Collaborative Research: Type 1 - LOIL02170097: Decadal Predictability of Extreme Events: Impact of a Model Error Representation and Numerical Resolution

类型1 - LOIL02170097：极端事件的年代际可预测性：模式误差表示和数值分辨率的影响（合作研究）研究人员将在社区大气模式中实施随机后向散射方案，并探索如何改善内部变率，特别是在年代际和区域尺度上对极端事件的预测。只有少数出版物将极值理论应用于气候模型，许多问题仍未解决。虽然已经进行了一些工作，将模式和再分析与恒定温室强迫进行比较，但该领域发表的主要工作集中在气候变化中极端事件的发生，以及不同低分辨率模式中极端事件的气候趋势的稳稳性。研究人员的重点是非常不同的：他们将研究在恒定的温室强迫下模型的内部变异性。研究人员关注低分辨率气候模式在年代际和全球空间尺度上预测极端事件的能力，以及用随机模式误差方案替代低分辨率气候模式的缺失变率的可行性，以及该方案是否能改善极端事件的年代际预测。采用随机后向散射方案和不采用随机后向散射方案对模型进行积分，并利用极值统计来确定该方案对极端事件发生的影响。为了比较，同样的统计量将使用ERA40、ERA-Interim分析和/或encep /NCAR再分析作为多年代际观测的最佳代理来计算。

Type 1 - LOIL02170097: Decadal predictability of extreme events:Impact of a model error representation and numerical resolution(collaborative research)The investigators will implement a stochastic backscatter scheme into the CommunityAtmosphere Model and explore how to improve the internal variability and, in particular,the prediction of extreme events on decadal and regional scales. Only a small number ofpublications apply Extreme Value Theory to climate models and many questions remainopen. While some work has been conducted comparing model and reanalysis with constantgreenhouse forcing, the major body of published work in this area focuses on the occurrenceof extreme events in a changing climate and on the robustness of climate trends of extremeevents across di^erent low-resolution models.The emphasis of the investigators is very di^erent: they will look at the internal variabilityof models under a constant greenhouse forcing. The investigators focus both on the ability oflow-resolution climate models to realistically predict extreme events on decadal time-scalesand global spatial scales, and on the feasibility of replacing the missing variability due tolow-resolution with a stochastic model error scheme and if such a scheme can improve thedecadal prediction of extreme events. Model integrations with and without a stochasticbackscatter scheme would be conducted and extreme value statistics be used to determinethe impact of the scheme onto the occurrence of extreme events. For comparison, the samestatistic would be computed using the the ERA40, the ERA-Interim analysis and/or theNCEP/NCAR reanalysis as best proxy for multi-decadal observations.