Cloud cover or similar data - Modis Aqua

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Cloud cover or similar data - Modis Aqua

by miguelmies » Tue Nov 14, 2023 11:27 pm America/New_York

Dear colleagues,

I recall a few years back seeing a "cloud cover" product on the Modis-Aqua database (at the previous version of this website: https://oceancolor.gsfc.nasa.gov/l3/order/). However I cannot find it anymore.

Can anyone tell me if there is any cloud cover (or similar) product available through Modis-Aqua? Preferably available for use with SeaDAS.

Thank you very much,

Miguel Mies

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Re: Cloud cover or similar data - Modis Aqua

by GES DISC - jimacker » Tue Nov 21, 2023 2:15 pm America/New_York

Miguel,

Both MODIS-Aqua and MODIS-Terra have a cloud fraction product, as well as AIRS. I don't know the best way to incorporate it for use with SeaDAS. I have provided a link to the Giovanni system at the GES DISC (not OBDAAC) that will allow you to examine it. The higher resolution Level 2 files reside with the MODAPS system.

https://giovanni.gsfc.nasa.gov/giovanni/#service=TmAvMp&starttime=&endtime=&variableFacets=dataProductPlatformInstrument%3AAIRS%2CMODIS-Aqua%2CMODIS-Terra%3B&dataKeyword=cloud%20fraction

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Re: Cloud cover or similar data - Modis Aqua

by miguelmies » Tue Nov 21, 2023 3:13 pm America/New_York

Dear jimacker,

Thank you very much for the info - very helpful. I'll dig into it.

One last thing: at the (https://oceancolor.gsfc.nasa.gov/l3/order/) website, in the "product" menu, there are several measurements at different wavelengths. Does any one of them refer to different cloud products?

Thanks again and best regards,

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Re: Cloud cover or similar data - Modis Aqua

by GES DISC - jimacker » Tue Nov 21, 2023 3:47 pm America/New_York

Miguel,

No, those are all in-water products. If you get a file with some ocean color data and some missing data, it is common for the missing data to be due to clouds, but it can also be due to the gaps between the MODIS scanning swaths, high aerosol concentrations in the atmosphere (dust can do this), and other conditions. The Level 3 data products are created from the best quality data, so data that is affected by conditions that affect the data quality is flagged in the Level 2 data, which are processed to produce the Level 3 files.

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Re: Cloud cover or similar data - Modis Aqua

by miguelmies » Tue Nov 21, 2023 3:52 pm America/New_York

jimacker,

Perfect - thank you very much! I really appreciate your help!

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Re: Cloud cover or similar data - Modis Aqua

by GES DISC - jimacker » Tue Nov 21, 2023 4:06 pm America/New_York

You are welcome. OBDAAC personnel may be able to advise on cloud cover data in SeaDAS; there may be a cloud mask that can be generated or used in the system.

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Re: Cloud cover or similar data - Modis Aqua

by OB SeaDAS - xuanyang02 » Tue Nov 21, 2023 4:33 pm America/New_York

We do provide cloud mask with Level 2 data. The gray area is cloud/ice. See the attached
Screenshot 2023-11-21 at 4.31.23 PM.png
Screenshot 2023-11-21 at 4.31.23 PM.png (410.92 KiB) Not viewed yet

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Re: Cloud cover or similar data - Modis Aqua

by miguelmies » Tue Nov 21, 2023 4:35 pm America/New_York

Dear xuanyang02,

That's excellent news, thank you very much! Where can I access that data?

Best regards

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Re: Cloud cover or similar data - Modis Aqua

by OB SeaDAS - xuanyang02 » Tue Nov 21, 2023 5:22 pm America/New_York

You can access our level 2 data directly here -- https://oceandata.sci.gsfc.nasa.gov/directdataaccess/Level-2/

Or through l2 browsers -- https://oceancolor.gsfc.nasa.gov/cgi/browse.pl?sen=amod

Bing

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Re: Cloud cover or similar data - Modis Aqua

by miguelmies » Tue Nov 21, 2023 5:28 pm America/New_York

Bing,

Thank you very much. If you don't mind me asking, as I am a bit inexperienced with this, how can I retrieve only the cloud fraction data from the files in the first link you sent me? It seems like there is all sorts of data in it.

As for the second link, how do I access cloud data specifically? Which setting should I select?

Thanks again and I'm sorry for the newbie questions.

Abraços (cheers in portuguese)

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