SeaDAS Training ~ NASA Ocean Biology Processing Group

1

Ocean color and SST data product validation

NASA Ocean Biology Processing Group

Goddard Space Flight Center, Greenbelt, Maryland, USA

SeaDAS Training Material

SeaDAS Training ~ NASA Ocean Biology Processing Group

2

Ocean color level-2 match-ups using SeaBASS data

SeaWiFSSept 1997 - Present

MODIS-AquaJuly 2002 - Present

color key: valid match excluded

“match-up” defined as: (1) in situ measurement collected within +/- 3 hours of satellite overpass(2) 5x5 satellite pixel box centered on in situ lat/lon target(3) homogeneity and sensor/solar geometry tests applied(4) filtered median of valid (non-flagged) pixels, if >50% remain

SeaDAS Training ~ NASA Ocean Biology Processing Group

3

Comparison of coincident satellite and in situ nLw()

SeaWiFSMODIS-Aqua

Wavelength # Matches Mean Ratio* % Difference** r2

MODIS SeaWiFS MODIS SeaWiFS MODIS SeaWiFS MODIS SeaWiFS MODIS SeaWiFS

412 412 120 553 0.747 0.905 30.898 24.098 0.742 0.827443 443 133 702 0.862 0.915 18.811 17.480 0.815 0.830488 490 109 660 0.923 0.918 14.563 15.101 0.907 0.821531 510 32 479 0.933 0.918 11.178 13.739 0.934 0.849551 555 120 702 0.940 0.915 12.255 16.878 0.943 0.931667 670 107 666 0.682 0.920 36.392 45.717 0.735 0.876

SeaDAS Training ~ NASA Ocean Biology Processing Group

4

Comparison of coincident satellite and in situ Chl

Sensor # Matches Mean Ratio % Diff r2

SeaWiFSMODIS/Aqua

1293263

0.9981.084

33.140.4

0.7960.780

SeaWiFSMODIS-Aqua

Bailey and Werdell, Rem. Sens. Environ. 102, 12-23 (2006)

http://seabass.gsfc.nasa.gov/matchup_results.html

SeaDAS Training ~ NASA Ocean Biology Processing Group

5

Ocean color level-3 validation

Level-2 match-ups are sparse and do not provide detailed temporal (e.g., seasonal) or spatial (e.g., latitudinal, along scan, across detectors) statistics.

Level-3 sensor-to-sensor comparisons provide some insight into such temporal and spatial behavior.

Data are prepared by …

• binning globally at selected spatial resolution (4.6 or 9-km)• binned at equal time intervals (4- or 8-days from the start of each consecutive 32-day period)• identifying common bins for both sensors

Chl, 9-km 8-day common deep-water bins April-2006

SeaWiFSMODIS-Aqua

0.01 mg m-3 1 mg m-3

SeaDAS Training ~ NASA Ocean Biology Processing Group

6

Definition of Level-3 trophic subsets

deep water (depth > 1000 m) oligotrophic (Chl < 0.1 mg m-3)

mesotrophic (0.1 < Chl < 1 mg m-3) eutrophic (1 < Chl < 10 mg m-3)

SeaDAS Training ~ NASA Ocean Biology Processing Group

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nLw() temporal trends

412 nm

443 nm

488 nm

531 nm

551 nm

412 nm

443 nm

490 nm

510 nm

555 nm

2003 2006 20061998

SeaWiFSMODIS-Aqua

deep water, 4-day composites

SeaDAS Training ~ NASA Ocean Biology Processing Group

8

deep water, 4-day composites, common bins

Comparison of relative temporal stability of nLw()

MODIS-Aqua SeaWiFS

SeaDAS Training ~ NASA Ocean Biology Processing Group

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MODIS-Aqua / SeaWiFS ratio trends

oligotrophic mesotrophic eutrophic

Chl ratios

nLw() ratios

SeaDAS Training ~ NASA Ocean Biology Processing Group

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Comparison of spectral distribution trends

MODIS-Aqua & SeaWiFS mean nLw()

oligotrophicmesotrophiceutrophic

SeaDAS Training ~ NASA Ocean Biology Processing Group

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Seasonal Chl images

0.01-64 mg m-3

Summer 2004

Winter 2004

SeaWiFSMODIS-Aqua

Winter 2004

Summer 2004

SeaDAS Training ~ NASA Ocean Biology Processing Group

12

SST validation

buoy measurements

SeaDAS Training ~ NASA Ocean Biology Processing Group

13

References

Ocean color level-2 match-ups

http://seabass.gsfc.nasa.gov/matchup_results.html

S.W. Bailey and P.J. Werdell, Rem. Sens. Environ. 102, 12-23 (2006)

Ocean color level-3 validation

B.A. Franz et al., Proc. SPIE 5882, 304-316 (2005)

SST validation and match-up database

K.A. Kilpatrick et al., J. Geophys. Res. 106, 9179-9197 (2001)