The NPOESS Preparatory Project NPP OSU MODIS Workshop September 4 , 2003

1. The NPOESS Preparatory Project NPP OSU MODIS Workshop September 4 , 2003 Dr. Wayne Esaias NASA GSFC

2. What is NPP? • NPP is the NPOESS Preparatory Project • NPP is a “bridging mission” that provides for the continuation of measurement series initiated with EOS Terra & Aqua for NASA’s global change research • Climate change • Global carbon cycle • Global water cycle • NPP provides risk reduction for the National Polar-Orbiting Operational Environmental Satellite System (NPOESS) which will continue these measurements into the indefinite future • NPP is a joint program of NASA and the Integrated Program Office (IPO), the tri-agency activity that is responsible for NPOESS • NPP will launch in the fall of 2006

3. METOP NPOESS METOP NPOESS 0530 1330 0930 Local Equatorial Crossing Time NPOESS What is the NPOES Mission? Mission Provide a national, operational, polar-orbiting environmental capability Achieve National Performance Review savings by converging DoD and NOAA polar satellite programs Incorporate new technologies from NASA and others Incorporate, where appropriate, International Cooperation (EUMETSAT)

4. NPP Sensors • The Visible Infrared Imaging Spectroradiometer Suite (VIIRS) extends measurement series initiated by MODIS on EOS Terra & Aqua • Design is evolutionary from MODIS • The Cross-track Infrared Sounder (CrIS) continues measurement series initiated by AIRS on EOS Aqua • Utilizes a Michelson interferometer in contrast to AIRS, which is a spectrometer • The Advanced Technology Microwave Sounder (ATMS) continues the measurement series initiated by the AMSU on NOAA-15 • MMIC Technology used to reduce mass, power & volume • The Ozone Mapping and Profiling Suite (OMPS) continues the measurement series of SBUV & TOMS and adds a new limb profiler • The Clouds and Earth Radiant Energy Sensor (CERES) may be added to the payload to continue the radiation budget data record initiated by ERBE and continued by CERES on Terra and Aqua • Decision in late 2003

5. NPP & NPOESS Orbits • NPP has 824 km Sun synchronous orbit • 10:30 AM descending node • 98.74° inclination • Mimics Terra ground track repeat • 16 day ground-track repeat • Swath width of 3,000 Km (±56.06°) • NPOESS has 833 km Sun synchronous orbits • All 3 satellites will carry a VIIRS • 09:30 descending node • 13:30 ascending node • 17:30 ascending node • Swath width of 3,000 km (±56.06°)

6. Visible Infrared Imaging Radiometer Suite (VIIRS) • Purpose: Global observations of land, ocean, & atmosphere parameters at high temporal resolution (~ daily) • Predecessor Instruments: AVHRR, OLS, MODIS, SeaWiFS • Management: Integrated Program Office • Status:Phase C/D (Raytheon) • Approach: Multi-spectral scanning radiometer (22 bands between 0.4 m and 12 m) 12-bit quantization • Swath width: 3000 km • Changes to specifics of band dynamic ranges, bandpasses & band centers negotiated • Consideration of adding 6.7 micrometer water vapor band to FM3 & later models • CDR Completed March 2002

7. VIIRS Spectral Bands • 22 Bands • Subset of MODIS bands plus day-night panchromatic band • Two spatial resolutions • Imagery resolution bands: 370 m at nadir • Moderate resolution bands: 740 m at nadir • Features • 8 (Moderate) or 16 (Imagery) detectors per scan • Bands spatially nested • Some bands have dual gain • Maximize dynamic range without precision penalties • Constrained pixel growth with scan angle

8. Detector Aggregation Reduces Pixel Growth to 1060km To ~ To VIIRS Reduces Pixel Size Along Scan: Much Better HSR, SNR Toward Nadir AVHRR & MODIS “1 km” Bands: ~2x6km At Edge Vs. VIIRS 1.6x1.6 km At Edge Horizontal Sampling Interval to 1060km To ~ To Horizontal Sampling Interval Moderate and Imaging bands nest 2x2

