High Resolution MODIS Ocean Color Bryan Franz NASA

High Resolution MODIS Ocean Color Bryan Franz NASA Ocean Biology Processing Group MODIS Science Team Meeting, 4 -6 January 2006, Baltimore, MD

Concept • The goal is to investigate the utility of the 250 and 500 -meter land bands for ocean color applications. (talk by Arnone, posters by Gould, Gao)

MODIS Land Bands Band 1 2 3 4 Wavelength 645 859 469 555 Resolution 250 500

MODIS Land Bands Band 1 2 3 4 5 6 7 Wavelength 645 859 469 555 1240 * 1640 2130 Resolution 250 500 500 500 * band 5 failing on MODIS/Aqua

Concept • The goal is to investigate the utility of the 250 and 500 -meter land bands for ocean color applications. • A second goal is to investigate the use of the short-wave IR bands for use in atmospheric correction, especially for coastal applications. (paper by Wang & Shi)

Concept • The goal is to investigate the utility of the 250 and 500 -meter land bands for ocean color applications. • A second goal is to investigate the use of the short-wave IR bands for use in atmospheric correction, especially for coastal applications. • Develop these capabilities for regional analyses by Sea. DAS users, not for global production.

Concept • The goal is to investigate the utility of the 250 and 500 -meter land bands for ocean color applications. • A second goal is to investigate the use of the short-wave IR bands for use in atmospheric correction, especially for coastal applications. • Develop these capabilities for regional analyses by Sea. DAS users, not for global production. • The approach is to define a virtual sensor (HIRES MODIS) which includes all the 250 and 500 -meter channels, as well as a sufficient set of 1 km ocean channels to enable the operation of most standard ocean product algorithms.

HIRES MODIS Band 8 9 3 4 1 15 2 5 6 7 Wavelength 412 443 469 555 645 748 859 1240 * 1640 2130 Resolution 1000 500 250 1000 250 500 500 SNR 880 838 243 228 128 586 201 74 275 110 * band 5 failing on MODIS/Aqua (1 km SNR) (802) (750) (910) (516)

RGB Image 75% Standard MODIS vs HIRES MODIS 1 -km 250 -meter

Progress to Date • Initial implementation of HIRES MODIS processing into MSL 12 – – – replicating radiances and path geometries to 250 -meter pixels interpolating geolocation to 250 -meter resolution developed polarization LUTs for the land bands obtained Rayleigh tables from M. Wang interpolating aerosol tables • Initial vicarious calibration to MOBY – obtained MOBY radiances for the land band spectral response functions from D. Clark. • Testing and refinement of software and approach underway – coordination with NRL/Stennis

Ocean Color Processing Test • Using fixed aerosol type, with aerosol concentration from 859 nm band at 250 -meter resolution • OC 2 chlorophyll algorithm using 469 and 555 -nm bands at 500 -meter resolution (P. J. Werdell).

Chlorophyll Standard MODIS vs HIRES MODIS 1 -km 75% 250 -meter

1 -km 250 -meter 280% 70%

Full 5 -minute Granule 1 -km n. Lw(551) 28% 250 m n. Lw(555) 7%

Practical Considerations • The OBPG does not retain the land-band data within the ocean data processing and distribution system. The 250 and 500 -meter data are removed from the Level-1 A file during ingest. • Full Level-1 A or Level-1 B files must be obtained from the GES DAAC or via Direct Broadcast. DAAC L 1 A holdings are limited. • Each resolution is stored in a separate Level-1 B file (1 KM, HKM, QKM). All three are required to run 250 -meter processing. • Given Level-0 (Direct Broadcast) or Level-1 A, the Sea. DAS software can produce three L 1 B files using the latest LUT. • The files are big. Memory requirements are high. – Level-1 B 1 KM+HKM+QKM = 900 MB (5 minute granule)

Future Plans • Improved implementation into MSL 12 – interpolate all radiances and path geometry to 250 -meter – maybe include other 1 km bands (488, 869) ? – flexibility to switch resolution (1000 m, 500 m, 250 m), utilizing aggregated radiance fields from Level-1 B • Investigate use of SWIR bands for atmospheric correction – 1240 & 1640 (Terra) – 1640 & 2130 (Terra & Aqua) • Develop capabilities for subscene extraction at Level-1 A • Enhance Sea. DAS to support HIRES MODIS – processing and display

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