The Boundary-Layer Late Afternoon and Sunset Turbulence (BLLAST) project (ACP/AMT inter-journal SI)(ACP/AMT inter-journal SI)
The Boundary-Layer Late Afternoon and Sunset Turbulence (BLLAST) project (ACP/AMT inter-journal SI)(ACP/AMT inter-journal SI)
Editor(s): R. J. Beare, Y. Brunet, E. Pardyjak, and S. Galmarini Special issue jointly organized between Atmospheric Chemistry and Physics and Atmospheric Measurement Techniques
The planetary boundary layer plays a vital role in the earth system through its controls on the transfer of heat, momentum, humidity, and trace gases between the surface and the atmosphere. The transition that occurs in late afternoon, from the mixed convective boundary layer to a residual layer overlying a stably stratified surface layer in late afternoon raises several scientific issues that are still poorly understood. For example, there is still a need to relate the characteristics of the turbulence energy decay and its vertical structure with the boundary-layer processes and forcings. Also, the evolution of the characteristic length scales of turbulence remains unclear, and needs more observations and understanding.

The BLLAST project has gathered a group of research scientists from several countries in Europe and the US to work together with the purpose of increasing our knowledge of the late afternoon turbulence processes in order to improve the representation of the diurnal cycle in the numerical weather prediction and global models. The BLLAST project emerged in 2009, and lead to a field campaign that was conducted from 14 June to 8 July 2011 in southern France. The field campaign consisted of a range of integrated instrument platforms including: full-size aircraft, Remotely Piloted Airplane Systems (RPAS), remote sensing instruments, radiosoundings, tethered balloons, surface flux stations, and various meteorological towers deployed over different heterogeneous surfaces. These instruments measured the differences in the vertical structure and evolution of the late afternoon transition among a mosaic of vegetated surfaces. This special issue is an expose of current BLLAST studies that include: the analysis of field data, Large Eddy Simulations (LES) and mesoscale simulations. These issue aims to improve our understanding of processes, develop new parameterizations, and evaluate forecast models during this transitional period.

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02 Jun 2017
A new downscaling method for sub-grid turbulence modeling
Lucie Rottner, Christophe Baehr, Fleur Couvreux, Guylaine Canut, and Thomas Rieutord
Atmos. Chem. Phys., 17, 6531–6546,,, 2017
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06 Oct 2016
Proof of concept for turbulence measurements with the RPAS SUMO during the BLLAST campaign
Line Båserud, Joachim Reuder, Marius O. Jonassen, Stephan T. Kral, Mostafa B. Paskyabi, and Marie Lothon
Atmos. Meas. Tech., 9, 4901–4913,,, 2016
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06 Sep 2016
Turbulence fluxes and variances measured with a sonic anemometer mounted on a tethered balloon
Guylaine Canut, Fleur Couvreux, Marie Lothon, Dominique Legain, Bruno Piguet, Astrid Lampert, William Maurel, and Eric Moulin
Atmos. Meas. Tech., 9, 4375–4386,,, 2016
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29 Jul 2016
Estimation of the advection effects induced by surface heterogeneities in the surface energy budget
Joan Cuxart, Burkhard Wrenger, Daniel Martínez-Villagrasa, Joachim Reuder, Marius O. Jonassen, Maria A. Jiménez, Marie Lothon, Fabienne Lohou, Oscar Hartogensis, Jens Dünnermann, Laura Conangla, and Anirban Garai
Atmos. Chem. Phys., 16, 9489–9504,,, 2016
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21 Jul 2016
Boundary-layer turbulent processes and mesoscale variability represented by numerical weather prediction models during the BLLAST campaign
Fleur Couvreux, Eric Bazile, Guylaine Canut, Yann Seity, Marie Lothon, Fabienne Lohou, Françoise Guichard, and Erik Nilsson
Atmos. Chem. Phys., 16, 8983–9002,,, 2016
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19 Jul 2016
Turbulence kinetic energy budget during the afternoon transition – Part 1: Observed surface TKE budget and boundary layer description for 10 intensive observation period days
Erik Nilsson, Fabienne Lohou, Marie Lothon, Eric Pardyjak, Larry Mahrt, and Clara Darbieu
