A comparison of model ensembles for attributing 2012 West African rainfall
A comparison of model ensembles for attributing 2012 West African rainfall
复制标题
用于归因 2012 年西非降雨量的模型集合比较
DOI：
10.1088/1748-9326/aa5386
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发表时间：
2017
影响因子：
6.7
通讯作者：
Parker H
中科院分区：
文献类型：
--
作者：
Parker H
2012年，强降雨在西非各地造成洪水和破坏性影响。由于该地区许多人极易受到此类事件的影响，本研究调查了人为气候变化是否影响了此类强降水事件。我们使用概率事件归因的方法来评估人为温室气体排放的贡献，通过比较这种事件发生在气候模式模拟与所有已知的气候强迫的自然强迫模拟的概率。来自耦合模型相互比较项目第5阶段（CMIP 5）的10个模型的模拟集合与两个更大的仅大气模拟集合进行了比较，这两个集合来自气象局模型HadGEM 3-A和带有HadAM 3 P区域版本的weather@ home。这些被用来评估模型集合的选择是否会影响可以做出的归因陈述。结果表明，人为的温室气体排放减少了高降水的概率在大多数模式合奏。然而，减少的幅度和置信区间取决于所使用的集合，由于单一模型的集合规模较大，模拟受到更多限制，因此仅大气模型集合的幅度更具确定性。当考虑CMIP 5系综时，由于系综成员的减少，CMIP 5系综可以代表相关的遥相关，因此，系统的可靠性大大降低。在HadGEM 3-A中使用观测到的海表温度（SST）趋势进行自然模拟的高降水概率增加，突出表明需要确保自然SST的估计值与观测到的趋势一致，以便结果稳健。需要进一步的工作来确定人为强迫是如何影响这些模拟中的降雨过程的，以便更好地了解总体影响的差异。
In 2012, heavy rainfall resulted in flooding and devastating impacts across West Africa. With many people highly vulnerable to such events in this region, this study investigates whether anthropogenic climate change has influenced such heavy precipitation events. We use a probabilistic event attribution approach to assess the contribution of anthropogenic greenhouse gas emissions, by comparing the probability of such an event occurring in climate model simulations with all known climate forcings to those where natural forcings only are simulated. An ensemble of simulations from 10 models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) is compared to two much larger ensembles of atmosphere-only simulations, from the Met Office model HadGEM3-A and from weather@ home with a regional version of HadAM3P. These are used to assess whether the choice of model ensemble influences the attribution statement that can be made. Results show that anthropogenic greenhouse gas emissions have decreased the probability of high precipitation across most of the model ensembles. However, the magnitude and confidence intervals of the decrease depend on the ensemble used, with more certainty in the magnitude in the atmosphere-only model ensembles due to larger ensemble sizes from single models with more constrained simulations. Certainty is greatly decreased when considering a CMIP5 ensemble that can represent the relevant teleconnections due to a decrease in ensemble members. An increase in probability of high precipitation in HadGEM3-A using the observed trend in sea surface temperatures (SSTs) for natural simulations highlights the need to ensure that estimates of natural SSTs are consistent with observed trends in order for results to be robust. Further work is needed to establish how anthropogenic forcings are affecting the rainfall processes in these simulations in order to better understand the differences in the overall effect.
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影响因子：
6.7
作者：
Giannini, A.;Salack, S.;Ndiaye, O.
通讯作者：
Ndiaye, O.
影响因子：
4.6
作者：
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通讯作者：
Allen, Myles
影响因子：
5.1
作者：
Jones, C. D.;Hughes, J. K.;Zerroukat, M.
通讯作者：
Zerroukat, M.
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影响因子：
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作者：
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通讯作者：
R. Graham
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影响因子：
4.9
作者：
C. Skinner;M. Ashfaq;N. Diffenbaugh
通讯作者：
N. Diffenbaugh