Düsterhus, Andre and Brune, Sebastian (2023) The effect of initialisation on 20 year multi-decadal climate predictions. Climate Dynamics. ISSN 1432-0894

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Abstract

This study investigates initialised decadal predictions of 2-m air temperature over lead times of up to 20 years and compares them against uninitialised simulations in the time period 1960–2019. We demonstrate that in the North and South Atlantic,as well as in the Northeast Pacific, the effect of initialisation within the prediction persists for longer than 10 lead years. In these regions, the skill of the initialised decadal predictions does not necessarily regress back to the skill of the uninitialised simulations, which is indeed the case for other regions. We analyse the Atlantic Meridional Overturning Circulation (AMOC)and show that within the first 10 years after initialisation, it drifts towards a state, which is different from both the initial state and the state of the uninitialised simulations. We show that the AMOC stays within this new state for at least another 10 years. We find that in our decadal predictions, the correct determination of future external forcings plays an important role on the global scale, while correct initialisation increases prediction skill on the regional scale.

Item Type:	Article
Additional Information:	A.D. is supported by A4 (Aigéin, Aeráid,agus athrú Atlantaigh), funded by the Marine Institute (grant: PBA/CC/18/01). S.B is supported by Copernicus Climate Change Service,funded by the EU, under Contract C3S2-370. We like to thank Holger Pohlmann for the discussions. All simulations were performed with the facilities at and the help of the staff of the German Climate Computing Centre (DKRZ). Data from the RAPID AMOC monitoring project isfunded by the Natural Environment Research Council and are freelyavailable from www. rapid. ac. uk/ rapid moc.
Keywords:	Decadal climate prediction; Atlantic meridional overturning circulation; Initialisation;
Academic Unit:	Faculty of Social Sciences > Research Institutes > Irish Climate Analysis and Research Units, ICARUS
Item ID:	17621
Identification Number:	https://doi.org/10.1007/s00382-023-06941-1
Depositing User:	Corinne Voces
Date Deposited:	02 Oct 2023 09:14
Journal or Publication Title:	Climate Dynamics
Publisher:	Springer Verlag
Refereed:	Yes
Funders:	Marine Institute, Copernicus Climate Change Service
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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