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