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Rhine Valley (rhine + valley)
Selected AbstractsNumerical simulation of meso-gamma scale features of föhn at ground level in the Rhine valleyTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 608 2005G. Jaubert Abstract This paper examines the impact of a mesoscale analysis (2.5 km grid distance) on the simulation of the meso-gamma scale aspects of föhn in the Rhine Valley. The föhn event, documented during IOP15 (5 November 1999) of the Mesoscale Alpine Programme, was standard in terms of intensity and was characterized by an important temporal variability. Many instruments operating in the Rhine valley target area are used to validate the simulation, in particular the airborne nadir-pointing lidar LEANDRE 2 (flown over the lower Rhine valley) as well as a wind profiler and a radio accoustic sounding system collocated in Rankweil, Austria. The large observational dataset acquired during the IOP allowed documentation of the entire föhn life cycle. For most of the IOP, a cold pool remained near the ground in the lower northern part of the valley. The non-hydrostatic model Meso-NH, used in a grid-nesting configuration with two nested models and initialized with a mesoscale analysis, allowed us to simulate realistically the location and depth of the cold pool. The relationship between the föhn intensity and the large-scale environment is also examined. The flow regime is a ,flow around' the Alps. The variability of this flow at the western tip of the Alps could explain some of the temporal changes observed at low level in the Rhine valley. Copyright © 2005 Royal Meteorological Society [source] Nine polymorphic microsatellite loci for the parasitic wasp Neotypus melanocephalus (Hymenoptera: Ichneumonidae)MOLECULAR ECOLOGY RESOURCES, Issue 2 2006CHRISTIAN ANTON Abstract Nine polymorphic microsatellite loci were isolated from Neotypus melanocephalus (Gmelin), a parasitoid of the parasitic large blue butterfly Maculinea nausithous. Allelic diversity and heterozygosity were quantified in samples from the Upper Rhine valley in Southwest Germany. [source] Numerical simulation of meso-gamma scale features of föhn at ground level in the Rhine valleyTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 608 2005G. Jaubert Abstract This paper examines the impact of a mesoscale analysis (2.5 km grid distance) on the simulation of the meso-gamma scale aspects of föhn in the Rhine Valley. The föhn event, documented during IOP15 (5 November 1999) of the Mesoscale Alpine Programme, was standard in terms of intensity and was characterized by an important temporal variability. Many instruments operating in the Rhine valley target area are used to validate the simulation, in particular the airborne nadir-pointing lidar LEANDRE 2 (flown over the lower Rhine valley) as well as a wind profiler and a radio accoustic sounding system collocated in Rankweil, Austria. The large observational dataset acquired during the IOP allowed documentation of the entire föhn life cycle. For most of the IOP, a cold pool remained near the ground in the lower northern part of the valley. The non-hydrostatic model Meso-NH, used in a grid-nesting configuration with two nested models and initialized with a mesoscale analysis, allowed us to simulate realistically the location and depth of the cold pool. The relationship between the föhn intensity and the large-scale environment is also examined. The flow regime is a ,flow around' the Alps. The variability of this flow at the western tip of the Alps could explain some of the temporal changes observed at low level in the Rhine valley. Copyright © 2005 Royal Meteorological Society [source] Coriolis effects in mesoscale flows with sharp changes in surface conditionsTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 603 2004J. C. R. Hunt Abstract A general linearized ,shallow-layer' perturbation model, where the approximately neutral lower layer of thickness h0 is situated below a stable upper layer (i.e. an inversion with temperature change ,T), is developed for steady, mesoscale atmospheric flows over low-lying topography whose height is less than h0. With the Coriolis parameter f, sharp changes in surface conditions (surface roughness, terrain elevation, heat flux) are modelled as a distributed body force through the lower layer. The Froude number of this layer is small. Typical cases of mesoscale discontinuities are examined. The results are compared with those of a continuously stratified model and observations, and with numerical mesoscale model results for a meteorological case-study over the Dover Straits region of the English Channel. The main results are: (i) If the wind direction is parallel to the edge-line separating the change in surface roughness, there are marked increases and decreases in these coastal winds whose maxima can occur over the sea within a distance of order h0(,1 km) of a coast. The strength of these wind ,jets', which do not occur in the absence of Coriolis force, decrease away from the edge-line gradually over transverse length-scales of the order of the Rossby deformation radius . Changes to surface roughness lead to an increase in the wind speed perturbation in the downwind direction until limited by non-linear effects. When the wind is at an angle to a roughness change or coast, the maxima occur at the coastline. (ii) Where there are sharp changes in the orientation of contours of constant roughness length (e.g. at capes or bays on the coastline or wakes of high-drag areas), ,detached' jets are formed in the downwind direction. (iii) Changes in surface elevation at a coast produce effects different from those of roughness; a positive wind jet forms parallel to the coast in the direction of the wind when the coast is on the right (looking downwind) and a negative jet when the coast is on the left. These jets do not increase in strength along the flow and do not persist downwind. (iv) Coriolis effects also determine how the inversion height varies near coastlines and surface roughness changes; for example, increasing/decreasing inland over a distance LR