Time-spatial variability observed in velocity of propagation of the internal bore in the Strait of Gibraltar

Abstract

Some aspects of the time-spatial variability of the phase speed of the internal bore generated almost every tidal cycle in Camarinal Sill, are revised using a set of high resolution experimental data collected in two different positions of the Strait during May 2003. This variability is mainly driven by the intense tidal currents, comparable with the intrinsic propagation velocity of the first mode baroclinic bore. It is shown that the importance of the diurnal tide in the Strait of Gibraltar induces a considerable diurnal inequality on the bore velocity, with an observed maximum difference of 0.7 ms-1 between the speed of two consecutives bores propagating along the eastern part of the Strait. A regularly spatial pattern has been also found: the internal bore reaches its maximum velocity in Tarifa Narrows. A theoretical estimation predicts an extreme phase speed of 2.6 ms-1 during our period of study. Copyright 2008 by the American Geophysical Union.