What does bbs represent?

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sakvaka_env
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What does bbs represent?

Post by sakvaka_env »

Hi,

When the default water model is used (Park & Ruddick 2005), what does the Polymer's output band bbs actually represent?

It is named bbs (backscattering coefficient of suspended solids) in the output without any band description, but it is being optimized in the value range −3 ... 3. However, negative backscattering coefficients are not physically reasonable. Looking at water.pyx, lines 369 ... 387, it seems to be the log base 10 of a parameter named fb in the code, which acts like the concentration of suspended matter in the bio-optic model.

Am I right to suggest that bbs is not actually bbs in the P&R05 model?

Thanks!
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fsteinmetz
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Re: What does bbs represent?

Post by fsteinmetz »

Hello,

Indeed, this parameter is not named properly. The variable name "bbs" was used because in earlier versions of Polymer, another water reflectance model was used (Morel and Maritorena, 2001). This model is still implemented in Polymer, but the default is now PR05.
Your analysis is perfectly correct : this parameter represents the log10 of the parameter fb in (Park & Ruddick 2005), thus I have renamed it to logfb. This modification will be available in Polymer v4.15, to be released very soon.
Cheers, François
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