Flagging differences between chlor_a and FLH

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jsturner
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Flagging differences between chlor_a and FLH

by jsturner » Thu Feb 29, 2024 9:11 am America/New_York

Hello,
I am working on a project in coastal Antarctic waters and found a large discrepancy between chlor_a and FLH. See the attached figure (January 2022). While there are some possible "science" reasons for this (e.g., adjacency effects), I wanted to verify that both of these products use the same atmospheric correction (l2gen). Do they use the same atmospheric correction? Could you please provide information about the quality flagging that is performed for each product? Is the flag list different for chlor_a versus FLH? Perhaps High-light or something else is turned "off" for FLH allowing it to retain more coastal data? Any insights would be much appreciated. In the future, could the flagging process be documented on the algorithm pages for chlor_a and FLH?
Thank you,
Jessie Turner
jturner@uconn.edu
Attachments
January 2022 composite for level-3 MODIS chlor_a vs. level-3 MODIS fluorescence line height.
January 2022 composite for level-3 MODIS chlor_a vs. level-3 MODIS fluorescence line height.
Jan2022_Chl_vs_FLH_CoastalAntarctic.png (471.91 KiB) Not viewed yet

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OB ODPS - towens
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Re: Flagging differences between chlor_a and FLH

by OB ODPS - towens » Wed Mar 13, 2024 1:56 pm America/New_York

The flags used in processing are recorded in the L3 metadata:

%ncdump -h AQUA_MODIS.20240312.L3b.DAY.CHL.NRT.nc | grep :flaguse
:flaguse = "ATMFAIL,LAND,HILT,HISATZEN,STRAYLIGHT,CLDICE,COCCOLITH,LOWLW,CHLWARN,CHLFAIL,NAVWARN,MAXAERITER,ATMWARN,HISOLZEN,NAVFAIL,FILTER,HIGLINT" ;

%ncdump -h AQUA_MODIS.20240312.L3b.DAY.FLH.NRT.nc | grep :flaguse
:flaguse = "ATMFAIL,LAND,HILT,HISATZEN,STRAYLIGHT,CLDICE,COCCOLITH,LOWLW,CHLWARN,CHLFAIL,NAVWARN,MAXAERITER,ATMWARN,HISOLZEN,NAVFAIL,FILTER,HIGLINT,PRODWARN,MODGLINT" ;

Tommy

jsturner
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Joined: Fri Jan 24, 2020 9:52 am America/New_York
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Re: Flagging differences between chlor_a and FLH

by jsturner » Fri Apr 12, 2024 9:52 am America/New_York

Thank you!
-Jessie

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