Experiment proposal: Idealised experiments exploring the strength of Atlantic-Pacific interbasin interactions

Earth System Experiments
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Experiment title :bell:: Investigating Mechanisms of Trans-Basin Interactions Between the Tropical Pacific and Atlantic Oceans

Summary :bell:: This experiment investigates the mechanisms of trans-basin interactions between tropical ocean basins. Such connectivity has been linked to the recent cooling trends in the tropical east Pacific, amongst a host of other substantial impacts. However, the Atlantic-Pacific relationship varies across different observational periods as well as among climate models. One hypothesis is that the tropical Atlantic SST climatology relative to the tropical mean SST may significantly influence these trans-basin interactions. Therefore, this experiment is designed to explore how the tropical Pacific responds to long-term tropical Atlantic SST anomalies under warmer or colder tropical Atlantic SST climatology.

Scientific motivation: The experiment aims to investigate the atmospheric responses over tropical Pacific to tropical Atlantic SST anomalies under different background SST climatology in the tropical Atlantic. The climatology is based on a present SST data stored at:

/g/data/access/TIDS/CMIP6_ANCIL/data/ancils/n96e/timeseries_1870-2016/SstSeaIce

Six experiments (3 groups) designed as follows:

Control group:

Observed SST climatology,

Observed SST climatology + tropical Atlantic warm anomalies;

Warm tropical Atlantic group:

Warmer tropical Atlantic SST climatology,

Warmer tropical Atlantic SST climatology + tropical Atlantic anomalies;

Cold tropical Atlantic group:

Colder tropical Atlantic SST climatology,

Colder tropical Atlantic SST climatology + tropical Atlantic anomalies.

This setup allows us to test the Pacific atmospheric responses with different tropical Atlantic relative SST climatology based on the comparisons between the result of different experiments from the same group or different groups.

Experiment Name :bell:: Investigating Mechanisms of Trans-Basin Interactions Between the Tropical Pacific and Atlantic Oceans
People :bell:: Hao Wang and Shayne McGregor
Model: ACCESS-CM2 atmospheric model (UM 10.6)
Configuration: Atmosphere only at this stage ( cz934)
Initial conditions: /g/data/access/access-cm2/cmip6_restarts/bi889/restart/atm/bi889a.da09500101_00
Run plan: Forcing:

Observed SST climatology (1992-2011), or plus imposed tropical Atlantic SST anomalies;

Present-day control with fixed concentrations of GHGs, aerosols and ozone.
Simulation details: Run length: 50 years; Ensemble size: 6 experiments, 1 member per experiment
Total KSUs required :bell:: 600KSU

(Resources needed in total: ~4.6 KSU per simulated year, 4.6 KSU * 50 years * 6 experiments = 1380 KSU; however, we have already completed 35 years of 4 of these experiments
Total storage required :bell:: 7TB
Storage lifetime :bell:: 6 MONTHS
Long term data plan :bell:: Process and stored on k10 and MDSS
Outputs:
Restarts:
Related articles:

Analysis:

Conclusion:

1 Like
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I’m in favour of this :slight_smile:

What’s the difference between “tropical Atlantic warm anomalies” and “tropical Atlantic anomalies” here?

I presume you’ve seen Dave Bi’s Atlantic pacemaker. Is that data useful to combine with this study ?

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Hi Shayne, also as part of the nesp uncharted futures project, @zoegillett27 has recently finished 200 years of an experiment in which the Tropical Atlantic SST variability is replaced with climatology (piControl). We’re happy to discuss further!

1 Like
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Hi Jemma,

Good question, they are the same (tropical Atlantic anomalies = tropical Atlantic warm anomalies). Yes, we are aware of Dave’s experiments. The experiments we have designed may help to explain some of his results, and we may potentially use these moving forward if we carry out similar experiments the coupled model with Pacemaker simulations.

Regards, Shayne