Level2 Products about Rrs

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hxczjh123
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Level2 Products about Rrs

by hxczjh123 » Wed Apr 04, 2018 5:46 am America/New_York

Hello,
Are the Rrs in Level2 Products not including NIR Rrs?(such as:VIIRS?Aqua)?
If I want to validate NIR nLw after atmospheric correction,I can only use GOCI?
Thanks for your help!

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OB SeaDAS - knowles
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Level2 Products about Rrs

by OB SeaDAS - knowles » Wed Apr 04, 2018 8:23 am America/New_York

We don't distribute NIR Rrs Level2 products.  However you can create them yourself using SeaDAS.  Rrs can be generated for any of the VIIRS and Aqua bands using SeaDAS l2gen (one of the OCSSW processors).

I don't fully follow the second question, but it may be related to the first question.  To clarify just in case: nLw is atmospherically corrected, Lt is not atmospherically corrected.   Are you saying you are trying to validate Rrs with nLw?   

Danny

hxczjh123
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Level2 Products about Rrs

by hxczjh123 » Thu Apr 05, 2018 4:23 am America/New_York

Danny,
Thank you so much for your help!
Yes,I want to validate Rrs with nlw .
I have other questions when I read some papers:
Wang(2012) developed a NIR atmospheric correction algorithm for GOCI:Atmospheric correction using Near-infrared bands for satellite ocean color data processing in the turbid western Pacific region.
I'm not sure my following understanding is true or not:
This method use SWIR method to derieve nLw at VIS(We take them into initial nLw at VIS).Then calculate Kd(490) based on the relationship between nLw(VIS) and Kd(490).Then calculate nLw(748) and nLw(869) according to paper Wang(2012),so using nLw(748) and nLw(869) then we can derieve aerosol scattering radiance at these two NIR bands and extrapolate to VIS.Finally,we know nLw at VIS.

OB SeaDAS - knowles
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Level2 Products about Rrs

by OB SeaDAS - knowles » Thu Apr 05, 2018 9:29 am America/New_York

You are asking a new question in this thread.  You are asking about a paper by Wang(2012). 

You addressed this to me, but I cannot answer this question.  You should either ask Menghua Wang directly or create a new thread and not direct it to me.

We do appreciate being thanked directly, of course.  But if you both thank and add questions in the same post, you run the risk that no one else will try to answer the post since it is personally directed.

Danny

hxczjh123
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Level2 Products about Rrs

by hxczjh123 » Thu Apr 05, 2018 10:52 am America/New_York

Danny,
Thank you so much for your help!

lipeng
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Level2 Products about Rrs

by lipeng » Wed Apr 10, 2019 1:09 am America/New_York

Hello!
    I am using SeaDAS v7.5.3 to process GOCI L1B to get L2 product, I wonder how to choose aer_opt (default '-2')?  It is worth mentioning that the water in my research area is very turbid.

    Another question , what is the relationship between rhos and Rrs in L2 products?

OB.DAAC - SeanBailey
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Level2 Products about Rrs

by OB.DAAC - SeanBailey » Thu Apr 11, 2019 8:29 am America/New_York

aer_opt=<your selection>
If your selection is the default, you don't need to do anything.

Rrs is remote sensing reflectance, Lw/Es while rhos is Rayleigh (and gas)-corrected "surface" reflectance and so it includes aerosols.

Sean

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