Geophysical Research Letters

Near bottom velocity and temperature profiles observed by cyclesonde


  • A. Mercado,

  • J. Van Leer


Three days of twice hourly temperature and velocity profile data were obtained on the southwest Florida Continental Shelf. Measurements in the bottom boundary layer were made with a Cyclesonde to within 5m of the bottom in a depth of 200m with an average vertical resolution ∼ 5m. In the lowest 30m, temperature was nearly constant and the current vectors rotated clockwise from the bottom upward as in an Ekman spiral (total angle of veering ∼ 13°-18°), while in the 20m immediately above, the velocity was nearly constant. The bottom stress, τ o =0.22 to 0.48 dynes/cm ² was estimated by determining the non-geostrophic mass transport within the friction layer. The similarity constant relating the total veering angle and the geostrophic drag coefficient was about 2 to 3. The ratio of the boundary layer thickness to u * /f was about 0.3 to 0.4.