Re: [CF-metadata] new standard_name needed for cloud_phase (an enumeration type) - GOES-R
Dear Michael, Thank you for your reply - I will update the definition of the existing name as discussed. I am just about to start the standard name table update and this change will be included. Hopefully we can finalise the remaining six GOES-R names in time for the next update which will take place in September. Best wishes, Alison -- Alison Pamment Tel: +44 1235 778065 Centre for Environmental Data Analysis Email: alison.pamm...@stfc.ac.ukmailto:j.a.pamm...@rl.ac.uk STFC Rutherford Appleton Laboratory R25, 2.22 Harwell Oxford, Didcot, OX11 0QX, U.K. From: CF-metadata [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Carlomusto, Michael Sent: 07 July 2015 16:45 To: cf-metadata@cgd.ucar.edu Subject: Re: [CF-metadata] new standard_name needed for cloud_phase (an enumeration type) - GOES-R On 7 July 2015 - Reply by Mike Carlomusto: Alison, I agree with your assessment - the proposed standard name cloud_phase_category and the existing standard name thermodynamic_phase_of_cloud_water_particles_at_cloud_top are redundant. Your proposed addition of three values - clear_sky, super_cooled_liquid_water and unknown - to thermodynamic_phase_of_cloud_water_particles_at_cloud_top is an excellent solution and acceptable for the GOES-R Cloud Top Phase product. Mike On 3 July 2015 Alison Pamment wrote: Thread new standard_name needed for cloud_phase (an enumeration type) (http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2013/056424.html) Current status: Under discussion. cloud_phase_category (canonical units: 1) 'Cloud phase category is a string, taking one of the following standardised values: clear_sky, liquid_water, super_cooled_liquid_water, mixed_phase, ice, unknown. For a data variable it is encoded as an integer using flag_values and flag_meanings.' This name received some brief discussion on the mailing list and was agreed at the time. However, I was looking through existing names whose definitions also refer to flag_values and flag_meanings because I wanted to check that the wording of the proposed definition is broadly consistent. In doing so I came across the name thermodynamic_phase_of_cloud_water_particles_at_cloud_top, introduced into the standard name table at Version 24 (June 2013), for use with Meteosat Second Generation (MSG) data. The existing name is defined as follows: ' cloud_top refers to the top of the highest cloud. Water means water in all phases. A variable with the standard name of thermodynamic_phase_of_cloud_water_particles_at_cloud_top contains integers which can be translated to strings using flag_values and flag_meanings attributes. Alternatively, the data variable may contain strings which indicate the thermodynamic phase. These strings are standardised. Values must be chosen from the following list: liquid; ice; mixed.' Although the list of standardised values is not the same as proposed for GOES-R, I think the existing name is basically the same quantity as the one requested. My suggestion is that, instead of adding the new name, we expand the definition of the existing name to allow for all the strings needed for both MSG and GOES-R data, as follows: ' cloud_top refers to the top of the highest cloud. Water means water in all phases. A variable with the standard name of thermodynamic_phase_of_cloud_water_particles_at_cloud_top contains integers which can be translated to strings using flag_values and flag_meanings attributes. Alternatively, the data variable may contain strings which indicate the thermodynamic phase. These strings are standardised. Values must be chosen from the following list: liquid; ice; mixed; clear_sky; super_cooled_liquid_water; unknown.' The standardised strings for liquid_water and mixed_phase would be slightly different from those agreed in the discussion of the current proposal, but if the names are to be combined I think we would need to stick with the earlier strings so as not to invalidate existing MSG data. Expanding the list of standardised strings would not affect existing data as I don't think there is any requirement to use all possible values of flag_values and flag_meanings within a particular data variable. One of the reasons for using standard names in CF is to avoid accidental duplication of quantities with the same meaning but different names, so I think that expanding the existing definition is the right way to go. Do you agree? Michael Carlomusto mcarl...@harris.commailto:mcarl...@harris.com Harris Corp. Government Communications Systems Division (GCSD), GOES-R Ground System Melbourne, FL, USA (321) 309-7905 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] new standard_name needed for cloud_phase (an enumeration type) - GOES-R
