Tropical–Antarctic connections of an explosive cyclone in southern Brazil: rainfall stable isotope ratios and atmospheric analysis

• Main Authors: Reis, Pedro Amaral, Aquino, Francisco Eliseu, Schossler, Venisse, Bernardo, Ronaldo Torma, Simões, Jefferson Cardia
• Format: Article in Journal/Newspaper
• Language: English
• Published: Polar Research Institute of China - PRIC 2020
• Subjects: Atmosphere; Antarctic; Advances in Polar Science; Antarc*; Polar Science
• Online Access: http://library.arcticportal.org/2719/; http://library.arcticportal.org/2719/1/A2002003.pdf

This study analyzes the stable isotopic ratio (δ18O) and the synoptic characteristics of a precipitation event that occurred in the southernmost state of Brazil, Rio Grande do Sul, a region sensitive to explosive cyclogenesis in years with enhanced tropic-pole interactions. The main objective was to evaluate the influence of tropical and Antarctic climate systems on the event. Cavity ring-down spectroscopy was used for the water isotopic analysis, and NCEP CFSv2 data were employed for the synoptic analysis of rainfall over a 48-h period. An Amazonian isotopic signature on precipitated water was identified. A strong, low-level meridional flow from the Amazon Basin, combined with the development of a frontal system, resulted in intense cyclogenesis that generated an explosive cyclone.