Comparing the Paroscientific Sensor with Aspirated and NonAspirated Sensors

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Comparing the Paroscientific Sensor with
Aspirated and Non-Aspirated Sensors

• Mark Butler
• 3/16/2005

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Background

• CNO directed replacement of the Meteorological
  and Oceanographic Observation System (SMOOS)
• SPAWAR tested several sensors and recommended
  Paroscientific
• Project compared Paroscientific sensor against
  two sensors onboard RV Point Sur

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R/V POINT SUR SENSORS
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R/V POINT SUR SENSORS
Non-aspirated
Paroscientific
Aspirated
Sensors
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DATA COMPARSION

• Difference between
• Paroscientific aspirated temp
• Paroscientific non-aspirated temp
• Non-aspirated aspirated temp
• Paroscientific aspirated specific humidity
• Plotted against

Relative wind direction Ships heading Ships
Speed Over Ground (SOG) Solar irradiance/relative
wind speed Total irradiance/relative wind speed.
Time of day Solar irradiance Total
irradiance True wind speed True wind
direction Relative wind speed
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RESULTS
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ERRORS

• Low bias error between non-aspirated aspirated
• Low random error between Paro non-aspirated
• High bias random errors between Paro Asp

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BIAS
RANDOM
TYPICAL PLOT WITH ERRORS PLOTTED
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LATE AFTERNOON AT MAX HEATING WE HAVE PARO LOWER
THAN AVERAGE
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WITH HIGHER WIND SPEEDS THE RANDOM ERROR
BETWEEN PARO ASP DECREASES
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UNABLE TO DETERMINE EFFECT ON SPECIFIC HUMIDITY
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LITTLE DIFFERENCE BETWEEN PARO NON-ASPIRATED
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AS RADIATION INCREASES RWS DECREASES THE TEMP
DIFFERENCES INCREASES
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AFTERNOON DOWNWARD SPIKES ????
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TEMP DIFFERENCE BETWEEN PARO ASP
RELATIVE WIND SPEED KTS
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CONCLUSIONS

• High bias/random errors between Paro/Aspirated
• Lowest random error between Paro and
  non-aspirated
• Differences between Paro aspirated can be
  contributed to Paro being a non-aspirated sensor

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CONCLUSIONS

• Increasing wind speeds decreases the difference
  between Paro/Aspirated most likely a result of
  air being forced through Paro
• High heating/low wind speed conditions lead to
  large differences between Paro/Aspirated
• Afternoon spikes in differences between
  Paro/Aspirated can mostly likely be related to an
  increase in relative wind speed/direction

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SUMMARY

• Most problematic finding is distinct difference
  between Paroscientific and aspirated sensors with
  high heating low wind conditions.
• Differences of .75 to 1.25 degrees were observed
• Lead to numerous problems in predictions, i.e.
  TAWS, AREPS, duct calculations