when stable airflow approaches from the sea and the coast is on the right/left of an observer looking downwind (opposite in the southern hemisphere). This mechanism is consistent with observed increasing/decreasing cloudiness inland from a coast. (v) Other effects occur where the surface elevation changes gradually over a distance of order LR (e.g. a wide, shallow valley); frictional effects are comparable with buoyancy and Coriolis forces, and flows perpendicular to the elevation change are deflected to the left (in the northern hemisphere), as observed in the Rhine valley. (vi) The shallow-layer model simulates the major features of the low-level flow field computed using the numerical mesoscale model with a horizontal resolution of 2 km, i.e. of order h0. Broad features were captured using a coarser resolution of 12 km. (vii) The analysis provides a method of estimating errors associated with finite grid size in numerical mesoscale models. Copyright © 2004 Royal Meteorological Society [source] Is the combination of topsoil replacement and inoculation with plant material an effective tool for the restoration of threatened sandy grassland?APPLIED VEGETATION SCIENCE, Issue 4 2010Carsten Eichberg Abstract Question: Is it possible to restore dry calcareous inland sand ecosystems with their characteristic plant community structure within a 4-yr period by means of combined abiotic,biotic techniques (topsoil replacement, inoculation with raked/mown plant material from target areas)? Location: Upper Rhine valley, Germany. Methods: Two 4-year experiments were carried out on former arable land, each in the proximity of a reference area bearing a similar complex of threatened sandy grasslands (experiment 1: fine-scale; experiment 2: landscape scale). In both experiments we used nutrient-poor deep-sand substrate (abiotic approach), raked/mown inoculation material from target areas and grazing as management tool (biotic and management approach). The vegetation of the restoration and donor areas was sampled once a year and analysed by non-metric multidimensional scaling (NMDS) ordination and target-species ratios. Mixed linear models were calculated to determine effects of grazing (experiment 1) and year (both experiments). Results: NMDS revealed a continuous development of the restored sites towards the corresponding donor sites. Similarly, target-species ratios of the restored sites tended towards the ratios of the donor sites. To date, grazing effects have mainly been structural: reduction of a carpet-forming pleurocarpous moss species and of litter. In addition, cover of target species in relation to total plant cover was significantly enhanced by grazing in the last two study years. Conclusions: The combination of nutrient-poor substrate, inoculation with raked/mown plant material and grazing proved to be a very effective restoration method for dry base-rich sand ecosystems. After 4 yr the restored plant communities serve as well-developed parts of a habitat network. [source] The impact of site conditions and seed dispersal on restoration success in alluvial meadowsAPPLIED VEGETATION SCIENCE, Issue 1 2003Tobias W. Donath Wisskirchen & Haeupler (1998) Abstract. We studied the restoration success of flood plain meadows in the northern Upper Rhine valley, where between 1988 and 1992, 35 ha of arable land was converted into grassland and subsequently managed for nature conservation. Remnant populations of typical alluvial meadow species were found in old meadows and along drainage ditches that dissect the whole area. We analysed the site conditions and phytosociological relevés in old and new meadows. Small differences in site parameters between old and new meadows contrasted with a clear floristic differentiation between the two meadow types. The vegetation of old meadows was much more differentiated along prevailing environmental gradients than the vegetation of new meadows. Despite the favourable site conditions for the re-establishment of species-rich meadows on the former arable land, restoration success was limited to the vicinity of remnant stands. In contrast to old meadows, indicator species of new grassland were still typical species of regularly disturbed ruderal and arable habitats, often capable of building up a persistent seed bank. The precise mapping of 23 target species revealed that even wind dispersal predominantly leads to re-establishment in the close circumference of parent plants. We found no indication that regular flooding, hay-making and autumnal grazing had an impact on recolonization of newly created grassland. Even under favourable conditions for the re-establishment of target species, restoration success in alluvial meadows proved to be strongly dispersal limited. We discuss the implications of our findings for future restoration management in grasslands. [source] Siebengebirge , im Saum der Großlandschaften.BIOLOGIE IN UNSERER ZEIT (BIUZ), Issue 6 2009Die Exkursion Abstract Das rechtsrheinisch gegenüber Bonn gelegene Siebengebirge weist zwar nur eine Fläche von etwa 4800 ha auf, stellt aber als Landschaft ebenso wie als Naturraum ein recht ungewöhnliches Gefüge dar. Über kaum eine zweite Teillandschaft Deutschlands liegen vergleichbar zahlreiche Einzeluntersuchungen und Gesamtdarstellungen vor. Ein Exkursionsvorschlag entführt in diese faszinierende Teilregion am Ende des Unteren Mittelrheintals. The Siebengebirge Mountains, facing Bonn and situated between the Lower Rhine Bight and the well known Middle Rhine valley, cover an area of only some 4800 ha, but represent a fairly unusual complex with respect to landscape and nature. Already some famous exploring travellors of the 18th century such as Georg Forster, Johann Wolfgang von Goethe, and Alexander von Humboldt consistently emphasized the striking diversity and natural beauty of this area. No other part of Germany has hitherto been dealt with by a comparable array of special (geologically as well as biologically centered) investigations and compiling contributions. An excursion proposal recommends a closer inspection of that fascinating landscape. [source] | |||||||||||||