MODIS/Aqua Ocean Reprocessing 1.1

The primary purpose of MODIS/Aqua Reprocessing 1.1 is to incorporate a new K_490 algorithm and to update the radiometric calibration coefficients for the ocean color bands. A new model for the sensor degradation is used to better track the apparent changes in instrument sensitivities as determined from the solar diffuser trends. In addition, a detector dependent radiometric calibration correction is introduced that significantly reduces the striping in the level 2 images over the full mission lifespan. This reprocessing also makes use of the reprocessed TOMS version 8 ozone dataset.

Users should take a look at the analyses presented here to determine whether or not the changes are significant enough for their application to justify downloading the revised products.

Changes Implemented

Modified time dependency of radiometric calibration

Striping reduction through detector dependent radiometric correction

Updated K490

Collection 5 production environment

Switch to TOMS V8 Ozone

Revised dimension of 9km SMI maps

Status of Current Operational Products

The current Aqua operational products are based on Reprocessing 1. Some of the changes discussed here were put into forward-stream production on 10 June 2005, as the instrument degradation was significantly deviating from the existing model and a quick update was deemed neccessary. Final refinements were completed and the forward stream was updated again on 27 July 2005. A full-mission retrospective processing with a consistent calibration is now underway.

Evaluation of Reprocessing Configuration

A complete mission reprocessing was performed on a temporal subset consisting of the first 4 days of each 32-day period. A generic discussion of the analysis methods is available here.

For a complete analysis of temporal trends, see:

MODIS/Aqua Reprocessing 1.1 versus Reprocessing 1

MODIS/Aqua Reprocessing 1.1 versus SeaWiFS Reprocessing 5.1

MODIS/Aqua Reprocessing 1.0 versus SeaWiFS Reprocessing 5

The reduction in striping in the derived products can be observed by comparing detector relative trends derived from global analysis of Level-2 match-ups to 7-day Level-3 means. As an example, the comparison of 443nm nLw residuals (%) for a day near the mid-point of the mission is shown below:

Reprocessing 1

Reprocessing 1.1

For a complete analysis of the detector-dependent residuals, see:

Detector Residuals, before destriping correction

Detector Residuals, after destriping correction

Curator: OceanColor Webmaster

Authorized by: gene carl feldman

Updated: Friday, 19-Jun-2009 11:44:40 EDT