Evolution of the Southern Annular Mode during the past millennium

• Main Authors: Nerilie J. Abram, Robert Mulvaney, Françoise Vimeux, John Turner, Matthew H. Engl
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2014
• Subjects: Antarctic; Antarctic Peninsula; Drake Passage; The Antarctic; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.682.1417; http://web.science.unsw.edu.au/%7Ematthew/Abram_et_al_SAM_NCC_2014.pdf

The Southern Annular Mode (SAM) is the primary pattern of climate variability in the Southern Hemisphere1,2, influencing latitudinal rainfall distribution and temperatures from the subtropics to Antarctica. The positive summer trend in the SAM over recent decades is widely attributed to stratospheric ozonedepletion2; however, thebrevity of observational records from Antarctica1—one of the core zones that defines SAM variability—limits our understanding of long-term SAM be-haviour. Here we reconstruct annual mean changes in the SAM since AD 1000 using, for the first time, proxy records that encompass the full mid-latitude to polar domain across the Drake Passage sector. We find that the SAM has undergone a progressive shift towards its positive phase since the fifteenth century, causing cooling of the main Antarctic continent at the same time that the Antarctic Peninsula has warmed. The