OLCI Vicarious Calibration Coefficients

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OB.DAAC - SeanBailey
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Re: OLCI Vicarious Calibration Coefficients

by OB.DAAC - SeanBailey » Tue Jun 01, 2021 10:44 am America/New_York

Here is a set of preliminary gains to try with OLCI-S3B:

gain=[0.98928,0.988936,0.98734,0.97931,0.98508,0.98556,0.98588,0.98491,0.98252,0.98506,1.01325,0.9897,1.0,1.0,1.08547,0.99640,1.0,1.0161,1.0,1.0,1.0]

Regards,
Sean

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Re: OLCI Vicarious Calibration Coefficients

by aewindle110 » Thu Sep 16, 2021 1:02 pm America/New_York

Hi Sean,

Can you point me in the direction of where these OLCI/l2gen SVC gains came from? Is there a document reporting these? Would like to reference in a manuscript. Thanks!

Anna

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Re: OLCI Vicarious Calibration Coefficients

by OB.DAAC - SeanBailey » Fri Sep 17, 2021 8:14 am America/New_York

Anna,
The coefficients were derived by me following the procedures established many years ago and published in:

Bryan A. Franz, Sean W. Bailey, P. Jeremy Werdell, and Charles R. McClain, "Sensor-independent approach to the vicarious calibration of satellite ocean color radiometry," Appl. Opt. 46, 5068-5082 (2007) https://doi.org/10.1364/AO.46.005068

However, a paucity of viable MOBY target data required the use of the methods described in:

P. Jeremy Werdell, Sean W. Bailey, Bryan A. Franz, André Morel, and Charles R. McClain, "On-orbit vicarious calibration of ocean color sensors using an ocean surface reflectance model," Appl. Opt. 46, 5649-5666 (2007) https://doi.org/10.1364/AO.46.005649

but with the use of a model based on a climatology of chlorophyll at the MOBY site, rather than the BATS and HOTS sites.

Hope this answers you questions.

Sean

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Re: OLCI Vicarious Calibration Coefficients

by andrew.meredith » Wed Sep 29, 2021 12:34 pm America/New_York

I noticed the S3A vicarious calibration gains for OCSSW 2021.2 differ from the S3A gains in this post and was wondering if the S3A and S3B gains have been been finalized yet? And if so what values should i be using? If not, do you have an estimate when they might be?

Thanks,
Andrew

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Re: OLCI Vicarious Calibration Coefficients

by OB.DAAC - SeanBailey » Wed Sep 29, 2021 3:05 pm America/New_York

Until we process and release L2 files for the OLCI sensors, there is no "official" set to use. We hope to be able to process (and release) L2 data soon...but you may notice I said that almost 6 months ago. Use of either set "in the wild" will be better than using unity. Which is better...I'm not willing to say yet - but just so you know, neither will be the ones we ultimately use - in large part due to changes in the atmospheric correction process that will be part of R202# (hopefully # will still be a 1).

Sean

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