Analyse dendrochronologique des variations passées du régime hydro-climatique au complexe de la Grande Rivière dans le Nord du Québec

Dendrochronological analysis of past hydro-climatic variations in La Grande river complex in Northern Québec. In order to retrace the evolution of the hydrological regime parameters with time, we have reconstructed the main hydroclimatological variables used in forecast models. The study was conduct...

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Bibliographic Details
Main Authors: Bégin, Yves, Nicault, Antoine, Bégin, Christian, Savard, Martine, Arseneault, Dominique, Berninger, Frank, Guiot, Joël, Boreux, Jean-Jacques, Perrault, Luc
Format: Article in Journal/Newspaper
Language:French
Published: Paris : Société Hydrotechnique de France 2007
Subjects:
geo
Online Access:https://www.persee.fr/doc/jhydr_0000-0001_2007_act_29_1_986
Description
Summary:Dendrochronological analysis of past hydro-climatic variations in La Grande river complex in Northern Québec. In order to retrace the evolution of the hydrological regime parameters with time, we have reconstructed the main hydroclimatological variables used in forecast models. The study was conducted in the region of the James Bay hydroelectric complex of La Grande. Trees occupying sites sensitive to water availability variations (xeric, mesic and hydric sites) and those sensitive to thermal conditions (depending on exposition) give the opportunity to reconstruct climate variability between years. A calibration period with instrumental data is essential and it is also important to verify the models relating rings to climate with independent data. More than one hundred tree-ring series covering more than 180 years, tens series of more than 250 years and one series covering one thousand years have been reconstructed. These tree-ring series cover an area of 320 000 km² (800 km in longitude x 400 km in latitude). Summer temperatures, snow precipitation and seasonal water supply were reconstructed over the past 200 years by means of various tree-ring proxies : ring width, density (9 derived variables) and ratios of stable isotopes of oxygen and carbon. Dans le but de retracer les paramètres du régime dans le temps, nous avons reconstitué les principales variables hydro-climatiques servant dans les modèles de prévision hydrologique. Le travail porte sur un territoire de 3 200 km2 couvrant le complexe hydroélectrique de La Grande Rivière. Les arbres occupant des sites sensibles aux variations hydriques (milieux secs, mésiques ou hydriques) et aux conditions thermiques (selon leur exposition) offrent la possibilité de reconstituer les variations interannuelles du climat. Une période de calibration est nécessaire avec les données instrumentales et le modèle exprimant la relation cernes -climat est aussi vérifié sur la base de données indépendantes. Plus de 100 dendroséries de plus de 180 ans, une dizaine de plus de ...