Forward stream of L2 OC SNPP/VIIRS and NOAA20/VIIRS

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emanuele_bohm
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Forward stream of L2 OC SNPP/VIIRS and NOAA20/VIIRS

by emanuele_bohm » Wed Nov 02, 2022 7:09 am America/New_York

We have noticed that consolidated files (without "NRT" in filename) are not being updated as of OCT 1st.
Do you plan to resume dissemination anytime soon?
Best regards,
Emanuele Böhm
CMEMS/OCTAC Service Manager

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OB.DAAC - SeanBailey
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Re: Forward stream of L2 OC SNPP/VIIRS and NOAA20/VIIRS

by OB.DAAC - SeanBailey » Wed Nov 02, 2022 3:24 pm America/New_York

Yes, we do plan to produce the refined product, however we are waiting for the November lunar calibration maneuver before finalizing the calibration assessment. With R2022, we are following the same cadence with refined calibration that we use for the MODIS instruments.

Regards,
Sean

emanuele_bohm
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Re: Forward stream of L2 OC SNPP/VIIRS and NOAA20/VIIRS

by emanuele_bohm » Fri Nov 04, 2022 11:34 am America/New_York

Dear Sean,
when you state "...we are following the same cadence with refined calibration that we use for the MODIS instruments." do you mean that we should expect a delay of several months analogous to MODIS one? We need this info to properly inform the Marine Copernicus users.
Best regards,
Emanuele

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Re: Forward stream of L2 OC SNPP/VIIRS and NOAA20/VIIRS

by OB.DAAC - SeanBailey » Fri Nov 04, 2022 12:53 pm America/New_York

Emanuele,

There are two things that are required for the refined processing:
1) The availability of the refined ancillary data
2) The monthly calibration updates

The MERRA-2 reanalysis updates are done on a monthly basis, with each months data becoming available approximately between the 15th and 20th of the next month (e.g. October 2022 will be released between the 15th and 20th of Nov 2022).

The monthly calibration updates are (typically) accomplished before the MERRA2 release. So, at a minimum, refined data will be at least 2 weeks behind NRT. Since an entire month (typically) is processed at a time, it can be upward of two months lag (if you're interested in data from early in the month and the MERRA2 data are released later in the month).

Occasionally, Murphy's Law is in play, so there is no guarantee that the data will be at most 2 months behind NRT.

Regards,
Sean

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