Climatology of extratropical cyclones over the South American-southern oceans sector

Author(s)

Mendes, David ^{[1, 2]} ; Souza, Enio P. ^[3] ; Marengo, Jose A. ^[2] ; Mendes, Monica C. D. ^[1]

Affiliation

^[1] CPTEC, INPE, Sao Paulo - Brazil

^[2] Ctr Ciencia Sistema Terr, Inst Nacl Pesquisas Espaciais, BR-12630000 Sao Paulo - Brazil

^[3] Univ Fed Campina Grande, Dept Ciencias Atmosfer, Campina Grande, Paraiba - Brazil

• Document type: Journal article
• Source: THEORETICAL AND APPLIED CLIMATOLOGY; v. 100, n. 3-4, p. 239-250, MAY 2010.
• Web of Science Citations: 13

Abstract

A climatology of extratropical cyclones is presented. Extratropical cyclones, their main characteristics and their predominant tracks, as well as their interannual variability, affect weather in South America. For that purpose, a storm track database has been compiled by applying a cyclone tracking scheme to six-hourly sea level pressure fields, available from the National Center for Environmental Prediction-National Center for Atmospheric Research reanalyses II for the 1979-2003 period. The spatial distribution of the cyclogenesis frequency shows two main centers: one around Northern Argentina, Uruguay, and Southern Brazil in all seasons and the other near to the North Antarctic Peninsula. The lifetime of extratropical cyclones in the South American sector exhibits small seasonality, being typically of the order of 3.0 days during most of the year and slightly higher (3.5 days) in austral summer. The distance travelled by the cyclones formed in the South American sector tends to be smaller than the total paths found in other areas of the Southern Hemisphere. A k-mean clustering technique is used to summarize the analysis of the 25-year climatology of cyclone tracks. Three clusters were found: one storm-track cluster in Northeast Argentina; a second one west of the Andes Cordillera; and a third cluster located to the north of the Antarctic Peninsula (around the Weddell Sea). The influence of the Antarctic Oscillation (AAO) in the variability of extratropical cyclones is explored, and some signals of the impacts of the variability of the AAO can be observed in the position of the extratropical cyclones around 40A degrees S, while the impacts on the intensity is detected around 55A degrees S. (AU)

• FAPESP's process: 07/50145-4 - Improving meteorological downscaling methods with neural network models: South America rainfall
• Grantee: David Mendes
• Support Opportunities: Scholarships in Brazil - Post-Doctoral