Feature #444

Smoothing the application of CH4 surface constraints between different months

Added by Jason Williams over 6 years ago. Updated almost 4 years ago.

Target version:
Start date:
Due date:
% Done:


Estimated time:
24.00 h


Past analysis of the CH4 emission estimates available in the chemical budget files shows that for e.g. 50-70S there can be large fluctations between the monthly addition/reduction of CH4, which represents either a pseudo-emission or sink term. This is decoupled from the seasonal varibility in temperatures and photochemical activity (i.e. the strength of the chemical sink term). This is potentially related to differences in the monthly mean measurements at the 6 stations used to construct the yearly-specific surface fields. Therefore so as to introduce less erratic variability the smoothing term introduced for nudging the stratospheric mixing ratios is applied at the surface.

Currently this is coded for the recent past pre-2015.

There needs to be some modifications when moving to future years which apply growth in yearly emission fluxes according the RCP scenarios.


#1 Updated by Philippe Le Sager about 6 years ago

  • Status changed from New to In Progress
  • % Done changed from 30 to 50

I've committed (r335) the code provided by Narcisa for smoothing the nudging term for surface CH4. Have we decided what to do for future years?

#2 Updated by Twan van Noije almost 6 years ago

For the AerChemMIP simulations, it is important to apply a consistent method across the historical and future periods.

#3 Updated by Philippe Le Sager almost 6 years ago

  • Target version set to TM5-MP 2.0

#4 Updated by Twan van Noije over 4 years ago

I think this issue can be closed (see also #978).

#5 Updated by Twan van Noije almost 4 years ago

  • Status changed from In Progress to Resolved

#6 Updated by Twan van Noije almost 4 years ago

  • Status changed from Resolved to Closed

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