A laboratory and numerical study of the transient development of wind-driven coastal upwelling
Abstract
Laboratory and numerical experiments were carried out to investigate the transient response of a uniformly stratified fluid to steady, upwelling-favorable wind stress in a shelf-like geometry. We focus on the processes underlying transport and mixing in the inner-shelf zone and the formation, off-shore migration and instability of upwelling fronts. Fully resolved, non-hydrostatic numerical simulations are shown to compare favorably with laboratory measurements and are used in conjunction with these data to provide a detailed picture of the three-dimensional flow field. Two distinct types of instabilities are observed to be important in the overall flow development: (i) instability of the negatively buoyant, sheared surface Ekman layer in the inner-shelf zone and (ii) instability of the density front separating the inner- from the outer-shelf region. A simple model for estimating the position of an upwelling front in a developing flow, incorporating the effects of stratification, rotation, a sloping bathymetry and penetrative convective mixing, is developed and tested against the experimental data.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....7290W