Sea ice in the Weddell Sea and its relationship with the South Atlantic Subtropical High and precipitation in South America

Autor(es)

CAMILA B. CARPENEDO ^[1] ; TÉRCIO AMBRIZZI ^[2] ; RAFAEL CESAR SILVA ^[3]

Afiliação do(s) autor(es)

^[1] Universidade Federal do Paraná. Departamento de Solos e Engenharia Agrícola - Brasil

^[2] Universidade de São Paulo. Instituto de Astronomia - Brasil

^[3] Universidade Federal do Rio Grande do Sul. Programa de Pós-Graduação em Geografia - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Anais da Academia Brasileira de Ciências; v. 94, 2022-10-21.

Resumo

Abstract This study aims to evaluate the position and intensity of the South Atlantic Subtropical High (SASH), related to sea ice extent (SIE) retraction and expansion in the Weddell Sea, assessing precipitation in South America. We assess the difference between atmospheric fields related to SIE (four most intense retraction events minus four most intense expansion events) in February. To this end, we used NSIDC SIE, ERA-5 reanalysis, CHIRPS precipitation, ICOADS SST, ONI/SAM indexes (CPC/NOAA). In the following month, under neutral ENSO and SAM, we observed tropospheric warming in the Weddell Sea and cooling in the mid-latitudes South Atlantic. There is a weakening of both the Weddell Sea circumpolar low and the high pressures between tropical and subtropical latitudes, in addition to the equatorward shift of the Ferrel cell. Therefore, SASH weakens and contracts, resulting in a reduction of the tropical Atlantic moisture supply to South America and negative precipitation anomalies in the tropical region - similar to the suppression pattern of the South Atlantic Convergence Zone. Our results suggest that SIE retraction (expansion) in the Weddell Sea may contribute to the weakening (strengthening) of the SASH and an early-ending (longer-ending) or drier-ending (wetter-ending) rainy season in tropical South America. (AU)

• Processo FAPESP: 17/09659-6 - Variabilidade interanual dos transportes meridionais através da rede transatlântica SAMOC (SAMBAR)
• Beneficiário: Edmo José Dias Campos
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 14/50848-9 - INCT 2014: INCT para Mudanças Climáticas (INCT-MC)
• Beneficiário: Jose Antonio Marengo Orsini
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático