alps glacier change project

7/28/2019 Alps Glacier Change Project

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Scientific Research in Geography

Practical 8.

Alpine glaciers and their future.

Supervisor: Ian Evans Jan Feb. 2005

Where will your grandchildren be able to see

glaciers in the Alps? Starting from aninventory of late-twentieth-century glaciers,

changes can be predicted from glacier

altitude, aspect, gradient, size and type. A

given warming raises the snowline

(Equilibrium Line Altitude) and leads to

smaller glaciers. Thus analyses of the

present distribution can be used to predict

which glaciers will disappear, and how large

the remaining glaciers will be. Students will

be taught how to apply multiple regressions,

how to analyse aspect data with circular

statistics and graphics (within Stata), and how

to cope with missing data. Unfortunately

there can be no field trip; this is essentially an

applied data analysis practical. Inventories

can be supplied (and used) for other

mountain ranges if requested in week 1.

Week 1 Intro; the Alps, its glaciers and how

climate changes them. (CM 219)

2 Regression & graphs. (GRC computer

room)

3 Circular statistics.

4 Project completion

The aim is to use present data on glacier

distribution and characteristics to make somepredictions, based on assumptions (scenarios) of

climatic change. The objective is to explore

relations in a realistically large data set containing

different data types and some missing values.

This provides practice in statistical analysis and

interpretation using especially regression, scatter

plots, bar charts, and circular statistics. The

possibilities are multitudinous: you have freedom

to explore the data and develop the project in

whatever way you like. The following is a

suggestion:

Explore WGI-based data file (approximately

1970s situation) for 5183 glaciers in the Alps(from 1 ha upward)

Choose a region or glacier type and examine some

relations between variables (e.g. size and altitude).

Use relations provided to predict glacier ELA and

height range.

Produce maps and statistics of predicted glacier

distribution and characteristics e.g. for a) 1

warming cf. late C20; b) 3.5 warming; c) one

further scenario.

Include these in yourreport, commenting on

climatic sensitivities of glaciers, discussing

limitations and suggesting further work and/or

data needed.

Report text 1200 to 2000 words, 5 to 15 figures.

Data are provided on names, identifiers, location

(latitude and longitude, in decimal degrees, so

pseudo-maps can be plotted: at 46 N, 1 latitude is

111.15 km; of longitude, 77.47 km), regionallocation (see below), drainage basins, altitude

(highest and lowest), aspect, area, length (for a

subset; & estimated for all), gradient and type

(various classifications), and several derived

variables (e.g. height difference range in altitude,

and gradient) and transformations such as sine and

cosine of aspect, and log10 of length.

Data can be analysed at three spatial scales: 4

major divisions, 27 districts and 103 supergroups,defined on the basis of orography, compactness,

numbers (>20 per group, > 80 per district) and

similarity in glacier statistics. (Initially 133

glacier groups were defined, but some were too

small for statistical analysis.)

Report due Friday 18th Feb


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Alps Glacier Change Project, 2005:

I S Evans 17 January 2005

BACKGROUND

METHODS. Note that most changes involvetime-lags: it may be decades before mountain

glaciers adjust, and several oscillations (overshoot;

complex response) may occur before a new

equilibrium is attained, if ever.

The simplest way of changing glacier

distribution is to translate a climatic change into a

change deltain ELA (Equilibrium Line Altitude;

estimated as glacier mid-altitude), assuming that

the terminus changes but the upper limits remain

the same. Thus ifhigh and low are the initial

highest and lowest altitudes of a given glacier,

delta is achieved when low is changed by 2 delta.

Making the further assumptions that the change in

length from state1 to state 2 is in proportion to the

change in height range, and change in area is

proportional to the square of this change, it is easy

to estimate the glaciers extent in state 2.

For example, if a 2 km long glacier has an

area of 1.5 km2 and extends from 3500 to 2900 m

in state 1, an ELA rise of 120 m changes lowaltto

3140 m in state 2, and its height range is reduced

to 360/600 = 0.6 of the initial.Length in state 2 is then estimated at 0.6 * 2000 =

1200 m, and area as 0.36 * 1.5 = 0.540 km2. If

lowalt exceeds or equals highalt, the glacier will

disappear (in time).

Height difference, length and area can be

interrelated for a particular region or type of

glacier.

