WindSat Mission Overview and Status

1. WindSat Mission Overview and Status Peter Gaiser Remote Sensing Division, Code 7220 Naval Research Laboratory Washington DC peter.gaiser@nrl.navy.mil 05 June 2006

2. WindSat - Mission Overview Overview: • Demonstrate Ocean Surface Wind Speed and Direction Measurement Capability with Polarimetric Microwave Radiometry • Wind Vector Is a High Priority EDR for the Navy • Risk Reduction for NPOESS CMIS • Jointly Sponsored by US Navy and the NPOESS Integrated Program Office • Launched 06 Jan 2003 on STP’s Coriolis Satellite Bus Into a Sun-Synchronous Orbit • Current Plan Calls for Continued Operation Throughout Useful Life of Coriolis/WindSat • WindSat Brightness Temperature and Environmental Data Now Available to Science and User Community

3. WindSat Payload Configuration

4. WindSat Flight Build WindSat in TVAC Chamber Coriolis Satellite at Launch Site WindSat Feed Horn Array

5. WindSat Mission and Data • WindSat/Coriolis Flies in Sun Synchronous Orbit at an 840-km Altitude • 1800 LTAN • 1000-km Swath Width • Multiple Data Products Produced • SDRs: • Calibrated, Geolocated Brightness Temperatures • EDRs: • Ocean Surface Wind Vector, SST, Total Precipitable Water, Cloud Liquid Water, Ocean Rain Rate • Using Multiple Products Adds Insight and Value NOAA/NESDIS/ORA

6. Near Real Time Surface Wind Vector

7. WindSat Demonstrated Wind Vector Retrieval via Polarimetric Microwave Radiometry

8. WindSat SST

9. WindSat Total Precipitable Water

10. WindSat Cloud Liquid Water

11. WindSat Operational Data Products Katrina at Landfall Imagery Wind Field Operational Data Products Generated at FNMOC/NRL-MRY in Near Real Time

12. Near Real Time Data Availability • WindSat Data is Processed in NRT at Fleet Numerical Meteorological and Oceanographic Center (FNMOC) • Data is pushed to NESDIS (EDRs and SDRs) and NAVO (EDRs) • Data also goes to NRL-MRY for Tropical Cyclone Web Page and Data Assimilation Projects • WindSat NRT Data is Available via the Shared Processing Network • Contact Peter Gaiser at NRL or Jeff Tesmer of FNMOC • NESDIS ORA (soon to be STAR) Is Also Processing Data in NRT • Sharing with Tropical Prediction Center and Ocean Prediction Center for Testing and Evaluation • Documentation is Available • Data Descriptions, User Guide, Release Notes, File Formats, Reader Programs WindSat Team Is Happy to Support Users peter.gaiser@nrl.navy.mil http://www.nrl.navy.mil/WindSat

13. WindSat Data Archive • Data Release • Wind vector, SST, columnar water vapor and cloud liquid water, ocean rain rate • Access is password restricted; simple to request access • Data products accessible via the NASA/JPL PhysicalOcean Data Active Archive Center (PO.DAAC) • NRL ver. 1.9.1 Data Products covering Feb 2003 through November 2005 • NRL Optimal Estimation EDRs (ver. 1.9.1) • WindSat SDRs (Brightness Temperatures) (ver. 1.9.1) • GDAS, QuikSCAT match-up files being uploaded http://podaac.jpl.nasa.gov/windsat

14. Ongoing Work • Wind Vector Retrievals Continue to Improve • Wind Direction for Wind Speeds < 7 m/s • Ambiguity Selection Techniques to Improve Wind Direction Retrievals • Retrievals in Presence of Rain and Heavy Clouds • Developing Retrievals at Higher Spatial Resolutions • SST Retrievals • Sea Ice, Snow and Land Products • Validating Basic Products • Examining Added Information of Polarimetric Channels • Daily Ice Concentration Maps Being Delivered to National Ice Center for Evaluation • Working with Data Assimilation Groups and Operational Users to Fully Exploit WindSat Capabilities

15. WindSat Status and Outlook • WindSat Successfully Launched on Coriolis on 06 January 2003 • Will Continue to Operate Through Useful Life • Retrieval Performance Continues to Improve • NRT Data Products Available to Operational Users • WindSat Team Eager to Work with Users http://www.nrl.navy.mil/WindSat

16. Backup

17. WindSat Retrieval Performance • Six month data set • Wind speed and direction relative to QuikSCAT • SST relative to Reynolds OI • Water vapor and cloud relative to SSM/I Difference is Combination of WindSat and QuikSCAT Errors

18. Wind Direction vs. QuikSCAT

19. Utilization of WindSat Data • WindSat Data Processed in Near Real Time at FNMOC and Data Products put on Shared Processing Network • NOAA Will Begin Ingesting WindSat Data from SPN in Early 2006 • Many Organizations are Preparing to Acquire WindSat Data via this Path • NCEP, Joint Center for Satellite Data Assimilation (JCSDA), Tropical Prediction Center, UK MetOffice, ECMWF, Australian Met Service • WindSat Products Used Extensively for Tropical Cyclone Monitoring • NRL-MRY, FNMOC, JTWC, NHC • NAVO Is Pulling In WindSat SST Data • NRL 6.2 Program Underway to Assimilate WindSat Data into NOGAPS • NRL-DC working with NRL-MRY Team (Jim Goerss, Nancy Baker) • Joint Center for Satellite Data Assimilation (JCSDA) Testing Assimilation of WindSat Data for Their Applications • NRL-DC working closely with John LeMarshall (JCSDA Director) • Working with National Ice Center to Provide WindSat Ice and Imagery Products in Near Real Time

