Future changes in Northern Hemisphere summer weather persistence linked to projected Arctic warming.

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Authors

Kai Kornhuber , Talia Tamarin-Brodsky 

Abstract

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 mid-latitudes, 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 mid-latitude 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.

DOI

https://doi.org/10.31223/X5PG6Q

Subjects

Physical Sciences and Mathematics

Keywords

Climatic Change, Arctic Amplification, Large Scale Circulation

Dates

Published: 2020-12-17 20:35

License

CC BY Attribution 4.0 International

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