Climate of Brazil's nordeste and tropical atlantic sector: preferred time scales of variability

Autor: Dierk Polzin, Stefan Hastenrath
Jazyk: English<br />Portuguese
Rok vydání: 2014
Předmět:
Zdroj: Revista Brasileira de Meteorologia, Vol 29, Iss 2, Pp 153-160 (2014)
Druh dokumentu: article
ISSN: 1982-4351
0102-7786
DOI: 10.1590/S0102-77862014000200001
Popis: Resuming earlier research, this study explores rainfall variability in Brazil's Nordeste and underlying circulation mechanisms. The semi-arid northern Nordeste has its short rainy season centered around March-April-May, when temperature maximum, low pressure trough and wind confluence reach their southernmost position. Interannual variability can be understood as departures from the average annual cycle. Based on novel long-term datasets, the present study explores the preferred time scales of variability. In Nordeste rainfall and pertinent circulation indices in the tropical Atlantic sector most prominent are frequencies of 13.2, 9.9 and 5.6 years. Frequency peak of 13.1 years appears also in the record of Southern Oscillation, and of 5.6 years in North Atlantic Oscillation, indicative of causality chain.
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