Showing papers in "Geografisk Tidsskrift-danish Journal of Geography in 2008"

Climatic conditions at the Mittivakkat Glacier catchment (1994–2006), Ammassalik Island, SE Greenland, and in a 109-year perspective (1898–2006)

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):51–72, 2008 The present-day climate in the Mittivakkat Glacier catchment (65°N), Southeast Greenland, is investigated spatiotemporally based on time series (13 years, 1994–2006) and standard synoptic climate data from the meteorological station in Tasiilaq (Ammasslik), covering 109 years (1898–2006). Within the catchment, meteorological conditions are monitored at the coast (Station Coast, 25 m a.s.l.) for the period 1998–2006 and in the glacier area (Station Nunatak 515 m a.s.l.)for 1994–2006. During this 13-year period, solar radiation shows increasing values, averaging 0.5 W m−2 y−1, at the nunatak and decreasing values, averaging 1.4 Wm−2 y−1, at the coast. The mean annual solar radiation at Station Coast is 102 Wm−2y−1, which is about 10% lower than at Station Nunatak, and is probably caused by increasing and higher percentages of dense clouds and sea fog in the coastal area. The mean annual air temperature is increasing by 0.10.°C y−...

Managing rural landscapes in the Netherlands, Denmark and Sweden- comparing planning systems and instruments in three different contexts

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(2):1–16, 2008 Urban growth and sprawl have put pressure on surrounding rural areas for a long time, and planning history abounds with examples of how to cope with this development. The problem is also acknowledged in the European Spatial Development Perspective (ESDP), which, apart from recommending planning principles, also recommends common ways of arriving at solutions. This study compares three different planning systems and physical and socio-economic contexts (the Netherlands, Denmark and Sweden) to analyze different approaches to managing urban growth, dealing with the transformation of rurban areas, and ensuring green areas. The results show that population density, the relative abundance of land and the role of agriculture have not only shaped planning systems and policies historically, but still define how urban sprawl is perceived and managed in current planning practices. Although indications of a common discourse can be found, th...

Snow, runoff, and mass balance modeling for the entire Mittivakkat Glacier (1998–2006), Ammassalik Island, SE Greenland

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):121–136, 2008 SnowModel, a physically-based snow evolution modeling system that includes four submodels—MicroMet, EnBal, SnowPack, and SnowTran-3D—was used to simulate eight full-year (1998/99 through 2005/06) evolutions of snow accumulation, blowing snow sublimation, evaporation, snow and ice surface melt, runoff, and mass changes on the entire Mittivakkat Glacier (31 km2) in southeast Greenland. Meteorological observations from two meteorological stations inside the glacier catchment were used as model input, and glaciological mass balance observations were used for model calibration (1998/99 through 2001/02) and validation (2002/03 through 2005/06) of winter snow simulations. As confirmed by observations, the spatially modeled end-of-winter snow water equivalent (SWE) accumulation increased with elevation up to 700–800 m a.s.l. in response to elevation, topography, and dominating wind direction, and maximum snow deposition occurred on t...

Recent marginal changes of the Mittivakkat Glacier, Southeast Greenland and the discovery of remains of reindeer (Rangifer tarandus), polar bear (Ursus maritimus) and peaty material

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):137–142, 2008 During field observations in August 2005 antler remains of a reindeer were found at a recently deglaciated site at about 500 m asl., and bones from a polar bear were found at about 300 m asl. along the margin of Mittivakkat Glacier, Southeast Greenland. Radio carbon dating determined the age of the samples to 720 14C years and 350 14C years, respectively. In August 2006 old surface vegetation covering peaty material became exposed due to ice recession close to the site where the antler was found. The radio carbon age of small roots from the material was determined to 1530 14C years, and is in agreement with dating of woody remains of Salix glauca found close by, at the top of a nearby nunatak in 1999. The antler indicates that reindeer lived in the area when the glacier began to advance from a position where it was close to or smaller than today. The vegetation surface and peaty material indicate that the climate was warmer b...

