Christopher C. Burt is the author of 'Extreme Weather; A Guide and Record Book'. He studied meteorology at the Univ. of Wisconsin-Madison.
By: Christopher C. Burt , 8:16 PM GMT on August 25, 2012
Unprecedented snow melt and heat in the European Alps
The recent heat wave in Europe has especially been anomalous at higher altitudes resulting in some of the highest Alpine peaks in Europe being snow-free for the first time on record including the iconic peak Matterhorn.
Early snow melt and record temps at mountain-top stations in the Alps
On August 19th the temperature at Jungfraujoch, Switzerland (the highest railway station in Europe) reached 12.8°C (55.0°F) the warmest temperature ever measured at this site where records began in 1937. This observatory is located at an elevation of 3580m (11,745’) just above the famous railway station.
The Jungfraujoch Observatory of Switzerland is located at an elevation of 3580m (11,745’) and recorded its warmest temperature on record on August 19th this summer with a 12.8°C (55.0°F) reading. Photographer unknown (from Swiss tourism site). Please note that this photograph, and the others following, are archive images of these Alpine sites and do not represent the current situation.
The significance of this is that this site has been studied by European climatologists for 75 years and is considered a 'bell-weather' location because of its long POR and isolation from surrounding possible human-induced influence.
The Jungfraujoch Observatory has the longest (since 1937) temperature time series of any high-altitude (3000m+) weather station in Europe. Graphic and caption from Meteo Swiss.
Another site on the border of Switzerland and Italy near the summit of Mt. Rosa (2nd highest mountain in the Alps after Mt. Blanc) named Capanna Regina Margherita (also known as Mt. Signalkuppe) and located at an elevation of 4554m (14,940’) registered a record temperature of 8.3°C (47.0°F) on August 20th. This surpassed its previous record high of 7.2°C (45.0°F) although records have only been kept here for about 15 years. The minimum temperature at the site that day was -0.1°C (31.8°F), also a record. This is the highest weather station in Europe. The Plateau Rosa near here is snow-free for the first time on record.
The amazing Capanna Regina Margherita is the highest Alpine hostel in Europe at 4554m (14,940’). Weather records here go back to about 2000. On August 20, it measured its warmest temperature on record with a reading of 8.3°C (47°F). Photo from Italian Alpine club web site.
Aguille du Midi, a mountain in the Mt. Blanc massif in the French Alps, with an elevation of 3842m (12,605’) registered a high of 13.4°C (56.1°F) and low of 4.7°C (40.5°F) on August 19th, both records for the site since it was built in 1955. The peak is accessible by a cable car from the ski resort of Chamonix, France. Chamonix (elevation 1035m/3,396’) also recorded its all-time record warmest temperature on August 20th with a 34.4°C (93.9°F) reading. For the first time on record the peak of Aguille du Midi is now snow-free.
Another one of Europe’s spectacular high mountain observatories is just below the peak of Aguille du Midi above the French ski resort town of Chamonix. Both locations registered their warmest temperatures on record last week. Photographer unknown (from Chamonix tourist promotion site).
For the first time in memory many of the highest Alpine peaks, including the iconic Matterhorn, have lost their entire snow cover (aside from glaciers). Sonnblick Observatory in Austria (located at 3030 m/9,940’) had its earliest snow melt on record this summer when the last of the winter snow disappeared by July 31st. The previous earliest snow melt (since records began here in 1886) was August 12th, 2003, the year of the famous European heat wave.
Alpine Glacier Melt
It has been widely recognized (and researched) that most of Europe’s Alpine glaciers have been in retreat for the past 60 years or so. How much of this is due to solar radiation and how much to Global Climate Change remains a center of debate although it would seem that the two are related. An article in Geophysical Research Letters (Vol. 36, 2009) by M. Huss et al studied a 94-year time series of annual glacier melt at four high elevation sites in the Alps and found that the first massive melt off occurred in the late 1940s when “global shortwave radiation over the summer months was 8% above the long-term average and significantly higher than today”. Dimming of solar radiation from the 1950s until the 1980s reduced glacial melt rates. In the 1990s to the current time solar radiation has increased again but this time (since 2000) has also been accompanied by warmer summertime surface temperatures. Thus the glacial melt rates have exponentially increased in the past decade.
A graphic illustrating the Alpine glacier loss at 10 sites in Switzerland between 1980 and 2003. World Glacier Monitoring Service, Zurich.
