evolving ndbc buoy observations to add value to hurricane ... · michael ~30 ft seas. waves: 42039...
TRANSCRIPT
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Evolving NDBC Buoy Observations to Add Value to
Hurricane Research and Forecasting
Interdepartmental Hurricane ConferenceTropical Cyclone Research Forum
Karen Grissom12 March, 2019
National Data Buoy Center
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Individual Moorings
Satellites
Moorings Networks
Time and Space Observing Needs
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Value of In-Situ Buoy Observations
• Initializationo Provide background state prior to TC – improve initial
conditions
• Validation/ground truth
• Developmental testing & calibrationo Contribute to post storm understanding of magnitude &
duration of ocean response
• Captures temporal variability
• Impervious to cloud cover
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05/20 06/01 06/15 07/01 07/15 08/01 08/15 09/01 09/15 10/01 10/10980
990
1000
1010
1020
1030
Date (mm/dd)
Bar
omet
ric P
ress
ure
(mb)
0
2
4
6
8
10
Sig
Wav
e H
gt (m
)
• Ocean observations assimilation critical to improving initialization for intensity
• Observation (waves, SST) and derived integral properties (heat content) often used as constraint of mesoscale variability – background state
Initialization
Station 42039 N. GoM
Alberto Gordon Michael
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• Select locations • Observations for testing/validation of satellites and
models
Validation
Businger et al, 2015Tang et al, 2016
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Calibration
• Moored sensors can be re-calibrated to become in-situ reference stations for satellites and other type of sensors
Valamanesh et al, 2016
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Spatial Density
Historical DensityCurrent Density (2005-)
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NDBC Legacy Buoys
10-meter hull
6-meter hull
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NDBC Current Buoys
3-meter hull
2.1-meter hull
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Value Added
• Moved SST from hull mounted to in-situ bridle mount – faster response time
• Added capability for RT subsurface in-situ T,S,P (& currents)
• Excellent coverage of time domain & less time aliasing
• High-resolution near real-time data to GTS• Hurricane Supplemental Observations: Barometer,
wind speed and direction reports 1 min extreme
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Marine Weather:Hurricanes
Legacy Buoys
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09/27 09/30 10/03 10/07 10/10980
990
1000
1010
1020
1030
Date (mm/dd)
Bar
omet
ric P
ress
ure
(mb)
0
2
4
6
8
10
Sig
Wav
e H
gt (m
)
10/01 10/07 10/10 10/14 10/170
2.5
5
7.5
10
Date (mm/dd)
Sig
Wav
e H
gt (m
)
1,000
1005
1,010
1015
1,020
Bar
omet
ric P
ress
ure
(mb)
Michael
~30 ft seas
Waves: 42039 & 42003
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~30 ft seas
Waves: 41048
Florence
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-80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 600
50
100
150
200
250
300
350
400
450
500
OHC Difference (kJ/cm2)
Num
ber o
f Obs
erva
tions
Q = cp ρ ∫ 𝛥𝛥𝛥𝛥0𝑧𝑧(𝛥𝛥=26) (x,y,z,t) dz
Mean difference = 4.6 kJ cm-2 ± 15 kJ cm-2
Extra heatLess heat
Ocean Heat Content
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• Agreement diminishes with depth• Std dev increases from
± 0.2°C to ±0.6°
• Mean difference changes sign
Accuracy Required?
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Summary
• Value of buoy observations: initialization, validation, testing/calibration.
• Different spatial representation, buoys ~ order of magnitude smaller, capture temporal variability.
• Geographical sampling biases due to scarcity of high-quality buoy data
• Technology refresh o High-resolution RT data to GTSo Cameraso Subsurface observations – OHCo Accuracy