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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Intraseasonal variability of the Atlantic Intertropical Convergence Zone during austral summer and winter

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Nobile Tomaziello, Ana Carolina ; Carvalho, Leila M. V. ; Gandu, Adilson W.
Total Authors: 3
Document type: Journal article
Source: Climate Dynamics; v. 47, n. 5-6, p. 1717-1733, SEP 2016.
Web of Science Citations: 6

The Atlantic Intertropical Convergence Zone (A-ITCZ) exhibits variations on several time-scales and plays a crucial role in precipitation regimes of northern South America and western Africa. Here we investigate the variability of the A-ITCZ on intraseasonal time-scales during austral summer (November-March) and winter (May-September) based on a multivariate index that describes the main atmospheric features of the A-ITCZ and retains its variability on interannual, semiannual, and intraseasonal time-scales. This index is the time coefficient of the first combined empirical orthogonal function mode of anomalies (annual cycle removed) of precipitation, and zonal and meridional wind components at 850 hPa from the climate forecast system reanalysis (1979-2010). We examine associations between the intraseasonal variability of the A-ITCZ and the activity of the Madden-Julian oscillation (MJO). We show that during austral summer intraseasonal variability of the A-ITCZ is associated with a Rossby wave train in the Northern Hemisphere. In austral winter this variability is associated with the propagation of a Rossby wave in the Southern Hemisphere consistent with the Pacific-South American pattern. Moreover, we show that intense A-ITCZ events on intraseasonal time-scales are more frequent during the phase of MJO characterized by convection over western Pacific and suppression over the Indian Ocean. These teleconnection patterns induce anomalies in the trade winds and upper level divergence over the equatorial Atlantic that modulate the intensity of the A-ITCZ. (AU)

FAPESP's process: 10/17224-0 - Variability of the Atlantic Intertropical Convergence Zone during dry and rainy seasons of tropical South America
Grantee:Ana Carolina Nóbile Tomaziello
Support type: Scholarships in Brazil - Doctorate