Dear Jonathan, Thanks again.
On Fri, 2008-08-08 at 18:31 +0100, Jonathan Gregory wrote: > Dear Ian > > We now agree on > > Rename: > > water_flux_into_ocean > water_flux_into_ocean_from_rivers > water_volume_transport_into_ocean_from_rivers > wind_mixing_energy_flux_into_ocean > water_flux_into_ocean_without_flux_correction (proposal agreed with Martina) > > by replacing "ocean" with "sea_water". > > Include Newtonian relaxation in the definitions of water_flux_into_sea_water, > water_flux_out_of_sea_water (T5), water_flux_out_of_sea_ice_and_sea_water > (T3), virtual_salt_flux_into_sea_water (T6). > > New names: > > T1 water_flux_out_of_sea_water_due_to_sea_ice_thermodynamics (kg m-2 s-1) > T3 water_flux_out_of_sea_ice_and_sea_water (kg m-2 s-1) > T4 minus_one_times_water_flux_into_sea_water_from_rivers (kg m-2 s-1) > T5 water_flux_out_of_sea_water (kg m-2 s-1) > T6 virtual_salt_flux_into_sea_water (kg m-2 s-1) > T7 ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity (m) > T8 heat_flux_into_sea_water_due_to_newtonian_relaxation (W m-2) > T9 water_flux_out_of_sea_water_due_to_newtonian_relaxation (kg m-2 s-1) > T10 virtual_salt_flux_into_sea_water_due_to_newtonian_relaxation (kg m-2 s-1) > T11 ocean_rigid_lid_pressure_expressed_as_sea_surface_height_above_geoid (m) > T12 model_level_number_at_base_of_ocean_mixed_layer_defined_by_sigma_theta (1) > T13 depth_at_maximum_upward_derivative_of_sea_water_potential_temperature (m) > T15 > integral_of_sea_water_potential_temperature_wrt_depth_expressed_as_heat_content > (J m-2) > T17 sea_ice_albedo (1) > U2 bolus_sea_water_x_velocity (m s-1) > U3 x_derivative_of_ocean_rigid_lid_pressure (N m-3) > V2 bolus_sea_water_y_velocity (m s-1) > V3 y_derivative_of_ocean_rigid_lid_pressure (N m-3) > G4 angle_of_rotation_from_east_to_x (degree) > G5 angle_of_rotation_from_east_to_y (degree) > G6 cell_area (m2) > G7 model_level_number_at_sea_floor (1) > Agreed. > Diffusivities: > > You pointed out Martina's proposed ocean_vertical_tracer_diffusivity and we > also have atmosphere_heat_diffusivity and atmosphere_momentum_diffusivity. > Hence I think we should have ocean, not sea_water, for consistency. Would you > be happy with > > W2 ocean_vertical_heat_diffusivity (m2 s-1) > W3 ocean_vertical_tracer_diffusivity_due_to_convection (kg m-2 s-1) > W4 ocean_vertical_momentum_diffusivity (m2 s-1) > W5 ocean_vertical_momentum_diffusivity_due_to_convection (m2 s-1) > W6 ocean_vertical_salt_diffusivity (m2 s-1) > W7 vertical_component_of_ocean_xy_tracer_diffusivity (m2 s-1) > They sound good to me. > The distinction atmos/air and ocean/sea_water is a bit tricky. It started with > the best of intentions, because it is "natural" to use atmos/ocean for > large-scale ideas, such as atmos water transport and ocean heat content, and > "natural" to use air/sea_water for small-scale ones like air temperature and > sea-water density. But in the middle there are things like diffusivity where > it is unclear whether they are properties of the substance or the medium. > Thanks - I assumed that was the ocean/sea_water distinction, but as you say, (eddy) diffusivity is neither one thing nor the other. > There's another issue we have not considered in your names or Martina's, that > stress is a tensor, so we might have to become clear about whether "vertical > momentum diffusivity" means the diffusivity is vertical or the momentum is > vertical. At present we do not consider vertical momentum since our models are > hydrostatic. We can cross that bridge when we come to it, if you like; at that > time we could alias the existing names to more precise replacements. I agree. I'd favour something explicit like "zz_component_of_tracer_isopycnal_diffusivity". But let's not worry about it now. > (NB In > W7 I have repositioned the "xy".) > That's fine. > If T2 applies to the open ocean, it needs "where ice_free_sea" in its > cell_methods, as well as its standard name. Without that, it applies to the > whole grid box, both sea-ice and leads. > I see. T2 is defined everywhere, so we won't need to restrict its domain with cell_methods. > T14. I don't think we can have a standard name just to suit stashcodes! > Geopotential height with different vertical coordinates will also get mapped > to a common stash code. > We have to make the translators use a combination of > metadata to translate the stash code, not the standard name alone. So I think > we should stick with plain depth for this. > I think that sounds the right thing to do in the long term, but in the short term why can't we have ocean_isotherm_depth (m) for people to choose if they wish? I think it's a bit of a "special case" for oceanographers, don't you? (I'm not sure how many of them would look at "depth" in a list of variables in a file and say to themselves "I'll just go and check the coordinates to see it this is the isotherm depth"? To me, a 2D field of "depth" would suggest sea-floor depth. And I'd probably ignore it.) And even if you don't like this, I think it would still help in the short term to have ocean_isotherm_depth - we can always revert to "depth" once the metadata machinery is in place to handle it. > G1-3. I like your suggestion of "position", to be defined in these standard > names as a vector in units of distance. Would it be OK to state in the > guidelines that "derivative" is to be understood as "partial derivative"? Yes, I think that's a good idea - something along the lines of "derivative_of_X_wrt_Y | [X]/[Y] | dX/dY (keeping any other independent variables constant, ie the partial derivative if appropriate). > Then > we can have > > G1 magnitude_of_derivative_of_position_wrt_x_coordinate_index (m) > G2 magnitude_of_derivative_of_position_wrt_y_coordinate_index (m) > G3 magnitude_of_derivative_of_position_wrt_model_level_number (m) > That sounds good. So, apart from T14, I think we're agreed. If you can let me know your thoughts on that, I'll set up a final list, with units and definitions, and post it here. Regards and best wishes, Ian. > Best wishes > > Jonathan -- Ian Culverwell B-2-81 Ocean and Sea Ice Modelling Met Office FitzRoy Road Exeter Devon EX1 3PB United Kingdom Tel: +44 (0)1392 884017 Fax: +44 (0)1392 885861 E-mail: [EMAIL PROTECTED] http://www.metoffice.gov.uk Met Office climate change predictions can now be viewed on Google Earth http://www.metoffice.gov.uk/research/hadleycentre/google/ _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
