MODIS/Aqua Reprocessing #1 Analysis Summary

An explaination of the analysis methods used to produce these plots is available here.

Relative to operational processing, the reprocessing configuration without f/Q shows improved agreement with in situ match-up radiances at all wavelengths, with the exception of 412, but the impact is not dramatic. Statistical analysis indicates that the agreement is significantly degraded when the f/Q correction is applied (to both in situ and satellite retrievals). The complete analysis is available here.

MODIS/Aqua Radiance Comparison to In Situ

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

The updated LUT, among other changes, has resulted in a significant improvement in consistency of the annual cycle observed in the MODIS/Aqua deep-water nLw trends. The improvement is most significant for 2004 relative to previous years. The consistency is approaching that of SeaWiFS.

Annual Repeatability of MODIS/Aqua Radiance Trends, Deep Water Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

Annual Repeatability of SeaWiFS Radiance Trends, Deep Water Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

Direct comparison of the deep-water trends to SeaWiFS over the common mission lifetime clearly shows improved agreement between the two sensors, especially toward end of mission. The f/Q correction significantly reduces some seasonal differences between the two sensors, thereby flattening the ratio trends. Some mid-mission bias in the comparison seems to be revealed after seasonal differences have been removed. Deep water chlorophyll was trending 30% high in operational results; trend is eliminated in reprocesing configuration; bias minimal with f/Q included. Agreement in aerosol optical thickness is much better after removing straylight-contaminated retrievals in MODIS/Aqua.

Radiance Ratios to SeaWiFS, Deep Water Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

Chlorophyll Ratios to SeaWiFS, Deep Water Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

AOT Ratios to SeaWiFS, Deep Water Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

The seasonal differences between SeaWiFS and MODIS/Aqua are most pronounced in mid to high southern latitudes. The regional trends indicate that the f/Q correction significantly reduces this assymetry.

nLw Ratios to SeaWiFS, North Atlantic (AtlN) Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

nLw Ratios to SeaWiFS, South Atlantic (AtlS) Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

At higher southern latitudes, seasonal differences between SeaWiFS and MODIS/Aqua are still significant, and the relative improvement due to f/Q correction is not as pronounced. The cause of this high-southern-latitude disagreement may not be f/Q.

nLw Ratios to SeaWiFS, PacN50 Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

nLw Ratios to SeaWiFS, PacN20 Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

nLw Ratios to SeaWiFS, PacS20 Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

nLw Ratios to SeaWiFS, PacS50 Subset

Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

The next set of plots show global trends derived from binning three of the 4-day test periods centered on a winter and a summer solstice, with the data expressed as a function of latitude. Clear-water nLw comparison of SeaWiFS (dashed-line) with MODIS show that the proposed reprocessing configurations improve agreement between the sensors, with best agreement obtained using f/Q. The f/Q removes a substantial component of the north-south trend from the MODIS to SeaWiFS ratios, however, some systematic disagreement is still evident. Most notable is a substantial depression in the MODIS radiances relative to SeaWiFS (of order 10%) which occurs at ~40N in northern hemisphere winter and 40S in northern hemisphere summer, or about 63-deg solar zenith. This is clearly seen in the deep-water ratio trends. We are still investigating this effect.

Latitude Trends, Clear Water nLw 551 Comparison to SeaWiFS 555

Winter
Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q
Summer
Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

Latitude Trends, Clear Water nLw Ratios to SeaWiFS

Winter
Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q
Summer
Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q

Latitude Trends, Deep Water nLw Ratios to SeaWiFS

Winter
Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q
Summer
Current Operational Processing Reprocessing #1 Reprocessing #1 with f/Q