Tropical-Antarctic connections of an explosive cyclone in southern Brazil: rainfall isotope ratios and atmospheric analysis
at : May 21, 2020 08:38:57  (view:274)

P A REIS*,  F E AQUINO,  V SCHOSSLER,  R T BERNARDO & J C SIMÕES

Centro Polar e Climático, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, Rio Grande do Sul, Brazil

*Corresponding author, E-mail: pamaralreis@gmail.com

Abstract:  This study analyzes the isotopic and synoptic characteristics of a precipitation event that occurred in the southern state of Brazil, Rio Grande do Sul, a region that is sensitive to explosive cyclogenesis during years with enhanced tropic-pole interactions. The main objective was to evaluate the influence of tropical and Antarctic climate system on the event. Cavity ring-down spectroscopy was used for the isotopic analysis, and NCEP CFSv2 data was used for the synoptic analysis of rainfall over a 48-hour period. An Amazonian isotopic signature on precipitated water was identified. The strong low-level meridional flow from the Amazon Basin combined with the development of a frontal system resulted in an intense cyclogenesis that generated an explosive cyclone. Keyword: Antarctica, amazon, South American Low-Level Jet (SALLJ), cyclogenesis