Improving interpretation of sea-level projections through a machine-learning-based local explanation approach

Process-based projections of the sea-level contribution from land ice components are often obtained from simulations using a complex chain of numerical models. Because of their importance in supporting the decision-making process for coastal risk assessment and adaptation, improving the interpretabi...

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Bibliographic Details
Published in:The Cryosphere
Main Authors: Rohmer, Jeremy, Thieblemont, Remi, Le Cozannet, Goneri, Goelzer, Heiko, Durand, Gael
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2022
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Online Access:https://doi.org/10.5194/tc-16-4637-2022
https://noa.gwlb.de/receive/cop_mods_00063336
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00062406/tc-16-4637-2022.pdf
https://tc.copernicus.org/articles/16/4637/2022/tc-16-4637-2022.pdf
Description
Summary:Process-based projections of the sea-level contribution from land ice components are often obtained from simulations using a complex chain of numerical models. Because of their importance in supporting the decision-making process for coastal risk assessment and adaptation, improving the interpretability of these projections is of great interest. To this end, we adopt the local attribution approach developed in the machine learning community known as “SHAP” (SHapley Additive exPlanations). We apply our methodology to a subset of the multi-model ensemble study of the future contribution of the Greenland ice sheet to sea level, taking into account different modelling choices related to (1) numerical implementation, (2) initial conditions, (3) modelling of ice-sheet processes, and (4) environmental forcing. This allows us to quantify the influence of particular modelling decisions, which is directly expressed in terms of sea-level change contribution. This type of diagnosis can be performed on any member of the ensemble, and we show in the Greenland case how the aggregation of the local attribution analyses can help guide future model development as well as scientific interpretation, particularly with regard to spatial model resolution and to retreat parametrisation.