How to remove clouds over sea ice?

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hwaga
Posts: 2
Joined: Mon Jul 19, 2021 5:55 pm America/New_York

How to remove clouds over sea ice?

by hwaga » Mon Jul 19, 2021 6:08 pm America/New_York

Greetings,

I'm processing MODIS/Aqua Level 1 data to create Level 2 cloud-free surface reflectance using SeaDAS l2gen. The goal is to produce cloud-free surface reflectance images like the MYD09GA without daily composite. I know the Level 2 Ocean Color Flag "CLDICE" removes both sea ice and cloud, but I want cloud-free surface reflectance over sea ice.

Could someone provide some suggestions?

Best regards,
hwaga

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gnwiii
Posts: 612
Joined: Fri Jan 29, 2021 5:51 pm America/New_York
Answers: 1

Re: How to remove clouds over sea ice?

by gnwiii » Tue Jul 20, 2021 1:34 pm America/New_York

I doubt there is a way to do this without using multiple passes and/or microwave
sensor products.

Quoting <https://modis-snow-ice.gsfc.nasa.gov/up ... ce_ist.pdf>:

"Because the swath algorithm will often map clouds as sea ice,
we use the MODIS cloud mask product to mask the clouds. If
the cloud mask fails to map a cloud, then it will be mapped by
the sea ice algorithm as sea ice. To avoid such errors of commis-
sion, the algorithm that produces the eight-day composite maps
requires that sea ice be visible two days in a row in order to be
mapped as sea ice."

hwaga
Posts: 2
Joined: Mon Jul 19, 2021 5:55 pm America/New_York

Re: How to remove clouds over sea ice?

by hwaga » Tue Jul 20, 2021 2:53 pm America/New_York

Hi gnwii,

It seems like there is no way other than utilizing MYD/MOD35_L2 cloud mask or MYD/MOD09GA products. This is not what I hope, but anyway, thanks for the reply!

Cheers,
hwaga

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