MMM SEMINAR NCAR
Turbulent Flow Over Slow And Fast Moving Water Waves
National Center for
Atmospheric Research
Boulder, CO
Air-sea interaction processes influence weather, climate, and scalar transport over a wide spectrum of scales ranging from millimeters to hundreds of kilometers. In this presentation, the impact of an idealized surface wave field on turbulent flow in the atmospheric PBL is studied using turbulent simulations (direct and large-eddy simulations). Using DNS, we first consider the regime of slow moving waves where non-separated sheltering and critical-layer dynamics are active and discuss how these processes lead to wave growth. Next, LES is used to examine the influence of large-scale, fast-moving swell on a weak wind atmospheric surface layer. In this special regime, LES solutions exhibit positive (upward) momentum flux, low-level jets, and the flux-profile relationships are not well predicted by surface similarity theory. Furthermore, if light winds and swell persist for sufficient time the wave-driven surface layer can induce a large scale collapse of the atmospheric boundary layer. Recent measurements from the Coupled-Boundary Layers Air-Sea Transfer (CBLAST) field campaign show the existence of wave-driven wind events and support the results from the simulations.
Tuesday, 29 March 2005, 3:30
PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg 2 Auditorium (Rm1022)