Meeting Minutes 2025: Atmosphere Working Group

Atmosphere Working Group
8

Atmosphere Working Group Meeting 22 October 2025
22 participants on zoom

Charmaine Franklin - LFRIC update

· LFRIC assessment is complete

· ACCESS-A

· next 12 months RAL4 tests.

· Met Office - RAL5 - scale aware convection scheme included. - able to deal with shallow convection at say 4 km resolution.

· Simplified aerosol scheme included.

· Orographic drag representation

· Irrigation scheme - JULES

Matt Woodhouse CSIRO

· with Beck Jackson RNS glomap turned on coupled to CASIM

· improvement in emissions - marine aerosol

· think about incorporating into ACCESS-rAM3.

· can’t run from reanalyses.

· contact Matt if interested in using this setup.

Yi Huang W21C

· 21st Century Weather update

· Global AM3 25 km successfully running, CABLE.

· Flagship - 10 km Australia region, then higher resolution sub domains.

Heidi ACCESS-NRI

· ACCESS-rAM3 latest release RAL 3.3 UM 13.5; anomalous rainfall spin-up in GAL9 nest fixed.

· Looking for alpha testers.

· Feedback by 10 Nov welcomed!

· 2025 ACCESS Workshop feedback - biannual workshops possible, contact Heidi with your thoughts.

· Some expressed satisfaction with current annual format; enjoyed discussions across WGs.

Marcus Thatcher - SHEP

  • Sub-Hourly Extreme Precip (SHEP) Flagship Pilot Study.

  • CORDEX

  • 2-3 year pilot study.

  • Aims - quantify sub hourly events over Australian cities. Projected changes.

  • multi model intercomparison project, Australia/New Zealand.

  • 2 main activities

  • Events to inform climate analysis - few day runs. Validation runs - can events be reproduced? BARRA boundary conditions.

  • Climate.

    • 10 min rainfall as target duration for choosing events.
    • Psuedo global warming experiments

  • Perturbed environments on present day extreme events.

    • 50 TB storage required over 3 years. Is our WG interested in this data for ACCESS-NRI to host data?

  • 3 people expressed interest in the data, amd if space is limited, then then UM data component. ACCESS-NRI need to know if others are interested in using this data.

  • 21st Century Weather will be involved with SHEP

  • Question about domain sizes, potential boundary effects in small domains.

  • Questions about relying on particular schemes and resolutions, different setups - different results.

Shixue Li - ACCESS-AM3

  • Progress in ACCESS-AM3 v4

  • UM + CABLE

  • 20 to 25 km resolution - global. N512

  • mproved convective structures in tropics.

  • Crashing issues. Errors in vertical motion - south pole. high res ozone issues.

  • Model was not told the ozone was 2D.

  • Greenland high humidity issue.

  • Various issues have been overcome. bugs, ozone.

  • Extreme local values at some points in ancil file

  • lakes incorrect in some areas, triggering high temperatures and instability.

  • Need for thorough checks to find and fix issues.

  • n512 18 KSU per month. Optimization has improved efficiency of runs

  • Future next stage is 5 km.

  • negative soil moistures - also found in earlier setups. - could be a particular soil moisture variable that can be negative.

  • Data available on scratch for those interested.

  • Questions about tests to see benefits of global high res.

Heidi - closing

· Please continue discussion on high-res AM3 development in this subsection on the ACCESS-Hive forum

· Meetings for development and evaluation of ACCESS-CM3. Please see this Hive Forum post and slides for more info.

· Apply for working group resources (875 KSU available for Q4). See here for how to apply.

· Next meeting will be held in November, probably Wed 11:30am (not last week of Nov) . Announcement to follow.

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