Future Changes in Northern Hemisphere Summer Weather Persistence Linked to Projected Arctic Warming
Future Changes in Northern Hemisphere Summer Weather Persistence Linked to Projected Arctic Warming
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DOI：
10.1029/2020gl091603
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发表时间：
2021-02-28
影响因子：
5.2
通讯作者：
Tamarin-Brodsky, Talia
中科院分区：
文献类型：
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作者：
Kornhuber, Kai;Tamarin-Brodsky, Talia
了解大规模大气环流对气候变化的响应仍然是一个关键挑战。具体来说，赤道与极地温差的变化被认为会影响中纬度地区，可能导致更持久的极端天气，但迄今为止尚未达成科学共识。在这里，我们通过应用跟踪算法来降低对流层涡度和温度场来分析其传播速度的变化，从而量化夏季天气的持续性。我们在观测和模型中发现传播较慢的天气系统与赤道到极地温差较弱之间存在显着联系。到本世纪末，中纬度地区温度异常的传播预计将减少-3%，在高排放情景下（CMIP5 RCP8.5），北美南部区域最强（-45%）。在预测赤道与极地温差减小的模型中发现了更高的降幅（-10%、-58%）。我们的研究结果提供了证据，表明炎热的夏季天气可能会变得更持久，并带来更持续的极端高温的风险。
Understanding the response of the large-scale atmospheric circulation to climatic change remains a key challenge. Specifically, changes in the equator-to-pole temperature difference have been suggested to affect the midlatitudes, potentially leading to more persistent extreme weather, but a scientific consensus has not been established so far. Here we quantify summer weather persistence by applying a tracking algorithm to lower tropospheric vorticity and temperature fields to analyze changes in their propagation speeds. We find significant links between slower propagating weather systems and a weaker equator-to-pole temperature difference in observations and models. By end of the century, the propagation of temperature anomalies over midlatitude land is projected to decrease by -3%, regionally strongest in southern North America (-45%) under a high emission scenario (CMIP5 RCP8.5). Even higher decreases are found (-10%, -58%) in models which project a decreasing equator-to-pole temperature difference. Our findings provide evidence that hot summer weather might become longer-lasting, bearing the risk of more persistent heat extremes.