A shifting jet stream in a changing climate. Exploring the response of the polar jet stream in the Northern Hemisphere to various climate futures.

地球气候系统预计将在21世纪经历重大变化，但这些变化预计不会以统一的方式发生。虽然当前一代气候模型的结果表明，进入21世纪，北极的地表温度预计将比地球上其他地区变暖得更快，但热带地区的哈德利环流预计将扩大，推动副热带干旱区和风暴路径进一步向两极移动(Serreze等人，2009，Hu等人，2018)。这些类型的气候变化将极大地影响北半球目前存在的热力学关系，改变那里天气系统的位置和特征。尽管如此，气候模型和观测结果之间普遍缺乏关于当前控制天气制度变化的动态的一致意见，部分原因是(在上一代气候模型中)模拟的高层大气的粒度，以及对于可以使用哪个代理来研究这一现象缺乏共识(CMIP5，Cohen等人，2020)。这一博士学位的主要目的是利用最新的耦合模式对比项目(CMIP6)的成果，在各种未来气候情景下的最新气候模型中探索喷流的反应，喷流就是其中之一。利用CMIP6模拟，该项目将寻找新出现的和观测到的约束，以评估气候模式整体的未来急流行为的准确性，并限制对其预测。

Earth's climate system is projected to experience significant changes into the 21st Century, but these changes have not expected to happen in a uniform way. While outputs from the current generation of climate models suggest surface temperatures in the Arctic are projected to warm faster than other parts of the planet into the 21st century, the Hadley circulation in the Tropics is expected to expand pushing both the sub-tropical dry zones and storm tracks further polewards (Serreze et al., 2009, Hu et al., 2018). These types of climatic shifts would considerably influence the current thermodynamic relationships that exist in the Northern Hemisphere, altering both the positioning and characteristics of weather systems there. Despite this, there is a general lack of agreement between climate models and observations on the current dynamics controlling changes in weather regimes, in part owing to granularity of the simulated upper atmosphere (in previous generation of climate models) and a lack of consensus over which proxy can be used study this phenomena (CMIP5, Cohen et al., 2020). The main aim of this PhD is to explore the response of the jet-streams, one such proxy, in state-of-the-art climate models across various future climate scenarios - making use of outputs from the latest Coupled Model Intercomparison Project (CMIP6). Using CMIP6 simulations, this project will search for emergent and observational constraints to evaluate the accuracy of, and constrain projections for, future jet-stream behaviour across the climate model ensemble.