# Presentation: 664216

## 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
- 	WindSat
- 6. Summary

- 1 STG, Inc
- 2 SAIC

## NOAA Forecast Responsibility

**           **_**High Seas Wind Warning Categories**_
**GALE – 34-47 knots****	****   ****	****Force 8/9**
**STORM – 48-63 knots                ****	****Force 10/11**
**HURRICANE FORCE - **_**>**_**64 knots ****	****Force 12**

## 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

**SST impact on winds**

**GOES SST Composite**

**SST impact on winds**

**GOES – Magnitude of SST Gradient**
**QuikSCAT 25 km wind speeds**

**SST impact on winds**

**GOES – Magnitude of SST Gradient**
**QuikSCAT GFS 10 wind speed difference (knots)**

**SST impact on winds**

**GOES – Magnitude of SST Gradient**
**30 day wind speed bias (knots) slightly stable PBL**

**SST impact on winds**

**GOES – Magnitude of SST Gradient**
**30 day wind speed bias (knots) slightly unstable PBL**

## Hurricane Force Extratropicals

## 5 Year total

- Atlantic 134
- Pacific   126

- 12.5 km resolution QuikSCAT became available

## Atlantic Tracks 2005-06

**LOW**
**GALE**
**STORM****HURCN FORCE**

## Pacific Tracks 2005-06

**LOW**
**GALE**
**STORM****HURCN FORCE**

## Slide 13

## 66%

**66%**
**75%**

## Composite of maximum winds (knots)

- 300nm
- 200nm
- 100nm

**HF FORCE**
**STORM**
**GALE**

- 300nm
- 200nm
- 100nm

- North Atlantic				North Pacific
- 11 QuikSCAT passes			32 QuikSCAT
- 					      passes

## Slide 16

## SLP Retrievals

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

## Slide 18

## Slide 19

**Notes:**
This is the 0600 UTC Ocean Prediction Center hand drawn surface analysis superimposed over the GOES12 0615UTC Image.

## Slide 20

**Notes:**
This is the Ocean Prediction Center hand drawn surface analysis for 0526 0600 UTC with the surface vorticity field from the uwpbl model overlaid.  The vorticity field is actually a composite of three consecutive passes (0543, 0648 and 0834 UTC). The vorticity pattern shows the locations of the frontal zones quite well.

**Quikscat Evaluation**

**QuikSCAT**
**Old Rain Flag**

**Quikscat Evaluation**

**QuikSCAT**
**New Rain Flag**

## Quikscat Evaluation

**QuikSCAT**
**Old Wind Speeds**

**Quikscat Evaluation**

**QuikSCAT**
**New Wind Speeds**

**WindSat Evaluation**

## 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

- Interpolated to grid
- Wind Speed
- Wind Direction
**Cloud Liquid Water**
- Total Precip Water
- Rain Rate
- SST

**WindSat Evaluation**

- Interpolated to grid
- Wind Speed
- Wind Direction
- Cloud Liquid Water
- Total Precip Water
**Rain Rate**
- SST

**WindSat Evaluation**

- Interpolated to grid
- Wind Speed
- Wind Direction
- Cloud Liquid Water
**Total Precip Water**
- Rain Rate
- SST

**WindSat Evaluation**

- WindSat
- Wind Speed
- CLW
- QuikSCAT
- Wind barbs

**Equatorial Atlantic**

**E of Newfoundland**

## 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 EDR’s 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***** **