Articles | Volume 9, issue 5
Research article
08 Sep 2015
Research article |  | 08 Sep 2015

Evolution of Ossoue Glacier (French Pyrenees) since the end of the Little Ice Age

R. Marti, S. Gascoin, T. Houet, O. Ribière, D. Laffly, T. Condom, S. Monnier, M. Schmutz, C. Camerlynck, J. P. Tihay, J. M. Soubeyroux, and P. René

Abstract. Little is known about the fluctuations of the Pyrenean glaciers. In this study, we reconstructed the evolution of Ossoue Glacier (42°46' N, 0.45 km2), which is located in the central Pyrenees, from the Little Ice Age (LIA) onwards. To do so, length, area, thickness, and mass changes in the glacier were generated from historical data sets, topographical surveys, glaciological measurements (2001–2013), a ground penetrating radar (GPR) survey (2006), and stereoscopic satellite images (2013). The glacier has receded considerably since the end of the LIA, losing 40 % of its length and 60 % of its area. Three periods of marked ice depletion were identified: 1850–1890, 1928–1950, and 1983–2013, as well as two short periods of stabilization: 1890–1894, 1905–1913, and a longer period of slight growth: 1950–1983; these agree with other Pyrenean glacier reconstructions (Maladeta, Coronas, Taillon glaciers). Pyrenean and Alpine glaciers exhibit similar multidecadal variations during the 20th century, with a stable period detected at the end of the 1970s and periods of ice depletion during the 1940s and since the 1980s. Ossoue Glacier fluctuations generally concur with climatic data (air temperature, precipitation, North Atlantic Oscillation, Atlantic Multidecadal Oscillation). Geodetic mass balance over 1983–2013 was −1.04 ± 0.06 w.e.a−1 (−31.3 ± 1.9 m w.e.), whereas glaciological mass balance was −1.45 ± 0.85 m w.e. a−1 (−17.3 ± 2.9 m w.e.) over 2001–2013, resulting in a doubling of the ablation rate in the last decade. In 2013 the maximum ice thickness was 59 ± 10.3 m. Assuming that the current ablation rate remains constant, Ossoue Glacier will disappear midway through the 21st century.

Short summary
Pyrenean glaciers are currently the southernmost glaciers in Europe. Using an exceptional archive of historical data sets and recent accurate observations, we propose the reconstruction of the length, area, elevation, and mass balance of Ossoue Glacier (French Pyrenees) since the Little Ice Age. We show that its evolution is in good agreement with climatic data. Assuming that the current ablation rate stays constant, Ossoue Glacier will disappear midway through the 21st century.