Moored current meter data at BBL dynamic structure studies of the North-West Africa shelf and continental slope

Moored data collected by means of current meters on the shelf and continental slope of NW Africa have been utilized to reveal peculiarities of meso- and smallscale dynamic structure of the bottom boundary layer (BBL). Clear upwelling features in the bottom currents on the shelf in the time domain were found out and were shown to be due to the wind action and the Ekman transport in the surface layer. The vertical distribution of the mean currents and their veering in the BBL over the shelf were in accordance with a model of Ekman mixing in stratified media. Based on experimental data the parameters of the BBL Ekman layer over the shelf were estimated. Over the slope the data did not match this simple model. Spectral features in high the frequency subinertial interval help to explain the clear difference in the mixing regimes for two the sites.