Browsing by Author "Schor, Tatiana"

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    Hydrologie et production agricole dans le nord-ouest de l'Amazonie
    (Bulletin de l’association de géographes français, 2016-09) Ronchail, Josyane; Schor, Tatiana; Espinoza, Jhan Carlo; Sabot, Manon; Pinheiro, Heitor; Filizola, Naziano; Gomez, Percy; Drapeau, Guillaume; Michot, Véronique; Guyot, Jean-Loups; Martinez, Jean-Michel; Sultan, Benjamín
    En « Amazonie des rivières », la période de basses eaux permet la mise en culture de vastes zones exondées et fertiles sur les berges des rivières et dans les plaines d'inondation. La variabilité des extrêmes hydrologiques et celle de la structure du cycle de décrue, facteurs réputés importants pour la qualité des récoltes sont explorés à la station fluviométrique de Tamshiyacu sur le fleuve Amazonas. Le riz, culture rentable dans cette région, est notre référence. Les résultats ne présentent pas les liens supposés entre résultats agricoles et durée de la saison de basses eaux ou vitesse de remontée des eaux. Néanmoins, ils montrent la baisse des étiages, l'allongement de la durée de décrue en relation avec un retard de la montée des eaux et une accélération de la remontée des faux pendant la période 1985-2015.
    Palabras clave:HydrologyHydrological cycleRecession period
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    The flood recession period in western Amazonia and its variability during the 1985–2015 period
    (Elsevier, 2018-02) Ronchail, Josyane; Espinoza, Jhan Carlo; Drapeau, Guillaume; Sabot, Manon; Cochonneau, Gérard; Schor, Tatiana
    Study region The upper Amazon River, where the water level measured at the Tamshiyacu station (Peru) shows seasonal variability of seven meters. Study focus Key parameters for the flood recession period (beginning, end and duration of the low-water period, velocity of water falling and rising, and inversions in the direction of stage change known as “repiquete” events) are analyzed for the period 1985–2015, along with their relationship to rainfall integrated in the upper Amazon basin at Tamshiyacu. New hydrological insights the low-water period lasts about four months, beginning, on average, at the end of July and ending in early November. Since the late 1990s, the low-water period has tended to end later, last longer and the flood recession ends more abruptly than it used to. This may be related to the increased frequency of dry days during the austral winter in the central and southern part of the basin and to increased and more intense rainfall in late spring (November–December). Repiquete events are frequent, 8 each year on average, and sometimes very acute: 18 events with a water-level reversal greater than one meter were registered during the 1985–2015 period. They are related to unusual, intense and extended rainfall during the week preceding the repiquete. Extensions of this preliminary work are suggested, as well as possible implications for recessional agriculture.
    Palabras clave:Flood recession periodWater levelRainfall