P1252108601QRVFN

1
SENSITIVITY OF BOTTOM TOPOGRAPHY ON THE DYNAMICS
AND SOUND SPEED STRUCTURE IN THE NORTHEN CANARY
CURRENT SYSTEM

• Sound Speed Results
• Features of the NCCS can have a significant
  impact on the sound speed structure
• Can lead to large changes in sound speed (up to
  25 m/s) and can distort the vertical sound speed
  profile
• Greatest change in sound speed (25 m/s) is caused
  by upwelling in the NCCS
• Could significantly impact Navy sonar operations

LT Alicia Hopkins (Dec 06) Advisors Dr. Mary L
Batteen, Dr. John A Colosi Beneficiary DOD/
FNMOC improved littoral current modeling, sound
speed variability awareness
Experiment Number Annual Climatology Bottom Topography
1 Horizontally Averaged Flat
2 Horizontally Averaged Smoothed with a 2-D Gaussian Filter Method
3 Full Smoothed with a 2-D Gaussian Filter Method
4 Full Smoothed with the 1-D Direct Iterative Method
Upwelling Surface Eddy

• Experiment Results
• In all experiments, surface current,
  undercurrent, upwelling all occur
• Only in Experiments 3 and 4 do the Iberian
  Current form
• Due to Full Thermohaline Forcing
• In all experiments, Meddy formation occurs off of
  Cabo da Roca
• Meddy forms off Figueira da Foz in all except
  Experiment 1
• Only in the flat bottom ( Experiment 1) and the
  iterative bottom topography (Experiment 4) do we
  get Meddy development off Cabo de Sao Vicente

-25 m/s change in sound speed. -25 m/s change in
sound speed. ? Significant
Meddy
6 m/s change in sound speed. ? Significant
Undercurrent
6 m/s change in sound speed. ? Not significant