Hi Stephen,
thanks, that is clear. There may be an issue with the CF standard name ... we usually have "integral_wrt_depth" in the name for such quantities. Perhaps Jonathan or Alison can comment on that,
regards,
Martin
________________________________
From: Stephen Griffies - NOAA Federal <stephen.griffies at noaa.gov>
Sent: 10 June 2018 16:52
To: Juckes, Martin (STFC,RAL,RALSP)
Cc: cf-metadata at cgd.ucar.edu; Jonathan Gregory; Karl Taylor; Pamment, Alison (STFC,RAL,RALSP); Durack, Paul J.
Subject: Re: tendency_of_sea_water_conservative_temperature_expressed_as_heat_content units
Hi,
Thanks for the question.
As discussed in Griffies et al (2016), we request heat and salt budgets to be integrated over the thickness of a grid cell. For the heat budget, this thickness weighting then leads to units of W m-2 rather than W m-3.
There is a good reason to ask for the diagnosed budgets to be integrated over the thickness of a grid cell. Namely, most ocean models have time-dependent grid cell thicknesses. So the only way to ensure budgets can be closed with offline diagnostics is to have each model perform the thickness weighting online.
Make sense?
Best,
Stephen
On Sun, Jun 10, 2018 at 9:58 AM, Martin Juckes - UKRI STFC <martin.juckes at stfc.ac.uk<mailto:martin.juckes at stfc.ac.uk>> wrote:
Dear Jonathan, Stephen, Karl,
I'm puzzled by the units of the CMIP6 variable ocontemptend and teh associated standard name tendency_of_sea_water_conservative_temperature_expressed_as_heat_content -- in the data request and the standard name table respectively with units "W m-2". This is consistent with the Griffies et al 2016 paper on ocean diagnostics and with the discussion on the CF mailing list. However, it is requested as a function of depth, so I would expect to see units of "W m-3" for the tendency of a heat density.
The units "W m-2" are usually used for a surface heat flux. There are a number of variables related to ocontemptend with the same units.
Am I missing something, or should we change the units or the depth dependency?
regards,
Martin
--
Dr. Stephen M. Griffies
NOAA Geophysical Fluid Dynamics Lab
201 Forrestal Road
Princeton, NJ 08542
USA
Received on Sun Jun 10 2018 - 11:52:18 BST
