Global temperature change causing wavier jet streams

A recently published study has linked the unequal rise in global temperatures to a wavier jet stream.

Using mathematical formulas, the research team produced a group of simulations of changes to the jet stream in response to global warming. The results, published open-acess in Proceedings of the National Academy of Sciences, show increased waviness to the jet stream.

In recent years, the jet stream has become wavier than it used to be, with the peaks and troughs becoming more extreme. This has led to changes in weather patterns, with more 'blocking' weather events that lead to longer periods of wet or dry weather around the globe.

Increasingly intense winter storms have been a feature of recent years in the UK (Mark Bolton).

It has previously been suggested that the increased waviness is due to asymmetric rise in global temperatures, as the Arctic is heating up much faster than more southerly latitudes. This causes notable changes in winds in the upper atmosphere.

Using mathematical formulas, taking in to account the differences both above and below the jet stream, the simulations showed what the researchers were expecting: increased waviness, caused by a weakening of the jet stream as the Arctic warms faster than areas to the south.

This leads to amplified changes in the upper atmosphere, exerting a wavering influence on the jet stream, resulting in higher peaks, lower troughs and more waves in general. This means less stability and an increase in extreme weather events.

Reference

Woosook Moon, Kim, B-M, Yang, G-H & Wettlaufer, J S. 2022. Wavier jet streams driven by zonally asymmetric surface thermal forcing. Proceedings of the National Academy of Sciences. DOI: https://doi.org/10.1073/pnas.220089011