Decay of a long-term monitored glacier: Careser Glacier (Ortles-Cevedale, European Alps)

Abstract

Abstract. The continuation of valuable, long-term glacier observation series is threatened by the accelerated mass loss which currently affects a large portion of so-called "benchmark" glaciers. In this work we present the evolution of the Careser Glacier, from the beginning of systematic observation at the end of the 19th century to its current condition in 2012. In addition to having one of the longest and richest observation records among the Italian glaciers, Careser is unique in the Italian Alps for its 46 yr mass balance series that started in 1967. In the present study, variations in the length, area and volume of the glacier since 1897 are examined, updating and validating the series of direct mass balance observations and adding to the mass balance record into the past using the geodetic method. The glacier is currently strongly out of balance and in rapid decay; its average mass loss rate over the last 3 decades was 1.5 m water equivalent per year, increasing to 2.0 m water equivalent per year in the last decade. Although these rates are not representative at a regional scale, year-to-year variations in mass balance show an unexpected increase in correlation with other glaciers in the Alps, during the last 3 decades. If mass loss continues at this pace, the glacier will disappear within a few decades, putting an end to this unique observation series.

Analysis of the mass balance time series of glaciers in the Italian Alps

“…It is characterized by a flat surface, prevailing southern exposure, quite low mean elevation and feeding by snowfall. Its area decreased from 5 km 2 in 1967 to 1.6 km 2 in 2012 (Carturan et al, 2013a). In the 1980s, observations started in two other glaciers of the Ortles-Cevedale: Fontana Bianca and Sforzellina.…”

“…yr −1 (WGMS, 2015;Carturan, unpublished data). Assessments based on the comparison between the direct and the geodetic mass balance have been published for the Careser, La Mare and Lunga glaciers, indicating that the discrepancy between the two methods is lower than the lowest detectable bias (following Zemp et al, 2013), and revealing that a calibration of the direct mass balance results is not required (Carturan et al, 2013a;Galos et al, 2015;Carturan, unpublished data).…”

Air temperature variability over three glaciers in the Ortles–Cevedale (Italian Alps): effects of glacier fragmentation, comparison of calculation methods, and impacts on mass balance modeling

“…This 36 km 2 experimental watershed is the subject of detailed studies concerning the impacts of climate change on the cryosphere and hydrology. The area has previously been selected for studying the behavior of meteorological variables at high altitude (Carturan et al, 2012b) and for developing an enhanced temperature-index glacier mass balance model (Carturan et al, 2012a , while La Mare Glacier still has an accumulation area and shows "active" retreat towards higher altitudes (Zanon, 1982;Small, 1995;Carturan et al, 2009Carturan et al, , 2014. Long-term monitoring programs started in 1967 on Careser and in 2003 on La Mare.…”

“…The study was focused on the variability of air temperature over the three glaciers which differ in size, geometric characteristics, and reaction to climatic changes (Carturan et al, 2014). In this paper, we analyze the temporal and spatial behavior of air temperature and glacier cooling effect in the study area, testing existing methods for calculating on-glacier temperatures from off-site data and evaluating their impact in mass balance simulations using a distributed enhanced temperature-index model.…”

“…It regulates the accumulation processes via the snowfall elevation limit and the snowpack metamorphism (which affect redistribution phenomena) and regulates the ablation processes via turbulent fluxes and long-wave radiation. It is also closely related to important feedbacks such as albedo, the mass balanceelevation feedback, and the glacier cooling effect, which changes as glaciers adjust their size in response to climatic fluctuations (Khodakov, 1975;Klok and Oerlemans, 2004;Paul et al, 2005;Raymond and Neumann, 2005;Haeberli et al, 2007;Fischer, 2010;Paul, 2010;Carturan et al, 2013).…”