Radiance to Reflectance Algorithm

snap
#1

I was wondering why in the Radiance to Reflectance Processing algorithm there isn’t Sun distance from Earth. I used to know it is a relevant parameter for the conversion to Ref.
Is that an approximation or a different formula from the classic one?

Thanks

Ander

SNAP formula

1 Like
#2

Hi there,
I found this ATDB: https://sentinel.esa.int/documents/247904/349589/OLCI_L2_ATBD_Instrumental_Correction.pdf

They say at some point this: “It also provides the nominal in-band solar irradiance (at reference Sun- Earth distance) that may be used to convert reflectance output by either step 1 or step 2 back to radiance.”

So I guess the Sun distance from Earth is previously included in the calculation of the irradiance.

2 Likes
#3

Thank you really much for your answer!
It was helpfull!

Regards

Ander

#4

Thanks so much, really helpfull.