More sophisticated calculations are of

course possible, and you may propose changes

other than ELA rise. Mass balance curves aresteeper in the ablation zone, mainly because ice

has a higher albedo and melts faster than snow. A

change in precipitation might shift the mass

balance v altitude curve laterally, whereas a T

change is more likely to shift it vertically

(Oerlemans and Hoogendoorn 1989); or the

gradients may change. The latter (Table III)

suggest that in Austria (Sonnblick climate) ELA

will rise by 131 m per 1 rise in T, or fall by 228

m for an albedo rise of 0.1, 26 m for a 0.1 increase

in cloudiness, or 62 m for a 20% rise in

precipitation.

Some climatic changes will affect different

glaciers differently. Increased sunniness may have

a greater effect on south-facing glaciers, increased

cloud the opposite. Increased storminess may

favour leeward glaciers. Changed precipitation

may have a regional pattern, e.g. more change to

windward or to leeward, in the northern Alps or

the southern, in the outer massifs or the inner

(Kerschner & others, 2000). If retreat causes

massive rockfalls (by debuttressing), the debriswill greatly reduce melt in the covered glacier

(Benn & Lehmkuhl 2000).

P = pressure T = temperature


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GLACIER RESPONSE to climate changes.

Although changing velocities and

geometries may be influenced by changing ice

temperature, glacier drainage, water P,

longitudinal extension or subglacial deformation,

these effects are thought to be minor except insurging or calving glaciers. Most changes are

driven by mass balance, and hence climate and

albedo. In the Alps, glaciers are favoured by

oceanic winter conditions, cold springs, June

snowfall, and monsoonal summers: they suffer

from anticyclonic summer conditions and fine

September weather.

The effects of a given mass balance on

glacier activity depend on the existing state of the

glacier - whether it has recently thinned or

thickened, or been near balance. Changes in

accumulation and ablation work their way down

the glacier, affecting velocities and surface slopes,

and eventually producing advance or recession of

the terminus. Increased melt at the terminus may

cause immediate recession.

Neighbouring glaciers with different

geometries, aspects or altitudes may respond

differently. Components of mass balance vary

between climates; continentalglaciers have low

turnovers and are sensitive to variations in T (these

correlate with variations in cloudiness andradiation receipt). Maritime glaciers (in coastal

Alaska, B.C., Chile, Norway & Iceland) are

affected more by changes in snowfall, but are also

more sensitive to T changes than are continental or

sub-polar glaciers. (Alpine glaciers are sub-

maritime to sub-continental.)

Glacier surfaces respond immediately to

changes in local mass balance, but termini respond

with a time lag which increases with glacier

length, and decreases with ice velocity: their

variation integrates the various changes going on

upstream. For example, in response to 'the goodyears' of the 1970s, four Swiss glaciers


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GLACIERS IN THE ALPS

Alpine summits reach over 2000 m between 5.5E(Grand Vaymont, 2346 m) and 15.8E(Schneeberg, 2076 m); and between 44N (M.Saccarello, 2138 m) and 47.7N (Gross Piel, 2515m). According to inventories dating from the1970s, glaciers are found throughout the higher

parts of the Alps, from 5.9 to 14.6E and 44.1 to47.6N. East of 13.7E however, there are noglaciers in Austria, though various summits reachbetween 2000 and 2740 m. The two east-mostglaciers are in Slovenia, on Triglav and Skuto(Sifrer 1987). There are no glaciers in the FrenchPre-Alps southwest of the Arve or 6.8E, and onlya few small glaciers in the French-Italian FrontierRanges south of the Val di Susa (45.1N). Thewidening of the Alps east of the Rhine and Lago diComo is reflected in a broader distribution ofglaciers, albeit thinly scattered around theDolomites.

A map by Dainelli (1963) shows thesnowline at 2500 m in western Slovenia and alongthe northern margin of the Alps, and variousmaxima in high massifs, up to near 3200 m in thewest, on Monte Rosa and Monte Viso. (Thetreeline shows a broadly similar pattern.)Likewise Mller et als (1976) map of ELA inSwitzerland shows multiple maxima on internalmassifs. The present results confirm that ratherthan any linear trend, the snowline or EquilibriumLine Altitude (ELA) in the Alps rises from allsides toward the interior: its summary requiresmulti-term polynomials. It is a reflection largelyof the pattern of precipitation at altitudes around2900 m.

The 1990s have seen recession or thinningof almost all glaciers in the Alps, after thewidespread advances of 1965-85. For example inItaly, the 90 glacier fronts observed averaged 18 mhigher up in 1999 compared with 1980 (C.G.I.website): in 1986 they had been 7 m lowerthan in1980 Horizontal recession averaged 95 m. 1990sloss is associated with temperatures higher thanthe 1970s, 1910s and1890s, with little change insnowfall at high altitudes.

