The first meeting of 2024 will be on 13-March from 9 - 10a. The first half of the meeting will be an invited speaker, Helene Serrousi (Dartmouth Engineering) and the second half will focus on the ISM selection progress.
Invited talk: Helene Serrousi (Dartmouth Engineering), title/abstract below.
Ice Sheet Model selection update
Excluded models
Ranking strategy
Timeline/process
Next meeting (confirm date & call for any agenda items)
Invited Speaker: Helene Serrousi (Dartmouth Engineering) Title:
Evolution of the Antarctic Ice Sheet over the next three centuries from an ISMIP6 model ensemble
Abstract:
The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary effort of CMIP6 (Coupled Model Intercomparison Project-Phase 6) focusing on ice sheets, designed to provide an ensemble of process-based projections of the ice-sheet contribution to sea-level rise over the 21st century. However, the behavior of the Antarctic Ice Sheet (AIS) beyond 2100 remains largely unknown: several instability mechanisms can develop on longer time scales, potentially destabilizing large parts of AIS.
Projections of AIS evolution until 2300 are presented here, using an ensemble of 16 ice-flow models and forcing from global climate models. Under high-emission scenarios, the Antarctic sea-level contribution is limited to less than 30 cm sea-level equivalent (SLE) by 2100, but increases rapidly thereafter to reach up to 4.4 m SLE by 2300. Simulations including ice-shelf collapse lead to an additional 1.1 m SLE on average by 2300, and can reach 6.9 m SLE. Widespread retreat is observed on that timescale in most West Antarctic basins, leading to a collapse of large sectors of West Antarctica by 2300 in 30-40% of the ensemble. While the onset date of retreat varies among ice models, the rate of upstream propagation is highly consistent once retreat begins. Calculations of sea-level contribution including water density corrections lead to an additional ~10% SLE and up to 50% for contributions accounting for bedrock uplift in response to ice loading. Overall, these results highlight large sea-level contributions from the AIS and suggest that the choice of ice sheet model remains the leading source of uncertainty in multi-century projections.
Bio:
Helene Seroussi is an Associate Professor at Dartmouth College. Her research interests are focused on better understanding and explaining ongoing changes of the ice sheets, as well as reducing uncertainties in the ice sheet contribution to sea level rise by combining numerical models with remote-sensing and in-situ observations. She is one of the co-founders and main developers of the Ice-sheet and Sea-level System Model (ISSM) and a member of the scientific committee of ISMIP6.
Apologies for the late notice - No CMWG meeting tomorrow (9-Apr) but please stay tuned for more details on the Ice Sheet Model Community Assessment process.
Please join us for the next CMWG meeting on Wed 5 June at 3-4p AEST. We have an invited speaker - Florence Colleoni (OGS) for the second half of the meeting.
We have a new Hive option to add this event to your calendar (links below). However, @fmccormack still also has the calendar invite (contact her if you’d like to be added to that).
mtetley
(Mike Tetley, ACCESS-NRI Ice Sheet Modelling Team Lead)
16
Hi all,
Two reminders for the upcoming ACCESS-NRI Community workshop!
Reminder 1: ACCESS Training Day survey
Tell us what you want to learn at the 2024 ACCESS Workshop Training Day! Fill out this (very) short form!
This will help the User Training team organize the most relevant and useful content for you!
mtetley
(Mike Tetley, ACCESS-NRI Ice Sheet Modelling Team Lead)
17
Hi all, just a reminder that abstract submissions for the ACCESS Community Workshop 2024 close this coming Sunday 28 July 2024 at midnight (AEST).
We welcome submissions that focus on scientific and technical areas related to ACCESS use, model development and model and data integration. The program committee will prioritise scientific or technical talks that would be of interest to the broader community.
If you would like to be considered for an oral presentation (which can be either a 10+ min talk or a 1-2 min lightning talk + poster, please fill out the abstract submission form before Sunday. All poster-only submissions (i.e. those without an associated oral presentation) will be automatically accepted when workshop general registrations close on Sunday 21 August 2024.
Our next CMWG meeting will be held from 4-5 pm on Wednesday 31st July. Please note the time change: this will be our default time going forward, every 4 weeks, unless we have overseas speakers from different time zones.
This week we will be focussing on discussing an ice sheet model recipe book, similar to the COSIMA cookbook. So please bring your ideas on analyses that would be helpful for ice sheet modelling and be prepared for some discussions.