Holocene changes in climate and vegetation in the Ammassalik area, East Greenland, recorded in lake sediments and soil profiles

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):21–50, 2008 Holocene climatic, vegetational and environmental changes on the Ammassalik Island in SE Greenland (65.5 N and 37.5 W) have been studied in lake sediments and soil profiles. Based on the stratigraphy of sediments, geobiochemical characteristics, pollen and other biological proxies, a history of the land is outlined. The overall and continued climatic cooling during the Holocene basically seems to be orbitally controlled and due to both decreasing annual and summer insulations. The very early Holocene, concurrent with and following the final postglacial melting of glaciers in the landscape, appears to have experienced the warmest Holocene summer conditions, ice-free seas and limited snow covers. The climate situation seems to have been to a considerable extent based on internal regional meteorological processes and largely without strong and regular cyclonic impacts from lower latitudes. Generally decreasing insulation, a still ...

The application of lichenometry in dating of glacier deposits

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):143–151, 2008 Different field methods, which may result in lichen growth curves and lichenometric dating curves, respectively, are outlined and discussed. Emphasis is laid on various factors that need to be taken into consideration in order to avoid errors. The importance of having many control points and minimizing of heterogeneous habitat factors in establishing the sample areas are stressed. It is also important to be aware of some problems regarding the lichen taxa, which are commonly used for lichenometric purposes. A recent example of the application of this particular technique on a glacier foreland at the Mittivakkat Glacier on Ammassalik Island in South East Greenland is discussed.

Oxygen depletion and phosphorus release following flooding of a cultivated wetland area in Denmark

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(2):17–25, 2008 The rewetting of altered wetlands is becoming increasingly widespread. When flooding cultivated soils, the oxygen (O2) availability is reduced, subsequently, ferric hydroxides can dissolve and associated inorganic phosphorus (P) will be mobilized. This study shows the temporal and spatial dynamics of O2 depletion following flooding using planar optodes and the subsequent release of Fe and P in two depth intervals in an experimental column set-up. The column was kept flooded for 48 days and thereafter partly drained and flooded again. Results document that large amounts of P (0.2 t P ha-1) have accumulated in the present plough-layer (Ap) during the last 22 years, which represent roughly 15% of the present inorganic P stock in the Ap. As a result of flooding, fully anoxic conditions were observed within 3 days (within 10 h in Ap) and concentrations of dissolved Fe and P in the soil solution increased simultaneously after 7 days ...

Geomorphology of the Ammassalik Island, SE Greenland

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):5–20, 2008 Ammassalik Island is located on the elevated, passive continental margin of SE Greenland. The island itself is dominated by high...

Hydrology, sediment transport and water resources of Ammassalik Island, SE Greenland

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):73–95, 2008 A review and a synthesis of results from previous investigations are presented. New studies and results from the Mittivakkat Glacier catchment are used in an attempt to upscale results to other catchments on Ammassalik Island, SE Greenland. A snow-evolution modelling system: Snow Model, together with the hydrological model: NAM, were used to simulate the water balance components for periods when direct measurements were not possible. The total annual precipitation (TAP) was 1,500 mm w.eq. y−1 (1999–2006) for the whole Mittivakkat Glacier catchment, and 984 mm w.eq. y−1 (1961–1990) uncorrected at the meteorological station in Tasiilaq (Ammassalik). The solid precipitation was 67–85% of the annual precipitation. Evapotranspiration was 250 mm w.eq. y−1, sublimation during winter time was found to be 200 mm w.eq. y−1, or 12% of the annual precipitation. The Mittivakkat Glacier had a negative mass balance in 9 out of 11 years (1995–...

A late Holocene palaeoenvironmental record from Altona Bay, St. Croix, US Virgin Islands

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(2):59–70, 2008 A reconstruction of the palaeoenvironmental development of Altona Bay, St. Croix, northeastern Caribbean, has been made based on the sedimentological, geochemical and pollen analyses of a 1.83 m long vibracore. For chronological control, AMS 14C measurements were made at 5 levels downcore. The sedimentary sequence covers the last c. 4,700 years, containing both (mangrove) peat and fine-grained clastic sediment units. Comparison with regional Holocene sea level data demonstrates a gradual marine flooding of a mangrove environment around 3,500 cal BP was presumably related to a regional late Holocene sea-level rise, from a position, c. 2 m lower than present. After a c. 1,000 year period of marine sedimentation lasting until c. 2,500 cal BP, renewed formation of tropical wetland occurred at the site. This development may be attributed to the increased isolation of the shallow Altona Bay, most likely due to sea- ward formation of ...

