English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

This work analyzes the relationship between climatic index and rainfall in the Northeastern (NE) and Southern (S) Brazil, in decadal timescale. The climatic indices were obtained from the reanalysis data from NCEP/NCAR (National Center for Environmental Prediction/National Center for Atmospheric Research) between 1948 and 2008. Subsequently, (indices and rainfall correlation coefficients derived from the GPCP (Global Precipitation Climatology Project) dataset were calculated using filtered and non-filtered time series, within the decadal frequency). The results show that ElNi ˜no Southern Oscillation (ENSO) is the main phenomenon influencing NE rainfall due to related changes in tropical circulation while the Intertropical Convergence Zone (ITCZ) annual cycle also affects rainfall in the NE to a lesser extent. Meanwhile, in the Southern region, the most important phenomenon is the Southern Annular Mode (SAM) which controls cyclones activity in mid-latitudes. The Tropical Atlantic dipole index (ADI) also influences the rainfall in the Southern, and this might be related to moisture being transported from the ocean to the continent, which is then carried to the South by the Low Level Jet. It is also suggested that the decadal variability of the Tropical Atlantic Ocean and its influence on the precipitation in NE andS regions of Brazil are episodic because no significant correlations were obtained at decadal frequency. Finally, the spectral analysis revealed that the interannual timescale is the main frequency of variability in both studied regions, affecting differently each one of them. RESUMO: Este trabalho analisa as relacoes entre indices climaticos e a precipitacao no Nordeste (NE) e Sul (S) do Brasil, em escala decadal. Os indices climaticos foram obtidos a partir de dados da reanalise do NCEP/NCAR (National Center for Environmental Prediction/National Center for Atmospheric Research), para o periodo de 1948 a 2008. Posteriormente, foram obtidos os coeficientes de correlacao entre os indices e as anomalias de precipitacao advindas do banco de dados do GPCP (Global Precipitation Climatology Project) nestas regioes, utilizando series nao filtradas e series filtradas na frequencia decadal. Os resultados sugerem que o principal fenomeno que modula a precipitacao no NE e o El Ni˜no-Oscilacao Sul (ENOS), devido as alteracoes na circulacao tropical, e tambem o ciclo anual da Zona de Convergencia Intertropical (ZCIT), que modula a estacao chuvosa do NE. Na regiao S, o fenomeno que mais influencia a precipitacao em escala decadal e o Modo Anular Sul (SAM), por modular a atividade ciclogenetica em latitudes medias, alem do indice do dipolo do Atlântico Tropical (DA), que pode estar ligado ao aporte de umidade oceânica para o continente, e levada ao S pelo jato de baixos niveis. Tambem se sugere que a variabilidade decadal do Atlântico tropical e sua influencia na precipitacao no NE sejam episodicas, e nao periodica, ja que nao foram obtidas correlacoes importantes para este indice, na frequencia estudada. Finalmente, a analise espectral revelou que a escala interanual e a principal frequencia de variabilidade temporal em ambas as regioes, com efeitos diversos em cada uma delas. Palavras-chave : precipitacao, ENOS, Atlântico, SAM.

PLANETARY-SCALE CLIMATIC INDICES AND RELATIONSHIP BETWEEN DECADAL VARIABILITY OF RAINFALL IN NORTHEASTERN AND SOUTHERN BRAZIL