MODIS AQUA chla degradation since 2023 and its use?

[avalente]

Hello,

I would like to use timeseries of MODIS-Aqua ocean color data (Chl-a, SST, PAR, Kd490, PIC, POC) from 2002 up to, ideally, 2025.

Could you please advise if it is acceptable to use these data for research purposes since 2023, given the degradation notice of MODIS starting in 2023 (viewtopic.php?t=5333
)? I have noticed that some papers still use MODIS Chl-a time series up to 2024.

Alternatively, would it be better to collate VIIRS (SNPP_VIIRS) data after 2023?

Any guidance on how to handle this issue would be greatly appreciated.

Thank you very much for your help!

Best regards,
Andre

[andrei_mitrich]

Hi,

I do not know the answer but also would be glad to hear any updates on this. I believe initial degradation started being observed some time around 2018-2019 and was getting worse with the time?

I'd like to take a liberty to add couple of related questions in addition to the initial question from Andre:
1) was there any improvement in MODIS results observed with ocssw/l2gen processing calibration updated last few years?
2) we observed similar behavior in VIIRS Suomi data after 2019 when using quite old (now) versions of l2gen configuration; are VIIRS data more accurate with the latest 9.11-V2025.5?

Thank you.
Cheers,
Andrei