Villar J. C. E. auteur aut IRD Guyot Jean-Loup auteur aut IRD Ronchail Josyane auteur aut IRD Cochonneau Gérard auteur aut IRD Filizola N. auteur aut IRD Fraizy Pascal auteur aut IRD Labat D. auteur aut IRD de Oliveira E. auteur aut IRD Ordonez J. J. auteur aut IRD Vauchel Philippe auteur aut IRD text journalArticle eng text/pdf born digital access Former hydrological studies in the Amazon Basin generally describe annual discharge variability on the main stem. However, the downstream Amazon River only represents the mean state of the Amazonian hydrological system. This study therefore uses a new data set including daily discharge in 18 sub-basins to analyze the variability of regional extremes in the Amazon basin, after recalling the diversity of the hydrological annual cycles within the Amazon basin. Several statistical tests are applied in order to detect trends and breaks in the time series. We show that during the 1974-2004 period, the stability of the mean discharge on the main stem in Obidos is explained by opposite regional features that principally involve Andean rivers: a decrease in the low stage runoff, particularly important in the southern regions, and an increase in the high stage runoff in the northwestern region. Both features are observed from the beginning of the nineties. These features are also observed in smaller meridian sub-basins in Peru and Bolivia. Moreover we show that the changes in discharge extremes are related to the regional pluriannual rainfall variability and the associated atmospheric circulation as well as to tropical large-scale climatic indicators. specialized Amazon basin Discharge trend Rainfall and runoff variability Brazil Peru Bolivia 062 375 3-4 297-311 2009 0022-1694 https://www.documentation.ird.fr/hor/fdi:010048252 10.1016/j.jhydrol.2009.03.004 0022-1694 [F B010048252] https://www.documentation.ird.fr/hor/fdi:010048252 https://www.documentation.ird.fr/intranet/publi/2009/10/010048252.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2009-11-09 2017-08-23 fdi:010048252 fre