@RachelLaw Could you (or @alexnorton) run the carbon conservation script over (any) of the existing runs, applying it to two months’ output. That should show up if there’s a problem in the STASHC (but does assume that the model is actually conserving).
Actually you don’t even need to do that - just comparing the output and restarts for a December month would show up if the CNP-pools are the same surely?
@inh599 - that was a good suggestion. I have checked the leaf carbon pool from December (confirming it is timestamped with Jan 1 00:00) and it is the same as the leaf carbon pool in the restart file from the same time. This was from an emissions-driven historical case.
This guidance documents on grids may be of use @RachelLaw @rbeucher
I think we are mostly following it already
We talked in the NESP project meeting today about whether to approximate monthly mean CNP pools by interpolating between end of month values and setting up a run to test this. I remembered that I had tried an amip test with monthly output of pools (naively just changing ITIM=20 to ITIM=3 in the STASHC file). I no longer have the original output but it did run for a few years and I have got output for the leaf carbon pool (though not with a correct timestamp). This figure shows example output from one month and one pft (evergreen broadleaf). Top left is the February mean (using ITIM=20), bottom left is the average of the end of Jan and end of Feb output. Top right is the absolute difference (gC/m2) and bottom right is the difference as a fraction, so less than 3%.
Some results from testing nitrogen deposition 2.0 (current runs have been with v1.2). Martin ran a 100 year control run. These plots are GPP (carbon uptake by photosynthesis). The left plot is the difference in 50 year mean between running with Ndep2.0 and Ndep1.2 (the last 50 years of the run). To give an idea of whether the differences are likely related to the change in Ndep, the right plot is the difference between two 50 year periods from the run with Ndep1.2. Given the differences are comparable in magnitude and spatial extent, it looks like any difference due to the change in Ndep is in the noise.
It looks like the ocean carbon fluxes that we put into the atmosphere in an emissions-driven run do not account for land fraction. I’ve described the issue here: Ocean co2 flux applied in atmosphere without accounting for land fraction? · Issue #208 · ACCESS-NRI/UM7.
In practice, this doesn’t change the total flux into the atmosphere by very much, but when fluxes are close to zero in a control run, it can change the sign. If this is a bug, then it would be nice to sort it out now as it would impact all emissions-driven simulations (though likely not seriously).
Good news - we’ve finally got some progress on our EMD submission and have some grid numbers allocated. So far, it is the 3 atmosphere horizontal sub-grids and the atmosphere and land vertical grid. I’ve put the grid numbers into the spreadsheet (first column on HGrid_Subgrids and Vertical Grid sheets) here: EMD_Model_Template_v1.0.xlsx. The numbers weren’t allocated in the order that I put in the issues so I’ve been careful matching them.
Next step is to use the gNNN and vNNN numbers to put issues in the atmosphere and land grids. I also need to start the process applying for gNNN numbers for the ocean sub-grid.
Do you mean GitHub issues to add this to the grid file metadata?
We should also add this grid information to the global metadata that is added to the output files. See Integration with data specifications · Issue #313 · ACCESS-NRI/access-esm1.6-configs · GitHub
@Aidan - what I meant by ‘next step’ is following the sequence here: Submission Guide. So far we’ve managed ‘stage 1’ for the atmosphere grids and ‘stage 2’ for the vertical part of the atmosphere and land grids. I tried to do ‘stage 2’ for the horizontal atmosphere grid, but the issue submission has pull down menus for the gNNN numbers that you want to use - but our numbers (g114,g115,g116) aren’t showing up in the pull down menu (yet?). While I wait to see if they appear in the next few days, I need to start ‘stage 1’ for the ocean.
Once we have everything registered, then, yes I assume it will need to go into the metadata for the output, at least post-cmorisation.
