Antarctic temperatures over the past two centuries from ice cores

Abstract

[1] We present a reconstruction of Antarctic mean surface temperatures over the past two centuries based on water stable isotope records from high-resolution, precisely dated ice cores. Both instrumental and reconstructed temperatures indicate large interannual to decadal scale variability, with the dominant pattern being anti-phase anomalies between the main Antarctic continent and the Antarctic Peninsula region. Comparative analysis of the instrumental Southern Hemisphere (SH) mean temperature record and the reconstruction suggests that at longer timescales, temperatures over the Antarctic continent vary in phase with the SH mean. Our reconstruction suggests that Antarctic temperatures have increased by about 0.2°C since the late nineteenth century. The variability and the long-term trends are strongly modulated by the SH Annular Mode in the atmospheric circulation. Citation: Schneider,

An ice‐core proxy for northerly air mass incursions into West Antarctica

“…Examples include strong associations between icecore Na + concentrations and the ASL pressure system (Kreutz et al, 2000;Kaspari et al, 2004), icecore methanesulphonic acid concentrations and sea ice extent (Welch et al, 1993;Meyerson et al, 2002;Curran et al, 2003;Abram et al, 2007), ice-core stable isotopes and temperature (Schneider et al, 2004(Schneider et al, , 2006, and icecore non-sea-salt-Ca 2+ (nssCa) concentrations used as a NAMI proxy in this study. A previous ice-core nssCa study (Yan et al, 2005) established that a statistically significant positive relationship exists between the strength of SH westerlies and nssCa concentrations in two West Antarctic ice cores (SDM-94 and 00-1) from 1948 to 2002.…”

Winter warming in West Antarctica caused by central tropical Pacific warming

“…S7a). We would thus expect West Antarctica to have warmed for the same period, as is found in reconstructed temperature fields since the 1950s (refs 2,3) and in proxy data from West Antarctic ice cores over the past century 17,32 . Furthermore, strong JJA warming in the central tropical Pacific is a common characteristic of general circulation model responses to scenarios of future greenhouse gas radiative forcing (Supplementary Fig.…”

Ice cores record significant 1940s Antarctic warmth related to tropical climate variability

“…Our eight records are restricted to the Pacific sector (60W-180W), and should reflect anomalies of common sign with respect to the Southern Annular Mode and El Niño-related teleconnection patterns (4), assuming that the spatial patterns from observations hold through time. A study of five Antarctic-wide highresolution ice cores showed evidence that the most prominent pattern in temperature variability, with negative anomalies in the Peninsula region and positive anomalies over the bulk of the continent, and vice versa, has been present throughout the 20th Century (14).…”