Mass balance observations at Mittivakkat Glacier, Ammassalik Island, Southeast Greenland 1995–2006

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):111–120, 2008 Measurements of mass balance were made at Mittivakkat Glacier, Ammassalik Island, Southeast Greenland during the period 1995–2006 using the stake method, usually called the direct glaciological method, for determining the net accumulation and ablation of snow and ice during the accumulation(September—May) and ablation (June-August) period, and the net mass balance year (September—August). For the period 1995–2006, mean values of measured winter, summer and net balance were 1.19 m, -1.96 m and–0.78 m, respectively. The measurements showed that 9 out of 11 balance years had a negative balance and 2 balance years had a slightly positive balance. The cumulative mass balance during the period 1995—2006 was -8.1 m w. eq., corresponding to a mass loss of about 7% of the total glacier ice volume determined in 1994. The observations also showed that during 4 balance years the mass balance was negative on the entire glacier. A comparis...

Landscape and sediment processes in a proglacial valley, the Mittivakkat Glacier area, Southeast Greenland

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):97–110, 2008 During the Little Ice Age (LIA), the present proglacial Mittivakkat Valley, stretching 1.5 km ENE-WSW from the terminus of the Mittivakkat Glacier tongue to a delta terminating in the Sermilik Fjord, Southeast Greenland, was transgressed by the glacier as indicated by a terminal moraine near the valley mouth. The first recordings of the glacier terminus in 1933 show a frontal retreat of about 300 m since the Little Ice Age (LIA). Since then, the glacier has retreated another 1200 m leaving a valley train characterized by steep slopes flanking a 150–300 m wide flat-bottomed, sediment-floored trough. The larger part of the valley is floored by fluvial sediments and shows a typical valley sandur stream, the Mittivakkat stream, with one or two main water-channels, which branches out in a braided stream system with numerous intervening channel bars. In the outer part of the valley train, the Mittivakkat stream is erosive and divide...

Suspended particulate matter (SPM) in the North Sea-Baltic Sea transition: Distributions, inventories, and the autumn 2002 inflows

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(2):37–47, 2008 The present study describes the spatial distribution of suspended particulate matter (SPM) in the North Sea—Baltic Sea transition in autumn 2002 based on cruises in August, September, and October. The cruises comprised CTD and optical backscatter measurements supplemented with water sampling and determination of SPM concentrations. Each cruise covered 4 days whereby a close to synoptic SPM distribution was obtained in each of the 3 months. Supplementary cruises were carried out in February 2002 and November 2004. Results showed that surface water SPM concentrations varied around 2–4 g m−3 in the transition with no temporal variation during the autumn. In comparison, bottom water SPM concentrations varied around 4–6 g m−3 except at the Skagerrak/Kattegat boundary where concentrations reached up to 20–22 g m−3. Total SPM inventory, which comprises the Kattegat, the Belt Sea, and the western Baltic Sea, is in the range 2.06* 106- ...

GIS-facilitated spatial narratives: Danish plantations in Ghana

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(2):49–57, 2008 The paper examines the implementation and dissemination of spatial narratives within a geographical information system context with specific reference to portable GPS-enabled devices The overall goal is to establish a framework for the creation of computer assisted ‘guided tours’ based on the thematically and narrative linking of a set of locations within an area A spatial narrative that describes the—largely unsuccessful—history of Danish plantations on the Gold Coast (1788–1850) is implemented through the Google Earth client This client is seen both as a type of media in itself for ‘home-based’ exploration of sites related to the narrative and as a tool that facilitates the design of spatial narratives before implementation within portable GIS devices The Google Earth-based visualization of the spatial narrative is created by a Python script that outputs a web-accessible KML format file The KML-file defines extended func

Meteorological observations 2006 and ground temperature variations over 12-year at the Sermilik Station, Ammassalik Island, Southeast Greenland

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(1):153–161, 2008 Meteorological stations have been in operation since 1993 at the Sermilik Research Station (65°40′N, 38°10′W), Ammassalik Island, Southeast Greenland. This note presents meteorological observations for the calendar year 2006 from the two meteorological stations: Station Nunatak (515 m a.s.l.) and Station Coast (25 m a.s.l.). The year 2006 record is not complete due to a temporal break down of Station Coast (from end-of June through beginning of August). Special focus is given to ground temperature measurements at the meteorological Station Nunatak (1994–2006) 0.1 and 0.3 m below the surface. Data are presented to illustrate the intra- and inter-annual temperature variability and possible trends in the upper part of the soil.

