Adding prognostic chlorophyll to WOMBATlite generic tracers

[pearseb]

Changes to light field, light attenuation, phytoplankton growth...

closes #9

[pearseb]

Posting a figure here to show that these updates are stable and that we are getting some expected behaviour in the prognostic chlorophyll, although things are by no means perfect in this intermediate stage of development.

[pearseb]

Hi @dougiesquire and @matt-csiro

I'm happy with the updates here and everything looks good at this intermediate stage. I made some slight changes to:

• the parameter names and values
• the iron stoichiometry
• added some new diagnostics as output (phy growth rates, limitation terms, chlorophyll growth term)

Annual average surface chlorophyll in mg/m3 looks good:

February Air-->sea flux of CO2 looks like this:

And after 3 years the annual mean flux is +0.15 Pg C per year into the ocean.

Depth of the euphotic zone (annual average):

Light limitation term for phytoplankton looks like this:

• In January at the surface

  

• In January in meridional transect through 230ºE

  

Phytoplankton biomass along the same transect at 230ºE looks like: So those small blips of no light limitation at depth are not having any appreciable effect on phytoplankton growth and biomass.

Here is the output of the jobscript for 1 year. Takes 27 minutes to run for 1 year.

              Resource Usage on 2024-10-16 17:48:59:

Job Id: 126924357.gadi-pbs Project: p66 Exit Status: 0 Service Units: 262.24 NCPUs Requested: 288 NCPUs Used: 288
CPU Time Used: 107:48:41
Memory Requested: 1000.0GB Memory Used: 162.26GB
Walltime requested: 02:00:00 Walltime Used: 00:27:19
JobFS requested: 600.0MB JobFS used: 8.16MB

[dougiesquire]

Thanks @pearseb. Once you've pushed your latest changes I can have a (hopefully final) look.

[pearseb]

I've made some additional changes in line with @dougiesquire suggestions above. I also took the opportunity to update the light attenuation scheme so that now we calculate the mean light availability in the grid cell, not just the light at the mid point, which can be different particularly at the surface (although the differences are minor).

I also changed how we calculate the euphotic zone depth so that it is the maximum depth before light is either 1% of incident radiation or the maximum depth before light decreases beneath 1 W/m2.

The model runs well and is producing near identical output to that shown above.