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Information concerning classification, naming and measurements

Contents

  • Classification of the glaciers


  • Naming of the glaciers


  • The measurements of the various parameters



  • Classification of the glaciers

    What really is a glacier? According to the most often used definition it is a mass of ice, most of which lies on land, which is in motion. A mass of ice which lies still is therefore no glacier, but dead ice. Of course it is a continuum; Snow field - Dead ice - Glacier. This, along with the size of the ice masses constantly changing from year to year, of course means that there are border cases. No matter what you do there are cases which are questionable.

    I have here used a number of different sources; the mountain maps, special maps, Atlas over breer i Nord-Skandinavia, various other litterature, air-photos, vocal and written communication, and own pictures and observations (see the literature list). In all this I have tried to achieve a sensible synthesis. It is not to be denied that if any ice-mass has been right on the balance, as it were, I have included it, along with a note of its uncertain status.

    The current mountain maps are in my opinion rather unsatisfactory from a glacier point of view. Not just because they donīt display some of the ice masses I count as glaciers, but also because the contours of the ones that are displayed sometimes are quite up the creek. Seemingly totally for no reason the contour is sometimes drawn hundreds of metres from a mountain wall or a valley side, when all photos show the ice reaching right up to the side. More understandable are then such errors which have occurred when surface till (e.g. medial moraines) has been interpreted as ice-free area. The very newest printing of the mountain maps are actually a change for the worse, since the height contours have been levelled out - detail have disappeared. Still, the contours have been improved in one regard; they mirror the large-scale topography better. For some unimaginable reason former displayed nunataks have also disappeared from the newest map.

    There are two different ways of categorizing separate glaciers:

    1. All continuos ice is treated as one glacier.
    2. Separate ice streams within a continuos ice field are treated as separate glaciers.

    Neither of these methods is right, or wrong, so I use both. Often the result of method 1 and 2 of course coincide, and then there are no problems. Naturally it is also a matter of interpretation whether an ice field is to be divided into separate ice streams. Here I have required that the divide should occur in the accumulation area, and that the separate part should not be too insignificant. Here common sense has ruled. If an ice field has been judged to consist of several ice streams it has been classified as a glacier complex.

    When it comes to the division into different types of glaciers I have followed a simple morphological classification: besides the former mentioned glacier complexes I use the types valley glacier, cirque glacier, and ice cap. Valley glaciers fill up a larger or smaller valley, cirque glaciers only a cirque. The former har a much higher length/width ratio than the latter. Ice caps in the strict sense (with an ice dome as highest point) are very rare in Sweden, but pretty common in Norway. In this type I here also include ice masses lying in shallow hollows or on mountain slopes. In Norway there is also the outlet glacier type, an ice stream, which accumulation area is of ice cap type but the tongue is a valley glacier. Of course it is a continuos gradation between the types here as well.

    Another way of classifying glaciers is according to their temperature structure: there are temperate ("warm") and polar ("cold") glaciers. A temperate glacier is one where the temperature of the entire mass of ice rises to 0°C in summer. A polar glacier is one where no part of the ice reaches 0°C. An intermediate type is a subpolar glacier, where some parts reach zero degrees, but others not. Most glaciers in Scandinavia are temperate, but there are some subpolar ones.


    Naming of the glaciers

    There are a number of different words to describe masses of land-ice in movement. In Swedish we have the main word "glaciär", but also the older "jökel" (which of course is the same as "jökull" in Icelandish). In Lappish the word is "jekna" (other forms "jiekna", "jietna", and "jiekki"), while there are a number of different words in Norwegian. In Norway the main word is "bre", while the words "is", "fonn", "jökul", "skavle", and "skåki" are more local.

    Most of the glaciers of Scandinavia are nameless, or in any case lack official names. Here I have defined a name as official if it is present on the mountain maps. If a glacier has an official name it has almost always been used - for Lappish names with spelling according to the former orthography, however. Those cases where an "official" namn hasnīt been used is attributed to where this name only exist on the newest maps. The word "jökel" has in all occurring cases been changed to "glaciär", the same way as the other forms in Lappish have been modified to "jekna". Some inofficial names have also been used, if they are established. Where the same glacier has several different names (not just different forms), the other(s) has been stated as well.

    The glaciers lacking both official and unofficial name I have assigned a suitable one in connection to the surrounding mountains, valleys, streams etc. Here I have followed the principle of not mixing languages: Swedish names have been connected to the suffix "-glaciären", Norwegian to "-breen", while Lappish ones have received "-jekna". Thus "Mellantoppsglaciären", but "Leirvassbreen" and "Kassajekna" (one exception being Kebnepakteglaciären, which has kept its hybrid name, because of it being so established). The Lappish names often contain placement or characteristic prefixes, according to the following:

    LappishSwedishEnglish
    NuortapNorraNorthern
    ÅrjepSödraSouthern
    AlepVästraWestern
    LulepÖstraEastern
    KaskaMellerstaMiddle
    PajepÖvreUpper
    VuolepNedreLower
    StuorStoraBig
    UnnaLillaSmall


    The measurements of the various parameters

    The height values for lowest and highest point are calculated from the mountain maps, (or special maps, where available) with an accuracy of about 5 m. Where the map clearly does not correspond to reality the values have been adjusted according to other observations. The heights of passes and lakes have been estimated the same way. The difference is of course the latter minus the former. The length of the glaciers is measured with a distance-meter for maps, along the longest possible flow line. The accuracy is roughly 2-5 %; the higher value where the lie of the flowline is harder to determine. One exception is glacier complexes because they have a flowline for each part; there length is the longest dimension of the complex (the birdīs way).

    The areas of the glaciers have been measured in a perhaps "primitive", but effective and pretty accurate way. At first various kinds of planimeters were tested, but the results varied enormously. In particular they seemed to be exceedingly sensitive to the measurement beginning and ending in exactly the same point (to the tenth of a mm). Instead the contours (according to my interpretation) are transferred to tracing-paper, which then is placed onto cross-ruled (5 mm) paper. A rectangle (or right-angled polygon) with the approximate area is drawn over the contour, and then the protruding and intruding parts are "set off" against each other, one part at a time. Finally only a small part remain, inside or outside the polygon, the area of which easily can be determined. The total area thus is the area of the polygon plus or minus the pro- or intruding part.

    This may sound as a primitive and amateurish method, but in reality it has shown itself having many advantages. It is reliable, fairly accurate, pretty fast, and does not require access to expensive equipment. By repeated measurements of the same glacier I have been able to assess the accuracy of the method to 0.5-2 % (larger glaciers having better relative, but worse absolute precision). This is far better than I ever achieved with planimeter, and faster to boot. Of course a computer measurement in a GIS (Geographical Information System) would have been even better, but I had no access to any such data (if indeed they exist).


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    Last updated: March 17, 2001 Unless otherwise specified; text, tables, photographs, maps and other
    graphics © 1999-2001 Gunnar Ljungstrand