20. WindSat and NPOESSRisk Reduction • NPOESS Fulfilling the Ocean Wind Speed and Direction Requirement With Polarimetric Microwave Radiometry - CMIS • Microwave Radiometers Measure Many EDRs In Addition to Wind Vector • WindSat Provides Risk Reduction to NPOESS and CMIS in Several Ways • Space Borne Demonstration of Capability of Polarimetric Microwave Radiometry to Measure the Ocean Surface Wind Direction • Real PMR Data From Space For Model Function and Retrieval Algorithm Development • WindSat Lessons Learned • Hardware Development and Testing (Antenna Characterization, Receiver Design and Testing) • Calibration and Data Processing (Warm Load Target Design, On-orbit Anomalies, RFI Detection and Mitigation) • WindSat Data Products Used to Prepare for NPOESS Data Assimilation • Coriolis/WindSat Mission Uses NPOESS Ground Segment for Data Downlink and Distribution • Working to Ensure That NPOESS Provides Quality Data for Navy Applications

21. Summary • WindSat Successfully Demonstrated Measurement of Ocean Surface Wind Vector with Polarimetric Radiometry • Providing Key Risk Reduction for NPOESS CMIS Development • WindSat Data Products Available in Archive and in Near Real Time for Operational Users and the Science Community

22. Ongoing Work • Improved ambiguity selection techniques • Higher resolution retrievals • Wind speed bias improvements for wind speeds > 20 m/s • Refinements to calibration of the brightness temperatures • Additional cal/val using bouy winds and SST • Atmospheric forward model improvements • Improve understanding of the physics • two-scale modeling of surface emissivity • improved atmospheric modeling • foam effects • rain effects

23. WindSat Rain Rate RetrievalsQualitative Comparison with TRMM Microwave Imager (TMI) WS Rev. 00814 1649UTC TMI Rev. 30217 1648UTC Very Good Agreement Between WindSat and TMI; WindSat Spatial Resolution Results in Smearing of Some Features

24. WindSat Measures Ocean Rain Rates Hurricane Maria; 07 Sep 2005

25. WindSat Sea Ice • WindSat Sea Ice Products • Finalizing work done under NPOESS IGS task • Sea Ice Concentration Based on SSM/I NASA Team Algorithm • Modified for WindSat Channels and Geometry • Modified Weather Filter • Not Exploiting Polarimetric Channels • Working with Pablo Clemente-Colon of the National Ice Center (NIC) to ensure that WindSat data is available and used in their mission • Have provided archived products to the NIC to get them started • Plan to provide operational (NRT) products shortly 15-17 Mar 2004

26. SST Performance vs. Reynolds OI Overall Bias: 0.04 K Std. Dev.: 0.85 K

27. SST Performance vs. Bouys WindSat SST retrievals collocated with TAO bouys (equatorial Pacific Ocean) 14364 collocations Bias: 0.01 deg. C Std. Dev.: 0.51 deg. C

28. Wind Speed vs. QuikSCAT

29. 4 - 6 m/s 6 - 8 m/s 8-10 m/s > 10 m/s 3.3 0.9 0.1 0.0 Wind Direction vs. NDBC Buoys Percent 90 deg. edited Wind Speed Bias: 0.36 m/s Std. Dev.: 1.30 m/s

30. Windsat & QSCAT (dir. edit) vs. NDBC -- Rain-Free(Courtesy of M. Freilich, OSU) Rain-Free Cases Max 50 km separation from buoy

31. Constant a priori TS, W, V, L Retrieval TS, W, V, L Stage 1 φR Four Retrievals TS, W, V, L, φR Regression Retrieval φR φR + 90 Stage 2 φR + 180 φR + 270 Median Filter Final Retrieval Ocean Retrievals • Physically-based Algorithm Using Nonlinear Optimization (NRL) • Uses Physical Forward Model • Solves for All Edrs Simultaneously • Empirical Regression Technique (NRL) • Two-stage Regression for Wind Vector Components • MLE for Final Wind Direction • Retrieved EDRs • Ocean Surface Wind Vector • Sea Surface Temperature • Columnar Water Vapor • Cloud Liquid Water • Rain Rate

32. WindSat Provides GlobalSea Surface Temperature

33. WindSat Imagery

34. Available from “Dual Polarization” Systems (SSM/I, SSMIS) New Capability Available from “Polarimetric” Systems (WindSat) Polarimetric Radiometry • Ocean Surface Emission and Scattering Vary With Wind Vector - Wind Direction Dependence Arises From Anisotropic Distribution and Orientation of Wind Driven Waves • Polarimetric Radiometry Measures Stokes Vector - Polarization Properties of Emitted/Scattered Radiation (Contains Directional Information) - Wind Direction Signal Is Two Orders of Magnitude Smaller Than Background Signal ΔTu, K