Winter climate change on the northern and southern Antarctic Peninsula

Abstract

Differences in the decadal trend in the winter surface temperature in the northern and southern Antarctic Peninsula have been analysed. Time series from the two stations Esperanza and Faraday/Vernadsky since the early 1950s are used. The two time series are strongly correlated only during the 1980s and 1990s when their variability and trends are associated with both the Niño-4 region and Southern Annular Mode impacts. The winter cooling at the Faraday/Vernadsky station contrasts with the winter warming at the Esperanza station during the period of 2006–17. The different temperature trends are accompanied by weak correlations between the temperatures at these two stations. Linearly congruent components of the station temperature trends in 2006–17 indicate a dominant contribution of Southern Annular Mode (tropical sea surface temperature anomalies) to warming (cooling) in the northern (southern) Peninsula. Distinctive impacts of climate modes are observed in combination with the recent deepening of the negative sea-level pressure anomaly to the west of the peninsula and the related change in the zonal and meridional wind components. These factors apparently contribute to the occurrence of the boundary that crosses the peninsula and divides it into sub-regions with warming and cooling.

The 16-year periodicity in the winter surface temperature variations in the Antarctic Peninsula region

“…As shown by Marshall (2007), a boundary between the regions where temperatures are positively and negatively correlated with SAM exists, and the line that separates these regions moves through the FV latitude twice a year. The recent SAM-related winter deepening of the negative SLP anomaly to the west of the AP, accompanied by a change in the zonal and meridional wind components, also contributes to the occurrence of the boundary that crosses the AP and divides it into sub-regions with warming and cooling (Evtushevsky et al 2020). In the interannual temperature variations, the difference between SAM (prevailing periods of 2-5 years) and ENSO (2-8 years) (Yuan and Yonekura 2011; Rahaman et al 2019) seems to correspond to the difference between ESP-ORC and FV, respectively, in their spectra (Fig.…”

“…3a and 3c) and cooling (or no warming, Fig. 3e), respectively (Oliva et al 2017;Evtushevsky et al 2020).…”

“…Because of the variability in the ENSO-SAM coupling, regional circulation anomalies provide differences in the winter climate change in the different parts of the AP through redistribution of the zonal and meridional ows and dominant advection of warm or cold air towards the AP. A local decrease of sea level pressure can lead to greater cyclonic activity to the west, north or east of the AP in the Amundsen-Bellingshausen Seas, Drake Passage or Weddell Sea, respectively (Clem and Renwick 2015;Turner et al 2016;Evtushevsky et al 2020), in uencing the temperature change across the AP. Owing to the multiplicity of interactions between the climate modes and to the relatively short records, the most important factors affecting the Antarctic temperatures are still unclear (Turner et al 2020) and need to be determined.…”