75 years of research at the Sermilik Station: 1933–2008

Abstract: In 1933, the geologist K. Milthers participated in an expedition to Ammassalik led by the famous polar researcher Knud Rasmussen. One of his duties was to carry out a survey of glaciers and glacial geomorphology in the area. From Milthers' diary we know that he first visited the Mittivakkat Glacier on July 21, 1933. Later the same summer, he returned and took photos of the margin of the glacier and the proglacial valley and carried out measurements of the ablation. Because of his mapping of its margins, the Mittivakkat Glacier area was chosen as one of the Danish research sites during the International Geophysical Year in 1957-58. At that time, the glacier terminus had retreated 0.6 km since 1933 (Fristrup, 1960). Included in the fieldwork programme were, for the first time in Greenland, combined measurements of climate and runoff. Valeur (1959) clearly demonstrated and analysed the relationships between climate induced variations in the ablation and runoff from the glaciated catchment. During the investigation a jokulhlaup occurred, which underlined the great importance of event-driven hydrological and geomorphological processes in glaciated catchments in the Arctic. Field measurements were resumed in 1969, and in 1970 a permanent field station, the Sermilik Station, was established to provide a logistical base for the ongoing glaciological, hydrological and geomorphological investigations of the Mittivakkat Glacier and its catchment (Fristrup, 1970). The station consisted of a 90 m2 house prefabricated in Norway, and a depot building. The station functioned well, but in the spring of 1972, after an unusually snow-rich winter, a local hunter observed that the roof of the hut had turned. The research leader B. Fristrup rushed to the station and found that a slow avalanche had destroyed the house but spared the depot building. Again in 1972, the fieldwork had to be carried out from a tent camp (Hasholt, 1976). After the instruments from the collapsed house had been recovered, measurements of hydrology and sediment transport were initiated. Also, fixed points were surveyed so that the area could be mapped using aerial photos. Local workers were hired to remove the remnants of the house, and the timber was donated to the local community. One of the workers, M.B. Kofoed, has been the attendant at the station since then. A new 60 m2 house designed by architect W. Claesson was built in 1973, only about 100m from the first station building but closer to the coast and better protected from accumulating snow. The focus of the research was still on glaciology and glacially driven geomorphological processes, but in 1975, Professor N. Kingo Jacobsen, together with researchers from the Royal Veterinary and Agricultural University, initiated research on soils (e.g. Jakobsen, 1990). In 1976, B. Fristrup retired as leader of the field station, and B. Hasholt took over the responsibility for the field station. Until then, travel costs for research purposes were subsidised by the Ministry of Greenland, but from 1976 this support ceased. The reduction in basic funding was a serious problem for the long-term research planned in the glaciated Mittivakkat catchment, and the only way to secure resources for the expensive and increasing travel and logistic costs was to include students and researchers in applications for specific research grants. In 1980, B. Hasholt applied data from the research at the station in an evaluation of the hydro power potential in the area (Hasholt, 1980). At that time, the Greenland Technical Organization (GTO) was surveying hydro power potential all over Greenland. GTO agreed to pay the travel costs for students and researchers in return for the maintenance of GTO's monitoring stations and discharge measurements in the area. The demand for persons with \"arctic knowhow\" was great, and a spin-off from specific research projects and GTO related activities was that a lot of students, after finishing their Masters degree, were employed by GTO or other institutions related to the Arctic and Greenland. The hydro power \"boom\" dwindled during the eighties, but further research grants were obtained from the Danish Natural Science Research Council and the

A peatland landscape at Akraberg, Suðuroy, Faroe Islands: Peat mounds and a cautionary lesson

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 108(2):27–35, 2008 The peatland landscape above the headland of Akraberg at the southern tip of Suðuroy in the Faroe Islands features relict peat cuttings of various age—from the 1950s and perhaps centuries before—as well as mounds of peat. Superficially, the latter might be thought to be abandoned stacks. In fact they are ‘torvloð’ (singular ‘torvlað’) representing platforms of fragmentary peat upon which stach had been constructed after turves had passed through several intermediate drying stages. The removal of dried peat from the torvloð and the continued use of the platforms led to a gradual increase in torvlað height. General comparisons are made with peat mounds from the British Isles. The peatscape at Akraberg yields implied lessons for studies of ethnography and warns of potential dangers in landscape misinterpretation.