CHLFAIL and CHLWARN physical definition

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clebreton
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CHLFAIL and CHLWARN physical definition

by clebreton » Fri Mar 09, 2018 9:55 am America/New_York

Hello,

I am trying to understand how the CHLFAIL and CHLWARN flags are raised, when looking at MODIS L2 chlorophyll data.
I have been searching, but could not find a physical definition of those flags, such as which criteria and/or thresholds are applied.
The only thing I found in one Forum Post was the chl range from 0.01 to 100 for CHLWARN. Is this still valid?
What about CHLFAIL?

Thank you in advance for you help,
Carole

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OB.DAAC - SeanBailey
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CHLFAIL and CHLWARN physical definition

by OB.DAAC - SeanBailey » Fri Mar 09, 2018 1:43 pm America/New_York

Carole,

CHLWARN is set when the retrieved chl value is outside the range of 0.0-100 mg/m3.
The CHLFAIL flag is set when the algorithm fails.   For the empirical algorithms, there are very few conditions that will cause this to happen - in fact only when the input Rrs values are invalid.

Sean

clebreton
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CHLFAIL and CHLWARN physical definition

by clebreton » Tue Mar 13, 2018 4:15 am America/New_York

Thanks Sean for the explanations :-)
Carole

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