On 7 July 2015 - Reply by Mike Carlomusto: Alison, I agree with your assessment - the proposed standard name cloud_phase_category and the existing standard name thermodynamic_phase_of_cloud_water_particles_at_cloud_top are redundant. Your proposed addition of three values - clear_sky, super_cooled_liquid_water and unknown - to thermodynamic_phase_of_cloud_water_particles_at_cloud_top is an excellent solution and acceptable for the GOES-R Cloud Top Phase product. Mike On 3 July 2015 Alison Pamment wrote: Thread new standard_name needed for cloud_phase (an enumeration type) (http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2013/056424.html) Current status: Under discussion. cloud_phase_category (canonical units: 1) 'Cloud phase category is a string, taking one of the following standardised values: clear_sky, liquid_water, super_cooled_liquid_water, mixed_phase, ice, unknown. For a data variable it is encoded as an integer using flag_values and flag_meanings.' This name received some brief discussion on the mailing list and was agreed at the time. However, I was looking through existing names whose definitions also refer to flag_values and flag_meanings because I wanted to check that the wording of the proposed definition is broadly consistent. In doing so I came across the name thermodynamic_phase_of_cloud_water_particles_at_cloud_top, introduced into the standard name table at Version 24 (June 2013), for use with Meteosat Second Generation (MSG) data. The existing name is defined as follows: ' cloud_top refers to the top of the highest cloud. Water means water in all phases. A variable with the standard name of thermodynamic_phase_of_cloud_water_particles_at_cloud_top contains integers which can be translated to strings using flag_values and flag_meanings attributes. Alternatively, the data variable may contain strings which indicate the thermodynamic phase. These strings are standardised. Values must be chosen from the following list: liquid; ice; mixed.' Although the list of standardised values is not the same as proposed for GOES-R, I think the existing name is basically the same quantity as the one requested. My suggestion is that, instead of adding the new name, we expand the definition of the existing name to allow for all the strings needed for both MSG and GOES-R data, as follows: ' cloud_top refers to the top of the highest cloud. Water means water in all phases. A variable with the standard name of thermodynamic_phase_of_cloud_water_particles_at_cloud_top contains integers which can be translated to strings using flag_values and flag_meanings attributes. Alternatively, the data variable may contain strings which indicate the thermodynamic phase. These strings are standardised. Values must be chosen from the following list: liquid; ice; mixed; clear_sky; super_cooled_liquid_water; unknown.' The standardised strings for liquid_water and mixed_phase would be slightly different from those agreed in the discussion of the current proposal, but if the names are to be combined I think we would need to stick with the earlier strings so as not to invalidate existing MSG data. Expanding the list of standardised strings would not affect existing data as I don't think there is any requirement to use all possible values of flag_values and flag_meanings within a particular data variable. One of the reasons for using standard names in CF is to avoid accidental duplication of quantities with the same meaning but different names, so I think that expanding the existing definition is the right way to go. Do you agree? Michael Carlomusto mcarl...@harris.commailto:mcarl...@harris.com Harris Corp. Government Communications Systems Division (GCSD), GOES-R Ground System Melbourne, FL, USA (321) 309-7905 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] new standard_name needed for cloud_phase (an enumeration type)
Jonathan: Answering your questions… (1) clear_sky instead of clear is fine. (2) super_cooled_liquid_water is a subset of liquid_water. Thus, the definition you have suggested for: standard_name: cloud_phase_category with definition: The variable is a string, taking one of the following values to indicate cloud phase category: clear_sky, liquid_water, super_cooled_liquid_water, mixed_phase, ice, unknown. For a data variable it is encoded as an integer using flag_values and flag_meanings. is fine. very respectfully, randy On Apr 19, 2013, at 8:22 AM, Jonathan Gregory wrote: Dear Randy We are planning on using flags with numeric values as you suggest Your input is helpful in that is is deemed unnecessary to specifically identify values in the definition as is the case with the binary_masks, This provides additional flexibility to data producers. Yes, exactly. standard_name: cloud_phase_category definition: A numeric value indicating one of the following categories: clear; liquid water; super-cooled liquid