Glaciological and volumetric mass-balance measurements: error analysis over 51 years for Glacier de Sarennes, French Alps

• Published in: Journal of Glaciology
• Main Authors: Thibert, Emmanuel, Blanc, R., Vincent, Christian, Eckert, Nicolas
• Other Authors: Érosion torrentielle, neige et avalanches (UR ETGR (ETNA)), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), GLACIOCLIM Observatoire de Recherce en Environnement (ORE), Programme d'Observation des Glaciers (POG), Institut National des Sciences de l'Univers, France (INSU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Journal of Glaciology
• Online Access: https://insu.hal.science/insu-00381089; https://insu.hal.science/insu-00381089/document; https://insu.hal.science/insu-00381089/file/glaciological-and-volumetric-mass-balance-measurements-error-analysis-over-51-years-for-glacier-de-sarennes-french-alps.pdf; https://doi.org/10.3189/002214308785837093

International audience The mass balance of Glacier de Sarennes, French Alps, has been measured since 1949, using the glaciological method based on core and ablation stake data, and area extrapolations, to find the overall glacier balance. The cumulative balance obtained in this way is very dependent on systematic errors that can increase linearly with the number, N, of measurement years, whereas random errors rise with √N. The volumetric−balance method based on aerial photogrammetry provides results whose errors do not depend on the number of years. This method was used to test field measurements for the period 1952-2003 and gives a mass balance of −32.30±1.04 m w.e. compared to −34.89±1.15 m w.e. based on field data. The discrepancy between the two methods is discussed on the basis of a careful error analysis. Moreover, the possibility of using the volumetric method to detect biases in field measurements is evaluated in terms of two types of errors. The number and locations of measurement sites required to account for all the spatial and temporal variabilities of the mass balance is discussed by variance analysis. Methodological implications and recommendations are presented to provide massbalance measurements of the best possible accuracy.