations of processes in SABL clouds showing dust acting as cloud condensation nuclei (CCN) and ice nuclei (IN) at −15 °C, (5) dual-aircraft observations of the SABL dynamics, thermodynamics and composition in the Saharan heat low region (SHL), (6) airborne observations of a dust storm associated with a cold pool (haboob) issued from deep convection over the Atlas Mountains, (7) the first airborne chemical composition measurements of dust in the SHL region with differing composition, sources (determined using Lagrangian backward trajectory calculations) and absorption properties between 2011 and 2012, (8) coincident ozone and dust surface area measurements suggest coarser particles provide a route for ozone depletion, (9) discrepancies between airborne coarse-mode size distributions and AERONET (AERosol Robotic NETwork) sunphotometer retrievals under light dust loadings. These results provide insights into boundary layer and dust processes in the SHL region – a region of substantial global climatic importance.

Published in Atmospheric Chemistry and Physics

ISSN: 1680-7316 (Print); 1680-7324 (Online)
Publisher: Copernicus Publications
Country of publisher: Germany
LCC subjects: Science: Physics; Science: Chemistry
Website: http://www.atmospheric-chemistry-and-physics.net/

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