Mass Balance of Langenferner
Langenferner is a small valley glacier in the eastern Alps, located at the head of Martell-Valley, in the Ortles-Cevedale Group in the Autonomous Province of Bozen, northern Italy (46.47° North / 10.60° East). The glacier surface area is 1.61 km² (2013) and it extends from 3370 down to 2711 m a.s.l. Langenferner is one of several glaciers flowing down from the Cevedale-Massive. Its upper section is mainly exposed to the North, while the tongue is flowing eastwards. The glacier is part of the catchment of the river Plima which comprises an area of 162 km² and contributes to the river Etsch, the main water resource for the intensive agriculture in the Vinschgau.
Area changes are detected using differential GPS, as well as data originating from airborne LIDAR-campaigns in 2005, 2011 and 2013 and Orthophotos (2008). In the period 2005 to 2013 the glacier area reduced from 1.86 km² to 1.61 km² in 2013 reflecting a tongue retreat of about 280 m during the same period.
Ground penetrating radar measurements were carried out by the ACINN in spring 2010 which resulted in an estimated ice volume of approximately 0.08 km³ with a maximum thickness of about 130 m in the upper glacier part.
As other long term glacier monitoring programs in the region (Careser Glacier since 1967 and Weißbrunnferner since 1983) seem to be (i) threatened by the massive glacier retreat during the recent decades and (ii) are considered to be of limited regional representativity, the Langenferner program was initiated in 2003 in order to create a new monitoring site which allows the temporal extension of glaciological monitoring in this region into the upcoming decades.
The mass balance studies are carried out by the ACINN in cooperation with the Hydrographic Office Bozen applying the direct glaciological method. Full winter balance measurements are performed annually at the beginning of May. Ice ablation is measured at 29 (2014) operational ablation stakes which are commonly read two to six times a year - depending on the respective location. Accumulation is measured in snow pits at the end of the hydrological year in late September.
The first ten years of the mass balance record show a persistent mass loss in the range of -221 mm w.e. (2013) to -1637 mm w.e. (2008). Winter balance values in the same period range from 642 mm w.e. in the exceptionally dry winter 2006/07 to 1343 mm w.e. in 2008/09 (see Table 1 for detailed information on the measured mass balances).
The mass balance of 2013/14 was the only positive mass balance measured at Langenferner.
Exceptional precipitation amounts during Winter 2013/14 led to very high winter accumulation at the glacier (winter balance: 1642 mm w.e.). The relatively cool summer 2014 with several summer snow falls at least in the upper parts of the glacier, together with the persistent winter snow cover and hence high albedo resulted in low melt rates during the ablation season.
b_a [mm w.e.]
b_w [mm w.e.]
b_s [mm w.e.]
Table 1: Glaciological key parameters for the ten observation years at Langenferner: glaciated area derived from airborne laser scanning or Orthophotos (2008), mean specific mass balance b_a, mean specific winter balance b_w, mean specific summer balance b_s, equilibrium line altitude ELA and accumulation area ratio AAR.
The results of the mass balance studies are submitted annually to the World Glacier Monitoring Service. Annual short reports are published by the Hydrographic Office Bozen: http://www.provinz.bz.it/wetter/glacierreport.asp.
Detailed information on the measurements in the form of annual reports is available at the ACINN on request.