Extreme events in a polar warming scenario--a laboratory perspective

TL;DR

This study uses laboratory experiments to explore how Arctic warming influences mid-latitude jet stream behavior, extreme events, and temperature variability, revealing significant impacts on atmospheric dynamics and potential climate change implications.

Contribution

It provides experimental evidence linking Arctic warming to jet stream alterations and extreme event frequency, supporting recent theoretical and observational findings.

Findings

Decreased meridional temperature difference slows jet stream propagation

Warming increases the frequency of extreme atmospheric events

Temperature variability trends are latitude-dependent and consistent with reanalysis data

Abstract

We report on a set of laboratory experiments to investigate the effect of Arctic warming on the amplitude and drift speed of the mid-latitude jet stream. Our results show that a progressive decrease of the meridional temperature difference 1) slows down the eastward propagation of the jet stream, 2) complexifies its structure, and 3) increases the frequency of extreme events. Extreme events and temperature variability show a clear trend in relation to the Arctic warming only at latitudes influenced by the jet stream, whilst such trend reverses in the equatorial region south of the subtropical jet. Despite missing land-sea contrast in the laboratory model, we find similar trends of temperature variability and extreme events in the experimental data and the National Centers for Environmental Prediction (NCEP) reanalysis data. Moreover, our data qualitatively confirm the decrease in temperature variability due to the meridional temperature gradient weakening (which has been proposed recently based on proxy data). Probability distributions are weakly sensitive to changes in the temperature gradient, which can be explained by recent findings using quasigeostrophic models.