ACCESS-ESM1.5 freshwater hosing experiments at 49,000 years ago (ka)

Experiment title:
ACCESS-ESM1.5 freshwater hosing experiments at 49,000 years ago (ka)

To run a freshwater experiment from the 49ka control run (performed by Himadri Saini) by adding a 0.4Sv of freshwater flux in the North Atlantic to simulate the shutdown of the Atlantic Meridional Overturning Circulation (AMOC) during Heinrich event 5.

Scientific motivation:
Heinrich events (HEs) during the Last Glacial Period (LGP) are characterised by events of rapid and massive iceberg discharges from the margins of the Northern Hemisphere ice sheets (mainly the Laurentide) flowing into the North Atlantic Ocean. These HEs were accompanied by a substantial weakening or even a collapse of the AMOC.

A 49ka control simulation with modified boundary conditions (e.g. orbital parameters, greenhouse gas concentrations, vegetation, ice sheets, land-sea mask, topography, and river runoff) has been performed by Himadri Saini and others under the ARC Discovery Project DP220102134 to investigate the climate conditions during the LGP. The AMOC shutdown will be simulated on top of the control simulation to simulate Heinrich event 5, allowing us to better understand climate variability in the Southern Hemisphere and regional Australia in relation to AMOC variability.

Experiment Name: 49ka_fwf

People: Yanxuan Du, Josephine Brown, in collaboration with Himadri Saini, Laurie Menviel and David Hutchinson

Model: ACCESS-ESM1.5

Configuration: 49ka control simulation

Initial conditions: restart year 650 from the 49ka control simulation

Run plan: to apply a constant 0.4 Sv freshwater flux for 300 years and monitor the model response for another 100 years.

Simulation details: Will be run in Q3

Total KSUs required: 440 KSU (400 x 1.1 KSU/yr)

Total storage required: ~4 TB temporary



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