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A glacier is an extensive body of land ice which moves downhill under its own weight in response to gravitational force, transporting ice from an area of accumulation to an area of ablation. Glaciers can form in a mountain region above the snow line where the perennial average amount of snow falling is greater than the amount of snow melting. The snow is gradually transformed into glacier ice which moves downhill reaching far down below the snow line. The key factors of ablation are the following: solar radiation, air temperature, precipitation and wind.

Changes in glacier volume and extent are an illustrative indicator of climate changes. During the last decade, the trend of rapid glacier retreat has been characteristic of all Alpine glaciers. In Slovenia, there are two glaciers, i.e. the Triglav glacier and the Skuta glacier, both exceptionally sensitive to climate changes due to their extreme south-eastern position and low elevation. Since the above mentioned Slovenian glaciers are small, their relative shrinkage in respect of their present extent and volume is greater than is the case with other Alpine glaciers.


Charts

Figure PS05-1: Changes in the Triglav glacier surface area
Sources: 

Anton Melik Geographical Institute at the Science and Research Centre of the Slovenian Academy of Sciences and Arts, 2007

Show data
1992 1995 1999 2003 2005 2006
surface ha 4.3 3 1.1 0.7 1.1 0.7
Figure PS05-2: Extent of the Triglav glacier by individual year
Sources: 

Anton Melik Geographical Institute at the Science and Research Centre of the Slovenian Academy of Sciences and Arts, 2006


Goals

Glaciers are highly sensitive to climate changes; therefore the oscillations in their surface area and volume constitute a reliable indicator of climate changes. Global understanding of climate changes can prove helpful in the preparation of adjustment procedures for the newly arising conditions and mitigation of possible adverse effects (National Environmental Action Programme).


Typical of all Alpine glaciers are similar oscillations within the last 400 years. Following the peak at the onset of the 17th century, glaciers remained at their maximum extents for the next 250 years, undergoing relatively insignificant changes. A majority of glaciers in the Eastern Alps reached their second peak between 1770 and 1780, and in the mid-19th century. However, the post-1920 period records a continuous retreat of glaciers; the only variations occurring between individual years and decades were those concerning the rate of glacier retreat. The Triglav glacier shrinking progressed during the 1990’s. The increasingly rapid thinning of the ice sheet caused individual rock formations appearing in the middle of the glacier finally cutting it into two completely separated parts in 1992. The shrinking of the Triglav glacier is still continuing, with occasional halts in the process occurring in years with exceptionally high snow cover during late spring.

Similar trends are typical of all Alpine glaciers. The variations in change rates are the result of different elevations, geographical positions and glacier extents.


Ever since 1946, the Anton Melik Geographical Institute at the Science and Research Centre of the Slovenian Academy of Sciences and Arts conducts regular annual measurements of the Triglav and Skuta glaciers.

In 1946, measuring points were set up around the Triglav glacier from which the distance to the glacier was measured with a measuring tape. On the basis of these measures glacier drawings were made by individual year as well as assessments of the glacier's surface area. With the glacier retreating, several measuring points became too remote, and subsequent years saw the establishment of new ones. Given that the locations of all measuring points are geodetically measured, it has been possible all these years to make fairly accurate calculations of the glacier's surface area. Along with performing measurements, the expert team of the Anton Melik Geographical Institute also took regular photographs of the glacier from the Begunjski vrh. Moreover, these photographs serve as an excellent source for the reconstruction of the glacier's extent throughout the past decades. Since 1976, there is also a regular monthly photographing of the glacier from two fixed locations on Kredarica. As a rule, regular annual measurements are performed in mid-September, at the end of the melting period. In individual years measurements were, however, rendered impossible by early snow falls.

In 1952, 1995 and 1999, the glacier was also measured geodetically. Since 1999, an airborne photogrametric survey has been organised every second year. This photographic material has facilitated the calculations of changes in the glacier’s surface area and volume between individual years.
In 1999 and 2001, geo-radar measurements were carried out for the provision of data on ice layer thickness by individual cross-section.

Data for Europe: World Glacier Monitoring Service based in Zurich collects data on glacier oscillations. In several glaciers, the series of data dates as far back as 1894.


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