Comparison

1
Comparison of Calculated Geostrophic
Currents and ADCP data and Observation of
Features in Leg II
LT Rodrigo Obino OC3570 Final Project
2
Objectives

• Use of temperature, calculated salinity and
  pressure
• data from CTD Seabird SBE 911Plus casts to
  calculate
• Geostrophic currents along transects and Dynamic
  Height
• Anomaly at levels
• Plot ADCP current data perpendicular to cruise
  track
• Obtain satellite and model products

3
Data Distribution
67
D
CUC
X
Y
Z
Q
R
77
4
Dynamic Height Anomaly at Surface
5
Sea Surface Height x Dynamic Height Anomaly
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Dynamic Height Anomaly x ADCP
ADCP 15 to 25 m
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Sea Surface Temperature
10
Temperature and Salinity Horizontal Sections at
250 m
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Geostrophic Current

• Assume CF HPGF, Hydrostatic Balance,
• no acceleration, no friction and one level of no
  motion

adp dF -gdz

• Geopotential distance between 2 isobaric surfaces

• Geostrophic velocity at upper surface between
  stations

• Matlab programs sw_gpan (geopotential anomaly)
• and sw_gvel (geostrophic velocity) relative to
  the surface

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ADCP x Geostrophic Currents
Line CUC
13
Sigma-t
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Line Y
15
Sigma-t
16
Line X
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Sigma-t
18
Line Q
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Sigma-t
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Factors that may lead to differences

• Tide currents in shallow waters (depth to 200m)
• Friction at Ekman Layers
• Non-linearities due to eddies
• Non-linearities due to Internal waves
• Variation of wind stress

21
Questions ?