World Inventory — Inventaire mondial des (Proceedings of the Riederalp Workshop, September 1978; Actes de l'Atelier de Riederalp, septembre 1978): 1AHS-AISH Publ. no. 126, 1980.

West Greenland outlet glaciers: an inventory of the major iceberg producers

R.C. Koilmeyer

Abstract. By an international treaty between 22 nations involved in North Atlantic shipping, the United States Coast Guard has been assigned a statutory mission to act as the International Ice Patrol. The International Ice Patrol was formed shortly after the iceberg sinking of the RMS Titanic. Ice Patrol duties include studies of the current conditions affecting the drift and persistence of icebergs in the North Atlantic Ocean and the glacial origin of the ice. In 1968 the US Coast Guard commenced an examination of the major iceberg producing glaciers along the west coast of Greenland. This programme, called the West Greenland Glacier Survey, is attempting to visit and revisit every major outlet glacier along the western edge of the . Terminus locations have been surveyed along with height measurements on 27 major outlet glaciers. A total of 59 glaciers have been photo-documented. Most of the glaciers exhibit retreat. Les glaciers émissaires du Groenland occidental: un inventaire des principaux producteurs d'icebergs Résumé. Un traité international signé entre 22 pays engagés dans le commerce maritime de l'Atlantique Nord a confié à la Garde Côtière des EU la mission d'agir en tant que Patrouille Internationale des Glaces. Cette patrouille a été créée à la suite du naufrage du RMS Titanic, survenu à la suite d'une collision avec un iceberg. Les tâches de la Patrouille des Glaces comprennent l'étude des conditions actuelles qui influencent la dérive et la durée de vie des icebergs dans l'Atlantique Nord et l'étude de la provenance des glaces. En 1968, la Garde Côtière des Etats Unis à commencé à examiner les glaciers qui produisent la plupart des icebergs le long de la côte ouest du Groenland. Ce programme, nommé 'Surveillance des Glaciers du Groenland occidental', prévoit de visiter et de revisiter tous les principaux glaciers émissaires situés le long de la limite ouest de la banquise. On a observé la position et l'altitude du front des 27 principaux glaciers émissaires. Au total, on a réuni des documents photographiques sur 59 glaciers. La plupart des glaciers semblent se trouver dans une période de recul.

BACKGROUND.

Icebergs produced along the West Greenland coast are carried by winds and currents to the Canadian shore and then south by the Labrador current to the Grand Banks of Newfoundland. The Grand Banks have been traversed by transatlantic shipping for centuries. These transiting vessels have always been menaced by icebergs and prevalent fog particularly in the spring and early summer. In 1912 the RMS Titanic struck an iceberg and sank with a great loss of life. One year later in London the International Conference on Safety at Sea established the International Ice Patrol. In 1914 the United States Coast Guard assumed these responsibilities and commenced patrolling the Grand Banks of Newfoundland each spring, reporting the iceberg presence to passing ships and has continued this service to the present day. From the first ice patrol, the Coast Guard also undertook a systematic series of océanographie and ice studies. By 1928, these studies included the glacier origins of the icebergs. Coast Guard expeditions to Western Greenland were carried out between 1928 and 1935 and identified 21 glaciers which make major contributions to iceberg occurrence in the North Atlantic Ocean. Average annual production rates for these glaciers were estimated and glacier front advances or retreats were determined qualitatively within the limits of available information. 57 58 R. C. Kollmeyer Some 33 years later in 1968 the West Greenland Glacier Survey was established to resume the research of the sources of the North Atlantic icebergs. The decades of the 1950s and 1960s showed a decline in the mean number of icebergs drifting into the Grand Banks Ice Patrol area. The decline was precipitous in comparison to the steady iceberg populations during the preceding 50 years. Future planning and budgeting for International Ice Patrol as well as planning for the possibility of greater arctic shipping activities required a re-inspection of the general productivity of the glaciers that produce the icebergs which hazard shipping. Trends during the first half of the 1970s turned out to be the reverse of the 1950s and 1960s. 1972 became the greatest year ever for icebergs on the Grand Banks and 1974 ended up to be the second greatest year on record. Conflicting interpretations of these data are clearly possible, e.g. advancing glaciers, abnormal meteorological conditions or a catastrophic breakup of the great floating ice tongues of West Greenland. Obviously, information of this sort is required for the planning and budgeting of the International Ice Patrol.

