Large eddy simulations of boundary layer turbulence during late afternoon transition
Darbieu, Clara ; Lohou, Fabienne ; Couvreux, Fleur ; Lothon, Marie ; Durand, Pierre ; Guichard, Françoise ; Patton, Ned
In an effort to guide the BLLAST instrument deployment and sampling strategies, the present numerical study aimed at answering basic questions such as : what is the start-time of the late afternoon transition (LAT)? Which atmospheric layers have to be experimentally investigated in priority ? To address these questions, two Large Eddy Simulations (LES) codes ? the NCAR LES, and Meso-NH from Laboratoire d'Aérologie and CNRM/GAME were used to simulate a decaying convective boundary layer. Besides guiding the experimental design, this numerical study had two additional goals:
1/ To compare the two codes and their ability to simulate this delicate period during which the surface buoyancy flux is decreasing.<br>2/ To study the turbulence characteristics during this period. Results found in the literature are revisited and further analysed.
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