Thanks,
Felicity
1 Like
mtetley
(Mike Tetley, ACCESS-NRI Ice Sheet Modelling Team Lead)
19
EOI: Hosting ACCESS-NRI Ice Sheet Modelling team
Expressions of interest are invited from ACCESS-NRI partners to host one of two fully-funded, 3 year positions. Forming part of the ACCESS-NRI Ice Sheet Modelling (ISM) team led by Mike Tetley, the hosted positions will work closely with both their respective host institution research teams and the ACCESS-NRI ISM team. They will help to introduce, develop and integrate the Ice-sheet and Sea-level System Model (ISSM) into the ACCESS model suite. Ultimately, the hosted positions will contribute to coupling ISSM with both ACCESS-OM3 and AM3 models, with the overarching objective to include ISSM within the ACCESS-ESM3 model.
Alongside actively contributing to ISSM development, the hosted positions will play an active role within the ACCESS-NRI ISM team through regular participation in team meetings, workshops, training sessions and conferences. In addition, they will contribute to ACCESS-NRI ISM team objectives including the development of an ACCESS-ISSM Cookbook, an ACCESS-ISSM Python API and NCI-optimised ISSM configurations. These positions will play an important role in the successes of the Ice Sheet Modelling team.
Expressions of interest should be coordinated through the ACCESS-NRI Board member of the host institution. For further enquiries, please contact access.nri@anu.edu.au.
Our next CMWG meeting will be held from 9-10 am on Wednesday 28th Aug. Our invited speaker, Prof Mathieu Morlighem, will give talk at 9:30 - 10 am.
Invited Speaker: Prof Mathieu Morlighem (Dartmouth Engineering) Title: Using observations to constrain ice sheet numerical models: can they capture recent trends?
Abstract:
Accurately projecting mass loss from ice sheets is critical to help societies best prepare for future changes in sea level. Despite tremendous improvements, several recent studies highlight that the agreement between models and the observational record remains poor. The inability of numerical models to reproduce observations raises concerns about their ability to provide accurate projections. Data assimilation approaches are great tools to infer unknown parameters by minimizing the misfit between model and observations. Inversions have been used in glaciology since the 1990s, but only for a given point in time. These “snapshot inversions” are routinely used to infer unknown parameters, such as basal friction, but they do not take advantage of the time series of observations to which we have access today. The advent of Automatic Differentiation and its recent integration in the Ice-sheet and Sea-level System Model (ISSM) makes it possible to assimilate almost any type of data using time dependent models. Here we discuss recent developments that allow to infer high resolution sensitivity maps and to apply transient calibration. We apply these approaches to the Amundsen Sea Embayment and Northwest Greenland using surface velocities from MEaSUREs and ITS_LIVE, and surface altimetry data from Cryosat and ICESat-2. We assess the performance of transient compared to snapshot calibrations in terms of capturing past and current trends in speed change, thinning, grounding line retreat, and mass change. We then compare future projections over the next 100 years. This exercise paves the way to future modeling work that makes use of more dense time series to constrain critical model parameters and reduce uncertainty in future sea level rise.
BIO:
Mathieu Morlighem is a Professor in the Department of Earth Sciences at Dartmouth. He is one of the founders and core developers of the Ice-sheet and Sea-level System Model (ISSM). He develops high-resolution numerical models of ice flow at the glacier scale and at the continental scale and investigates poorly constrained physical processes such as iceberg calving or ice-ocean interactions.
Content starts at ~00:25:00 mins in (sorry - Zoom auto-record!)
mtetley
(Mike Tetley, ACCESS-NRI Ice Sheet Modelling Team Lead)
22
Last call: ISM Team Python Specialist applications
Hi everyone!
This is a gentle reminder that applications for the Senior Research Software Engineer (Python Specialist) position within the ACCESS-NRI Ice Sheet Modelling team will officially close on Sunday 22 September @ 23:55 AEST.
The first of three new ISM Team positions, the Python Specialist will focus on developing new tools, workflows, data analysis and modelling capabilities (e.g. Python API, Cookbook, Toolbox, Data Pool etc) to support the integration of the Ice-sheet and Sea-level System Model (ISSM) with the ACCESS climate model suite.
For full position details, see the add on the ANU jobs page here or feel free to get in touch with me via email if you have any questions
Thanks,
Mike
mtetley
(Mike Tetley, ACCESS-NRI Ice Sheet Modelling Team Lead)
23
Hi all,
Please find a link to the recording of this month’s CMWG meeting below.
No CMWG meeting tomorrow (9-Apr) 
CMWG meeting shifted to 3.15p start time today