METHODS The region of study lies between 69° 10'N off Disko Island and 81°30'N in Hall basin. This region includes Jakobshavn as the southernmost glacier of interest and Petermann's as the furthest north. The following objectives of the West Greenland Glacier Survey are being pursued: (1) To survey the West Greenland iceberg-producing tidewater glaciers and compare the data thus obtained with earlier records to ascertain the advance or recession of the glaciers, changes in iceberg production rates, and future trends. (2) To determine the total annual number of icebergs calved from the major West Greenland glaciers and the regularity of production to allow further investigation of the causes of variations in the annual number of icebergs found on the Grand Banks. (3) To survey the environmental conditions affecting the discharge and drift seaward of icebergs from the parent glaciers. This includes configuration, sill depth and coastal circulation. (4) To provide a carefully obtained pictorial and data documentation of the present state of the outlet glaciers of the last continental ice sheet in the Northern Hemisphere for scientific use in the future. The procedures generally followed for the survey of an outlet glacier are: (1) Conduct a helicopter flight from a Coast Guard icebreaker standing by near the glacier to select sites from which physical measurements of the glacier can be made. Place one or two survey parties ashore to make the following observations and measurements: (a) Locate the survey site by using visual landmarks and establish a metallic marker (benchmark) to which all data are referenced. (b) Optically survey the using a theodolite and laser range- finder. Due to the size of some glaciers, triangulation is necessary from two different survey sites. (c) Measure optically the height of the calving terminus at as many points as possible. Measure floating tabular icebergs when present. (d) Make observations concerning: recently unglaciated or overrun terrain near the glacier, tidal markings on terminus, calving activity and freshness of the calving surface, iceberg population and fresh ice near the terminus, the presence of upwelling meltwater immediately in front of the glacier, streaming zones and noise. Sketch the glacier, mark the site with a rock cairn. (2) Concurrently, complete a detailed photographic overflight by helicopter. West Greenland outlet glaciers 59 (3) Conduct océanographie observations from the Icebreaker including fjord bathymetry, sill depth determination and coastal and fjord water properties. Variations in these procedures are often made depending on the glacier and the situation. Many minor glaciers are only photographed.

RESULTS Surveys have been conducted during the summers of 1968-1971, 1976 and 1978. A total of 27 major iceberg-producing glaciers have been extensively surveyed from the ground and 59 have been photographed from aircraft. Table 1 lists the glaciers for which survey data have been obtained. All the glaciers listed have been documented by photographs. A second visit to each of the major glaciers has commenced. Two more expeditions are planned to complete the project.

TABLE 1. Glaciers visited

Glacier Surveyed Glacier Surveyed Umiamako X Rinks X Great Karajak X Little Karajak - X Eqip X sextant angles Avangnarelleq (2) X Kujatdleq X (Torssukatak) Jakobshavn X Gade's X Helland Wulff Yngvar Nielson Mohn Unnamed! (Carlos) MoreË Docker Smith X Pearys X Kong Oscar X Nansen X Dietrichson X Sverdrup Steenstrup X Kjears Hayes X Giesecke X Upernavik X Cornell Ussings Nordenskiolds Humboldt X Petermann's X Bissels Morris Jesup X Clements Markham Diebitsch Meehan Verhoeff Sun Bowdoin X Tracy X Heilprin X Farquaar Academy (Leidy) X Petowik (Pitugfik) X Sermeissuaq (Moltke) X Knud Rassmussan Agpat Hart Sharp Melville Savage Berlingske Hurlbut Chamberlin Brother Johns Dodge San Martin Hubbard

High altitude (2424 m) stereo-overlapping vertical photography of all glaciers from Jakobshavn north to the Humboldt Glacier was accomplished during the years 1968- 1970 with annually repeated coverage for particular glaciers. It is possible to give only a brief summary of the accomplishments to date. An enormous amount of data have been collected since 1968. An attempt is made herein to try to indicate the type and scope of the information obtained. Time and space permit only a short examination of several of the more interesting outlet glaciers. Starting with the southernmost glacier of interest, Jakobshavn is certainly one of the most impressive. It has been in a state of recession since first monitored in 1850 60 R. C. Kollmeyer (Fig. 1) with several minor advances. (Bauer, 1968). The glacier is presently some 50 km from the fjord's mouth. The fastest moving portion of the glacier is confined to the northern side with the wider southern portion filling an embayment. A slight rise occurs in the southern part leading to the suspicion that land will soon emerge in the form of a nunatak if recession continues. The mouth of the isfjord is generally crowded with large icebergs waiting for the winds and higher tides to carry them over the sill.

&

1976

JAKOBSHAVN ISFJORD 1850

0 5 10 15 1 I I I ! I I I , I I MILES

FIGURE 1. Jakobshavn Glacier and its 1976 location in the isfjord.

