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Bug #23371

Scaling factor for strat. CH4 taken from wrong year?

Added by Andreas Hilboll 6 months ago. Updated 21 days ago.

Status:
Closed
Priority:
Normal
Assignee:
-
Category:
-
Target version:
-
Start date:
12/12/2019
Due date:
% Done:

0%


Description

When I run a simulation for January 2016 (using CB05 without KPP), the run output contains the following lines:

 Stratospheric CH4 year for previous month:         2014
 Stratospheric CH4 year for current month:         2015
 Stratospheric CH4 year for next month:         2015

So it seems to me that the displayed numbers are off by one year: the month previous to Jan 2016 is Dec 2015, and so on.

I don't understand the code in proj/cb05/boundary.F90 enough in order to assess if just the log output is wrong, or if actually the wrong data are being used.

I'm happy to investigate, but if someone with knowledge of this part of the code could help me out here, I would appreciate it.

History

#1 Updated by Twan van Noije 6 months ago

This was done on purpose. As the surface concentrations are used for the scaling, a one-year delay is applied to the stratosphere.

See also https://dev.knmi.nl/issues/978:
"In the stratosphere, zonal mean mixing ratios from the HALOE climatology are scaled based on global annual mean surface mixing ratios from the previous year. This one-year delay between the surface and the stratosphere is in line with the CMIP6 recommendation from Meinshausen et al. (GMDD, 2016)."

#2 Updated by Twan van Noije 6 months ago

The paper by Meishausen has meanwhile been published: https://doi.org/10.5194/gmd-10-2057-2017. The one-year delay between the surface and stratospheric concentrations of CH4 is proposed in Section 4 (see Equation 13).

#3 Updated by Philippe Le Sager 21 days ago

  • Status changed from New to Closed

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