论文标题
内部变异性在极端事件的全球气候预测中的作用
The role of internal variability in global climate projections of extreme events
论文作者
论文摘要
气候投影不确定性可以分为模型不确定性，场景不确定性和内部变异性。在这里，我们研究了每日最高温度和极端降水的预计频率的不同不确定性来源，这些频率定义为超过第99.97个百分位的事件。这是使用初始条件大型合奏在全球完成的。对于最高温度，内部可变性在未来二十年中占主导地位。在21世纪中叶和场景不确定性的左右成为热带地区的主要贡献，但内部变异性在热带地区仍然是主要的。到本世纪末，模型和场景不确定性在全球范围内的大约40％的贡献中增加到了大约40％。对于极端降水，除了一些热带地区（例如，西非）外，内部可变性在整个21世纪占主导地位。在内部变异性构成不确定性的主要来源的区域中，减少模型不确定性对气候投影的信噪比比率的潜在影响估计很小。我们讨论了使用方法的警告以及我们发现对未来气候模型的设计的影响。这里发现的内部变异性的重要性强调，大型合奏是理解气候预测的重要工具。
Climate projection uncertainty can be partitioned into model uncertainty, scenario uncertainty and internal variability. Here, we investigate the different sources of uncertainty in the projected frequencies of daily maximum temperature and precipitation extremes, which are defined as events that exceed the 99.97th percentile. This is done globally using initial-condition large ensembles. For maximum temperature extremes, internal variability dominates in the next two decades. Around the middle of the 21st century model and scenario uncertainty become the dominant contribution in the tropics but internal variability remains dominant in the extra-tropics. Towards the end of the century, model and scenario uncertainty increase to near equal contributions of ~40% each globally with large regional fluctuations. For precipitation extremes, internal variability dominates throughout the 21st century, except for some tropical regions, for example, West Africa. In regions where internal variability constitutes the major source of uncertainty, the potential impact of reducing model uncertainty on the signal-to-noise ratio of the climate projection is estimated to be small. We discuss the caveats of the methodology used and impact of our findings for the design of future climate models. The importance of internal variability found here emphasizes that large ensembles are a vital tool for understanding climate projections.
