Tree-ring stable isotopes for regional discharge reconstruction in eastern Labrador and teleconnection with the Arctic Oscillation

• Published in: Climate Dynamics
• Main Authors: Dinis, Lauriane, Begin, Christian, Savard, Martine, Marion, Joëlle, Brigode, Pierre, Alvarez, Cristian
• Other Authors: Geological Survey of Canada Québec (GSC Québec), Geological Survey of Canada - Office (GSC), Natural Resources Canada (NRCan)-Natural Resources Canada (NRCan), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Sud ), Centre Eau Terre Environnement Québec (INRS - ETE), Institut National de la Recherche Scientifique Québec (INRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Arctic; Canada; Churchill River
• Online Access: https://hal.science/hal-02272513; https://doi.org/10.1007/s00382-019-04731-2

International audience In northeastern Canada (Labrador), instrumental climatic data cover less than 70 years and long reconstructions from natural archives are non-existent. This study specifically aims at helping filling this gap of knowledge by testing the possibility of reconstructing the regional 1800–2009 discharge of the lower Churchill River from black spruce tree-ring δ13C and δ18O series. The results illustrate direct relationships of summer climatic variables/derived parameter (maximum temperature, total precipitation and vapor pressure deficit) with tree-ring isotope values. Importantly, they show an inverse correlation between combined tree-ring isotope series and regional river discharge due to common climate forcing. To a lesser extent, transpiration also affects the river discharge and tree-ring isotopic compositions. The reconstructed river discharge series agrees with an independent reconstruction based on the ANATEM method (1880–2009 period). The agreement between the two reconstructions validates the two approaches for reconstructing regional hydroclimatic conditions at high latitudes. Moreover, the reconstructions suggest that summer discharge has decreased over the past 200 years in eastern Labrador and more broadly at the Québec-Labrador peninsula scale. This trend correlates with the long-term summer Arctic Oscillation (AO) that influences summer regional climatic conditions. This research contributes with other studies to build up observations linking summer AO and eastern Canada climatic conditions, and calls for research on mechanisms explaining these relationships during summer.