[CF-metadata] Clarifications on some radiation and carbon flux terms

From: Martin Juckes - UKRI STFC <martin.juckes>
Date: Fri, 15 Mar 2019 14:21:49 +0000

Hello All,


I've been reviewing some of the flux terms used for CMIP6, and have a few questions:


(1) downward_heat_flux_at_ground_level_in_snow:

What does "at_ground_level" mean on an ice sheet? The description says "ground_level means the land surface (beneath the snow and surface water, if any)". If "ground_level" is beneath a km of ice, "ground_level_in_snow" does not really make sense, does it? Does it mean the heat flux at the lower boundary of the snow pack into the ice or solid earth? The corresponding CMIP6 variable, hfdsnb, is intended to have this meaning.


(2) surface_snow_and_ice_melt_heat_flux [W m-2]

Is this a flux into the atmosphere, or a flux into the column of snow and ice? The intention for the CMIP6 variable hfmlt is a little unclear.


(3) surface_net_downward_mass_flux_of_ ... [kg m-2 s-1]

There are 4 terms, e.g. surface_net_downward_mass_flux_of_carbon_dioxide_expressed_as_13C_due_to_all_land_processes, which refer to the "net_downward" mass flux. Most carbon mass flux terms simply refer to the downward mass flux (e.g. surface_downward_mass_flux_of_carbon_dioxide_expressed_as_carbon). "net" is included in radiation terms to avoid confusion with upwelling and downwelling fluxes, but the usage here with a mass flux appears anomalous. Should this be shortened (slightly) to surface_downward_mass_flux_of_carbon_dioxide_expressed_as_13C_due_to_all_land_processes?


regards,

Martin
Received on Fri Mar 15 2019 - 08:21:49 GMT