NASA released this statement at the annual AGU (American Geophysical Union) meeting in San Francisco last December (2011):
“Dec. 12, 2011: A new glacier inventory of the French Alps produced by Marie Gardent and colleagues at the University of Savoie has found that 100 square kilometers of glacier area has been lost between the early 1970s and today—a 26 percent loss. Using Landsat data together with historical aerial photography and maps, Gardent was able to evaluate and compare historic and contemporary glacier surface area.”
The BBC science correspondent, Jonathan Amos, summarized the AGU findings in this article he posted from the conference;
”Glaciers in the French Alps have lost a quarter of their area in the past 40 years, according to new research.
In the late 1960s/early 1970s, the ice fields slipping down Mont Blanc and the surrounding mountains of the European range covered some 375 sq km.
By the late 2000s, this area had fallen to about 275 sq km. The research has been presented at the American Geophysical Union (AGU) Fall Meeting, the world's largest annual gathering of Earth scientists.
It mirrors some findings of retreat occurring in other sectors of the Alps which sit across the borders of several nations, but predominantly Switzerland, Austria, Slovenia, Germany, France, and Italy.
The new French Alps glaciers inventory was produced by Marie Gardent, from the University of Savoie, and colleagues.
It assessed the roughly 600 glaciers in broad areas incorporating the Ecrins, Belledonne, Vanoise, Ubaye and Grande Rousse Arves massifs, as well as the famous Mont Blanc Massif in the north.
The team drew upon map archives, past satellite imagery and aerial photographs. Manual inspection was used to check the automatic delineation methods employed in the pictures was correct.
"We use manual delineation to verify the satellite data because there can be a problem with debris cover on a glacier," explained Ms Gardent.
Automatic delineation from satellite data will sometimes say there is no glacier when in fact we know there is one there. Also, deep shadows can hide the glacier margins."
A great deal of effort is now going into monitoring the status of Alpine glaciers.
The only existing glacial inventory from the French Alps was published four decades ago within the context of the World Glacier Inventory. It found the overall area of ice to be about 375 sq km.
By 1985-86, in spite of a short advancing period in the late 70s/early 80s, glacial coverage had decreased to a value close to 340 sq km, the new survey shows.
Since then, the withdrawal has accelerated, with the area being reduced to about 275 sq km in the late 2000s.
This represents an average loss of some 26% over the last 40 years. The retreat is not uniform across the French Alps, however. The greatest losses have been seen in the southern sectors. In the Belledonne Massif, for example, glaciers have almost completely disappeared; and in the Ecrins Massif, glacial retreat is more than three times stronger than in the Mont Blanc Massif.
“The glacier retreat is less important in the northern Alps than in the southern Alps," Ms Gardent emphasized, "We think this is because of the lower elevation of the mountains in the south, but also because of climatic conditions which are different. There is more precipitation in the north and there is also more cloud."
The northern region includes the biggest French glacier of all - La Mer de Glace, which falls over a 1,000m in altitude down Mont Blanc itself. Its area today is just over 30 sq km, a shade smaller than the 31.5 sq km in the late 1960s/early 1970s.
Efforts to assess and monitor glacier health are going on across the Alpine region.
At this very meeting three years ago, Swiss researchers reported that glaciers on their part of the European range were also losing mass at an accelerating rate.
The Pasterze Glacier in Austria as photographed in 1875 (top) and then again in 2004 (bottom). Bottom photo by Gary Braasch.
This summer has, no doubt, also had a dramatic affect on the on-going Alpine glacial retreat given the record warm temperatures measured at the highest elevations of the mountains.
KUDOS: Maximiliano Herrera for latest temperature data at high-altitude Alpine weather stations.
Strong Alpine glacier melt in the 1940s due to enhanced solar Radiation, Geophysical Research Letters (Vol. 36, Dec. 3, 2009) by M. Huss, M. Funk, and A. Ohmura.
French Alpine glaciers in retreat By Jonathan Amos Science correspondent, BBC News, December 6, 2011
“Potential climatic transitions with profound impact on Europe. Review of the current state of six ‘tipping elements of the climate system’ by Anders Levermann, Jonathan L. Bamber, Sybren Drijfhout, Andrey Ganopolski, Winfried Haeberli, Neil R. P. Harris, Matthias Huss, Kirstin Krüger, Timothy M. Lenton and Ronald W. Lindsay, et al. Climate Change (journal) Vol. 110, No. 3-4 (2012)
Christopher C. Burt
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