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

Individual Moorings

Satellites

Moorings Networks

Time and Space Observing Needs

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

05/20 06/01 06/15 07/01 07/15 08/01 08/15 09/01 09/15 10/01 10/10980

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• 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

• Select locations • Observations for testing/validation of satellites and

models

Validation

Businger et al, 2015Tang et al, 2016

Calibration

• Moored sensors can be re-calibrated to become in-situ reference stations for satellites and other type of sensors

Valamanesh et al, 2016

Spatial Density

Historical DensityCurrent Density (2005-)

NDBC Legacy Buoys

10-meter hull

6-meter hull

NDBC Current Buoys

3-meter hull

2.1-meter hull

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

Marine Weather:Hurricanes

Legacy Buoys

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Michael

~30 ft seas

Waves: 42039 & 42003

~30 ft seas

Waves: 41048

Florence

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OHC Difference (kJ/cm2)

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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

• Agreement diminishes with depth• Std dev increases from

± 0.2°C to ±0.6°

• Mean difference changes sign

Accuracy Required?

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