Search

Based on existing meteorological records, increases of annual air temperatures, annual precipitation sums, annual wind speeds, and of the frequencies and intensities of heavy rainfall and storm events in Norway are postulated. From a process-geomorphological point of view it is of growing importance to obtain an improved knowledge of the complex relationships between contemporary geomorphologic processes, vegetation cover and present-day climatic conditions to arrive at more realistic assessments of possible geomorphic effects of ongoing and future climate changes. This study analyzes the morphoclimate of a boreal-oceanic drainage basin system in central Norway and presents aspects of the contemporary wind, air temperature and precipitation regimes that control the type, frequency, intensity and duration of relevant denudational surface processes operating in the area. The work is based on statistical analyses (magnitude-frequency analyses) of existing meteorological data and process-geomorphologic field work conducted over a five-year investigation period (November 2011-October 2016) in the Homla drainage basin (156.3 km2) in central Norway. Due to the distinct characteristics of the present-day morphoclimate, runoff occurs year-round and chemical denudation clearly dominates over mechanical denudation. Mechanical denudation is strongly event-controlled and the highest share of annual fluvial transport occurs in May during the peak of spring snowmelt. Both chemical denudation (12.1 t km−2 yr−1) and mechanical denudation (3.6 t km−2 yr−1) are of low intensity which is explained by the cool climate combined with a nearly closed and continuous vegetation cover, small thicknesses of sedimentary covers, a high weathering resistance of the predominant bedrock and only low topographic relief in the upper parts of the Homla drainage basin. It is expected that the postulated changes of the wind, air temperature and precipitation regimes will lead to increasing chemical and mechanical denudation rates in the study area. [ABSTRACT FROM AUTHOR]

The various mountainous landscapes of Iceland, Sweden and Norway are characterized by Pleistocene glaciations and, connected to this, a dominance of glacially sculpted landforms like U-shaped valley systems, cirques, lakes and hanging valleys. The thickness of glacigenic deposits from this period can vary significantly across different mountain landscapes. In consideration of such legacies, these formerly glaciated landscapes today can be considered at a unique stage of readjustment (recovery) with respect to spatial organization of currently active geomorphic process domains and the magnitude and patterns of sediment storage and sedimentary fluxes. Accordingly, the postglacial relief development in these landscapes is controlled by a wide range of environmental drivers. This study focuses on trends of postglacial relief development in five selected valley systems in formerly glaciated mountain landscapes in eastern Iceland, northern Sweden and western Norway. The selected valley systems Austdalur (23.0 km2) and Hrafndalur (7.0 km2) in eastern Iceland, Latnjavagge (9.0 km2) in northern Sweden, and Erdalen (79.5 km2) and Bødalen (60.1 km2) in western Norway are considered to be representative valley systems for the respective mountain regions they are situated in. Our investigations include a quantitative compilation of contemporary mass transfers in the five valley systems, the quantitative analysis of current Ho/Hi index values for the slope systems in the valleys as well as a semi-quantitative description of changes of valley cross-sectional and longitudinal profiles since deglaciation. As a result, all U-shaped valley systems are characterized by an ongoing valley widening due to the continuing retreat of the existing rock-walls. However, the different valley systems show significant variations in the intensity of slope-channel coupling, in their slope and valley-floor storage behavior, in the development of their longitudinal valley profiles, and in the general intensity of postglacial relief modification. Accordingly, trends of postglacial relief development appear to be rather complex in the different mountain landscapes. It is found that the specific characteristics of the glacially sculpted and inherited valley morphometries are the most important control of the detected differences in slope-channel coupling, storage behavior and longitudinal valley profile development. Lithology and the given weathering resistance of the predominant bedrock are most important for the general intensity of postglacial relief modification. Apart from Hrafndalur which is characterized by rhyolites with particularly low weathering resistance, postglacial modification of the inherited glacially sculpted valley morphometries is altogether little and the landforms have not yet adjusted to the geomorphic surface processes that have been operating under postglacial morphoclimates. [ABSTRACT FROM AUTHOR]

