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.

中文翻译：

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北半球夏季天气持续性的未来变化与预计的北极变暖有关

理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。具体而言，已提出赤道与极点温度差的变化会影响中纬度，有可能导致更持久的极端天气，但迄今为止尚未建立科学共识。在这里，我们通过对低层对流层涡度和温度场应用跟踪算法来分析其传播速度的变化，从而量化夏季天气的持久性。我们在观测和模型中发现较慢的传播天气系统与较弱的赤道与极地温度差之间存在重要联系。到本世纪末，预计中纬度地区温度异常的传播将减少-3％，在高排放情景下（CMIP5 RCP8.5），是北美南部区域最强的地区（−45％）。在模型中发现赤道与极点之间的温差不断减小的情况，其下降幅度更大（−10％，− 58％）。我们的发现提供了证据，证明炎热的夏季天气可能会持续更长的时间，承受极端持续高温的风险。