气候变化领域集成服务门户(CCPortal): Investigating physical constraints on climate feedbacks using a perturbed parameter ensemble

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DOI	10.1007/s00382-020-05318-y
	Investigating physical constraints on climate feedbacks using a perturbed parameter ensemble
	Tsushima Y.; Ringer M.A.; Martin G.M.; Rostron J.W.; Sexton D.M.H.
发表日期	2020
ISSN	0930-7575
起始页码	1159
结束页码	1185
卷号	55
英文摘要	A large parameter-perturbed ensemble (PPE) of the Met Office climate model is used to explore the relationship between radiative feedbacks and the present-day simulation of the associated physical processes. We highlight three tropical regimes (deep convection over ocean and land, and marine stratocumulus) in which the same set of processes drives the present-day simulation of clouds and their feedbacks. In each case, the amount of the dominant cloud types reduces in response to warming and the reduction is approximately proportional to the amount simulated in the present day. In deep convective regions, convective process parameters lead the spread among multiple contributing processes, with vegetation processes contributing as well for the land regions. Multiple parameters, such as boundary layer processes, drive stratocumulus regions. However, the low-thick clouds are systematically overestimated, suggesting a structural error in their process representations which would limit the efficacy of the constraint. The influence of convection is largely confined to the tropical deep convective regions in the present day but extends to mid-latitudes under warming. Because of this, contributing processes to the spread in the present-day and the response are different in the extra-tropics, making it much more difficult to establish links between the present-day and the feedback within the region. This suggests that identifying a constraint on convective processes in the tropics for the present-day simulations could constrain both the tropical feedbacks and feedbacks in the extra-tropics. A parameter representing deep-convective entrainment links the present-day tropical mean high cloud and clear-sky longwave flux to their feedbacks in our model, suggesting a potential process constraint from the observations. Understanding and improving the detailed processes controlling feedbacks is ultimately only possible in individual models. Different process-based constraints might be inferred for different models. The approach described here could usefully extended to other single model ensembles and the collective understandings could be valuable for improving model process and feedbacks more generally. © 2020, Crown.
英文关键词	Circulation weakening; Climate feedbacks; Perturbed parameter ensembles; Process based constraints; Sensitivity analysis
语种	英语
scopus关键词	climate feedback; climate modeling; cloud cover; cloud radiative forcing; computer simulation; convective system; entrainment; numerical model; parameter estimation; stratocumulus
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/145374
作者单位	Met Office Hadley Centre, FitzRoy Road, Exeter, EX1 3PB, United Kingdom
推荐引用方式 GB/T 7714	Tsushima Y.,Ringer M.A.,Martin G.M.,et al. Investigating physical constraints on climate feedbacks using a perturbed parameter ensemble[J],2020,55.
APA	Tsushima Y.,Ringer M.A.,Martin G.M.,Rostron J.W.,&Sexton D.M.H..(2020).Investigating physical constraints on climate feedbacks using a perturbed parameter ensemble.Climate Dynamics,55.
MLA	Tsushima Y.,et al."Investigating physical constraints on climate feedbacks using a perturbed parameter ensemble".Climate Dynamics 55(2020).