Extended Abstract (104K)P4.11
Large-Eddy simulations of Stable Boundary Layer: exploration of ranges of applicability
Maria A. Jiménez, Instituto Nacional de Meteorologia, Madrid, Spain; and J. Cuxart
The Stable Boundary Layer is one of the less well-known regimes of the ABL. Its vertical extent is shallow and the turbulence is usually of small-scale and intermittent. Most of the phenomena occur sporadically and are determined by the local terrain conditions. The turbulence can be generated above the ground and transported downwards.
Explicit simulation of this regime through Large-Eddy simulation is difficult because of the above mentioned reasons. The grid mesh must be very small (below 10 meters) and this has a consequence the use of relatively small domains.
Using the computational facilities of the ECMWF, simulations with an average grid size of 5 meters are performed. The data used for initialisation and validation of the run come from two major campaigns held recently: SABLES-98 and CASES-99.
The run strategy is as follows: a sheared-neutrally stratified boundary-layer is simulated up to an equilibrium state in order to start from a fully developed turbulent regime. Afterwards, the flow is stratified from the bottom introducing a negative heat-flux. The simulation proceeds in consecutive sectors, changing the value of the heat flux and the strength of the wind. Data are available to check until what regime the Large-Eddy simulation is able to reproduce the observed experimental behaviour.
Introduction of additional forcings such as drainage flows, or traveling Internal Gravity Waves is foreseen at the time of writing this abstract.
Poster Session 4, Stable BLs; Chemistry and Dispersion in the ABL
Tuesday, 16 July 2002, 2:00 PM-2:00 PM
Previous paper Next paper