Http://samos.coaps.fsu.edu Height Matters. Wind, Temperature, and Humidity.
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Transcript of Http://samos.coaps.fsu.edu Height Matters. Wind, Temperature, and Humidity.
http://samos.coaps.fsu.edu
Height MattersHeight Matters
http://samos.coaps.fsu.edu
Wind, Temperature, and HumidityWind, Temperature, and Humidity
0
2
4
6
8
10
12
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18
20
0 1 2 3 4 5 6
Wind speed m/s
He
igh
t
Profile
Measurements
Sys-2 buoy
WHOTS-2 June 24 2006 Hr 6
0
2
4
6
8
10
12
14
16
18
20
24.4 24.6 24.8 25.0 25.2 25.4
Potential Temperature °C
Profile
Measurements
Surface
Sys-2 buoy
Assman
0
2
4
6
8
10
12
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18
20
14 15 16 17 18 19 20Humidity g/kg
Profile
Measurements
Surface
Sys-2 buoy
Assman
http://samos.coaps.fsu.edu
-25 -20 -15 -10 -5 0 5 10 15 20 251011.15
1011.2
1011.25
1011.3
1011.35
Air Temp (C)
Pre
ssur
e(m
b)
Air Temperature Effect
0 5 10 15 20 25 30 35 40 45 500
1
2
3
4
5
6
Sensor Ht (m)
Ps
- 10
10(m
b)
Surface Pressure Calculation
Ps = Pze(gz/RaT)
Pz = Station pressure (mb)Ra = Universal Constant (J/kgK)… 287.05;T = Temperature (K)g = gravity (m/s)… 9.81; z = height of pressure sensor (m)Ps = sea level pressure (SLP mb)
Rough guesstimate 1mb = 10m
SLP >= Station Pressure
Station Pressure to Sea Level calculation
7.67m
2.946m
2.883m
Deck2
Deck3
Deck1
Pilot House
7/11/2013 Measurements
Ship’s pressure sensor
PSD dynamic pressure port and sensor14.388m above water
Ship dynamic pressure port12.02m above water
Ship ~1.38 mb @ 25oCPSD ~1.66 mb @ 25oC
NWS barometer
Ship pressure12.02m above water
65”
Tygon tubing to dynamic pressure port
Ship pressure sensorPSD3 Hand Held barometer
Prior to resetting Vaisala unitw/30m offset
Ship pressure sensorVaisala PTB330
PSD3 Hand Held barometer
After resetting Vaisala unit7/11/2013 ~0115UTC
NWS barometer last calibrated 7/25/2011Appears to be reading Sea level pressure~.3-.5 mb higher than Vaisala
Sea Level
Station
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PressurePressure
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Accuracy TargetsAccuracy Targets
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Applying Heights in the FieldApplying Heights in the Field
Image Courtesy NOAA OAR
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Questions?Questions?
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Pressure ExercisePressure Exercise
• Using the equation • Given
• pz = 1010 hPa
• T = 290 K• g = 9.81 m s-2
• Ra = 287.05 J kg-1 K-1
• e = 2.718281
• Calculate the surface pressure (ps) for your vessel using your barometer height (z).
• Calculate the pressure difference (ps – pz) and add it to the list on the whiteboard.
} Pressure and temperature at a given time
} Constants