Role of the residual layer and large-scale subsidence on the development and evolution of the convective boundary layer 1Department of Applied Physics, Universitat Politècnica de Catalunya·BarcelonaTech, Barcelona, Spain
07 May 2014
2Institute of Space Studies of Catalonia (IEEC-UPC), Barcelona, Spain
3Meteorology and Air Quality Group, Wageningen University, Wageningen, the Netherlands
4Laboratoire d'Aérologie, Université de Toulouse and CNRS, Toulouse, France
Received: 05 Nov 2013 – Published in Atmos. Chem. Phys. Discuss.: 02 Dec 2013 Abstract. Observations, mixed-layer theory and the Dutch Large-Eddy Simulation model
(DALES) are used to analyze the dynamics of the boundary layer during an
intensive operational period (1 July 2011) of the Boundary Layer Late
Afternoon and Sunset Turbulence campaign. Continuous measurements made by
remote sensing and in situ instruments in combination with radio soundings,
and measurements done by remotely piloted aircraft systems and two manned
aircrafts probed the vertical structure and the temporal evolution of the
boundary layer during the campaign. The initial vertical profiles of
potential temperature, specific humidity and wind, and the temporal evolution
of the surface heat and moisture fluxes prescribed in the models runs are
inspired by some of these observations.
Revised: 28 Feb 2014 – Accepted: 07 Mar 2014 – Published: 07 May 2014
The research focuses on the role played by the residual layer during the
morning transition and by the large-scale subsidence on the evolution of the
boundary layer. By using DALES, we show the importance of the dynamics of the
boundary layer during the previous night in the development of the boundary
layer at the morning. DALES numerical experiments including the residual
layer are capable of modeling the observed sudden increase of the boundary-layer
depth during the morning transition and the subsequent evolution of the
boundary layer. These simulations show a large increase of the entrainment
buoyancy flux when the residual layer is incorporated into the mixed layer.
We also examine how the inclusion of the residual layer above a shallow
convective boundary layer modifies the turbulent kinetic energy budget.
Large-scale subsidence mainly acts when the boundary layer is fully
developed, and, for the studied day, it is necessary to be considered to reproduce the
Finally, we also investigate how carbon dioxide (CO2) mixing ratio
stored the previous night in the residual layer plays a fundamental role in
the evolution of the CO2 mixing ratio during the following day.
Citation: Blay-Carreras, E., Pino, D., Vilà-Guerau de Arellano, J., van de Boer, A., De Coster, O., Darbieu, C., Hartogensis, O., Lohou, F., Lothon, M., and Pietersen, H.: Role of the residual layer and large-scale subsidence on the development and evolution of the convective boundary layer, Atmos. Chem. Phys., 14, 4515-4530, doi:10.5194/acp-14-4515-2014, 2014.