ESM working group: Meeting notes 2024

Earth System Working Group
, ,
22

Date: 11/04/2024

Participants: 13

Apologies: @LaurieM @eunpalim

Chair: @ShayneM

Agenda:

1. Admin

  • @LaurieM has decided to step down as co-chair of the ESM Working Group. Thanks for all the work Laurie has put into establishing this working group.
  • Welcome to our new co-chair @dkhutch!
  • We currently have no volunteers to speak for the next meeting, or any subsequent meetings. Please volunteer to speak. Message @Aidan to discuss.

@spencerwong is willing to talk next (May 9th). @Dietmar_Dommenget on May 23rd.

Would like to have an interesting science talk for every meeting.

2. Shared experiments/ACCESS-NRI resources

  • ESM project lg87 has used 638KSU out of 825KSU allocation.

@Dietmar_Dommenget can use 2MSU.

@AndyHoggANU used time in last quarter. COSIMA used the bulk of the time in the last week. Better off using the quota and ask for more.

@Dietmar_Dommenget can run right now. @AndyHoggANU prepare new ones, talk to @clairecarouge and switch resources in a couple of weeks.

  • 33TB our of 100TB used of quota on /g/data/

@Dietmar_Dommenget Need maybe 10TB. @dkhutch working on archiving process. Can make it much smaller. Only keep what is scientifically relevant. Might need to store for 1 year.

Proposals for experiments for next quarter?

@Dietmar_Dommenget Will give a presentation in 2 weeks. Repeated GFDL experiments with ESM1.5. Looked at second 50 years. Results looked to have similar characteristics to low resolution GFDL. Using idealised basins. Repeating with high resolution model. Not all characteristics. @dkhutch Dietmar has been running them, but we’ve collaborated with the model setup and configuration. Drastically changed land-sea mask and worked ok. Want to reconfigure river-runoff, so not changed in these experiments. Large scale fluxes will be ok, so reasonable for these purposes.

3. Science talk

Andrew King presented “Exploring climate stabilisation at different global warming levels in ACCESS-ESM1.5.”

  • Long simulations run under net-zero CO2 to understand stabilisation processes
  • Address modelling capabilities gap from CMIP6
  • Paris Agreement aims to limit warming well below 2°C about pre-industrial which imply net-zero emissions.
  • Despite this CMIP6 do not address this well to look at implications of missing these targets
  • Experiments to address this gap. Rather than use concentration pathway turn off emissions at different times to achieve different final warming levels
  • Run ACCESS-ESM1.5 simulations to do this. Ran 7 1000 year experiments turning off CO2 increases over 5 year SSP trajectory. Look at how these climates evolve
  • Non-CO2 GHGs are fixed at PI levels
  • CO2 concentrations are determined by interactive carbon cycle, emissions are set to zero, so total CO2 concentration drops
  • The longer we delay achieving net-zero the higher the final land-ocean temperature anomaly
  • SSTs continue to rise slowly. Full Depth ocean heat continues to heat very strongly
  • Sea ice extent different between Arctic and Antarctic. Delaying net-zero reduces arctic sea ice extent. Antartica has continued sea ice extent regardless of time of net-zero emissions, still worse the later it is done
  • Sea-ice free events: arctic is just a function of amount of total warming. Antarctica has a time component also
  • Sea ice extent representation in ESMs is often biased, so caution is needed.
  • Different local responses over land and ocean. Sydney experiences significant additional warming compared to northern hemisphere cities.
  • Significant local temperature and precipitation changes post net-zero, and these grow over time
  • Preprint available:

Lots of discussion! See the video.

4. What’s going on?

@JulieA did you do CMIP6 stratospheric ozone only? @tiloz have to total ozone. LESMIP are extension of CMIP6 runs. Maybe only did ozone runs for LESMIP, not CMIP6. DAMIP ozone only was stratosphere only. Not much SAM response which is intriguing. If thinking tropospheric and stratospheric separately would be great. @sofarrell ESM1.5 is UMv7, might be limited in what is possible.

This is a wiki post , if you want to update any of the details in these meeting notes, or to add your own recollection of what was discussed then edit me rather than replying.