Atmos. Chem. Phys., 16, 8849–8872,,, 2016
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19 Jul 2016
Turbulence kinetic energy budget during the afternoon transition – Part 2: A simple TKE model
Erik Nilsson, Marie Lothon, Fabienne Lohou, Eric Pardyjak, Oscar Hartogensis, and Clara Darbieu
Atmos. Chem. Phys., 16, 8873–8898,,, 2016
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01 Jul 2016
A study of local turbulence and anisotropy during the afternoon and evening transition with an unmanned aerial system and mesoscale simulation
Astrid Lampert, Falk Pätzold, Maria Antonia Jiménez, Lennart Lobitz, Sabrina Martin, Gerald Lohmann, Guylaine Canut, Dominique Legain, Jens Bange, Dani Martínez-Villagrasa, and Joan Cuxart
Atmos. Chem. Phys., 16, 8009–8021,,, 2016
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24 Jun 2016
Exploring the potential of the RPA system SUMO for multipurpose boundary-layer missions during the BLLAST campaign
Joachim Reuder, Line Båserud, Marius O. Jonassen, Stephan T. Kral, and Martin Müller
Atmos. Meas. Tech., 9, 2675–2688,,, 2016
Short summary
09 Sep 2015
Turbulence vertical structure of the boundary layer during the afternoon transition
C. Darbieu, F. Lohou, M. Lothon, J. Vilà-Guerau de Arellano, F. Couvreux, P. Durand, D. Pino, E. G. Patton, E. Nilsson, E. Blay-Carreras, and B. Gioli
Atmos. Chem. Phys., 15, 10071–10086,,, 2015
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14 Aug 2015
Interactions among drainage flows, gravity waves and turbulence: a BLLAST case study
C. Román-Cascón, C. Yagüe, L. Mahrt, M. Sastre, G.-J. Steeneveld, E. Pardyjak, A. van de Boer, and O. Hartogensis
Atmos. Chem. Phys., 15, 9031–9047,,, 2015
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14 Jul 2015
A comprehensive investigation on afternoon transition of the atmospheric boundary layer over a tropical rural site
A. Sandeep, T. N. Rao, and S. V. B. Rao
Atmos. Chem. Phys., 15, 7605–7617,,, 2015
Short summary
29 Jun 2015
Lifted temperature minimum during the atmospheric evening transition
E. Blay-Carreras, E. R. Pardyjak, D. Pino, S. W. Hoch, J. Cuxart, D. Martínez, and J. Reuder
Atmos. Chem. Phys., 15, 6981–6991,,, 2015
24 Apr 2015
Study of a prototypical convective boundary layer observed during BLLAST: contributions by large-scale forcings
H. P. Pietersen, J. Vilà-Guerau de Arellano, P. Augustin, A. van de Boer, O. de Coster, H. Delbarre, P. Durand, M. Fourmentin, B. Gioli, O. Hartogensis, F. Lohou, M. Lothon, H. G. Ouwersloot, D. Pino, and J. Reuder
Atmos. Chem. Phys., 15, 4241–4257,,, 2015
16 Oct 2014
The BLLAST field experiment: Boundary-Layer Late Afternoon and Sunset Turbulence
M. Lothon, F. Lohou, D. Pino, F. Couvreux, E. R. Pardyjak, J. Reuder, J. Vilà-Guerau de Arellano, P Durand, O. Hartogensis, D. Legain, P. Augustin, B. Gioli, D. H. Lenschow, I. Faloona, C. Yagüe, D. C. Alexander, W. M. Angevine, E Bargain, J. Barrié, E. Bazile, Y. Bezombes, E. Blay-Carreras, A. van de Boer, J. L. Boichard, A. Bourdon, A. Butet, B. Campistron, O. de Coster, J. Cuxart, A. Dabas, C. Darbieu, K. Deboudt, H. Delbarre, S. Derrien, P. Flament, M. Fourmentin, A. Garai, F. Gibert, A. Graf, J. Groebner, F. Guichard, M. A. Jiménez, M. Jonassen, A. van den Kroonenberg, V. Magliulo, S. Martin, D. Martinez, L. Mastrorillo, A. F. Moene, F. Molinos, E. Moulin, H. P. Pietersen, B. Piguet, E. Pique, C. Román-Cascón, C. Rufin-Soler, F. Saïd, M. Sastre-Marugán, Y. Seity, G. J. Steeneveld, P. Toscano, O. Traullé, D. Tzanos, S. Wacker, N. Wildmann, and A. Zaldei
Atmos. Chem. Phys., 14, 10931–10960,,, 2014
03 Sep 2014
Countergradient heat flux observations during the evening transition period
E. Blay-Carreras, E. R. Pardyjak, D. Pino, D. C. Alexander, F. Lohou, and M. Lothon
Atmos. Chem. Phys., 14, 9077–9085,,, 2014
14 Aug 2014
Land surface spinup for episodic modeling
W. M. Angevine, E. Bazile, D. Legain, and D. Pino
Atmos. Chem. Phys., 14, 8165–8172,,, 2014
07 May 2014
Role of the residual layer and large-scale subsidence on the development and evolution of the convective boundary layer
E. Blay-Carreras, D. Pino, J. Vilà-Guerau de Arellano, A. van de Boer, O. De Coster, C. Darbieu, O. Hartogensis, F. Lohou, M. Lothon, and H. Pietersen
Atmos. Chem. Phys., 14, 4515–4530,,, 2014
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