CLIMATIC VARIABILITY OF THE SOUTH PACIFIC OCEAN DURING 1900–2010 IN THE ENVIRONMENTAL RECORDS OF WEST ANTARCTICA

• Main Authors: Rosa, José Mauro Dalla, Simões, Jefferson Cardia, Reis, Pedro Amaral, Aquino, Francisco Eliseu, Thoen, Isaías Ullmann, Bernardo, Ronaldo Torma, Auger, Jeffrey Daniel
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade Federal da Grande Dourados 2021
• Subjects: Pacific Ocean. West Antarctica. Climatology; Amundsen Sea; Antarctic; Mount Johns; Pacific; The Antarctic; West Antarctic Ice Sheet; West Antarctica; Antarc*; Antarctica; ice core; Ice Sheet; Sea ice
• Online Access: https://ojs.ufgd.edu.br/index.php/rbclima/article/view/15185

In this work, we present the climatic evolution of the South Pacific Ocean from 1900 to 2010 and its environmental influence over West Antarctica. We analyzed the sea surface temperature, mean sea level pressure, and meridional wind (850 hPa) of the South Pacific Ocean using ERA-20C reanalysis (European Center for Medium-Range Weather Forecasts), and compared these parameters with the regional temperature obtained indirectly (by proxy) from two ice cores from the West Antarctic ice sheet (Mount Johns and Ferrigno). The sea surface temperature increased in almost the entire South Pacific Ocean from 1900 to 2010; in the equatorial Pacific, it increased by 2.1 °C from 1916 to 1997, while in the middle latitudes of the South Pacific, it increased by 1.1 °C from 1923 to 2001. This increase occurred concurrently with a positive trend in the Southern Annular Mode and a change the mean sea level pressure anomaly from 1960 onwards. This atmospheric pressure increased at middle latitudes and decreased around Antarctica in the circumpolar low-pressure zone, strengthening the Amundsen Sea Low and changing the pattern of the meridional wind anomaly (850 hPa) between medium and high latitudes in the South Pacific. Furthermore, since 1960, a greater flow from north to south (onshore) has predominated from the southeast South Pacific to the north of West Antarctica. Such changes caused a reduction in the sea ice extent in the Amundsen and Bellingshausen Seas and an increase in average atmospheric temperature primarily in the coastal region of West Antarctica, as demonstrated by the Ferrigno ice core record. Conversely, the Mount Johns region did not show the same trend in atmospheric temperature, as it was influenced mainly by cold air masses from the Antarctic ice sheet.