The Use of Remotely Sensed Ocean Surface Winds at the NOAA Ocean Prediction Center

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The Use of Remotely Sensed Ocean Surface Winds
at the NOAA Ocean Prediction Center

• Joe Sienkiewicz, Joan Von Ahn1, Greg McFadden2

Outline 1. QuikSCAT impact on
operations 2. SST impacts on winds 3. Hurricane
Force Extratropicals 4. Sea-level pressure
retrievals 5. Ongoing evaluations QuikSCAT WindS
at 6. Summary
1 STG, Inc 2 SAIC
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NOAA Forecast Responsibility
High Seas Wind Warning Categories GALE
34-47 knots Force 8/9 STORM 48-63 knots
Force 10/11 HURRICANE FORCE - gt64
knots Force 12
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QuikSCAT impact on operations
QuikSCAT wide swath 2 passes per day
consistency large wind range Cultural change
revolutionized analysis and forecast
process more wind warnings, increased
accuracy differentiate between warning
categories focus on Hurricane Force
conditions SST gradients on surface winds
SLP retrievals improve analyses Lesson
learned - Success due to timely availability in
forecaster workstations
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SST impact on winds
GOES SST Composite
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SST impact on winds
GOES Magnitude of SST Gradient QuikSCAT 25 km
wind speeds
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SST impact on winds
GOES Magnitude of SST Gradient QuikSCAT GFS 10
wind speed difference (knots)
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SST impact on winds
GOES Magnitude of SST Gradient 30 day wind
speed bias (knots) slightly stable PBL
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SST impact on winds
GOES Magnitude of SST Gradient 30 day wind
speed bias (knots) slightly unstable PBL
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Hurricane Force Extratropicals
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12.5 km resolution QuikSCAT became available
5 Year total Atlantic 134 Pacific 126
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LOW GALE STORMHURCN FORCE
Atlantic Tracks 2005-06
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LOW GALE STORMHURCN FORCE
Pacific Tracks 2005-06
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66 75
0
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Composite of maximum winds (knots)
HF FORCE STORM GALE
300nm 200nm 100nm
300nm 200nm 100nm
North Atlantic North Pacific 11 QuikSCAT
passes 32 QuikSCAT passes
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SLP Retrievals

• QuikSCAT Winds
• University of Washington PBL Model
• Calculates Pressure Gradient
• Seed with Observations (mean SLP)
• SLP

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Quikscat Evaluation
QuikSCAT Old Rain Flag
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Quikscat Evaluation
QuikSCAT New Rain Flag
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Quikscat Evaluation
QuikSCAT Old Wind Speeds
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Quikscat Evaluation
QuikSCAT New Wind Speeds
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WindSat Evaluation
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WindSat Evaluation
Interpolated to grid Wind Speed Wind
Direction Cloud Liquid Water Total Precip
Water Rain Rate SST
WindSat WS Filled Contours QuikSCAT Wind Barbs
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WindSat Evaluation
Interpolated to grid Wind Speed Wind
Direction Cloud Liquid Water Total Precip
Water Rain Rate SST
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WindSat Evaluation
Interpolated to grid Wind Speed Wind
Direction Cloud Liquid Water Total Precip
Water Rain Rate SST
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WindSat Evaluation
Interpolated to grid Wind Speed Wind
Direction Cloud Liquid Water Total Precip
Water Rain Rate SST
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WindSat Wind Speed CLW QuikSCAT Wind barbs
Equatorial Atlantic
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E of Newfoundland
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Summary - Remotely Sensed Surface Winds

• Integral part of analysis and warning process
• Revolutionized operations
• QuikSCAT
• differentiate between warning categories
• SST influences
• Consistency
• Rain contamination
• SLP Retrievals extends applicability
• QuikSCAT changes
• Positive
• WindSat
• Additional EDRs crucial
• Sensitivity to Cloud Liquid Water Low threshold
  (overestimate WS)
• High CLW underestimate WS
• Lacks consistency(warning criteria)
• Still evaluating have not introduced to
  forecasters
• Paper Operational Impact of QuikSCAT Winds at
  the NOAA Ocean Prediction Center Von Ahn et al.
  2006 next issue Weather and Forecasting