Missing MODIS-Aqua granules/orbits from 8 to 13 October

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dem1
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Missing MODIS-Aqua granules/orbits from 8 to 13 October

by dem1 » Fri Oct 18, 2024 5:39 am America/New_York

Hi,

There are several missing MODIS-Aqua granules/orbits from 8 to 13 October.
Do you know the reason and when the missing data will be available? or are the gaps definitely lost?
We didn't found any communication concerning this issue.

Thanks,
Julien
Copernicus Marine OCTAC Service

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OB ODPS - towens
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Re: Missing MODIS-Aqua granules/orbits from 8 to 13 October

by OB ODPS - towens » Fri Oct 18, 2024 8:55 am America/New_York

I can trace the problem better if you tell me how you are accessing the data and provide an example of a missing granule.

Thanks
Tommy

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Re: Missing MODIS-Aqua granules/orbits from 8 to 13 October

by OB ODPS - towens » Fri Oct 18, 2024 9:11 am America/New_York

I'm seeing missing data on our source. I'll compare our counts with theirs and see if any can be recovered on our side. I doubt MODIS will be doing any recovery on their side. I'll update when I know more.

Tommy

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Re: Missing MODIS-Aqua granules/orbits from 8 to 13 October

by dem1 » Fri Oct 18, 2024 9:18 am America/New_York


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Re: Missing MODIS-Aqua granules/orbits from 8 to 13 October

by vforneris » Fri Oct 18, 2024 10:01 am America/New_York

Dears,

I run a test verifying how many "L2.OC.NRT.nc" are accessible via the https://oceandata.sci.gsfc.nasa.gov/directdataaccess/Level-2/Aqua-MODIS system. I see that usually there are mostly in the range 168-175 files per day.
In the period in analysis however we have few days when the number drops

n of occurrences (L2.OC.NRT.nc) for day 2024-10-08 = 163
n of occurrences (L2.OC.NRT.nc) for day 2024-10-09 = 167
n of occurrences (L2.OC.NRT.nc) for day 2024-10-10 = 167
n of occurrences (L2.OC.NRT.nc) for day 2024-10-11 = 125
n of occurrences (L2.OC.NRT.nc) for day 2024-10-12 = 158
n of occurrences (L2.OC.NRT.nc) for day 2024-10-13 = 137
n of occurrences (L2.OC.NRT.nc) for day 2024-10-14 = 177
n of occurrences (L2.OC.NRT.nc) for day 2024-10-15 = 169
n of occurrences (L2.OC.NRT.nc) for day 2024-10-16 = 173

days 11th-13th in particular seem missing some files (more evident than in other days), confirmed also by the L2 browse.pl app.

Hope it helps

Best Regards
Vega (CNR/Copernicus Marine Service)

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Re: Missing MODIS-Aqua granules/orbits from 8 to 13 October

by OB ODPS - towens » Fri Oct 18, 2024 11:13 am America/New_York

We have the same gaps at L0

Thanks
Tommy

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Re: Missing MODIS-Aqua granules/orbits from 8 to 13 October

by OB.DAACx - SeanBailey » Fri Oct 18, 2024 12:40 pm America/New_York

Julien,
The issue actually started on Oct 5th, and is a ground station issue. Increased solar activity during that time interfered with the ground stations' spacecraft tracking causing data loss during downlinks.

The data are likely not recoverable: https://landweb.modaps.eosdis.nasa.gov/displayissue?id=813

Sean

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