The mass balance of a glacier is the net balance between the mass gained by snow deposition and the loss of mass by melting and calving (production of icebergs).
From 2000, our research team takes care of the maintenance of a net of poles for mass balance and ice velocity measurements deployed on Johnsons and Hurd glaciers, near the Spanish Antarctic Station Juan Carlos I, Livingston Island, South Shetland. The aim of the mass balance and ice velocity measurements is to provide input data to the studies that relate glacier dynamics and climate, and, in particular, to the numerical simulations of the response of glaciers to climate changes.
These measurements are especially important in the case of the South Shetland glaciers, because they have a large proportion of temperate ice (i.e., ice at or near the melting temperature) and, therefore, are particularly sensitive to climate warming, as any increase in temperature immediately results in ice melting and flow acceleration by increased sliding of the glacier on its bed because of the higher amount of water available at the ice-bed interface. The study of Livingston Island ice cap during the last decade, jointly developed by our research team and the group of glaciology of the Department of Geodynamics and Geophysics of the University of Barcelona, has shown a clear dependence of the mass balance and ice velocity measurements with the meteorological trends observed in the South Shetland Islands and the Antarctic Peninsula region.
Some samples of the glacial recession are the images of the retreat of most ice fronts of Livingston Island glaciers during the period 1956-1996 (Calvet et al., 1999) and changes in ice volume of Hurd Peninsula glaciers during such period (Molina et al., 2007), the latter representing a 10% decrease in ice volume.
Calvet, J., García Sellés, D. y Corbera, J. (1999). Fluctuaciones de la extensión del casquete glacial de la isla Livingston (Shetland del Sur) desde 1956 hasta 1996. Acta Geológica Hispánica, 34, 365-374.
Molina, C., Navarro, F.J., Calvet, J., García-Sellés, D. y Lapazaran, J.J. (2007). Hurd Peninsula glaciers, Livingston Island, Antarctica, as indicators of regional warming: ice volume changes during the period 1956-2000. Annals of Glaciology, 46, 43-49.