Showing papers in "Geografisk Tidsskrift-danish Journal of Geography in 1998"

Sedmentation in the Central Baltic Sea as Viewed by Non-Destructive Pb-210-dating

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 98:1–9. A non-destructive gamma-spectrometric method was used to assay the sedimentation in the central Baltic Sea. Three cores from the Gotland D...

Coastal Morphodynamics at Skallingen, SW Denmark: High Energy Conditions

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 1998: 20–30. The present paper discusses some preliminary results from a field experiment on sediment transport and morphological change on a beach subjected to storm surge activity. The data were collected at the barrier spit of Skallingen during October/November 1996. This period was characterized by a succession of storms which resulted in high water and wave energy levels, culminating in a storm surge per se. The beach and the dune ramp eroded; however, contrary to expectations, a subtidal bar migrated onshore and the intertidal swash bar appeared to display a cyclic behaviour dependent upon strong linkages between morphology and hydrodynamics. Morphological changes in the intertidal zone were primarily accomplished by mean currents with oscillatory motions playing a subordinate role. Longshore sediment transport measured during conditions with moderately strong winds blowing alongshore, was dominated by wave-induced currents with aeolian tra...

Approaching Local Limits to Field Expansion - Land Use Pattern Dynamics in Semi-arid Burkina Faso

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 98: 56–70. Land use pattern dynamics at the local level significantly influence land cover changes and thus global environmental change. Expansion of cultivated land may mirror increased demographic pressure, climatic changes and soil degradation. The paper illustrates how subsistence farmers in semi-arid West Africa may alter their land use patterns in response to increased demographic pressure and environmental constraints. It presents an analysis of land use changes from South-Eastern Burkina Faso. Field measurement, household interviews and interpretation of a series of geometrically corrected aerial photos from 1956, 1972 and 1994 provide the background for a precise characterization of the cultivation expansion process and its relationship to socioeconomic and biophysical conditions for the agricultural system. Field expansions in the order of magnitude of 435% in 40 years are documented. Farmers' options and strategies to respond to rapidl...

Suspended Sediment Yield from the Ansager A river basin, Denmark

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 98: 38–45. Water samples have been collected since 1969, at the Lavborg Bridge gauging station, on the river Ansager A in South-West Jutland. Different regression equations of concentration versus discharge have been tested. The regression equations are used together with daily discharges to compute the daily suspended loads. Comparisons between measured and computedloads for different periods when water samples were taken twice a day suggest that the 25 computed annual load values have an uncertainty of less than ± 10%. The variation in annual loads shown is therefore significant and probably caused by increased rainfall in the eigthies. The average total suspended sediment yield for the 25 year period was 7 t/km2/year, of which the organic load contributed 3.2 t/km2/year.

Assessing Spatial Aspects of School Location- Allocation in Copenhagen

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 98: 71–80. Various spatial properties of public school districts may be assessed using location-allocation modelling tools of vector-based geograp...

Integrated Coastal Zone Management in Denmark

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 98: 31–37. This paper introduces the concept of Integrated Coastal Zone Management (ICZM) in a definition with relevance for Denmark. Partly influenced by the commitments signed at the Rio Conference the Danish government now deals with the concept of a sustainable development of the coastal areas, considering nature and the environment. The Danish legislation is currently revised working in the thought of sustainability to the object clauses of each Act concerning nature and the environment in the coastal zone.

Resuspension, Sediment Fluxes, and Suspended Sediment Diffusion Coefficients under Wave and Current Forcing in Two Coastal Environments

Abstract: Geografisk Tidsskrift, Danish Journal of Geography 98: 10–19. A stainless steel tripod equipped with five sediment traps placed at 0.35 m intervals above the seabed was deployed both in wave and current dominated shallow water environments. The length of tripod deployments varied between three and seven days. Sedimentation fluxes during resuspension in the wave-dominated environment ranged from 24.1 g m−2 day−1 at 1.75 m to 36.4 g m−2 day−1 at 0.35 m. In the current-dominated environment the fluxes ranged from 5.2 g m −2 day−1 at 1.75 m to 573.0 g m −2 day−1 at 0.35 m. Maximum shear stresses during the resuspension events in each of the two environments were of similar size, 0.042 and 0.06 N m −2, respectively. Additional deployments of the tripod during periods with low current speeds and no surface wave activity showed that the primary sedimentation varied between 3.0 g m −2 day−1 and 10 g m −2 day−1 in both environments. Sedimentation flux variation with height above the seabed was very small ...

Meteorological Observations 1997 at the Arctic Station, Qeqertarsuaq (69°15'N), Central West Greenland/A New Climate and Water-Balance Station on the Peninsula Skallingen, South West Jutland/A Quantitative Method for Analysing Landscape Structure

Abstract: An automatic meteorological station has been operating at the Arctic Station (69°15'N, 53°31'W) in West Greenland since 1990. This paper summarizes meteorological parameters during 1997, including snow and sea ice cover, ground temperatures and active layer development, and presents comments on the local permafrost thickness. In March 1997 an automatic climate and water balance station was established on the peninsula Skallingen, 55°30'N, 8°15'E. The data can be retreived by a cellular phone and a modem. The station and selected data are described. The present paper sketches out a method for a quantitative description of landscape structure, which can be used for biologically optimal landscape management. The approach suggested is based on a landscape ecological framework and emphasis is laid on spatial characterisation of the landscape. It aims at supplementing conventional landscape descriptive parameters of biological importance, which are derived from a range of empirical data, with ...