Visits have been made in 1968, 1971, 1976 and 1978. Measurements concerning the terminus elevation, surface velocities and tidal flexure have been carried out. Figure 2 shows the results of short term tidal movement measurements made in 1971. It is interesting to note that the vertical movement of the glacier is less, closer to the northern fjord wall than towards its centre. Figure 3 gives some representative surface flow velocities obtained in 1976. These measurements were made by placing coloured markers on several ice peaks and observing their motion using a theodolite in combination with a laser rangefinder and triangulation from three different locations. These values are slightly faster than those reported by Bauer (1968) who used aerial photography and patterns. Bauer found an average of 15 m/24 h. Our measurements are not as complete as his and no average was computed. Rinks Isbrae is located at 71° 45'N, approximately 300 km to the north of Jakobshavn with many interesting and equally important glaciers in between. Rinks was considered by Bauer (1968) to be highly productive with flow velocities up to 12 m/24 h and with vertical elevations approximately 70-75 m above sea level. Its productivity, when compared to other glaciers we have observed, seems rather low if iceberg populations in the can be used as a measure. Three of the highest face measurements found were 40 m, 59 m and 63 m across the 4.8 km terminus. No change in position was detected between the 1968 and 1971 visits. Data from 1978 remain to be reduced. These include velocity and tidal flexure measurements. Moving further north, Weidick (1958) presented an excellent documentation of the frontal variations at Upernavik Isstrom for the last 100 years showing the terminus West Greenland outlet glaciers 61

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4.5 w on ST " 16 I.O km FROM NORTH FJORD WALL 4.0 UJ L4 3.4 km FROM NORTH FJORD WALL I •3.5 o E - 1.2 -3.0ro < fet zI.O -25z o o «0.8 -2ofe>t UJ , UJ CJ0.6 .5 uj UJ UJ y 0.4 I.OÏ

§0.2 -05g

,1.1,1 i i i • i 16 18 20 22 24 2 4 6 8 10 12 16 TIME (HOURS) FIGURE 2. Tidal movement of Jakobshavn Glacier as determined by theodolite from the north fjord wall.

012345678 I I I I I I I I I KILOMETRES

GROUNDED ICE

FIGURE 3. Velocity of surface flow in metres per 24 h obtained optically in 1976. Survey sites 1, 2 and 3 are indicated. location as of 1953. The West Greenland Glacier Survey visited Upernavik Glacier in 1969 and again in 1978. Two survey sites were established. Site no. 1 was located on an island just to the north of the glacier edge and site 2 was on Umanaq Island just to the south. Figure 4 is a revised version of the map shown by Weidick (1958) which indicates the changes that have taken place since 1953. It can be seen that recession is continuing with new islands and nunataks becoming exposed. In the northern section of the glacier, a large nunatak is now showing and it is of interest to note that it is located between the two ice streams indicated on the Weidick chart. In addition, in the southern section the new islands which are emerging as the ice retreats are in a region where Weidick again indicated a slower flow. North of the island on which 62 R. C. Kollmeyer

FIGURE 4. 1969 update of the 1849 and 1953 icefront of Weidick (1958). survey site 1 was located, a minor nunatak and medial have appeared. A clearly visible rise also exists just to its west and one would suspect a new peak will soon appear if recession continues. Data obtained in 1978 show recession has continued to trim the terminus back another 2-3 km. at 74°50'N has shown a rather remarkable recession since 1947. Figure 5 compares the charted outline based on 1947 Danish mapping flights and 1970 Coast Guard data. As can be seen more than 6 km of wastage across a broad front has occurred in the span of 23 years. The iceberg production rate remains high. Significant numbers of large icebergs are still being produced. However, with recessional changes and the land that is beginning to emerge from under the glacier (locations marked with an asterisk (*) on Fig. 5 were not visible in 1947), one can only assume that here as in other sections of the coast the size and productivity of many of the floating ice tongues is diminishing. Continuing on north into the Melville Bight area we have surveyed the massive 25-km long Kjears Glacier that appears to flow out on the water, and the 32-km long Steenstrup ice sheet. Steenstrup has a long floating terminus where jigsaw puzzle type icebergs break off and float seaward. Some of these icebergs are in excess of 1 km in length. The last important glacier of the Cape York region is Gade's Glacier. The glacier is characterized by a wide range of heights along its calving face. To the north, a region which exhibits an apparent high flow velocity, the face elevations are remarkably uniform between 27 and 29 m. In the southern section, upthrusts as high as 55 m were measured. It is possible that only the northern portion is actually floating. High altitude photographs show the northern half produces icebergs which break off and float West Greenland outlet glaciers 63

FIGURE 5. Frontal variations of Hayes Glacier. Those nunataks marked with an asterisk (*) have not been previously observed.