Contemporary hillslope processes are extremely varied and are driven by a number of diverse physical, chemical, and biological processes. These processes span a wide range of spatial and temporal scales and are considered to react sensitively to climatic changes, anthropogenic impacts and other disturbances.We present ongoing GFL research activities focussing on environmental drivers of rockwall retreat, and denudational hillslope processes in a cold climate mountain environment (western Norway) and in a Mediterranean mountain setting (eastern Spain). In detail, we explore the influence of (i) lithological and structural characteristics, (ii) the rockwall temperature regime and (iii) the connected relative importance of physical-, chemical- and biological processes on weathering and resultant morphologies under these two contrasting climates. Special focus is on possible effects of ongoing and accelerated climate change and on the question how these effects differ under the two distinct climates. Our research is conducted on selected hillslope systems within two tributary valleys (max. elevation 2083 m a.s.l.) located on the western side of the Jostedalsbreen ice cap within the fjord landscape of western Norway. The lithology consists primarily of Precambrian granitic orthogneisses. The climate (slightly above sea level) is cool temperate oceanic with a mean annual air temperature of ca. 6°C and an annual precipitation sum of 1100 mm. January and February are the coldest months with mean monthly air temperatures below 0°C. Higher elevations are characterized by a distinct winter frost regime and a several months lasting closed snow cover. Maximum summer temperatures (June, July) are rarely exceeding 25°C but rockwalls having a favourable exposition can receive a rather high solar radiation. The selected hillslope systems in eastern Spain (Calpe) are located within the Sierra de Bernia mountains (max. elevation 1126 m a.s.l.) which consist of glauconitic and bioclastic marine limestones with alterations of marl. The area is characterized by a mild Mediterranean climate with a mean annual air temperature of ca. 18°C and an annual precipitation sum around 400 mm (slightly above sea level). During the coldest months (January, February) it can be comparably cold even with frost and snow in the mountains although they are situated close to the coast. In contrast, maximum summer temperatures (July, August) can easily exceed 30°C and south-facing rockwalls are exposed to a high solar radiation. Our investigations encompass detailed geological and geomorphologial mapping, the identification and monitoring of the most relevant hillslope processes in combination with detailed statistical analysis of meteorological data. The monitoring programme includes installed nets for collecting freshly accumulated rockfall debris, installed tracer lines and remote time-laps cameras for monitoring various mass transfers as well as near-surface and surface rockwall temperature sensors for monitoring the thermal rockwall regime.An improved and more comprehensive understanding of how different environmental factors interact and control hillslope processes under two contrasting and changing climates is expected to be essential for predicting possible effects of ongoing climate change in sensitive mountain environments. [ABSTRACT FROM AUTHOR]

Climate change, human activities and other perturbations (like, e.g., fires, earthquakes) are likely to influence existing patterns of weathering, erosion, transport and deposition of material across defined landscape components and units. While it is still a challenge to develop an improved understanding of how such changes interact and affect slope and fluvial processes, the connectivity within landscapes and between slope and fluvial systems, as well as contemporary denudation rates, source-to-sink fluxes, and sedimentary budgets, this kind of quantitative analyses promise to be an efficient framework to assess the impact of environmental changes and disturbances to sediment dynamics and to evaluate landscape sensitivity. The current knowledge on drivers and rates of contemporary sediment dynamics and denudation forms the basis for understanding and predicting the consequences of ongoing and accelerated environmental changes. Ongoing GFL research activities on drivers and quantitative rates of contemporary sediment dynamics and chemical and mechanical denudation in selected drainage basin systems in central Norway and eastern Spain are presented. The upper Driva drainage basin in central Norway (Oppdal) is situated in a cold climate and mountainous environment, has year-round discharge with a nival runoff regime, and the temporal variability of sediment transfers, runoff and fluvial transport are largely controlled by thermally and/or pluvially determined events. Our investigations include detailed geomorphological and permafrost mapping combined with the detailed statistical analysis of meteorological data and the continuous observation and year-round monitoring of sediment transfers, runoff and fluvial transport using a range of different techniques in different selected tributary systems of the upper Driva drainage basin. The Pou Roig and Quisi catchment systems in eastern Spain (Calpe) are located in a Mediterranean, partly mountainous and/or anthropogenically affected environment. Sediment transfers, the intermittent runoff and fluvial transport are almost entirely controlled by pluvial events. Our investigations in this study area include detailed geomorphological mapping combined with the detailed statistical analysis of meteorological data and the observation and monitoring of sediment-transfer, runoff and fluvial transport events using a combination of different observation, monitoring and sampling techniques. Our results on controls and the spatio-temporal variability of chemical and mechanical denudation within the two study regions contribute to an advanced understanding of key drivers and rates of contemporary sediment dynamics and denudation in different morphoclimatic environments, and provide the basis for improved predictions of possible effects of climate change and anthropogenic impacts on contemporary denudation rates in different morphoclimatic regions. [ABSTRACT FROM AUTHOR]