# Presentation: 696610

## High Resolution MODIS Ocean Color

- <date/time>

**High Resolution MODIS Ocean Color**

**Fred Patt****1****, Bryan Franz****1****, Gerhard Meister****2****, P. Jeremy Werdell****3**
**NASA Ocean Biology Processing Group**
**1****Science Applications International Corporation**
**2****Futuretech Corporation**
**3****Science Systems and Applications, Inc.**

**Concept**

- The goal is to investigate the utility of  the 250 and 500-meter land bands for ocean color applications, and to provide that capability to SeaDAS users.
- A second goal is to investigate the use of the short-wave IR bands for use in atmospheric correction (Wang 2005), especially for coastal applications, and to provide that capability to SeaDAS users.
- The approach is to define a virtual sensor which includes all the 250 and 500-meter channels, as well as the 1000-meter channels in the visible and near IR, at a consistent resolution.
- We call this virtual sensor HIRES MODIS, with Aqua and Terra variants known as HMODISA & HMODIST.

- Band	       Wavelength	         Resolution		SNR		Ltypical
- 	            (nm)	           (meters)                                         (W cm-2 m-1 sr-1)
-   8		412		1000		880		44.9
-   9		443		1000		838		41.9
-   3		469		500		243		35.3
-  10		488		1000		802		32.1
-  11		531		1000		754		27.9
-  12		551		1000		750		21.0
-   4		555		500		228		29.0
-   1		645		250		128 		21.8
-  13		667		1000		 910		9.5
-  14		678		1000		1087		8.7
-  15		748		1000		586		10.2
-   2		859		250		201		24.7
-  16		869		1000		516		6.2
-   5		1240 		500		74		5.4
-   6		1640 *		500		275		7.3
-   7		2130		500		110		1.0

** band 6 failing on MODIS/Aqua*

**Characteristics of MODIS Visible and NIR Bands**

** band 6 failing on MODIS/Aqua*

**RGB Image****Standard MODIS****vs****HIRES MODIS**

**250 m**

- 75%

**1 km**

**Progress to Date**

- The processing software has been modified to read the additional MODIS bands, and to allow processing at a user-specified spatial resolution (250, 500, or 1000-meters).
- Interpolation is used to raise the resolution of the lower-resolution bands when working at higher resolutions. When processing higher-resolution bands at reduced resolution, the Level-1B aggregated radiance fields are utilized.
- Geolocation and path geometries are appropriately interpolated for the defined processing resolution.
- Standard Rayleigh tables have been created for the full 16-band suite, and aerosol models have been spectrally interpolated.
- A full set of aerosol model tables, specific to the band suite, has also been generated, with testing now underway.
- Polarization sensitivities have been determined, and standard polarization corrections have been implemented for all bands.
- An initial vicarious calibration to MOBY has been performed.

**Processing Example**

- Using fixed aerosol type, with aerosol concentration from 869-nm band at 250-meter resolution
- OC2 chlorophyll algorithm using 469 and 555-nm bands at 500-meter resolution.

**Future Plans**

- Improved implementation into MSL12
- add support for thermal bands to allow co-registered SST retrievals
- update aerosol model tables
- finalize vicarious calibration
- Investigate use of SWIR bands for atmospheric correction
- NIR Lw correction
- aerosol model selection
- Enhance SeaDAS to support HIRES MODIS
- processing and display

**Subframe Striping**

- Subframe striping was found in band 3 ocean data
- Analysis of median DN of L1B ocean scenes shows subframe striping in bands 1-3, 5 and 7
- MCST indicates effect has been qualitatively known

**Possible Correction Approach**

- Look-up table of correction vs. radiance to be applied to the L1B radiances
- The best method of determining the correction is still being worked

**Acknowledgements**

- The work presented here is supported by the Ocean Biology Group (OBPG)
- at NASA Goddard Space Flight center, within the NASA Biogeochemistry Program.
- We also wish to acknowledge our ongoing collaboration with the Naval Research
- Laboratory (NRL) and the MODIS Characterization Support Team (MCST).

- Band 1

- Band 2

- Band 4

- Band 3

**nLw at 645nm**

**chlorophyll using OC2 algorithm**

- Wang, M. and W. Shi, “Estimation of ocean contribution at the MODIS near-infrared
- wavelengths along the east coast of the U.S.: Two case studies”, Geophys. Res. Letters, 32, 2005.