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