CLIMATE OF THE ALPS

Unlike most west-coast mountain ranges,the Alps have complicated climatic variations thatcannot be summarised by linear trends. Apartfrom the obvious altitudinal differences, the main

contrasts are between high central massifs andperipheral ranges, and between northern (centralEuropean) and southern (Mediterranean) regions.Although continentality increases eastward, eventhe easternmost glaciers do not experience a trulycontinental, Pannonian climate.

Even in the Alps, there are only three long-

term high-altitude climate stations, all north of47N: Sntis at 9.3E, Zugspitze at 11E, andSonnblick at 13E (1931-60 normals: Mller,1982). The weakness ofwest-east gradients isshown by annual ranges of mean monthlytemperatures, which at low altitudes are 19C inthe west and north, 21 in the east at Innsbruckand Vienna, and 23 in the southeast at Graz.They are only 14 to 15 at all three high-altitudestations. Diurnal ranges also are only slightlygreater in the east. Thus throughout the Alpsclimate is neither oceanic nor fully continental.Temperature inversions in winter are mostcommon between 700 and 1300 m altitude, andthus not relevant to glaciers except whenextrapolating temperatures from valley stations.

Mean annual temperature is 0 around2300 m, mean summer temperature likewisearound 3200 m, and ELA is between these. InSwitzerland, temperature at level 365 (thesnowline off glaciers) averages -5.7 (Escher,1973). Global radiation at ELA has beenmeasured on five glaciers as 250-293 W m -2 andprovides 53-84% of the heat for melting (Ohmuraand others 1992, tables 1 & 3).

In valleys, winds are either up- or down-valley and bear only a general relation to regionalflows: the three high stations are of greatestinterest. At Sntis (2500 m), the predominantwind is from WSW every month, and at Zugspitze(2960 m) it is from northwest. At Sonnblick (3107m), it is from southwest except for three months:January, February and June, when it is from north(Mller, 1982). Free-air observations at the 500hPa level (around 5570 m) show monthly resultantdirections from 250-304 above Munich, 1951-60,and 264-295 above Vienna, 1952-1966 (Scheppand Schirmer 1977 Table II), i.e. WNW in winterand west in summer. Likewise contours on themean 500 hPa surfaces show flow over the Alpsfrom just north of west in April, and from justsouth of west in October (Cant 1977, Fig. 18): ataltitude, westerlies are dominant everywhere andthroughout the year.


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Cyclogenesis in the Gulf of Genoa and(especially in summer) over the Po Plain (Cant1977, Fig. 2): is responsible for surprisingly highprecipitation in outer ranges of the southern Alps:the wettest area in the Alps is the Julian Alps northof Trieste, where the air in these depressions isforced to rise. Precipitation reaches over 3000

mm there, and over 2500 mm in all the highmassifs except in the western Alps south of MontBlanc. Even where the western Alps trend north-south, the eastern side in Piemonte receivesprecipitation from these lee depressions and is notas dry as might be expected. Thus the greatestprecipitation contrasts in the Alps, at any givenaltitude, are between drier, sunnier interior regionsand peripheral regions on all sides. On glaciers,winter mass balance at ELA is 1000-1950 mm,and summer precipitation is 200-750 mm (Ohmuraand others 1992, table 3)

In most of the Austrian and Swissmiuntains, maximum precipitation is in summer,extended often to May and sometimes September:never the less, more snow falls in winter, unlikemonsoon Asia. Precipitation peaks in Julythroughout the northern Alps. Much summerprecipitation is associated with convective activity,and cloudiness is greater in the afternoon. AtSntis the precipitation maximum is clearlysummer, but at the other two high stations it issummer and Spring and the minimum is inautumn. The inter-monthly range in precipitationat these three is less than two-fold, whereas at lowaltitude it is greater, over three-fold at Innsbruck,3.5-fold at Lugano and four-fold at Graz andDomodossala. In the French Alps there is a moreeven distribution in the north, and an autumnmaximum strengthening southward: both Brianonat 1298 m in France, and Domodossala at 300 m inItaly, have October and May maxima and sharethe winter minimum of the north. This dualmaximum is typical of the Pennine Alps. In theItalian Alps west of Turin, the Spring maximum isstrongest (Vivian 1977, p 180)

