Atmospheric blockings in Coupled Model Intercomparison Project Phase 5 models with different representations of Antarctic sea ice extent

Author(s)

CAMILA B. CARPENEDO ^[1] ; TÉRCIO AMBRIZZI ^[2]

Affiliation

^[1] Universidade Federal do Paraná. Setor de Ciências Agrárias - Brasil

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

• Document type: Journal article
• Source: Anais da Academia Brasileira de Ciências; v. 94, 2022-05-30.

Abstract

Abstract This study investigated whether there are differences in the frequency and position of Southern Hemisphere atmospheric blockings between Coupled Model Intercomparison Project Phase 5 models with different representations of Antarctic sea ice extent in historical experiments. In the model with the greatest sea ice underestimation (Model for Interdisciplinary Research on Climate version 5) there is a weakening of the polar jet and an increase in 500-hPa height. These atmospheric conditions favor the predomination of simulated blocking frequency overestimations (autumn-winter), in relation to the observed (ERA-Interim). On the other hand, in the models with the greatest sea ice overestimations (Community Climate System Model version 4) and the better sea ice representation (Norwegian Earth System Model version 1) there is a strengthening of the polar jet and weaker positive differences in 500-hPa height in the Antarctic region. These atmospheric conditions favor a predominance of simulated blocking frequency underestimations (all seasons). All models present a good representation of the preferred blocking regions (South Pacific), although they do not represent the longitudinal location of the maximum frequency. In years of sea ice retraction (expansion), there is a predominance of a higher (lower) blocking frequency in the 60°S for all models and observed data. (AU)

• FAPESP's process: 17/09659-6 - Interannual variability of the meridional transports across the SAMOC basin-wide array (SAMBAR)
• Grantee: Edmo José Dias Campos
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 12/17370-2 - Atmospheric blockings associated with the extreme variability of Antarctic sea ice and impacts in South America
• Grantee: Camila Bertoletti Carpenedo
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/50848-9 - INCT 2014: INCT for Climate Change
• Grantee: Jose Antonio Marengo Orsini
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants