Where does the land mask come from?

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Topic Products and Algorithms / Satellite Data Products & Algorithms / Where does the land mask come from? (4427 hits)

By Ferdi Date 2004-02-21 21:20

Hi People:

Can someone tell me where the MODIS land mask (in level 2) comes from? Is it calculated based on satellite reflectance or based on a-priory knowledge of the coastline? What is the spatial accuracy of that mask?

Specifics of my problem: I am looking at New York Harbor. There are a few (2-5) pixels in Upper New York Bay that are not "land masked". So according to MODIS I should be able to use the data. However, I am very concerned about possible contamination from non-water features...

Thanks,
Ferdi

By @bryan Date 2004-02-23 18:34

The land mask is purely geometric, based on the WVS database. The resolution is 1/128th degree or 0.9 km. The value of the mask is determined at the precise center of each grid point. If the center happens to be over water, that's what the mask indicates, even if land is very close to the center.

Be advised that retrievals in the NY harbor would be highly suspect. I'm amazed that you found any at all. I would expect those retrievals to be heavily contaminated by absorbing aerosols (which we do not correct for) and there are probably other contaminants in the water that scatter in the visible (like boats and big statues :-)

).

Topic Products and Algorithms / Satellite Data Products & Algorithms / Where does the land mask come from? (4427 hits)