Differences between north and south aregreater than between east and west, although theinner-Alpine zone between them is drier andsunnier than the peripheries. The south is about 2warmer and considerably wetter although withfewer rain days than the north: there are moreheavy convective showers, whereas in the northfrontal and orographic precipitation is more

important. Cloudiness is greater in the northernAlps in both January and July: in July it exceeds60% in most Austrian and northern Swiss regionswith glaciers (Schepp and Schirmer 1977, fig.26). Annual cloudiness averages 66% at and 71%at Sonnblick, with June and May maxima. Insummer the southern Alps are cloudier than the Po

plain, but in winter they are much clearer (40-50%cover).Variations of temperature and precipitation

with altitude may differ between regions.Castellani (1986) divided the French Alps intoseven regions, two of which are relatively low. Inthe Pre-Alps, including the high Giffre region,precipitation increases at 610 mm km-1, twice thatelsewhere, because of the windward location. Inthe other four regions, which contain glaciers, thegradient with altitude averaged 270 mm km-1. Thebase rainfall decreased to the southeast, and valuespredicted for 2000 m altitude in these regions werebetween 1690 mm in the north and 860 mm in thesouth. Although the regressions were acceptablylinear, the highest gauges were between 2040 and2730 m. The increase is expected to decline athigher altitudes, eventually passing a maximum asthe moisture-holding capacity of thin air declines.

REFERENCES, with Durham locations.

(those for Alpine climate not given not

necessary)

(Please do not remove any for > 24 hours)

The Alps:BECKEL, L. (ed.) 1998 The Atlas of Global Change.Macmillan, pages 70-71 and 130-137. Ref 912 ATL(level 4, confined)GROVE, J.M. 2004 Little Ice Ages: ancient and modern.2nd. Edn. Routledge, London. 551.583Ch.4 M. Blanc; ch. 5 Otztal; ch. 6 Switzerland; ch.7Southern Europe. (also 1988 1st. edn.)

HAEBERLI, W. 1994 Accelerated glacier & permafrostchanges in the Alps. In M. Beniston (ed.)Mountainenvironments in changing climates. Routledge, pages91-107.HAEBERLI, W., and HOELZLE, M., 1995: Applicationof inventory data for estimating characteristics of andregional climate-change effects on mountain glaciers: apilot study with the European Alps.Annals ofGlaciology 21: 206-212. 55(05)HOELZLE, M., MHL, D.V. & MAISCH, M., 1999:Les glaciers des Alpes suisses en 1997/98. Les Alpes


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10/1999, 28-40 - & on the Web:http://www.geo.unizh.ch/wgms/mbb- links SwissGlacier Reports.HORMES A., MULLER B.U. & SCHLUCHTER C.2001 The Alps with little ice: evidence for eightHolocene phases of reduced glacier extent in theCentral Swiss Alps. The Holocene. 11, 255-265. on-line & 55(05)

KERSCHNER, H., KASER, G. and SAILER, R., 2000:Alpine Younger Dryas glaciers as palaeo-precipitationgauges.Annals of Glaciology 31: 80-84. 55(05)VIVIAN, R., 1975: Les glaciers des Alpesoccidentales. Allier, Grenoble, 513 pp.551.324(234.3)/VIV

See also abstracts in:http://www.disat.unimib.it/comiglacio/abstract.htm(in English even for Italian titles) andhttp://www.disat.unimib.it/comiglacio/glaciologicalcommittee.htm

For further info. on the World Glacier Inventory, fromwhich alps05lean is a considerably edited subset, seehttp://nsidc.org/data/docs/noaa/g01130_glacier_inventory/

Glacier change and climate:

FOR FUNDAMENTALS: SEE -BENN, DOUGLAS J. & EVANS, D.J.A., 1998,Glaciers & glaciation, E. Arnold pages 66-90.Res & 551.324 (2 copies)

BAMBER, J.L. and PAYNE, A.J. 2003 Mass balance

of the cryosphere: observations and modelling ofcontemporary and future changes. Cambridge U.P.551.32 MASBENN, D.I., AND GEMMELL, A.M.D, 1997Calculating equilibrium-line altitudes

of former glaciers by the balance ratio

method: a new computer spreadsheet.GlacialGeology and Geomorphology, 1997, tn01http://ggg.qub.ac.uk/papers/full/1997/tn011997/tn01.htmlBENN, D.I. & LEHMKUHL, F. 2000 Mass balanceand ELAs of glaciers in high-mountain environments.Quaternary International, 65/66, 15-29. 55(05) & on-lineBRAITHWAITE R.J. & ZHANG Y. 2000 Sensitivityof mass balance of five Swiss glaciers to temperaturechanges assessed by tuning a degree-day model.J. Glaciology 46 (152), p 7-14 55(05)[also1999 Modelling changes in glacier mass balancethat may occur as a result of climate changes.Geografiska Annaler Series A-Physical Geography.81A, 489-496. on-line & 55(05) ]HAEBERLI, W., FRAUENFELDER, R., HOELZLE,M. & MAISCH, M., 1999 On rates and acceleration

