[CF-metadata] Final 17 terms for CMIP6 LS3MIP.

From: Martin Juckes - UKRI STFC <martin.juckes>
Date: Thu, 24 May 2018 13:38:36 +0000

Dear All,

there are 17 terms from LS3MIP which require new standard names, covering a broad range of diagnostics. Proposed names are listed below,

regards,
Martin

Albedo [2]

We already have names such as ?soil_albedo? (Soil albedo is the albedo of the soil surface assuming no snow). Two new terms are requested, for canopy and snow
1.1 albc Canopy Albedo [1]
canopy_albedo
"Canopy" means the plant or vegetation canopy. Albedo is the ratio of outgoing to incoming shortwave irradiance.

1.2 albsn Snow and Ice Albedo [1]
Albedo of snow and ice covered surface.
snow_and_ice_albedo
Snow and ice albedo.
-- OR --
This could be handled with existing name surface_albedo and a new area type "snow_or_ice". [Note that "landice" appears to exclude ice on lakes, which may be a significant component of this albedo]

2. Evaporation and transpiration fluxes [3]
Variations on the theme of the existing water_evaporation_flux term.
2.1 ec Interception evaporation [kg m-2 s-1]

water_evaporation_flux_from_canopy_due_to_intersection
?Canopy interception is the precipitation, including snow, that is intercepted by the canopy of a tree and then evaporates from the leaves?, expanding on the existing name water_evaporation_flux_from_canopy

2.2 eow Open Water Evaporation [kg m-2 s-1]

A new term "water_evaporation_flux_from_open_water" would work here, but it might make more sense to define an area type for open water and use the existing standard name "water_evaporation_flux".

2.3 et Total Evapotranspiration [kg m-2 s-1]
?Evapotranspiration? is a new concept to the CF standard names, but appears to be clearly defined.
evapotranspiration_flux
?Evapotranspiration refers to the flux of water into the atmosphere from a combination of transpiration by plants and evaporation from soil and other land surfaces.?

3. Heat fluxes [2]
3.1 hfrs Heat transferred to snowpack by rainfall [W m-2]
A variation of ?temperature_flux_due_to_rainfall_expressed_as_heat_flux_into_sea_water?.

temperature_flux_due_to_rainfall_expressed_as_heat_flux_into_snow_and_ice

3.2 hfsbl Energy of sublimation [W m-2]
Variation of: surface_upward_latent_heat_flux
The definitions of latent heat flux state that the latent heat flux includes sublimation heat flux, so it makes sense to use the same pattern:
surface_upward_sublimation_heat_flux

4. Nudging increments [2]
There are no terms referring to ?nudging increments? in the CF convention, but there are a number referring to ?flux correction?. The following help text is proposed for nudging increments: ?A nudging increment refers to an amount added to parts of the model system. nudging_increment_in_X refers to an increment in quantity X over a time period which should be defined in the bounds of the time coordinate.? These should be encoded with cell_methods ?time: sum? and a bounds variable to give the time over which nudging is summed. The convention requires that, with this construction, the time periods should be contiguous.

4.1 nudgincsm Nudging Increment of Water in Soil Moisture [kg m-2]
nudging_increment_in_mass_content_of_water_in_soil
4.2 nudgincswe Nudging Increment of Water in Snow [kg m-2]
nudging_increment_in_surface_snow_and_ice_amount

5. River in- and out-flow [2]
water_volume_transport_in_river_channel and water_volume_transport_into_sea_water_from_rivers exist. The new variables represent cell averages of river fluxes directed inwards and outwards respectively.
5.1 rivi River Inflow Water flux from upstream [m3 s-1]
river_water_volume_transport_into_cell
'"Cell" refers to a model grid-cell. "River water" refers to the water (liquid and solid) in the fluvial system (stream and floodplain).'

5.2 rivo River Discharge [m3 s-1]
river_water_volume_transport_out_of_cell

6. Roots [1]

6.1 rzwc Root zone soil moisture [kg m-2]
This is a variation on mass_content_of_water_in_soil_layer, but with a layer defined by the presence of roots rather than a coordinate range (cf. ?stratosphere? in atmosphere).

mass_content_of_water_in_root_zone
?The root zone refers to the soil which surrounds the roots of vegetation.?

7. Water fluxes [5]
7.1 qgwr Groundwater recharge from soil layer [kg m-1 s-1]
There are no usage of ?groundwater? in existing CF terms, the following has been suggested in connection with the LS3MIP term dgw: ?Groundwater is the water present beneath Earth's surface in soil pore spaces and in the fractures of rock formations.?
water_flux_from_soil_to_groundwater

7.2 sblnosn Sublimation of the snow free area [kg m-2 s-1]

This is a variation of the CMIP5 variable "sbl" which used the existing term surface_snow_and_ice_sublimation_flux. Here, we just drop "and_ice" to get a term referring to the ice only.
surface_ice_sublimation_flux

7.3 snmsl Water flowing out of snowpack [kg m-2 s-1]
This is a variation of snm [surface_snow_melt_flux], but considering only the component of the flux into soil:

surface_snow_melt_flux_into_soil

7.4 snwc Snow intercepted by the vegetation [kg m-2]

There is an existing term ?canopy_water_amount?, hence:
 canopy_snow_amount

7.5 sw Surface Water Storage (excluding snow) [kg m-2]
The existing term surface_water_amount refers to ?.. the amount on the ground, excluding that on the plant or vegetation canopy?, and "water" is assumed to refer to all phases. There is a term ?land_based_water_amount? under discussion for PMIP which refers to ?This quantity is often known as Terrestrial Water Storage. It includes surface water (water in rivers, wetlands, lakes, snow, vegetation and reservoirs) and subsurface water (soil moisture, groundwater)?.

Assuming that this term is intended to be a variation on the first, surface_water_amount, and the amount includes only liquid phase water (excluding snow and ice):
surface_liquid_water_amount
Received on Thu May 24 2018 - 07:38:36 BST