Gerber Edwin P, DallaSanta Kevin, Gupta Aman
Courant Institute of Mathematical Sciences New York University New York NY USA.
J Adv Model Earth Syst. 2019 Sep;11(9):2862-2867. doi: 10.1029/2019MS001753. Epub 2019 Sep 13.
The atmospheric circulation response to global warming is important for accurate prediction of climate change on regional scales. For the midlatitudes, shifts in the extratropical jet streams have important consequences for precipitation, blocking, and extreme events. It has proven to be a challenge, however, to predict. For example, the North Atlantic jet stream plays a vital role in the climate of eastern North America and Europe; in the last intercomparison of state-of-the-art climate models, the models did not even agree on the sign of its wintertime response to global warming. Perhaps this should not come as a surprise, as we also lack a comprehensive theory for the impact of warming on the midlatitude circulation. In a recent study, Tan et al. (2019, https://doi.org/10.1029/2018MS001492) constructed models of simpler atmospheres to explore the response of the midlatitude jet to global warming. Their idealized atmospheres highlight the difficulty of developing a comprehensive theory for the midlatitude circulation but also provide pathways to improve models of Earth's atmosphere. Models of simpler atmospheres allow one to isolate the impact of specific atmospheric processes and connect theoretical understanding with comprehensive climate prediction systems. Such models can also be used to explore very different atmospheric regimes, from Earth's past to distant planets.
大气环流对全球变暖的响应对于区域尺度气候变化的准确预测至关重要。对于中纬度地区，温带急流的变化对降水、阻塞和极端事件具有重要影响。然而，事实证明，预测这一点具有挑战性。例如，北大西洋急流在北美东部和欧洲的气候中起着至关重要的作用；在最近一次最先进气候模型的对比中，这些模型甚至在其冬季对全球变暖的响应符号上都未达成一致。也许这并不奇怪，因为我们也缺乏关于变暖对中纬度环流影响的全面理论。在最近的一项研究中，谭等人（2019年，https://doi.org/10.1029/2018MS001492）构建了更简单大气的模型，以探索中纬度急流对全球变暖的响应。他们理想化的大气突出了为中纬度环流建立全面理论的困难，但也提供了改进地球大气模型的途径。更简单大气的模型使人们能够分离特定大气过程的影响，并将理论理解与综合气候预测系统联系起来。这样的模型还可用于探索非常不同的大气状态，从地球的过去到遥远的行星。
