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Does anyone have a feel for how comparable the re-processed CZCS nLw550 and SeaWiFS nLw555 might be? are there any systematic offsets that should be considered in any time-series analysis?
The current CZCS products we distribute have NOT been vicariously calibrated to
our atmospheric correction code. These data were processed using the calibration
described in Evans and Gordon, 1994. While our current atmospheric correction code
has it's heritage in the original CZCS code, a lot has changed. We are in the process
of evaluating the CZCS calibration, and hope to have a revised product soon.
The expectation is that the CZCS nLw550 will be similar to SeaWiFS nLw555. They
are not likely to be identical, as they are 5nm different in nominal wavelength and
differ in bandpass (SeaWiFS is 20nm, CZCS is 40nm).
For example, in low chl waters (0.03 - 0.3 mg/m3), CZCS 550 should be between
4 to 6% higher than SeaWiFS's 555nm (estimated using a clear water model and
convolving the spectra with SeaWiFS and CZCS respective bandpasses)
Hope this helps,
Thanks Sean, that's a great help. do you have a timeline for the revised czcs product?
No, but my best guess would be by the end of September