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AURAOMI ozone files with anomalous values

Posted: Tue Jul 20, 2021 4:18 am America/New_York
by jstum
Hello,

This post is to warn you that AURAOMI ancillary files exhibit anomalous ozone values in southern hemisphere since day 138 (18 May 2021). Total ozone is obviously wrong (more than twice its normal value). This anomaly affects chlorophyll maps (wrong chl blooms at the location of the Aura tracks) built from your level 2 products.

Best regards,

Jacques

Re: AURAOMI ozone files with anomalous values

Posted: Tue Jul 20, 2021 8:20 am America/New_York
by OB.DAAC - SeanBailey
Jacques,
Thanks for the note. Yes, it appears that there is an issue with the ozone source. We are investigating.

Regards,
Sean

Re: AURAOMI ozone files with anomalous values

Posted: Mon Aug 30, 2021 10:58 am America/New_York
by david.haffner
Hello Jacques and all,

I am responsible for the OMI total ozone algorithm. Thank you for posting your observations about the anomalous OMI ozone data the began showing up in late spring. As you probably are aware, OMI has an instrument anomaly that degrades the quality of the data in a subset of the cross-track positions within the swath. The effects change with solar angle and also time to a degree.

We have an error detection code that flags the affected data but occasionally there is a glitch. We found that this had occurred in this case and made adjustments to the flagging. The updated data were distributed to the Goddard archive (GESDISC) but I don't know if they have reached the data source you access. If they have not, please let me know.

Best regards,
Dave

Re: AURAOMI ozone files with anomalous values

Posted: Mon Aug 30, 2021 11:29 am America/New_York
by david.haffner
Posting image of properly flagged data.

Re: AURAOMI ozone files with anomalous values

Posted: Tue Sep 07, 2021 9:26 am America/New_York
by jackyjoy123
david.haffner wrote:
> Hello Jacques and all,
>
> I am responsible for the OMI total ozone algorithm. Thank you for posting
> your observations about the anomalous OMI ozone data the began showing up
> in late spring. As you probably are aware, OMI has an instrument anomaly
> that degrades the quality of the data in a subset of the cross-track
> positions within the swath. The effects change with solar angle and also
> time to a degree.
>
> We have an error detection code that flags the affected data but
> occasionally there is a glitch. We found that this had occurred in this
> case and made adjustments to the flagging. The updated data were
> distributed to the Goddard archive (GESDISC) but I don't know if they have
> reached the data source you access. If they have not, please let me know.
>
> Best regards,
> Dave

Thanks for the awesome information.