Dear Philip and Alison, Philip: Thanks for your valuable comment. This discussion started in November and has been revived last week.
Alison, I think based on Philips comment we can exclude the two standard names which use the defined_by suffix. What do you think? (I thought that these defined_by suffixes were a good way to differentiate between these physical quantities...) >> In your case above, it appears to me that there is only one physical >> quantity, thermodynamic_phase_of_cloud_water_particles_at_cloud_top, but >> multiple ways to try and measure it (that may give different answers because >> of errors and limitations of the measurements). Do you have suggestions on how we could differentiate between these variables in a CF compatible way? In our MSG CPP NetCDF files, should we use the same standard_name for the two different variables? When we use a viewer like IDV for example, how can we see the difference between these variables? I have never tried this in IDV, so I don't know what happens in this case... That is way we would like to have distinguishable standard names. Best regards, Maarten PS, the new list: - platform_zenith_angle; degree - angle_of_rotation_from_solar_azimuth_to_platform_azimuth; degree - thickness_of_liquid_water_cloud; m - effective_radius_of_cloud_condensed_water_particles_at_cloud_top; m - thermodynamic_phase_of_cloud_water_particles_at_cloud_top; 1 On 01/26/2011 02:04 AM, Cameron-smith, Philip wrote: > Hi Maarten, > > Sorry for this last minute reply (I don't think this was addressed before). > My comment relates to the following proposed names: > > - thermodynamic_phase_of_cloud_water_particles_at_cloud_top (status_flag > liquid, ice and mixed): "The thermodynamic phase of particles at the top of > the cloud"; > - > thermodynamic_phase_of_cloud_water_particles_at_cloud_top_defined_by_infrared_radiance > (status_flag liquid, ice and mixed): "The thermodynamic phase of particles at > the top of the cloud derived by using infrared radiances"; > - > thermodynamic_phase_of_cloud_water_particles_at_cloud_top_defined_by_near_infrared_radiance > (status_flag liquid, ice and mixed):" The thermodynamic phase of particles at > the top of the cloud derived by using near-infrared radiances". > > It appears that your use of 'defined_by' may be different than that currently > used by other std_names in CF. > > Specifically, 'defined_by' is currently used for ocean_mixed_layer_thickness, > which can be different depending on which physical quantity is used to > diagnose it (eg, ocean_mixed_layer_thickness_defined_by_temperature, > ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity). To me, > each of these is a different physical quantity. > I presume the same would apply to the atmospheric boundary layer and the > tropopause. > > In your case above, it appears to me that there is only one physical > quantity, thermodynamic_phase_of_cloud_water_particles_at_cloud_top, but > multiple ways to try and measure it (that may give different answers because > of errors and limitations of the measurements). > > Following standard CF practice I think only > thermodynamic_phase_of_cloud_water_particles_at_cloud_top should be added as > a std_name. > > The only argument I can see for making these different physical quantities is > that the definition of 'cloud_top' presumably differs a bit for each > wavelength. Personally I doubt that the difference is great enough to > warrant different std_names, but please correct me if I'm wrong :-). And if > this does warrant different std_names, then the wavelengths will need to be > clearly specified. > > Best wishes, > > Philip > > ----------------------------------------------------------------------- > Dr Philip Cameron-Smith, [email protected], Lawrence Livermore National Lab. > ----------------------------------------------------------------------- > > >> -----Original Message----- >> From: [email protected] [mailto:cf-metadata- >> [email protected]] On Behalf Of [email protected] >> Sent: Monday, January 24, 2011 6:03 AM >> To: [email protected]; [email protected] >> Subject: Re: [CF-metadata] MSG Cloud physical properties codification >> >> Dear Maarten and Jonathan, >> >> Maarten has reminded me that the following names were discussed a few >> weeks ago: >> >> - platform_zenith_angle (degree): "Platform zenith angle is the the >> angle between the line of sight to the platform and the local >> vertical"; >> - angle_of_rotation_from_solar_azimuth_to_platform_azimuth (degree): >> "The angle of rotation between the solar azimuth angle and the platform >> azimuth angle"; >> - thickness_of_liquid_water_cloud (m): "Cloud thickness (cloud top >> height minus cloud base)"; >> - effective_radius_of_cloud_condensed_water_particles_at_cloud_top (m): >> "Particle effective radius for both liquid and ice water particles"; >> - thermodynamic_phase_of_cloud_water_particles_at_cloud_top >> (status_flag liquid, ice and mixed): "The thermodynamic phase of >> particles at the top of the cloud"; >> - >> thermodynamic_phase_of_cloud_water_particles_at_cloud_top_defined_by_in >> frared_radiance >> (status_flag liquid, ice and mixed): "The thermodynamic phase of >> particles at the top of the cloud derived by using infrared radiances"; >> - >> thermodynamic_phase_of_cloud_water_particles_at_cloud_top_defined_by_ne >> ar_infrared_radiance >> (status_flag liquid, ice and mixed):" The thermodynamic phase of >> particles at the top of the cloud derived by using near-infrared >> radiances". >> >> I think these names all follow the pattern of existing names and their >> meanings are generally clear. One question - in your products, are >> 'infrared' and 'near_infrared' separate ranges of >> wavelengths/frequencies? Please could you tell me the ranges so that I >> can include at least indicative values in the explanations of the >> names. For the three status flag names, I suggest that the units >> should be '1', i.e. a dimensionless value, assuming that the variables >> will be accompanied by flag_values and flag_meanings attributes. If we >> can clarify these points then I think the names can be accepted for >> inclusion in the standard name table. >> >> Best wishes, >> Alison >> >> ------ >> Alison Pamment Tel: +44 1235 778065 >> NCAS/British Atmospheric Data Centre Fax: +44 1235 446314 >> STFC Rutherford Appleton Laboratory Email: >> [email protected] >> R25, 2.22 >> Harwell Oxford, Didcot, OX11 0QX, U.K. >> >> >> From: [email protected] [mailto:cf-metadata- >> [email protected]] On Behalf Of Maarten Plieger >> Sent: 30 November 2010 16:49 >> To: Jonathan Gregory >> Cc: [email protected] >> Subject: Re: [CF-metadata] MSG Cloud physical properties codification >> >> Dear Jonathan, >> >> Good point. That is OK with us, off course. Thanks again! >> >> Regards, Maarten >> >> Jonathan Gregory schreef: >> Dear Maarten >> >> Yesterday I didn't notice that these don't have _radiance on the end. I >> think >> that would make them clearer, if OK with you. >> >> >> thermodynamic_phase_of_cloud_water_particles_at_cloud_top_defined_by_in >> frared >> thermodynamic_phase_of_cloud_water_particles_at_cloud_top_defined_by_ne >> ar_infrared >> >> When everybody agrees with these standard names, units and >> descriptions: >> what would be the next step? >> >> Alison will consider them. She is responsible for moderating >> discussions and >> updating the standard name table with agreed additions. >> >> Best wishes >> >> Jonathan >> >> >> >> >> -- >> Maarten Plieger >> KNMI, R&D Information and Observation Technology, De Bilt >> (t) +31 30 2206330 >> -- >> Scanned by iCritical. >> _______________________________________________ >> CF-metadata mailing list >> [email protected] >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > -- Maarten Plieger KNMI, R&D Information and Observation Technology, De Bilt (t) +31 30 2206330 _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
