SST Measurements Comparison

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SST Measurements Comparison
OC 3570 Operational Oceanography Winter 2006 LT
Cherrett
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• OUTLINE
• Significance of accurate SST data
• Comparisons of all SST measurements
• Radiometers
• Thermistors
• 4. Conclusions/Questions

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• Significance
• Assimilation into models
• Air-Sea interaction
• Moisture Flux
• Sensible Heat Flux
• Bulk measurements to determine EM/EO refractive
  properties
• Aircraft based collection
• Near simultaneous measurements over large region
• Remote sensing validation

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Evaporation Duct Height Model
Evaporation Duct Height Model
Wind Speed 5 m/s
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Evaporation Duct Height Model
Evaporation Duct Height Model
Wind Speed 10 m/s
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SST measurements taken aboard RV Pt Sur

• Bucket measured by hand
• Intake into Seachest
• Intake into TSAL
• Boom Probe (platinum probe)
• Radiometer mast (Apogee IR probe)
• - 31 spot / 8-14 micron
• 6. Radiometer bridgedeck (OS43L)
• - 301 spot / 8-14 micron
• 7. Expensive Radiometer
• 8. Cheap Radiometer

LW PIR 3 - 50 micron
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Comparisons
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Comparisons
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Radiometers
Corrected using regression fit
Expensive-Bucket N 140 points Mean 0.2097
deg STD 0.9189 deg Variance 0.844 deg2
Cheapo-Bucket N 146 points Mean -3.2767
deg STD 1.8830 deg Variance 3.5458 deg2
Corrected for sky temp
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Radiometers
Corrected further using temperatures between -10
and 10 deg C using PIR
Corrected using expensive handheld sky
temperatures
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Radiometers
Rad (bridge) Exp Rad N 139 points Mean 0.46
deg STD 1.134 deg Variance 1.286 deg2
Rad (top) Exp Rad N 146 points Mean -0.69
deg STD 1.013 deg Variance 1.026 deg2
Rad (bridge) bucket N 143 points Mean 0.24
deg STD 0.907 deg Variance 0.823 deg2
Rad (top) bucket N 151 points Mean -0.89
deg STD 0.537 deg Variance 0.289 deg2
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Radiometers
Rad (top) Bucket (Sun is up) N 54 points Mean
-0.88 deg STD 0.496 deg Variance 0.246 deg2
Rad (bridge) Bucket (Sun is up) N 54
points Mean -0.46 deg STD 0.939
deg Variance 0.882 deg2
Rad (bridge) Bucket (Sun is down) N 89
points Mean 0.67 deg STD 0.555
deg Variance 0.309 deg2
Rad (top) Bucket (Sun is down) N 89
points Mean -0.90 deg STD 0.567
deg Variance 0.321 deg2
Significant using two sample T-dist
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Intakes
vs Bucket
Intake (Seachest)-Bucket N 158 points Mean
0.3206 deg STD 0.3354 deg Variance 0.1125
deg2
TSAL-Intake N 171 points Mean 0.2 deg STD
0.02 deg Variance 0.0004 deg2
TSAL-Bucket N 158 points Mean 0.5206 deg STD
0.3319 deg Variance 0.1102 deg2
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Seachest vs Bucket
Seachest-Bucket (Sun is up) N 66 points Mean
0.158 deg STD 0.232 deg Variance 0.054
deg2
Seachest-Bucket (Sun is down) N 92 points Mean
0.437 deg STD 0.351 deg Variance 0.123
deg2
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Boom Probe vs Bucket
Boom Probe - Bucket N 9 points Mean 0.4389
deg STD 0.1201 deg Variance 0.0144 deg2
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Thermistors
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• Errors and variance
• Bucket measured by hand
• HUMANS!
• Thermometer
• Time of day
• Ship movement/mixing
• Intake into Seachest
• Subsurface collection
• Ships sensitive heat flux
• 3. Intake into TSAL
• Subsurface collection
• Ships sensitive heat flux
• 4. Boom Probe (platinum probe)
• Fell into a rabbit hole early

• 5. Radiometer Top (Apogee IR probe)
• Slant distance
• Spot size (31)
• Roll/Pitch of ship
• Sky temp (measured in other direction
• Wake (mixing of top 50 microns)
• 6. Radiometer bridgedeck (OS43L)
• Same as Apogee
• 7. Expensive Handheld Radiometer
• Angle held
• Eyeball quickly changing values
• Wake
• 8. Cheap Handheld Radiometer
• Same as above,
• You get what you pay for

Bottom line Not an absolute process of data
collection.
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Questions???