1. The Operational Impact of QuikSCAT Winds at the NOAA Ocean Prediction Center Joe Sienkiewicz – NOAA Ocean Prediction Center Joan Von Ahn – STG/NESDIS ORA Outline OPC overview Impact Warnings and Features Hurricane Force Winds SST impacts on near surface winds Summary and Recommendations

2. OPC Responsibility Wind Warning Categories GALE – 34-47 knotsForce 8/9 STORM – 48-63 knotsForce 10/11 HURRICANE FORCE - 64 knots and greater Force 12

4. Wind speed (knots)

6. Warning Impact Percent Change in Short-Term Warning Decisions by OPC Timelines added Additional training Forecaster query Forecaster input only Interpreted forecaster comments

7. Changes to Warning Category Changes to Wind Speed Changes to Wind Field Changes to position of surface features Changes to Warning Category Changes to Wind Speed Changes to Wind Field Changes to position of surface features Winter 2004 (Feb 15 to Mar 15) When QuikSCAT was available, changes were made to: 68 % of the events in the Atlantic 50% of the events in the Pacific Event- Lows, Highs and Wind areas (speed and aerial extent) Atlantic Pacific

8. Hurricane Force Winds (a)(b) QuikSCAT able to distinguish between STORM and HURRICANE FORCE winds

9. APL China – Oct 1998 OOCL America M/V Explorer

10. Hurricane Force Cyclones…What have we learned? Period of StudyAtlanticPacific 2001-20022215 2002-20032322 2003-20041522 Winter events – October through March (April) Most frequent – Atlantic (January); Pacific (December) Minimum SLP (avg. 965 to 970 hPa) Minimum SLP - larger range in Atlantic Explosive deepeners Western portion of basins (most frequent); preferred tracks Short lived (less than 24 hours) (avg. lifecycle 5 days) Shallow warm core seclusion Wind max S to SW of low Most difficult to forecast at day 4 forecast time over North Pacific Less than 10 % forecast 4 days in advance!! Number of HF Cyclones observed

11. Composite of maximum winds (knots) Pacific (11 cyclones) Atlantic (5 cyclones) Composite of QuikSCAT winds for 11 North Pacific and 5 North Atlantic HF storms. This plot shows the distribution of maximum winds as observed by QuikSCAT for all cyclones in the composite. HF winds are Red, Storm -Yellow and Gale –Green. HF FORCE STORM GALE XX Pacifi c Atlantic

12. SST Impacts on Near Surface Winds

13. 12.5 km QuikSCAT3-day GOES SST Composite 25 km QuikSCATWind speed difference (GFS 10m-QuikSCAT)

14. GFS 10 WInds12.5 km QuikSCAT Bias corrected 10m Winds Wind speed difference (knots) (GFS 10m-QuikSCAT)

15. Eta 10m GFS 10m GFS 9950 Sigma 30 day avg. diff 11/05/04 Model Winds - QSCAT Very Unstable PBL  975 -  skin < -4

16. 30 day avg. diff Model Winds - QSCAT Very Stable PBL  975 -  skin > 4 Eta 10m GFS 10m GFS 1 st Sigma Eta 10m GFS 10m GFS 1 st Sigma

17. SST impacts on Wind Field Due to QuikSCAT OPC forecasters are more conscious of underlying SST on near surface winds (always knew an impact but forecasters can now see it) Forecaster tools model soundings stability indices mix of 1 st sigma and 10m winds wind speed difference fields

18. QuikSCAT Rain Quandry January 4, 2005

19. 12.5 km QuikSCATSSM/I Wind Speeds 25 km QuikSCAT SSM/I Rain Rate

20. 12.5 km QuikSCATQuikSCAT Ambiguities 25 km QuikSCAT SSM/I Rain Rate There are times when our forecasters do not know what to believe!

21. Summary Impact - Significant Cultural change to ocean analysis and forecasting within OPC 10 % Wind Warnings determined by QuikSCAT Assessment of features more accurate Ability to assess initial numerical model conditions Can differentiate between significant and extreme winds Storm versus Hurricane Force Significance of PBL stability on near surface winds QuikSCAT winds have changed the way we do business Precip Quandry At times just do not know impact on wind retrievals

22. Recommendations (for future instruments) Large swath width Independent rain measurement Ability to quantify impact of rain Large retrievable wind range (0 to Hurricane Force) 12.5 km resolution or better Reduced land mask ( less than 30 km ) Minimum 4 looks per day per ocean (from operational platforms) Data access near-real time ( 1 to 1.5 hour delivery after acquisition…no more ) Available in forecaster workstations in comprehensive form