Difference between Rhos and Rrc ?

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madjidh
Posts: 25
Joined: Wed Feb 27, 2019 10:05 am America/New_York

Difference between Rhos and Rrc ?

by madjidh » Wed Jan 13, 2021 8:23 am America/New_York

Hello,

I wonder if there is a difference in what SeaDAS produces as Rhos and Rrc, the Rayleigh corrected reflectance used for FAI/AFAI algorithms.
Can you tell me the formula for both products (if they are different ?)
I would expect :
Rhos = pi * (Lt - Lr) / F0 * mu0, but I am not 100% certain.

Tags:

jared
Posts: 8
Joined: Thu Jul 09, 2020 1:29 pm America/New_York

Difference between Rhos and Rrc ?

by jared » Wed Jan 13, 2021 9:52 am America/New_York

Hello,
  rhos in SeaDAS is calculated from:  pi / F0 / mu0* (Lt/tg_sen/tg_sol - Lr)/tsol/tsen.
  I don't think there is a Rrc product from SeaDAS. For FAI, Rrc= pi / F0 / mu0* (Lt/tg_sen/tg_sol - Lr).

Minwei

madjidh
Posts: 25
Joined: Wed Feb 27, 2019 10:05 am America/New_York

Difference between Rhos and Rrc ?

by madjidh » Thu Jan 14, 2021 8:15 am America/New_York

Hello Minwei thank you,
Sad we can't write proper equations, could you write it with one single fraction please ? It is a bit hard to understand the way you wrote it.

Is it :
( pi * ((Lt / (tg_sen * tg_sen)) - Lr)) / ( F0 * mu0 * tsol * tsen ) ?

Sean wrote, https://oceancolor.gsfc.nasa.gov/forum/oceancolor/topic_show.pl?tid=2229 :
rhos = PI / F0 / mu0  * (Lt / tg_sol / tg_sen - Lr)  / t_sol / t_sen / t_o2 / t_h2o

Has the / t_o2 / t_h2o been removed since ?
Regards

jared
Posts: 8
Joined: Thu Jul 09, 2020 1:29 pm America/New_York

Difference between Rhos and Rrc ?

by jared » Tue Jan 19, 2021 10:26 am America/New_York

sorry for the confusion. It is ( pi * ((Lt / (tg_sen * tg_sen)) - Lr)) / ( F0 * mu0 * tsol * tsen ). 
The / t_o2 / t_h2o is not removed. I don't know the reason for the division of t_o2 and t_h2o but it seems t_o2 only affects band at 765 nm and t_h2o affects sensor SeaWIFS. For the majority of bands (and sensors), t_o2 and t_h2o are unity,  so have no effect.

Minwei

madjidh
Posts: 25
Joined: Wed Feb 27, 2019 10:05 am America/New_York

Difference between Rhos and Rrc ?

by madjidh » Tue Jan 19, 2021 11:47 am America/New_York

Perfect, thank you !

carros
Posts: 1
Joined: Fri Mar 26, 2021 1:42 pm America/New_York

Re: Difference between Rhos and Rrc ?

by carros » Fri Mar 26, 2021 4:46 pm America/New_York

Hi there,

Surface reflectance (rhos) is a product that can be output with SeaDAS.

RRC (Root Raised Cosine) Use of the RRC filtering is adopted in commercial communications, like cellular technology, andused extensively.. its use in space communication is still new

regards

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