On the drivers of temperature extremes on the Antarctic Peninsula during austral summer

Sai Wang,Ge Liu,Tingfeng Dou,Ting Wei,Minghu Ding,Wenqian Zhang,Cunde Xiao,Wen Chen

doi:10.1007/s00382-022-06209-0

Abstract

This study investigates the role of atmospheric circulation on intraseasonal and synoptic time scales in driving the temperature extremes over the Antarctic Peninsula (AP) during austral summer. It is found that the advection term induced by intraseasonal oscillations (ISOs) makes the largest contribution to the formation and development of temperature extremes. The synoptic variation-induced advection term affects the temperature anomalies around the peak time. The upstream ISO Rossby wave packet propagating along the jet stream south of Australia precedes the extreme temperature events. The ISO wave packet propagates eastward and eventually affects downstream circulation and relevant temperature anomalies over the AP. The perturbations triggered by the ISO wave packet can also gain energy from the mean flow through the potential energy conversion, contributing to the development and maintenance of ISO Rossby wave. The eastward propagation of the synoptic-scale Rossby wave is faster than that of the intraseasonal one. As such, the anomalous synoptic circulations rapidly change and facilitate the development of extreme temperature events. The synoptic Rossby wave activity before the warm events is much stronger than that before cold, which can be partly attributed to the background of more active baroclinicity before the warm events.

Highlights

Variations in surface air temperature (SAT) may have pronounced impacts on glaciological, oceanographic, chemical and biological processes in the Antarctic and surrounding ocean areas (Scambos et al 2000; Cook et al 2005; Meredith and King2005; Turner et al 2017)
On the basis of observational SAT from the Great Wall Station, the present study identified 42 warm events and 48 cold events over the Antarctic Peninsula (AP) during the 1985/86 to
It was found that the temporal evolutions of SAT anomalies during the lifetimes of the warm and cold events were closely related to the development of SAT anomalies over the Drake Passage region

Summary

Introduction

Variations in surface air temperature (SAT) may have pronounced impacts on glaciological, oceanographic, chemical and biological processes in the Antarctic and surrounding ocean areas Winter, and spring seasons, apparent warming signals have occurred over the western AP (King 1994; Turner et al 2005; Ding and Steig 2013; Clem and Fogt 2015) related to tropical Pacific forcing during autumn. The change in the phase of the SAM can exert the greatest control on the interannual variability in SAT across the AP (Marshall and Thompson 2016; Turner et al 2020). The variations in the phase of the El Niño-Southern Oscillation (ENSO) and the associated tropical Pacific-high latitude teleconnection can influence winter temperatures on the AP (Marshall and King 1998; Clem et al 2016; Clem et al 2017). Investigating the dynamic mechanisms governing extreme temperatures on the AP can improve our understanding of the climate variability on the AP.

Data and methods

The evolution of SAT anomalies

Diagnostic analysis of SAT anomalies

The associated atmospheric circulation anomalies

Summary