Atmospheric circulation patterns associated with surface air temperature variability trends between the Antarctic Peninsula and South America

• Published in: Anais da Academia Brasileira de Ciências
• Main Authors: CAMILA B. CARPENEDO, DENILSON R. VIANA, CLÁUDIA K. PARISE, FRANCISCO E. AQUINO, RICARDO B. BRAGA
• Format: Article in Journal/Newspaper
• Language: English
• Published: Academia Brasileira de Ciências 2023
• Subjects: Climate; SAM; ENSO; SACZ; Science; Q; Antarctic; Antarctic Peninsula; Austral; Pacific; The Antarctic; Antarc*
• Online Access: https://doi.org/10.1590/0001-3765202320220591; https://doaj.org/article/34d251d8662a442b8d07102de3029a71

Abstract This study investigated the spatial patterns of atmospheric circulation associated with surface air temperature variability trends between the Antarctic Peninsula and South America, during the austral summer (1979-2020). The first mode shows a positive score trend, with warming in northern Antarctic Peninsula and southern South America. This mode is mainly associated with the positive/neutral Southern Annular Mode and La Niña phases. There is an anomalous low pressure in the Southeast Pacific, a strengthening (weakening) of the polar (subtropical) jet and a strengthening and/or south/southwest displacement of the South Atlantic Subtropical High, which can prevent the passage of transient systems over the continent. In addition, there is a negative phase pattern of the South Atlantic Dipole, which contributes to the strengthening of the South Atlantic Convergence Zone convective activity. The second mode shows a negative score trend, with cooling in the Antarctic Peninsula/southernmost South America and warming between 10-40°S over South America. This mode is mainly associated with the spatial pattern of Central Pacific El Niño. There is a strengthening of the low-level jet and a strengthening of the western branch of the South Atlantic Subtropical High, all of which contribute to the suppression of the South Atlantic Convergence Zone.