Jonathan:
Thanks for taking the time to reply.
Some of the algorithms that generate our level 2 products using hyper spectral observation data are sensitive to the solar zenith angle. For these products, variables capturing the percentage of the product image in day, night, and twilight (i.e. terminator region) are included in the product.
Your counter-proposal to have a single standard name of area_fraction_of_solar_zenith_angle is fine. This form could be useful for area fractions of other angles, such as platform zenith angle.
As far as a definition goes, how about:
fraction of horizontal area resulting from the projection of the solar zenith angle. A
coordinate variable of solar_zenith_angle with boundaries indicating the
angular extent must be specified.
very respectfully,
randy
On Jan 3, 2014, at 11:53 AM, Jonathan Gregory <j.m.gregory at reading.ac.uk> wrote:
> Dear Randy
>
> Thanks for this proposal. If I understand it correctly, you divide time (and
> hence area) into day, night and something intermediate (twilight, I suppose).
> Since you have to define these three in terms of solar zenith angle, maybe it
> would be simpler to have just one standard_name. Looking at the guidelines, I
> think this quantity could reasonably be called
> probability_distribution_of_solar_zenith_angle
> with a coordinate of solar_zenith_angle as you say, but perhaps "probability"
> doesn't convey the right impression in this case. It could be called
> area_fraction_as_a_function_of_solar_zenith_angle
> We haven't used the phrase as_a_function_of before, although it's a common
> phrase, so I'm wondering if there is something we have used before that would
> convey the same meaning. Perhaps simply
> area_fraction_of_solar_zenith_angle
> would work?
>
> Best wishes
>
> Jonathan
>
>> I would like to propose the following three standard names in support of
>> our environmental products generated from observation data.
>>
>> day_area_fraction
>>
>> "X_area_fraction" means the fraction of horizontal area occupied by X.
>> "X_area" means the horizontal area occupied by X within the grid cell. A
>> coordinate variable of solar_zenith_angle with boundaries indicating the
>> day extent should be specified.
>>
>>
>>
>> night_area_fraction
>>
>> "X_area_fraction" means the fraction of horizontal area occupied by X.
>> "X_area" means the horizontal area occupied by X within the grid cell. A
>> coordinate variable of solar_zenith_angle with boundaries indicating the
>> night extent should be specified.
>>
>>
>>
>> day_night_terminator_area_fraction
>>
>> "X_area_fraction" means the fraction of horizontal area occupied by X.
>> "X_area" means the horizontal area occupied by X within the grid cell. A
>> coordinate variable of solar_zenith_angle with boundaries indicating the
>> terminator extent should be specified.
>>
>>
>>
>> happy new year !
>>
>> very respectfully,
>>
>> randy
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
____________________________________
Randy C. Horne (rhorne at excaliburlabs.com)
Principal Engineer, Excalibur Laboratories Inc.
voice & fax: (321) 952.5100
url:
http://www.excaliburlabs.com
Received on Fri Jan 03 2014 - 10:35:52 GMT
