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Explore the potential of 250 and 500-meter land bands for ocean color applications and investigate the use of short-wave IR bands for atmospheric correction in coastal settings. The concept includes developing these capabilities for regional analyses by SeaDAS users, not global production. Discover how a virtual sensor, HIRES.MODIS, can be defined to include all necessary channels for ocean product algorithms. Progress to date, practical considerations, and future plans are outlined for further enhancement of capabilities.
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High Resolution MODISOcean 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 Wavelength Resolution 1 645 250 2 859 250 3 469 500 4 555 500
MODIS Land Bands Band Wavelength Resolution 1 645 250 2 859 250 3 469 500 4 555 500 5 1240 * 500 6 1640 500 7 2130 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 SeaDAS 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 SeaDAS 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 1km ocean channels to enable the operation of most standard ocean product algorithms.
HIRES MODIS Band Wavelength Resolution SNR (1km SNR) 8 412 1000 880 9 443 1000 838 3 469 500 243 (802) 4 555 500 228 (750) 1 645 250 128 (910) 15 748 1000 586 2 859 250 201 (516) 5 1240 * 500 74 6 1640 500 275 7 2130 500 110 * band 5 failing on MODIS/Aqua
75% RGB ImageStandard MODISvsHIRES MODIS 1-km 250-meter
Progress to Date • Initial implementation of HIRES MODIS processing into MSL12 • 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 • OC2 chlorophyll algorithm using 469 and 555-nm bands at 500-meter resolution (P. J. Werdell).
75% Chlorophyll Standard MODISvsHIRES MODIS 250-meter 1-km
1-km 250-meter 70% 280%
28% 7% Full 5-minute Granule 1-km nLw(551) 250m nLw(555)
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-1A file during ingest. • Full Level-1A or Level-1B files must be obtained from the GES DAAC or via Direct Broadcast. DAAC L1A holdings are limited. • Each resolution is stored in a separate Level-1B file (1KM, HKM, QKM) . All three are required to run 250-meter processing. • Given Level-0 (Direct Broadcast) or Level-1A, the SeaDAS software can produce the three L1B files using the latest LUT. • The files are big. Memory requirements are high. • Level-1B 1KM+HKM+QKM = 900MB (5 minute granule)
Future Plans • Improved implementation into MSL12 • interpolate all radiances and path geometry to 250-meter • maybe include other 1km bands (488, 869) ? • flexibility to switch resolution (1000m, 500m, 250m), utilizing aggregated radiance fields from Level-1B • Investigate use of SWIR bands for atmospheric correction • 1240 & 1640 (Terra) • 1640 & 2130 (Terra & Aqua) • Develop capabilities for subscene extraction at Level-1A • Enhance SeaDAS to support HIRES MODIS • processing and display