Monitoring Bio-Optical Processes Using NPP-VIIRS And MODIS-Aqua Ocean Color Products

1. Monitoring Bio-Optical Processes Using NPP-VIIRS And MODIS-Aqua Ocean Color Products Robert Arnone(1), Sherwin Ladner(2), Giulietta Fargion(3), Paul Martinolich (4), Ryan Vandermeullen(1), Jennifer Bowers(3), Adam Lawson(2) 1 University of Southern Mississippi, Stennis Space Center, MS. 2 Naval Reserach laboratory, Stennis Space Center MS. 3 San Diego State University, San Diego, CA. 4 QinetiQ Corp, Stennis Space Center, MS. SPIE – Baltimore - April 2013

2. Monitoring ocean Processes Uncertainty in Ocean products Objective – How rapidly do bio-optical processes change and “Can they be detected using ocean color? “ How do these “ color” changes affect Calibration and Validation Procedures? --------------------------------------------------- Evaluate changes from satellite retrieved bio-optical products Assess sensor and processing characteristics that impact hourly changes Assess the satellite retrieved products uncertainty .

3. Ocean Color products Uncertainty • MODIS – VIIRS - Short term variability – (Hours) • Assumption is satellite is looking at Same ocean color water .. • Uncertainty associated with Inter-comparison of sensors (MODIS / VIIRS) What must we consider in evaluating time change of bio-optical processes ? 1) Water mass advection and physical processes 2) Ocean Color Changes from bio-optical changes - Biological Changes - Growth / decay particle resuspension, 3) Sensor and processes calibration, characterization , angular affects , BRDF, Atmosperhc correction etc . Half Angle Mirror (HAM) left and right side. • Optimum “tracking” is to use the “same” sensor, for assessing changes. Such as - Geostationary Satellite (example – GOCI)

4. Approach- - Sequential orbits from MODIS and S-NPP – VIIRS S-NPP Left Side of Scan 18: 15 S-NPP Right Side of Scan 19:56 -70 56 42 28 14 MODIS – Aqua 18:45 Sensor Zenith degrees 70 35 0 35 70 S-NPP - Daily Orbital Overlap at ~ 30 degree latitude ~ 700 pixel Overlap - Very Similar Solar Zenith ~ 40 degrees. 3 Overlapping ocean Color Products with 110 minutes ! 0 800 1600 2400 3200 Pixel

5. Nov1, 2012 Processed using L2gen Examine the “nLw445” and “ nLw555” and Chlorophyll (OC2) ratio (445/555) (488/555) S- NPP 306.1101.181524 S- Npp 306.1101.195623 MODIS 306 18:45

6. 18:15 - NPP Line 1- Plumes Line 2 – WavCis 19:56 –NPP 18:45 – MODIS WavCis -90 29’ 28 52’ Transect #2- - Wide range of water “type” Open and Coastal - East West Angle dependence - Transect through Aeronet – SeaPrism Site • Cloud Development • And formation

7. WaveCis cloud South Pass 18:15 - NPP Line 1- Plumes Line 2 – WavCis 19:56 –NPP 18:45 – MODIS

8. WaveCis cloud South Pass 18:15 - NPP Line 1- Plumes Line 2 – WavCis 19:56 –NPP 18:45 – MODIS NPP 19:55 Eastern Side NPP 18:15 Western Side Wavcis -90 29’ 28 52’ Line 4 Offshore 55 Aqua 1845

9. Along Line 2 transect - NPP and MODIS variations of radiance with 110 minutes Aeronet Sensor Zenith Angle variations

10. Variation Sequential along the Transect NPP- Orbits How does the 110 minutes Difference changes affects Open and coastal waters - - High scatter at 443 - 19:55 Bias Higher - Low scatter at 551 How impacts Chlorophyll Product? 1:1 1:1

11. NPP Chlorophyll variation with 110 minutes along transect Note linear Chlorophyll scale . 18:15 orbit – lower chlorophyll at high concentrations / 1:1 This results address the “Product Uncertainty” with 110 minutes with same sensor. Differences results from a) Biological Processes, b) water mass advection or c) Sensor processing

12. Impact of Sensor Zenith Angle of ocean color retrievals NPP 18:15 – 1955 difference along the Transect Line nLw 555 Aeronet

13. Impact of Sensor Zenith Angle of ocean color retrievals NPP 18:15 – 1955 difference along the Transect Line nLw 445 Aeronet

14. Impact of Sensor Zenith Angle of ocean color retrievals NPP 18:15 – 1955 difference along the Transect Line 19:55 110 minute Chlorophyll Bloom ?

