Dear Philip, Jonathan, Uma, and Martin, being busy with writing a longer reply on Philips thorough review of my proposed standard names, I'd like to make a comment concerning the use of "backscattering" and "backwards_scattering". I proposed hemispheric in "hemispheric_backscattering_coefficient", which is integrated over the rearward hemisphere as measured by some integrating nephelometers, from the "backscattering_coefficient" that isn't integrated over any solid angle (to be proposed soon), e.g. as measured by a lidar. In the examples you mention however, the terms "backscattering" and "backwards_scattering" are both already used for a property integrated over a solid angle. I've pondered over this one quite a while, but I keep coming back to the point that a standardised word for distinguishing angular integrated from non-angular integrated scattering properties is needed - like "hemispheric". That wouldn't be a nice solution, since it implied aliases for 5 existing standard names, but it would be structured and consistent. Any better ideas?
Best regards, Markus -----Original Message----- From: Jonathan Gregory [mailto:[email protected]] Sent: Montag, 12. März 2012 14:14 To: Cameron-smith, Philip Cc: Markus Fiebig; Shankar, Uma; X:[email protected]; [email protected] Subject: Re: [CF-metadata] Duplicate vocabulary attenuation/extinction and backscatterin/backwards_scattering. Dear Philip > 1) _attentuation_ and _extinction_ appear to have the same physical meaning, > although the comments note that attenuation is more commonly used for radar > and extinction is more commonly used for visible light. The number of > std_names using each of them is 2 and 1, respectively, so it should be easy > to fix with aliases. > 2) _backscattering_ and _backwards_scattering_ also appear to have the same > definition. The number of std_names using each of them is 1 and 4, > respectively, so it should be easy to fix with aliases. Although it is less > common, I prefer _backscattering_ because it is a single word, and will > generalize better to _forwardscattering_. These are good points and I tend to agree with you. I am not an expert and if there is a distinction someone will point it out, I hope. If there is no distinction, the reason for the different choices would be because of what is generally said, or from personal preference, I presume. It's a difficult balance between making standard names use familiar terms, or making them use consistent terms, but I would prefer consistency if it is still obviously comprehensible to an expert. Regarding the Mie scattering proposal, again I am not an expert on the science, but I would comment that X_assuming_Y is generally used to indicate what X would be in some hypothetical situation of assuming_Y e.g. surface_albedo_assuming_no_snow which is not, in general, the same as surface_albedo as it truly is (although it is often the same). It does not indicate a method of calculating X and, as you say, we keep that out of standard names, because in principle a method of measurement should not affect the definition of the quantity being measured. Best wishes Jonathan _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