9. Reduced Pixel Growth Along Scan Ratio of Off-nadir pixel to nadir pixel ~1500 km

10. Spec. Values Unaggregated Pixels - Dual Gain Bands Meet Ocean & Land Needs 412 nm Band High Gain:a = 1.1628E-04 b = 3.4392E-03 Low Gain:a = 1.1628E-04 b = 1.6177E-02

19. Calibration • Stray light much better than MODIS • Driven by needs of the day-night (DNB) • Rotating telescope, extensive baffling reduces scattered light • V-grove blackbody similar to MODIS • Baffled to avoid Earth illumination • Emissivity of 0.9998 • Controlled to 290K by pulsed voltage • Heat to 315K • Solar Diffuser (SD) evolutionary from MODIS • 1 time door • New design eliminates “ripples” • Solar Diffuser Stability Monitor (SDSM) evolutionary from MODIS • 7 bands • Views 70% of SD area • Planning to use 2nd order polynomial for all bands • Characterization plan similar to MODIS • Lunar views possible thru space-view port

20. VIIRS Status • Critical Design Review was held in March 2002 • Algorithms delivered from Raytheon to Northrop Grumman Space Technologies (NGST) in Fall of 2002 • Further algorithm testing by NGST until late 2004 • Sequential release of algorithms to Raytheon Aurora for conversion to operational code • SST delivered March 31, 2003 • Ocean color to be delivered April 30, 2003 • Some additional algorithm work possible after delivery for operationalization • Problem with VIIRS optical design discovered in October 2002 • Detectors see inside of rotating telescope which varies in temperature • 3 design options examined by Red Team in December • Design fix identified • Optics will be reduced from f/6.0 to f/6.2 resulting in small performance degradation • CDR on new design May 8, 2003 • No slip in delivery schedule

21. NRA Status • Approximately 70 proposals were received in response to the NPP NRA • The team will assist NASA in preparing to use the operational system for long term climate research • Which EDRs can be used as CDRs? • What steps need to be taken to assure climate quality data? • Use simulations based on real and synthetic data sets • Provide insight into sensor characterization • Selection of team planned for summer 2003 • A second science team selection will be made closer to the launch of NPP • NASA HQ working on plans for discipline-based themes to produce Climate Data Records

22. Some Web Sites • A description of the NPP mission may be found at: • http://jointmission.gsfc.nasa.gov/ • The VIIRS instrument is described at: • http://www.ipo.noaa.gov/viirs.html • The VIIRS ATBDs are at: • http://npoesslib.ipo.noaa.gov/atbd_viirs.htm • The complete list of NPOESS requirements may be obtained at: • http://npoesslib.ipo.noaa.gov/Req_Docs.htm

23. Summary • MODIS quality measurements will be continued in the operational system (NPOESS) • VIIRS draws heavily on its MODIS heritage • Some research capabilities (e.g. fluorescence, CO2 slicing bands) are not continued • Overall similar radiometric quality • Improved geometric resolution • Continued commitment to characterization and calibration • NASA science team to be competed soon

24. Separately Mounted Electronics Module Solar Diffuser FPIE Blackbody Half-angle Mirror Cryoradiator Cold FPA Dewar Assembly 3-Mirror Anastigmat All reflective Rotating telescope 4-Mirror Anastigmat All Reflective Aft Optics Imager Visible Infrared Imaging Spectroradiometer (VIIRS)

25. Rotating Telescope Warm Focal Plane Dewar Half Angle Mirror Cold Focal Planes (Inside) Aft Optics Yields Lower Scattered Light than MODIS

26. VIIRS’ 0ptimized Bandset Provides Rich Data for All EDRs

27. Ocean Color/Chlorophyll EDR - RDR Data Summary

28. Performance Summary for Low-gain State of Dual-gain Bands

29. Performance Summary for Single Gain or High Gain