of temperature-sensitive ice core and tree growth records to reconstruct a 1000-year history of the Southern Annular Mode. This work suggests that the Southern Annular Mode is currently in its most extreme positive phase over at least the last 1000 years, and that recent positive trends in the SAM are attributed to increasing greenhouse gas levels and later stratospheric ozone depletion. See also Anticyclone Arctic oscillation North Atlantic oscillation Pacific decadal oscillation Roaring forties References External links http://www.antarctica.ac.uk/met/gjma/sam.html Observation-based SAM index from 1957–present http://hurricane.ncdc.noaa.gov/pls/paleox/f?p=519:1:0::::P1_STUDY_ID:16197 1000-year Southern Annular Mode reconstruction Monthly Southern Hemisphere Annular Mode (SAM) Index or Antarctic Oscillation (AAO) Index 1850 - 2013 Daily Southern Hemisphere Annular Mode (SAM) Index or Antarctic Oscillation (AAO) Index 1948 - 2013 http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/aao/aao.loading.shtml https://web.archive.org/web/20081216220433/http://stratus.astr.ucl.ac.be/textbook//pdf/Chapter_5.pdf (chapter 5.2.3) SOUTHERN ANNULAR MODE IN AUSTRALIA – What is it? The Southern Annular Mode Introduction to climate dynamics and climate modelling, Université catholique de Louvain Climate of Antarctica Regional climate effects Environment of Antarctica Climate of Australia Climate oscillations