HYDROGRAPHY OF THE NAVO CENCAL REGION FOR DEC01

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HYDROGRAPHY OF THE NAVO CENCAL REGION FOR DEC01

• LT Kitch Kennedy
• OC3570

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What is hydrography

• Historically, the term hydrography has meant the
• scientific study of the physical conditions of
  systems
• of water. Within the field of physical
  oceanography,
• hydrography is the branch of our field which
  looks
• to understand the movements of the ocean through
• its measurable physical properties, including
• temperature, salinity, and oxygen, and chemical
• constituents.
• http//www.oce.orst.edu/po/hydro.html

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Project Domain
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Dynamic Topography

• General circulation through the entire layer of
  the CCS.
• California Current (CC)
• California Undercurrent (CUC)
• Davidson Current (CC)
• Dynamic through driving flow.

Contour - 0.02 dyn-m
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Dynamic Topography

• Surface signature
• Meandering CC
• Weak Davidson current present.
• Strong onshore flow into Monterey Bay

Contour - 0.005 dyn-m
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Dynamic Topography

• Heart of the CUC
• Product of large scale gradients
• Relatively strong poleward flow
• CC weakening
• Max depth 500m

Contour 0.003 dyn-m
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Dynamic Topography

• Both CC and CUC still apparent
• Breakdown of dynamic trough
• Overall weakening currents
• Topography influencing CUC

Contour 0.003 dyn-m
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Pressure fields on Sigma level

• Pressure btwn 50-80 dbar
• Dome of low pressure corresponds to dynamic
  trough
• CC and DC

Contour 4 dbar
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Pressure fields on Sigma level

• Pressure btwn 90-150 dbar
• Stronger gradients stronger currents
• CUC influencing poleward flow along the coast
• Onshore flow building pressure max in Monterey Bay

Contour 5 dbar
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Pressure fields on Sigma level

• Pressure 280-335 dbar
• More variability in the flow
• Core of the CUC
• Meander in CC not present at upper levels

Contour 5 dbar
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Density vs. Salinity Curve
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Surface Salinity

• Weak salinity gradient in the heart of the data
  region
• Fresh water signatures
• Mouth of San Francisco bay
• Pacific Sub-artic water
• Larger salinity gradient correlates well with
  0/200 dynamic height contours

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Salinity Analysis

• Fresh water run-off near SF Bay not evident
• Salinity max near coast
• Equatorial water advected north by DC and CUC
• Mixing of Sub-artic and Equatorial waters
• Strong gradient may represent the boundary of the
  CC

Contour 0.03
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Salinity Analysis

• CUC advection high salinity along the coast
• Relatively fresh pool created by subduction of
  surrounding waters
• CTD cast plots

Contour 0.02
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Salinity Analysis

• Distinct boundary btwn water masses
• Stronger currents allowing less mixing

Contour 0.01
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Sea Surface Temperature

• Poor indicator of current dynamics
• Warm water in region of dynamic trough
• Highly influenced by air-sea interactions
• Cooler water in vicinity of Monterey and San
  Francisco Bays
• Cold water intrusion from SW

Contour 0.2 degC
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ADCP Data

• Qualitative comparison
• Strong correlation with 0/200 and 25.8 Sigma-lvl
  pressure contours

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QUESTIONS?