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WindSat Mission Overview and StatusWindSat Mission Overview and Status

Peter Gaiser

Remote Sensing Division, Code 7220

Naval Research Laboratory

Washington DC

peter.gaiser@nrl.navy.mil

05 June 2006

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WindSat - Mission OverviewWindSat - 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

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WindSat Payload ConfigurationWindSat Payload Configuration

Freq, GHz Channels BW, MHz EIA, deg IFOV, km

6.8 v, h 125 53.5 40x60

10.7 v, h, ±45, lc, rc 300 49.9 25x38

18.7 v, h, ±45, lc, rc 750 55.3 16x27

23.8 v, h 500 53.0 12x20

37.0 v, h, ±45, lc, rc 2000 53.0 8x13

Height 10.5 ft

Width 8.25 ft

Mass 661 lbs.

Power 311 Watts

Spin Rate 31.6 rpm

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WindSat Flight BuildWindSat Flight Build

Coriolis Satellite at Launch SiteWindSat in TVAC Chamber

WindSat Feed Horn Array

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WindSat Mission and DataWindSat 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

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Near Real Time Surface Wind VectorNear Real Time Surface Wind Vector

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WindSat Demonstrated Wind Vector Retrieval via Polarimetric Microwave Radiometry

WindSat Demonstrated Wind Vector Retrieval via Polarimetric Microwave Radiometry

EDR RMS IORD

Wind Speed (< 10m/s) 1.0 m/s 2.0 m/s

Wind Speed (< 20 m/s) 1.5 m/s 2.0 m/s

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WindSat SSTWindSat SST

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WindSat Total Precipitable WaterWindSat Total Precipitable Water

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WindSat Cloud Liquid WaterWindSat Cloud Liquid Water

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WindSat Operational Data ProductsWindSat Operational Data Products

Katrina at LandfallImagery Wind Field

Operational Data Products Generated at FNMOC/NRL-MRY in Near Real Time

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Near Real Time Data AvailabilityNear 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 Userspeter.gaiser@nrl.navy.mil

http://www.nrl.navy.mil/WindSat

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WindSat Data ArchiveWindSat 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 Physical Ocean 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

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Ongoing WorkOngoing 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

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WindSat Status and OutlookWindSat 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

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BackupBackup

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WindSat Retrieval PerformanceWindSat Retrieval Performance

Difference is Combination of WindSat and QuikSCAT Errors

EDR Bias Std.Dev.

SST (K) 0.04 0.81

W Selected (m/s) 0.07 0.79

Water Vapor (mm) 0.01 0.91

Cloud Water (mm) 0.004 0.03

• Six month data set

•Wind speed and direction relative to QuikSCAT

• SST relative to Reynolds OI

•Water vapor and cloud relative to SSM/I

MHB-20060222

Wind Direction vs. QuikSCATWind Direction vs. QuikSCAT

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Utilization of WindSat DataUtilization 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

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WindSat and NPOESSRisk Reduction

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

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SummarySummary

• 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

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Ongoing WorkOngoing 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

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WS Rev. 00814 1649UTC TMI Rev. 30217 1648UTC

Very Good Agreement Between WindSat and TMI;WindSat Spatial Resolution Results in Smearing of Some Features

WindSat Rain Rate RetrievalsQualitative Comparison with TRMM

Microwave Imager (TMI)

WindSat Rain Rate RetrievalsQualitative Comparison with TRMM

Microwave Imager (TMI)

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WindSat Measures Ocean Rain Rates

WindSat Measures Ocean Rain Rates

Hurricane Maria; 07 Sep 2005

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WindSat Sea IceWindSat Sea Ice

15-17 Mar 2004• 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

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SST Performance vs. Reynolds OISST Performance vs. Reynolds OI

OverallBias: 0.04 KStd. Dev.: 0.85 K

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SST Performance vs. BouysSST Performance vs. Bouys

WindSat SST retrievals collocated with TAO bouys (equatorial Pacific Ocean)

14364 collocationsBias: 0.01 deg. CStd. Dev.: 0.51 deg. C

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Wind Speed vs. QuikSCATWind Speed vs. QuikSCAT

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Wind Direction vs. NDBC BuoysWind Direction vs. NDBC Buoys

4 - 6 m/s 6 - 8 m/s 8-10 m/s > 10 m/s

3.3 0.9 0.1 0.0

Percent 90 deg. edited

Wind SpeedBias: 0.36 m/sStd. Dev.: 1.30 m/s

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Windsat & QSCAT (dir. edit) vs. NDBC -- Rain-FreeWindsat & QSCAT (dir. edit) vs. NDBC -- Rain-Free(Courtesy of M. Freilich, OSU)(Courtesy of M. Freilich, OSU)

Windsat & QSCAT (dir. edit) vs. NDBC -- Rain-FreeWindsat & QSCAT (dir. edit) vs. NDBC -- Rain-Free(Courtesy of M. Freilich, OSU)(Courtesy of M. Freilich, OSU)

Rain-Free CasesMax 50 km separation from buoy

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Ocean RetrievalsOcean 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

Constanta priori

TS, W, V, L

Final Retrieval

Stage 2

Stage 1RetrievalTS, W, V, L

Four RetrievalsTS, W, V, L, φR

Median Filter

Regression Retrieval φR

φR

φR + 90

φR + 180

φR + 270

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WindSat Provides GlobalSea Surface TemperatureWindSat Provides GlobalSea Surface Temperature

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WindSat ImageryWindSat Imagery

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Polarimetric RadiometryPolarimetric Radiometry

Available from “Dual Polarization” Systems (SSM/I, SSMIS)

New Capability Available from “Polarimetric” Systems(WindSat)

• 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