trends of global mass balance changes. GeografiskaAnnalerA 81, 585-591 55(05) & on-lineHAEBERLI, W., HOEZLE, M. & SUTER, S. (eds.)1998 Into the second century of worldwide glaciermonitoring prospects and strategies. Paris: Unesco, forIHP & GEMS. UNESCO Studies & reports inHydrology 56, 227 pp. 551.321 INTNESJE, A. & DAHL, S.O., 2000 Glaciers &

environmental change. Arnold, London Res &551.32OERLEMANS, J. (ed) 1989 Glacier fluctuations &climatic change. Kluwer, Dordrecht 551.324.63OERLEMANS, J. (ed) 2001 Glaciers & climatechange: a meteorologists view. 148 pp. A.A. Balkema,Lisse. 551.324.63OERLEMANS, J. & HOOGENDOORN, N.C. 1989Mass-balance gradients and climatic change J.Glaciology 35 (121), p 399-405 55(05)OERLEMANS, J. 1992 Climate sensitivity of glaciers insouthern Norway... J. Glaciology 38 (129), p 223-232

[also 2000 Relating glacier mass balance 46 (152), p1-6 ] 55(05)OERLEMANS, J., ANDERSON, B., HUBBARD, A.,HUYBRECHTS, P., JOHANNESSON, T., KNAP,W.H., SCHMEITS, M., STROEVEN, A.P., VAN DEWAL, R.S.W., WALLINGA, J., ZUO, Z., 1998:Modelling the response of glaciers to climate warming.Climate Dynamics, 14, 267-274. On-lineOHMURA, A. KASSER, P. & FUNK, M. 1992 Climateat the equilibrium line of glaciers. J. of Glaciology 38(130), 397-411 55(05)SCHNEEBERGER, C., BLATTER, H., ABE-OUCHI,

A. & WILD, M. 2003 Modelling changes in the massbalance of glaciers of the northern hemisphere for atransient 2 x C)2 scenario. Journal of Hydrology 282,145-163. 55(05) & on-line.VINCENT, C. & VALLON, M. 1997 Meteorologicalcontrols on glacier mass balance: empirical relationssuggested by measurements on glacier de Sarennes,France. J. Glaciology 43(143), 131-137 55(05)WALLINGA, J. & van de WAL, R.S.W. 1998Sensitivity of Rhonegletscher, Switzerland, to climatechange: experiments with a 1-D flowline model. J.Glaciology 44(147), 383-393 55(05)

On the Web:http://faculty.washington.edu/scporter/Rainierglaciers.htmlhttp://www.geo.unizh.ch/wgms/mbb - links SwissGlacier Reports.
http://www.geo.unizh.ch/wgms/mbbhttp://www.disat.unimib.it/comiglacio/abstract.htmhttp://nsidc.org/data/docs/noaa/g01130_glacier_inventory/http://nsidc.org/data/docs/noaa/g01130_glacier_inventory/http://ggg.qub.ac.uk/papers/full/1997/tn011997/tn01.htmlhttp://ggg.qub.ac.uk/papers/full/1997/tn011997/tn01.htmlhttp://ggg.qub.ac.uk/papers/full/1997/tn011997/tn01.htmlhttp://ggg.qub.ac.uk/papers/full/1997/tn011997/tn01.htmlhttp://faculty.washington.edu/scporter/Rainierglaciers.htmlhttp://www.geo.unizh.ch/wgms/mbbhttp://www.geo.unizh.ch/wgms/mbbhttp://www.geo.unizh.ch/wgms/mbbhttp://www.disat.unimib.it/comiglacio/abstract.htmhttp://nsidc.org/data/docs/noaa/g01130_glacier_inventory/http://nsidc.org/data/docs/noaa/g01130_glacier_inventory/http://ggg.qub.ac.uk/papers/full/1997/tn011997/tn01.htmlhttp://ggg.qub.ac.uk/papers/full/1997/tn011997/tn01.htmlhttp://ggg.qub.ac.uk/papers/full/1997/tn011997/tn01.htmlhttp://faculty.washington.edu/scporter/Rainierglaciers.htmlhttp://www.geo.unizh.ch/wgms/mbb

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