Browsing by Author "Barichivich, Jonathan"

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    Recent intensification of Amazon flooding extremes driven by strengthened Walker circulation
    (American Association for the Advancement of Science: Science Advances, 2018-09-19) Barichivich, Jonathan; Gloor, Emanuel; Peylin, Philippe; Brienen, Roel J. W.; Schöngart, Jochen; Espinoza, Jhan Carlo; Pattnayak, Kanhu C.
    The Amazon basin is the largest watershed on Earth. Although the variability of the Amazon hydrological cycle has been increasing since the late 1990s, its underlying causes have remained elusive. We use water levels in the Amazon River to quantify changes in extreme events and then analyze their cause. Despite continuing research emphasis on droughts, the largest change over recent decades is a marked increase in very severe floods. Increased flooding is linked to a strengthening of the Walker circulation, resulting from strong tropical Atlantic warming and tropical Pacific cooling. Atlantic warming due to combined anthropogenic and natural factors has contributed to enhance the change in atmospheric circulation. Whether this anomalous increase in flooding will last depends on the evolution of the tropical inter-ocean temperature difference.
    Palabras clave:FloodAtmospheric circulationHidrology
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    Record-breaking warming and extreme drought in the Amazon rainforest during the course of El Niño 2015–2016
    (Nature Research, 2016-09-08) Jiménez-Muñoz, Juan C.; Mattar, Cristian; Barichivich, Jonathan; Santamaría-Artigas, Andrés; Takahashi, Ken; Malhi, Yadvinder; Sobrino, José A.; Van der Schrier, Gerard
    The El Niño-Southern Oscillation (ENSO) is the main driver of interannual climate extremes in Amazonia and other tropical regions. The current 2015/2016 EN event was expected to be as strong as the EN of the century in 1997/98, with extreme heat and drought over most of Amazonian rainforests. Here we show that this protracted EN event, combined with the regional warming trend, was associated with unprecedented warming and a larger extent of extreme drought in Amazonia compared to the earlier strong EN events in 1982/83 and 1997/98. Typical EN-like drought conditions were observed only in eastern Amazonia, whilst in western Amazonia there was an unusual wetting. We attribute this wetdry dipole to the location of the maximum sea surface warming on the Central equatorial Pacific. The impacts of this climate extreme on the rainforest ecosystems remain to be documented and are likely to be different to previous strong EN events.
    Palabras clave:Climate-change impactsEnvironmental impactENSO