Re: [CF-metadata] add_offset for time dimension
Dear John and Benno No, CF doesn't specifically exclude add_offset for coordinate variables, but it only talks about it regarding packing data variables, and in Table A it is listed only as an attribute of data variables, not coordinate variables. I think that's because coordinate variables don't take up so much space anyway so there is not the same need for packing. Best wishes Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
[CF-metadata] CMIP5 carbon cycle standard names
Sorry, one other one which Pierre didn't remark on. This name is rather obscure, even bizarre :-) miscellaneous_living_compartments_carbon_content I wonder if we could convey this meaning any more plainly? What about carbon_content_of_miscellaneous_living_matter ? Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
[CF-metadata] CMIP5 cryosphere standard names
Dear Alison and Siobhan Sorry for late comments on the cryosphere names. I commented this week on shear. I was wrong to suggest that sea ice shear is like wind speed shear, because the latter is the vertical derivative of a horizontal speed, whereas sea ice shear is (I think) a horizontal derivative of a horizontal velocity or speed. I wonder what the quantity required is symbolically? Is it du/dy or dv/dx? These, I think, are two distinct components of a tensor, but I might be wrong. Perhaps the name should be tendency_of_fractional_growth_in_ice_volume_due_to_ridging or tendency_of_fractional_growth_in_ice_area_due_to_ridging. I think we need to call the quantity a tendency because that is the term we normally use in standard names to mean the time rate of change. I agree that it should be a tendency, and I suspect the quantity could be called tendency_of_sea_ice_area_fraction_due_to_ridging which is a contribution to (or perhaps identical with) the existing quantity tendency_of_sea_ice_area_fraction_due_to_dynamics Best wishes Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
[CF-metadata] CMIP5 cryosphere standard names
Dear Alison surface_downward_heat_flux_in_snow; Wm-2 I think there is a need to have distinct surface heat fluxes in the media on either side of the surface because there might be a phase change going on actually at the interface, so there would then be a vertical divergence in heat flux at the interface. 2. sea_ice_surface_temperature; K The CMIP5 long_name for this quantity is 'Temperature at Interface Between Sea Ice and Snow'. I would like to amend my suggestion for this name to be temperature_at_interface_between_sea_ice_and_snow which I think makes the meaning clearer and far less likely to be confused with sea ice temperature at the interface with the atmosphere (which is just surface_temperature). I think I prefer your original suggestion, because there might not be any snow. If all the snow melts, your new quantity seems to become meaningless. However, the sea_ice_surface_temperature still exists, and is identical with the surface_temperature. 3. sea_ice_transport OR sea_ice_transport_across_line; kg s-1 The CMIP5 output document asks for 'Sea Ice Mass Transport Through Fram Strait'. We already have the standard name sea_ice_transport_across_line defined as 'Transport across_line means that which crosses a particular line on the Earth's surface; formally this means the integral along the line of the normal component of the transport.' I am not sure how the Fram Strait transport is defined - is it calculated along a notional line or do we need a more general quantity? I think sea_ice_transport_across_line is sufficiently general. Any application which wants to use it will have to define the line. The exact definition of the line across the Fram Strait in a model will be model-dependent, but the idea is well defined. Best wishes Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] Seeking new CF standard names (9) for sea surface wave parameters
Hello Jonathan, The term 'statistics' has a slightly different meaning for wave data. Essentially, what wave instrumentation does is record vertical displacement of the sea surface at very high frequency for a period of say ten minutes. Spectral analysis techniques are then used to derive 'statistics', such as the period and direction of the most energetic waves, the average height of the highest 1/3 of the displacements (one definition of significant wave height), from the raw spectra. This process is repeated every hour or so. Consequently, the usable data comprise an hourly set of 'statistics' at a given location. Describing the derived values as 'parameterisations' might give a clearer picture of what they represent. I therefore think that these belong in standard names rather than cell methods. Cheers, Roy. -Original Message- From: cf-metadata-boun...@cgd.ucar.edu [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Jonathan Gregory Sent: 17 September 2010 16:22 To: andrew walsh Cc: Patrick Gorringe; cf-metadata@cgd.ucar.edu; Katherine Tattersall; Mark Kulmar; g...@metoc.gov.au; Moninya Roughan; Roger Proctor; Paul Tildesley; Pauline Mak Subject: [CF-metadata] Seeking new CF standard names (9) for sea surface wave parameters Dear Andrew Thanks for your list of wave height names. Although the standard name table already contains some wave quantities which are defined statistically (as you know, such as significant wave height) this larger list makes me wonder if describing the statistics in the standard name remains the right approach. This is not generally what we do in CF. For example, time-mean, maximum and minimum are not indicated in standard names, but by the cell_methods attribute. Is the idea of these quantities that they describe the statistics of wave height observed over a long period at a given location? If so, perhaps we could distinguish them by cell_methods rather than standard_name. Best wishes Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] CMIP5 carbon cycle standard names
Again, OK for me. On 17/09/2010 13:26, Jonathan Gregory wrote: Sorry, one other one which Pierre didn't remark on. This name is rather obscure, even bizarre :-) miscellaneous_living_compartments_carbon_content I wonder if we could convey this meaning any more plainly? What about carbon_content_of_miscellaneous_living_matter ? Jonathan attachment: P_Friedlingstein.vcf___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
