Edward Hyer Naval Research Laboratory JCSDA Symposium 11 October 2012

1. NPP VIIRS Aerosol Products:Overview, early cal/val results, and data assimilation results from NAVDAS-AOD Edward Hyer Naval Research Laboratory JCSDA Symposium 11 October 2012

2. In this talk • Overview of NPP VIIRS aerosol products • Status of NPP Cal/Val effort • Comparison of MODIS and VIIRS products • Preparation of DA-ready obs from VIIRS • Impact of VIIRS obs in NAAPS • Future Work • MODIS DA-ready AOD now available from LANCE

3. NPP Visible Infrared Imaging Radiometer Suite (VIIRS) 0130, 1330 local time orbits “Early afternoon slot” October 28 2011 Credit: NASA

4. Heritage Operational and R&D Sensors Operational Sensors • OLS OLS AVHRR • High Spatial Resolution • Day/Night Band • Minimize Resolution Growth Over Scan • Radiometric Accuracy • SST Band Continuity • 74 kg • 2 bands • 33 kg • 5 bands VIIRS R&D Sensors OMM EM MODIS • 275 kg • 22 bands SeaWiFS • Band Selection/Continuity • Thin Cirrus Band • Solar Diffuser • Earthshine Lessons Learned • Ocean ColorBands • RotatingTelescope • 220 kg • 36 bands • 45 kg • 8 bands Credit: Northrup Grumman & Raytheon

5. VIIRS DNB MODIS SeaWiFS AVHRR Heritage Capabilities OLS Low Light Imagery 0.4 0.5 0.6 0.7 0.8 0.9 1.2 1.8 2.4 4 6 8 10 12 14 Breaks in scale Visible Mid wave IR Long wave IR [micron] Credit: Northrup Grumman & Raytheon

6. Simplified VIIRS Aerosol Process VIIRS Cloud Mask SDR: Calibrated TOA Radiances / Reflectances Aerosol EDR VAOOO (contains no NAAPS) Aerosol Intermediate Product IVAOT NAAPS Aerosol Optical Depth Met. Fields (NCEP) (NOGAPS backup)

7. VIIRS Aerosol EDR Product Aerosol EDR VAOOO • ~6km resolution • 8x8 ~750m pixels • Retrieved: • AOT • Angstrom Exponent • Suspended Matter Type • Many Quality Flags: • Cloud (incl. adjacent) • Glint and other geometry • Input data quality • Retrieval is based on LUTs generated with 6S • Heritage is MOD09 Surface Reflectance • Over-ocean similar to MOD04 • Fine-coarse mixture retrieved explicitly • Over-land uses different aerosol models • Single model (fine+coarse) is retrieved via LUT

8. Status of Aerosol Cal/Val • Aerosol EDR is sum of Parts: • VIIRS SDR radiances/reflectances: These are still Beta, Provisional status will be considered later this fall • VIIRS Cloud Mask: basic tuning complete, product is still Beta • Aerosol EDR is recently partially advanced to ‘Beta’ maturity: • Global AOD • Over-ocean Aerosol Size Parameter • NOT over-land Aerosol Size Parameter • NOT Suspended Matter EDR

9. MODIS and VIIRS AOD VIIRS-NPP MODIS-Aqua Credit: Min Oo, Bob Holz, Atmospheres PEATE, University of Wisconsin http://peate.ssec.wisc.edu/flo/npp/gridding?date=2012%2F09%2F24

10. MODIS and VIIRS AOD VIIRS has wider swath– complete overlap even at equator GAP NOGAP VIIRS-NPP MODIS-Aqua Credit: Min Oo, Bob Holz, Atmospheres PEATE, University of Wisconsin http://peate.ssec.wisc.edu/flo/npp/gridding?date=2012%2F09%2F24

11. MODIS and VIIRS AOD VIIRS and MODIS show broad agreement in large features VIIRS-NPP MODIS-Aqua Credit: Min Oo, Bob Holz, Atmospheres PEATE, University of Wisconsin http://peate.ssec.wisc.edu/flo/npp/gridding?date=2012%2F09%2F24

12. MODIS and VIIRS AOD VIIRS and MODIS have different cloud screening– VIIRS is still being characterized. Both products must avoid clouds for accurate retrieval. VIIRS-NPP MODIS-Aqua Credit: Min Oo, Bob Holz, Atmospheres PEATE, University of Wisconsin http://peate.ssec.wisc.edu/flo/npp/gridding?date=2012%2F09%2F24

13. MODIS and VIIRS AOD VIIRS and MODIS show significant differences over land VIIRS-NPP MODIS-Aqua Credit: Min Oo, Bob Holz, Atmospheres PEATE, University of Wisconsin http://peate.ssec.wisc.edu/flo/npp/gridding?date=2012%2F09%2F24

14. VIIRS vs. AERONET AOD over ocean • Best QA only • Low mean bias • Not enough data to clearly diagnose bias at higher AOD

15. VIIRS vs. AERONET AOD over land • Best QA only • Significant positive mean bias • Positive bias for all AOD ranges observed

16. AOD Pre-processing for DA MODIS • NRL & University of North Dakota developed method starting with MOD04 Level 2 data • Extensive filtering for cloud, surface, etc. • Empirical Correction • Prognostic Uncertainty Model • Now a product produced in NRT at NASA LANCE NPP VIIRS • Method under development • Currently only filters using built-in QA • No corrections • Aggregated to NAAPS 1-degree resolution

17. NAVDAS-AOD Testbed Start with best analysis from research run (includes assimilated MODIS AOD)

18. NAVDAS-AOD Testbed Assimilate NPP VIIRS AOD (+/- 3 hours)

19. NAVDAS-AOD Testbed Initialize 72-hour forecasts from MODIS and MODIS+NPP analyses

20. NAVDAS-AOD Testbed MODIS obs do not show high AOD over ocean west of Hawaii Compare forecast with obs to evaluate propagation of differences

21. NAVDAS-AOD Testbed MODIS and VIIRS obs do not show high AOD over ocean west of Hawaii Compare forecast with obs to evaluate propagation of AOD differences

22. Much More Work To Do • Quantitative Evaluation of NAAPS-MODIS vs NAAPS-MODIS+NPP analysis and forecast • Determination of impact on forecast error of including over-ocean VIIRS AOD • Construction and evaluation of prognostic error model for VIIRS AOD • Construction of higher-resolution products

23. The NRL-UND MODIS Level 3 Aerosol Optical Depth Product • 0.5 degree, 6-hourly, available within 4 hours of overpass, HDF format with full metadata • Available now: nrt1.modaps.nascom.nasa.gov 14 April 2011 Hyer ISRSE34 Sydney 23 of 25

24. Thank you • Thanks to: • NPP VIIRS Cal/Val teams • Atmospheres PEATE (U. Wisconsin) • NRL Aerosol and Radiation Section • Jianglong Zhang and group at UND • Sponsors: • NOAA (NPP Cal/Val) • ONR (AOD Preprocessing and QA/QC) • NASA AQAST (transition of DA-ready AOD to LANCE)