away, retaining their original glacier orientation, while in the southern half the icebergs appear to be overturned or at least on their sides leading one to suspect a different calving mechanism is at work. Tracy and Heilprin are two impressive outlet glaciers at the head of Inglefield Bay north of Thule. Figure 6 shows the wastage that has occurred over the past 30 years. Tracy Glacier at one time touched Josephine Peary Island, but has retreated and retains an active calving position some 3 km to the east. The glacier continues to produce large flat icebergs as does Heilprin Glacier immediately to its south. The mighty Humboldt Glacier of Kane basin appears active along most of its 111 km terminus. However, successive high altitude photographs taken in 1969 and 1970 showed some icebergs remained in the same position for those two years. These photographs also show a few icebergs which appear to be on their sides allowing an estimation of their original thickness (approximately 400 m). It is suspected that much of the terminus is grounded or very nearly so. Icebergs may be able to drift off only on the higher storm tides which would account for their apparent lack of movement. The glacier was mapped in 1970 by a combination of satellite positioning and land survey points. The northernmost glacier covered by the survey is Petermann's Glacier in Hall basin, 81°30'N. It was first documented and examined during the United States 'Polaris' expedition under C. F. Hall in 1871. The fjord which holds Petermann's Glacier was described at that time: 'as far as they could see there was a confused accumulation of bergs, crowded closely together, leaving such spaces only as were due to irregularities of form. The fjord seemed filled from shore to shore with the bergs, which varied in shape and size but not much in height.' The as it exists 64 R. C. Kollmeyer

*7" . 66' *»'

FIGURE 6. Frontal recessions of Tracy Glacier and Heilprin Glacier. today has a very low terminus and badly erroded surface of only 3 to 4 m above the water, hardly as described by the Hall expedition. The glacier was originally discounted by myself as having any iceberg importance but data from Moira Dunbar (personal communication, 1977) of Canada and iceberg observations made by Robe et al. (1977) lead to the suspicion that it can and does occasionally contribute to the iceberg problem on the Grand Banks of Newfoundland. In summary, the observations made thus far confirm that general recession seems to be continuing from Kjears Glacier south to Jakobshavn. Data from the Melville Bight area and further north to Petermann's Glacier prior to 1970 are sparse. What recessional changes are occurring seem to be more gradual than those found to the south. My work is expected to continue until 1982 with probably greater emphasis being placed on remote sensing now that the benchmarks have been established. The extent, degree and form of publication of the data are unclear at this time. The coloured photographs alone would form an impressive volume.

REFERENCES Bauer, A. (1968) Missions aériennes de reconnaissance au Groenland 1957-1958. Expédition Glaciologique Internationale au Groenland, EGIG, 1957-1960 2, no. 3. Robe, R. Q., Maier, D. C. and Kollmeyer, R. C. (1977) Iceberg deterioration. Nature, 267, p. 505. Weidick, A. (1958) Frontal variations at Upernaviks Isstrom in the last 100 years. Gronland Geologiske Undersogelse. Misc. Papers no. 21, Geological Survey of Greenland, Copenhagen.

DISCUSSION Weidick: In Melville Bugt the photographs clearly show that the margin of the Inland Ice is a kind of floating ice shelf grounded on numerous skerries. If so, can you please tell us where it is grounded. West Greenland outlet glaciers 65 Kollmeyer: I agree that it is a kind of ice shelf but the coastline under this ice shelf has not yet been found. When we survey these glaciers for a second time I hope that we may be able to locate the strandline of these floating ice tongues.

Miiller: Have you made an inventory of the calving glaciers which you describe? The size and nature of the drainage basins might provide explanations for the differences in frontal changes and iceberg productivity.

Kollmeyer: The drainage basins are quite large and poorly defined. Their size and nature would be of great interest but is beyond the scope of the present study.

Swithinbank: In repeatedly visiting the same glaciers it would seem that a logical extension of your work would be to make radar depth soundings from the helicopter. Repeated thickness measurements along a fixed line between nunataks might show measurable changes within a year. It would also serve to locate the boundary between floating and grounded ice.

Kollmeyer: I agree. Recent technical advances in the radar instruments available will allow this. We will look into adding thickness measurements to our programme particularly for the location of strandlines.

Meier: The ice at the terminus of Jakobshavn Glacier is temperate, is it not? Thus I would not expect the radar suggested by Swithinbank to work.

Kollmeyer: I do not think that Jakobshavn is a temperate glacier. Crevasse depths alone (60-100 m) indicate otherwise. In any event Jakobshavn is only one of 27 glaciers for which radar information would be valuable.