Heterogeneous spatiotemporal streamflow response to large-scale climate indexes in the Eastern Alps

• Published in: Journal of Hydrology
• Main Authors: Pérez-Ciria, Teresa, Labat, David, Chiogna, Gabriele
• Other Authors: Technische Universität Munchen - Technical University Munich - Université Technique de Munich (TUM), Ludwig Maximilian University Munich = Ludwig Maximilians Universität München (LMU), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), Leopold Franzens Universität Innsbruck - University of Innsbruck, The first author acknowledges funding from the Doktoratsstipendium aus der Nachwuchsförderung and Frankreich-Schwerpunkt (Reise zu französischem Kooperationspartner) from the University of Innsbruck, the TUM ForTe - Forschungsförderung und Technologietransfer and the funding from the EU Horizon 2020 innovation action programme ARSINOE (Climate-resilient regions through systemic solutions and innovations) under Grant Agreement 101037424., European Project: 101037424,ARSINOE
• Format: Article in Journal/Newspaper
• Language: English
• Published: CCSD 2022
• Subjects: Streamflow variability; Wavelet analysis; Climatic indexes; Spatiotemporal patterns; Teleconnections; [SDU]Sciences of the Universe [physics]; [SDE]Environmental Sciences; Greenland; North Atlantic; North Atlantic oscillation
• Online Access: https://insu.hal.science/insu-04831629; https://doi.org/10.1016/j.jhydrol.2022.128698

International audience Analyzing temporal and spatial variability of river discharge and the impacts of large-scale climate oscillations on hydrological systems are of particular interest in Alpine catchments, which have been proved to be especially sensitive to climatic drivers. The impact of climate oscillation indexes may show a delayed response and therefore the correlation between climatic drivers and streamflow is challenging to be properly identified. For this purpose, wavelet transform (WT) is recognized as a suitable tool able to determine the crucial scales of variability. In this work, first we explore the periodicities and the coherence among several climatic indexes: North Atlantic Oscillation Index (NAO), Mediterranean Oscillation Index (MO), Greenland Blocking Index (GB), and Artic Oscillation Index (AO). This analysis shows the complementary information that different oscillation indexes provide and the need to consider their impacts on streamflow simultaneously. Previous work revealed a heterogeneous and complex response of the Inn river basin at long temporal scales, which could not be linked to analyzed anthropogenic impacts such as dams' construction and hydropower plants operation. Therefore, the trigger of changes in streamflow variability remained unclear. In this study, we elaborate a classification based on all considered indexes' coherence with fifty gauging stations of the Inn river catchment. We quantify similarity among stations with a focus on yearly and longer temporal scales. The results highlight the heterogeneous response of the streamflow towards changes in climatic indexes and give an overview of the possible drivers of detected long-term alterations. NAO and GB extreme phases are connected with cold winters and hot summers. We observe that from the 1980s changes detected in the streamflow behavior at yearly and longer temporal scales are in line with emerging patterns of the climatic indexes, such as the shift from constant to intermittent periodicities of the MO index. AO ...