15. Evaluation of the Atmosphere Correction on sequential NPP products NPP 18:15 – 1955 difference along the Transect Line Lt(l) = Lr(l) + La(l) + Lu(l) La 865 used for determining Aerosol Model and Epsilon (spectral La(l) )

16. Evaluation of the Atmosphere Correction on sequential retrievals NPP 18:15 – 1955 difference along the Transect Line b) Lt(l) = Lr(l) + La(l) + Lu(l) La 865 used for determining Aerosol Model and Epsilon (spectral La(l) • Aerosol model pair used • NPP 18:15 used 35-36, 34 – 35 ) , • Modis used 35- 36. • NPP 19: 56 used 32-33 and 33-34 • All very Similar .

17. Changes in ocean color products over short time scales • -Examined changes of the Spectral Channels 443 – 555 • Examined difference in Open and coastal water • Examined angular differences within NPP • Examine the Atmosphere channels – correction . • Examples of changes in short scale chlorophyll retrievals from MODIS and NPP

18. Changes in ocean color products over short time scales 121 – Minutes 20: 16 NPP 21: 22 MODIS 22:27 NPP Southern California Current June 25 , 2012 22:27 NPP 20: 16 NPP 21: 22 MODIS

19. 20: 16 S- NPP 21: 22 MODIS 22:27 S- NPP A A C C Monterey Bay B B Figure 8 - Southern California Chlorophyll Sequence within 111 minutes derived from S-NPP and MODIS from June 25, 2012 from 20:16 – 22:27 GMT . The lower “zoomed in” panels show possible bio-optical changes from upwelling and advective changes along the coasts.

20. Changes in Satellite retrievals Chlorophyll with 121 minutes Monterey Bay A B 20: 16 S- NPP 21: 22 MODIS 22:27 S- NPP

21. Sequential NPP Orbits 101 Minutes 17:37 GMT 19:18 17:37 Gulf Stream Florida Coast 19:18 Florida

22. A. Gulf Stream A A B B 19:18 17:37 C B. C Figure 9- a) November 3, 2012, NPP Chlorophyll products along the North Wall of the Gulf Stream off of Florida from 17:37 and 19:18 GMT b) Enlarged area along the chlorophyll from at changes at different locations. 17:37

23. SUMMARY: Monitoring Bio-Optical Processes Using NPP-VIIRS And MODIS- Aqua Ocean Color Products • 1) Sequential Orbits of NPP and MODIS within the same day were used to evaluate • Ocean Color Products for monitoring changes in bio-optical processes. • 2) Explored variability of bio-optical products within approximately 100 minutes • 3) Evaluated capability of ocean color to monitoring short scales bio-optical processes. • Examined : • 1. Water mass advection and bio-optical processes • 2. Examined uncertainty possibly resulting from sensor characteristics and • ocean color processing . • Demonstrated sequential satellite orbits can establish the satellite products uncertainty for calibration / validation. • Demonstrated ocean color capability to characterize the bio-optical processes by using overlapping orbits and multiple satellites. SPIE – Baltimore 2013

24. Questions? Acknowledgements: Thanks is given to the NOAA JPSS program for funding support

25. 19:31- NPP 17:50 – NPP

27. Nov 1 - 18:15 Sensor Zenith 19:56 66 52 52 56 Solar Zenith – Very Simialr

28. #2 South East US – Nov 3 Mosaic Mosaic 2 scenes from 1737 Can use the 2 boxes to extract . Day 308 19:18 33 Nov 3 , 2013 308. 1103. 173733

29. # 4 Feb 17, 2012 -- Have additional slides . Northern Gulf of Mexico VIIRS and MODIS 2 areas . Sequential orbits 2013 048 0217 -1750 2013 048 0217 1931 18 MODIS 101 minutes