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标题：The Tuning Strategy of IPSL-CM6A-LR
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作者：Juliette Mignot ; Frédéric Hourdin ; Julie Deshayes 等
期刊名称：Journal of Advances in Modeling Earth Systems
电子版ISSN：1942-2466
出版年度：2021
卷号：13
期号：5
页码：e2020MS002340
DOI：10.1029/2020MS002340
出版社：John Wiley & Sons, Ltd.
摘要：The assessment of current and future risks for natural and human systems associated with climate change largely relies on numerical simulations performed with state-of-the-art climate models. Various steps are involved in the development of such models, from development of individual components of the climate system up to free parameter calibration of the fully coupled model. Here, we describe the final tuning phase for the IPSL-CM6A-LR climate model. This phase alone lasted more than 3 years and relied on several pillars: (i) the tuning against present-day conditions given a small adjustment of the ocean surface albedo to compensate for the current oceanic heat uptake, (ii) the release of successive versions after adjustments of the individual components, implying a systematic and recurrent adjustment of the atmospheric energetics, and (iii) the use of a few metrics based on large scale variables such as near-global mean temperature, summer Arctic sea-ice extent, as targets for the tuning. Successes, lessons and prospects of this tuning strategy are discussed. Plain Language Abstract Evaluating current and future risks for natural and human systems associated with climate change is largely based on numerical simulations performed with models of the climate system, which includes the atmosphere, the land, the ocean, the cryosphere, and the oceanic and terrestrial biosphere. Various steps are involved in the development of such models. First, models for individual components are developed and tested. Second, many aspects are represented with parameterizations that summarize the effect of a missing process, such as those happening on scales that are smaller than the model grid sizes. The parameterizations in turn involve many parameters, sometimes poorly estimated from observations, that have to be calibrated. Here, we describe the final tuning phase of the IPSL-CM6A-LR climate model, which includes several novel aspects: first, the choice to calibrate the model against present-day observations, which implies taking into account the transient nature of the observed climate; second, the systematic and recurrent adjustment of the atmospheric radiative budget; third, the use of a few large scale observable variables as targets. Successes, lessons and prospects of this tuning strategy are discussed.
关键词：atmospheric energetic adjustment;calibration;climate model tuning;metrics;present-day control