MODIS-Aqua Reprocessing 2013.0

MODIS-Aqua Reprocessing 2013.0

1. Introduction

MODIS-Aqua Reprocessing 2013.0 is a partial mission reprocessing to utilize improved knowledge of instrument temporal calibration to improve temporal and cross-scan stability in the last few years of the mission (2011-2013).

2. Changes

2.1. Instrument Calibration

The basis of this reprocessing is the MODIS Calibration Support Teams (MCST) look-up table (LUT) V6.1.17.7_OC2. This is the same LUT that is being applied for the Collection 6 reprocessing of MODIS Aqua Land and Atmosphere products, but with recent updates to improve late-mission temporal calibration. This LUT includes time-varying corrections for changes in response versus scan angle (RVS) for bands 8 and 9, which were derived using observations of desert sites. These desert-based corrections largely replicate what the OBPG had previously derived from cross-calibration to SeaWiFS, and previously applied in recent Aqua reprocessings. The results using this MCST C6 LUT alone, however, still show significant artifacts (residual cross-scan variations and detector/mirror-side striping in derived products). To mitigate these effects, the OBPG applies a cross-calibration approach similar to Meister et al. 2011, but using global MODIS-Aqua Level-3 water-leaving radiance retrievals as the vicarious calibration source. Additionally, a new striping correction for the land bands (bands 1-4) is applied. The correction was derived using the ratio of the TOA radiances of the land bands to the spectrally nearest ocean band.

2.2. Processing Algorithms

Processing algorithms are identical with the previous reprocessing (R2010.0, R2012.0).

3. Results

The plot below shows the averages of the MODIS Aqua Rrs in global deep water as a function of time both for R2012.0 (AR2012.0, solid lines) and R2013.0 (AT95, dashed lines).

The plots below show the change in chlorophyll in oligotrophic, mesotrophic, and eutrophic waters.

For a complete analysis, see:

  1. MODISA R2013.0 (AT95) vs MODISA R2012.0 (AR2012.0)

4. Additional Information