Heat Budget in the California Current

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Heat Budget in the California Current

• Kathryn A. Kelly
• Applied Physics Laboratory
• University of Washington

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Outline

• Terms in the upper ocean heat budget
• Contributions of satellite data to terms
• Comparisons of surface heat fluxes
• Estimating advection geostrophic and Ekman

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Upper Ocean Heat Budget
In terms of mixed layer temperature
Advection
Surface heating
Entrainment
T mixed layer temperature h mixed layer
depth Qnet net surface heat flux
we entrainment velocity velocity geostrophic
Ekman
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Surface Heating Term

• Net flux shortwave longwave latent
  sensible
• shortwave longwave from NCEP
• turbulent fluxes also computed with COARE
  algorithm
• wind speed NCEP or QuikSCAT
• flux alternatives NCEP, NCEP/COARE, or
  QuikSCAT/COARE

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Net surface heat flux products
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Comparison with NCEP flux
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Effect of QuikSCAT winds on heat fluxes
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Evaluating surface fluxes with sea level

• heat content of the ocean

Expansion of a solid
Expansion of a fluid column
Net surface heat flux
Coefficient of thermal expansion
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JASON-1 in space
Radar altimeter launched August 2002
Successor to TOPEX/Poseidon (August 1992 -- )
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RMS Variability of Sea Surface Height
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Comparing SSH Anomalies with Heat Flux
time integral of net surface heat flux
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SSH response to net surface heat flux
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SSH response with mean flux removed
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Interannual and seasonal response to surface
heating
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Advection Term

• Velocity geostrophic Ekman
• geostrophic velocity anomaly from the T/P
  altimeter
• mean sea surface height needed (altimeter mean
  removed along with geoid)
• mean SSH derived from mean drifter velocity,
  assuming it is geostrophic
• Ekman velocity alternatives NCEP or QuikSCAT

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• surface geostrophic velocity from sea surface
  height

LOW
Plan view
section
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Altimeter Ground Tracks

• all subtracks for 10-day repeat cycle
• shown with WOCE drifter tracks in the California
  Current
• TOPEX/Poseidon and JASON-1
• Two altimeters interleaved, as of August 2002

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Entrainment

• Use climatological mixed layer depth (Levitus)
• Assume

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Heat Budget Lab
In terms of mixed layer temperature
geostrophic and Ekman advection
entrainment
heating

• Notes
• surface heating term (turbulent flux options)
• T from TMI (TRMM microwave imager)
• Ekman velocity from NCEP or QuikSCAT