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zenith angle of observation

Posted: Wed Jun 12, 2019 12:10 pm America/New_York
by yonisherman
Hi all,
I am trying to follow along with the calculations presented in Hout et al 2009 (nflh and quantum yield of fluorescence).
I am not entirely sure which data product represents the zenith angle of observation needed to calculate the upwelling radiance due to fluorescence.
Is this the csol_z values in the scan line attributes? or is sena/senaz?
Thank you,

Jonathan

zenith angle of observation

Posted: Wed Jun 12, 2019 12:32 pm America/New_York
by gnwiii
You can find "long" names of most level-2 data elements in the NetCDF4-CF metadata or in $OCSSWROOT/share/common/product.xml if you have the OCSSW software installed.

zenith angle of observation

Posted: Wed Jun 12, 2019 1:25 pm America/New_York
by yonisherman
Thank you for the response.
A far as I can tell from previously doing this I have looked at the long names, so I "know" what csol_z is (not the other two), but I guess for my question, I am not sure if that is in fact the value I need.
I am relying on the following quote from Huot et al 2009
"...In the remainder of this paper the dependence on ?em= 678 nm is implicit. This description is valid for nadir viewing; for non-nadir viewing conditions,  af is replaced by af/cos(?), where ? is the zenith angle of observation in water(as defined in Morel and Gentili 1996)..."

Jonathan

zenith angle of observation

Posted: Thu Jun 13, 2019 10:02 am America/New_York
by OB.DAAC - SeanBailey
Jonathan,

The csol_z data set in the scan_line_attributes group is a solar zenith angle for the center of the scan - has nothing to do with "zenith angle of observation".
We don't output the sensor zenith angle in our standard products.  To get that you would have to process from L1 and include "senz" in the list of output products.
...and then play with Fresnel to transfer the angle to in water.

BTW, I think you mean Huot et al., 2005... :grin:

Sean

zenith angle of observation

Posted: Thu Jun 13, 2019 10:19 am America/New_York
by yonisherman
Thank you for the answer.
I will do some l1 processing and play with the data, and yes Huot 2005 :)
Jonathan