ESM working group: Meeting notes 2024

Earth System Working Group
, ,
31

Date: 26/9/2024

Participants: 15

Chair: @dkhutch

1. Opening and Welcome:

  • There are no speakers confirmed for future meetings. Please consider presenting, or inviting a colleague to present. Members are encouraged to reach out to Aidan or any co-chair if they are interested in presenting.
  • Future scientific presentations do not need to be fully polished; works in progress or discussion-based topics are welcome.
  • Members were reminded to add any items they want to discuss to the working group agenda via the topic on the forum.

2. Shared experiments/ACCESS-NRI resources

  • ESM project lg87 has used 754 KSU of its 875 KSU allocation for this quarter. /g/data storage steady at 35TB
  • Should be sufficient for current users, doesn’t matter if there is some unused.
  • Any more proposals for shared experiments for next quarter?See guidelines for how to do this. There are often used resources we can access if there are projects to use them.

3. Workshop Feedback

4. Speaker

@YanxuanD: “The impacts of an AMOC slowdown on Australian climate at 8.2 ka in ACCESS-ESM1.5 model”

[Video will be embedded when available]

@YanxuanD presented findings from freshwater forcing experiments simulating the 8.2 Ka event. The experiments aimed to investigate the climate response over Australia under 8.2 Ka climate conditions.

  • Setup: The background state was set by changing orbital parameters and greenhouse gas concentrations, while other forcings remained the same as pre-industrial.
  • Experiments: Included short-duration pulses (1, 5 years) and a time-varying long-term freshwater forcing to simulate the lake outburst hypothesis.
  • Findings:
    - Only the long-term experiment showed a significant weakening of the AMOC for over 160 years.
    - Northern and North Atlantic surface air temperatures decreased significantly, while the South Atlantic experienced significant warming.
    - The AMOC weakening led to a bipolar seesaw effect, with warming in the Southern Hemisphere and cooling in the Northern Hemisphere during recovery.
  • Climate Response Analysis: climate response over Australia and other regions during the AMOC minimum period.
    • Temperature Changes:
      • Significant cooling over Northern Australia and warming over Southern Australia and New Zealand.
      • Widespread warming in the Southern Hemisphere, indicating a bipolar seesaw effect.
    • Precipitation Changes:
      • Strengthened Indo-Australian summer monsoon and increased precipitation over Northern Australia and New Guinea.
      • Slight weakening of westerly winds in Southern Australia with non-significant precipitation changes.
      • ITCZ shifted southward over the Atlantic and Western Pacific during DJF, and weakened across all ocean basins during JJA.
    • Monsoon Analysis:
      • South Asia and East Asia summer monsoons slightly weakened.
      • South American monsoon showed a southward shift with increased precipitation on the eastern side.

5. Other Business:

  • @Aidan Encouraged follow-ups from the workshop and highlighted issue created for offline ocean BGC spin-up and ongoing work on orbital parameter changes.
  • Spencer Wong: Shared progress on implementing capability to specify orbital parameter changes through a namelist, while ensuring consistency with existing simulations. Needs some more testing, but then will be in a position to share with some users to test.

These notes were generated automatically by AI. If you notice any errors or omissions please feel free to modify directly, or message @aidan.

Additional information