Kelvin Waves and Internal Bores in the Marine Boundary Layer Inversion and Their Relationship to Coastally Trapped Wind Reversals

Abstract

Abstract Detailed observations of a coastally trapped disturbance, or wind reversal, on 10–11 June 1994 along the California coast provide comprehensive documentation of its structure, based on aircraft, wind profiler, radio acoustic sounding system, and buoy measurements. Unlike the expectations from earlier studies based on limited data, which concluded that the deepening of the marine boundary layer (MBL) was a key factor, the 1994 data show that the perturbation was better characterized as an upward thickening of the inversion capping the MBL. As the event propagated over a site, the reversal in the alongshore wind direction occurred first within the inversion and then 3–4 h later at the surface. A node in the vertical structure (defined here as the altitude of zero vertical displacement) is found just above the inversion base, with up to 200-m upward displacements of isentropic surfaces above the node, and 70-m downward displacements below. Although this is a single event, it is shown that the vertic...