water; mixed phase; ice, and; unknown. But it would be a string-valued quantity in principle, although netCDF does not allow string-valued data variables. I think the definition should say The variable is a string, taking one of the following values to indicate cloud phase category: clear_sky, liquid_water, super_cooled_liquid_water, mixed_phase, ice, unknown. For a data variable it is encoded as an integer using flag_values and flag_meanings. Comments on the values: * clear_sky is a phrase already used in standard names. Could you use it here for consistency? * Is super_cooled_liquid_water a subset of liquid_water? If not, could you give an extra adjective to liquid_water to clarify this? Cheers Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata Randy C. Horne (rho...@excaliburlabs.com) Principal Engineer, Excalibur Laboratories Inc. voice fax: (321) 952.5100 url: http://www.excaliburlabs.com ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] new standard_name needed for cloud_phase (an enumeration type)
Jonathan: We are planning on using flags with numeric values as you suggest Your input is helpful in that is is deemed unnecessary to specifically identify values in the definition as is the case with the binary_masks, This provides additional flexibility to data producers. Revising the proposal per your recommendation … standard_name: cloud_phase_category definition: A numeric value indicating one of the following categories: clear; liquid water; super-cooled liquid water; mixed phase; ice, and; unknown. very respectfully, randy On Apr 19, 2013, at 5:59 AM, Jonathan Gregory wrote: Dear Randy There is another way to do it, which makes the files more self-describing and has been suggested for other similar situations. You could instead define the standard_name for a new string-valued quantity such as cloud_phase_category, but store the data in the file in numeric form using flag_values and flag_meanings. Then you don't have to standardise the actual numbers used. I suppose that the permitted strings should be part of the definition of the standard name (instead of defined numerical values). Best wishes Jonathan - Forwarded message from rho...@excaliburlabs.com rho...@excaliburlabs.com - From: rho...@excaliburlabs.com rho...@excaliburlabs.com To: cf-metadata@cgd.ucar.edu Date: Thu, 18 Apr 2013 18:05:09 -0400 Subject: [CF-metadata] new standard_name needed for cloud_phase (an enumeration type) Folks: The GOES-R ground system is generating a cloud phase quantity. This is derived from the imager aboard the geostationary satellite. The quantity can take on six value (i.e. it is an categorical / enumeration type) where each value defines a different cloud phase category - Clear(0), liquid water(1), super-cooled liquid water(2), mixed phase(3), ice(4), unknown(5). I looked through the current CF standard_name table and could not find any enumeration types other than the binary_masks. Here is a first cut at a proposal that generally follows the existing binary_mask standard_names: standard_name: cloud_phase_category definition: X_category has six categories where 0=clear, 1=liquid water, 2=super-cooled liquid water, 3=mixed phase, 4=ice, and 5=unknown. very respectfully, randy ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata - End forwarded message - ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata Randy C. Horne (rho...@excaliburlabs.com) Principal Engineer, Excalibur Laboratories Inc. voice fax: (321) 952.5100 url: http://www.excaliburlabs.com ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] new standard_name needed for cloud_phase (an enumeration type)
Dear Randy We are planning on using flags with numeric values as you suggest Your input is helpful in that is is deemed unnecessary to specifically identify values in the definition as is the case with the binary_masks, This provides additional flexibility to data producers. Yes, exactly. standard_name: cloud_phase_category definition: A numeric value indicating one of the following categories: clear; liquid water; super-cooled liquid water; mixed phase; ice, and; unknown. But it would be a string-valued quantity in principle, although netCDF does not allow string-valued data variables. I think the definition should say The variable is a string, taking one of the following values to indicate cloud phase category: clear_sky, liquid_water, super_cooled_liquid_water, mixed_phase, ice, unknown. For a data variable it is encoded as an integer using flag_values and flag_meanings. Comments on the values: * clear_sky is a phrase already used in standard names. Could you use it here for consistency? * Is super_cooled_liquid_water a subset of liquid_water? If not, could you give an extra adjective to liquid_water to clarify this? Cheers Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
