Investigation of vertical eddy fluxes under stable conditions in the surface boundary layer
| Project acronym: | HIII-CNRS18_Toulouse_DobrovolschiSteeneveldSBL |
| Name of Group Leader: | Dr. Dan Dobrovolschi, Romanian National Meteorological
Administration, Bucharest, Romania, dandobrov@gmail.com Dr. Gert-Jan Steeneveld, Wageningen University, The Netherlands, Gert-Jan.Steeneveld@wur.nl |
| User-Project Title: | Investigation of vertical eddy fluxes under stable conditions in the surface boundary layer |
| Facility: | Stratified Flume |
| Proceedings TA Project: | Investigation of the vertical eddy flux of momentum under stable conditions in the surface boundary layer over land using cnrs-toulouse stratified water flume |
| Data Management Report: | Data Management Reports Page You will need to login to view this page |
Summary:
Understanding and prediction of atmospheric stably stratified boundary layers (SBL) is a longstanding challenge in the field of meteorology (Louis et al., 1981; Holtslag and Nieuwstadt, 1986). In spite of previous SBL studies, either from field experiments (e.g. CASES-99, SHEBA, Cabauw tower, SABLES) or by LES numerical simulations, a need exists for improving the parameterization of turbulent transport of heat, momentum and scalars in the SBL (Cuxart et al., 2006; Steeneveld et al. 2006). This will improve the skill of models for weather forecasting; climate and air quality, in particular for winter and nocturnal conditions.
As an alternative laboratory experiments can provide an extensive dataset with very well-controled parameters such as wind and density vertical profile. Despite a few wind-tunnel experiments have been carried out on SBL, none have been performed with a stratified water flume although this equipment is excellent to investigate the SBL.
The current work extends these earlier approaches by parameterization development from laboratory experiments at the CNRM-GAME Toulouse stratified water flume, and compares with field studies and LES. This unique facility is indeed very pertinent for such a study, in particular due to its ability to generate density stratified flow at high Reynolds numbers with low confinement effect.
Preliminary tests were performed to ensure that a turbulent, well-developed boundary layer close to a statistical equilibrium can be physically simulated. Our main objectives now are to measure vertical turbulent fluxes of momentum and density, under different conditions of stability and mean flow velocity.
Fig. 1 (above) Experimental set-up at the CNRS-Toulouse stratified water flume
Fig. 2 The stable boundary
layer over land in the diurnal
cycle . An important scientific
challenge is to develop a
turbulent mixing scheme
which covers all three regimes
(Stull, 1988).
| Publication References |
| J. Cuxart, A. A. M. Holtslag, R. J. Beare, E. Bazile, A. Beljaars, A. Cheng, L. Conangla, M. Ek, F. Freedman, R.Hamdi, A. Kerstein, H. Kitagawa, G. Lenderink, D. Lewellen, J. Mailhot, T. Mauritsen, V. Perov, G. Schayes, G.J. Steeneveld, G. Svensson, P. Taylor, W. Weng, S. Wunsch, and K-M. Xu (2006): Single column model intercomparison for the stably stratified atmospheric boundary layer , Bound.-Layer Meteorol, 118, 273-303. |
| Dobrovolschi D., G.-J. Steeneveld, A. Paci, O. Eiff and L. Lacaze (2010): Investigation of the vertical eddy flux of momentum under stalble conditions in the surface bounndary layer over land using CNRS-Toulouse stratified water flume, proceedings of HYDRALAB-III Joint User Meeting. |
| Holtslag, A.A.M., and F.T.M. Nieuwstadt (1986): Scaling the Atmospheric Boundary Layer, Bound.-Layer Meteor., 36, 201-209. |
| Louis J-F, M. Tiedtke, and J.F. Geleyn (1981): Proc. Workshop on PBL Parameterization, Reading, UK, ECMWF, 59-79 |
| Steeneveld, G.J., B.J.H. van de Wiel, and A.A.M. Holtslag (2006): Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99, J. Atmos. Sci., 63, 20-935. |
| Stull, R.B., 1988: An Introduction to Boundary Layer Meteorology, Kluwer. |