10th Conference on Mountain Meteorology and MAP Meeting 2002

Thursday, 20 June 2002
Interaction of trapped lee waves and the convective boundary layer
Rolf F. Hertenstein, Colorado Research Associates, Boulder, CO; and G. S. Poulos
Poster PDF (669.7 kB)
Trapped lee waves have been observed to exhibit a transient nature. Three possibilities have been suggested to explain the transience: changes in the ambient upstream conditions, an evolving lee-side atmospheric boundary layer, or wave-wave interactions. Herein, we explore the interaction between trapped lee waves and an evolving convective boundary layer (CBL) using simulations with idealized topography. The first simulation is initialized with a wind and stability profile assuring trapped waves. In this simulation, no surface heating is emloyed. A second simulation is initialized with the same stability profile, but no wind. Surface heating is included via the model's radiation parameterization. A third simulation allows development of trapped lee waves and CBL simultaneously. Difference fields are calculated to quantify the influence of the trapped lee-wave system on the CBL and vice versa. In addition, vertical profiles of tendencies from model heat, moisture, and momentum equations are written out at each timestep for several points throughout the model's horizontal domain for each simulation. Regions of particular interest include the downslope flow along the lee slope, lee-wave updrafts and downdrafts, and the rotor located beneath lee-wave crests. Time series of the model tendencies are analyzed to describe and quantify the underlying dynamics associated with the lee-wave/CBL interaction.

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