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1.
Annett Bartsch Martin Gude Christer Jonasson & Dieter Scherer 《Geografiska Annaler: Series A, Physical Geography》2002,84(3-4):171-178
Sediment transport processes in the Kärkevagge are investigated concerning their spatial and temporal characteristics due to long–term monitoring. Within this study remote sensing techniques and GIS modelling in connection with geomorphic mapping are applied for identification and characterization of geomorphic process units. Relationships between geomorphometric parameters and slope processes like solifluction, talus creep and rockfall have been analysed. Multitemporal Landsat–TM5 scenes are used as source for landcover characteristics (Normalized Difference Vegetation Index) after preprocessing involving orthorectification and topographic normalization in order to remove possible terrain–induced effects. Additionally, a digital elevation model with a resolution of 20 m for the Kärkevagge catchment is developed and parameters like slope gradient, slope aspect and profile curvature are extracted as input for the analysis of the sediment transport system. The combination of landcover information, geomorphometrical and topological features allows the definition of areas for single process activities. They show specific sediment displacement characteristics depending on material conditions, topological and geometrical features. Geomorphic process units, which show a homogenous composition, are extracted from these available layers. 相似文献
2.
Eduard A. Titlyanov Tamara V. Titlyanova Bangmei Xia Inka Bartsch 《Ocean Science Journal》2016,51(3):485-506
Retrospective analysis of diversity and species composition of marine macroalgae of Hainan Island in the period 1933–1992 is presented in this paper. There are two extensive sample collection periods of benthic macroalgae: the early collection (EC) covers a period between the early 1930s and the 1980s before considerable urbanization and reef degradation took place and a late collection (LC) was performed in 1990/1992 during a phase of rapid urbanization. Analysis of data also including an earlier published inventory of green algae covering the same collection sites (Titlyanov et al. 2011a) revealed that the marine flora of the island comprises 426 taxa in total, with 59% red algae, 18% brown algae and 23% green algae. In total 59 species of red algae, 11 species of brown algae and 37 species of green algae sampled during the LC are new records for Hainan Island. Considerable floristic changes between EC and LC became evident. In the LC there were significantly more filamentous, tubular or fine blade-like, and often epiphytic, green and red algae with a high surface-to-volume ratio. Additionally a reduction of green, brown and red algal species with larger fleshy or foliose thalli and a low surface-to-volume ratio was observed. It is assumed that the changes reflect the degradation of the coral reef ecosystem around Hainan, which was damaged by human activities especially in the 1950s–1970s. 相似文献
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Martin Gude Gerhard Daut Susanne Dietrich Roland Mäusbacher Christer Jonasson Annett Bartsch & Dieter Scherer 《Geografiska Annaler: Series A, Physical Geography》2002,84(3-4):205-212
The analysis of Holocene geomorphic process activity demands long–term data sets, which are available for the Kärkevagge catchment due to 50 years of intensive geomorphologic field studies. This data set is used in combination with additional field measurements, remote sensing and digital elevation model (DEM) analysis to provide input data for modelling Holocene valley development. On the basis of this information, geomorphic process units (GPUs) are defined by means of GIS modelling. These units represent areas of homogeneous process composition that transfer sediments. Since the data base enables the quantification of single processes, the interaction of processes within the units can also be quantified. Applying this concept permits calculation of recent sediment transfer rates and hence leads to a better understanding of actual geomorphic landscape development activity. To extrapolate these data in time and space the process–related sediments in the valley are analysed for depth and total volume, primarily using geophysical methods. In this fashion the validity of measured process rates is evaluated for the Holocene time scale. Results from this analysis are exemplified in a cross–profile showing some of the principal sediment units in the valley. For example, the measured modern rates on a slush torrent debris fan seem to represent the Holocene mean rate. This approach should also be suitable for revealing Holocene geomorphic landscape development in terms of climate change. 相似文献
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Within this paper modern techniques such as satellite image analysis and tools provided by geographic information systems (GIS) are exploited in order to extend and improve existing techniques for mapping the spatial distribution of sediment transport processes. The processes of interest comprise mass movements such as solifluction, slope wash, dirty avalanches and rock‐ and boulder falls. They differ considerably in nature and therefore different approaches for the derivation of their spatial extent are required. A major challenge is addressing the differences between the comparably coarse resolution of the available satellite data (Landsat TM/ETM+, 30 m × 30 m) and the actual scale of sediment transport in this environment. A three‐stepped approach has been developed which is based on the concept of Geomorphic Process Units (GPUs): parameterization, process area delineation and combination. Parameters include land cover from satellite data and digital elevation model derivatives. Process areas are identified using a hierarchical classification scheme utilizing thresholds and definition of topology. The approach has been developed for the Kärkevagge in Sweden and could be successfully transferred to the Rabotsbekken catchment at Okstindan, Norway using similar input data. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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The objectives of the interdisciplinary pilot project "Development of a municipal environmental information system" in Hannover
encompassed the development, modification and improvement of data acquisition methods and methods for describing the environment
on the basis of this data, as well as methods for evaluating the data as a basis for measures affecting the environment taken
by the community.
The subproject "Urban Soils" had the following two main objectives: (i) development of a data acquisition method for soils
in municipal areas and a method for evaluating this data, and (ii) development of methods for making this information available
to local government in the form of a "soil information system" for urban areas.
To achieve these objectives, the following work was carried out: (1) a factor analysis to determine which factors affect the
soil in an urban area; (2) study of methods for mapping soils in cities; (3) development of a concept for a soil information
system; and (4) evaluation of environmental problems of the municipality using the soil information system.
Data acquisition was done in two steps: First, soil-relevant data was selected, standardized, digitized and stored in an alphanumeric
and a graphic database for a factor analysis. By intersection of the eight information levels, the factors affecting the soil
were determined for the city of Hannover (200 km2). To test the hypothesis that the results for one site can be transferred to another site with the same combination of factors,
43 test sites typical of urban land use were selected. These test sites were mapped in a way to fulfill geostatistical requirements;
physical and chemical analyses of the soils were made. A prognosis of soil distribution and properties was made on the basis
of the factor analysis. and compared with the actual conditions.
Concurrent with the pedological research, a prototype soil information system was developed. The system consists of databases,
a methodbase, a geometrical tool, and a control system. Alphanumeric data is stored in a relational database, the geometric
data in ISAM files. Methods for determining soil parameter values were selected and tested for their applicability.
Using the pedological data and the soil information system, information can be obtained about soil conditions in Hannover
as well as about soil processes (e.g. infiltration rates) and interaction with the atmosphere, hydrosphere, etc. This information
can be obtained in the form of thematic maps and statistical representations, which can be used by decision-makers at the
municipal level.
Received: 3 September 1994 · Accepted: 19 December 1995 相似文献
9.
Jason Timmons Young Min Cho Timothy Townsend Nicole Berge Debra Reinhart 《Geotechnical and Geological Engineering》2012,30(1):95-105
Commercially available hydraulic total overburden pressure cells were installed in the sand drainage layer of a municipal
solid waste landfill and monitored for a period of 3,110 days. Both overburden pressure and temperature were measured in the
landfill as it was filled with compacted waste. Topographic surveys of the landfill were periodically conducted to measure
the height of waste above the pressure cells and to determine the landfill volume for indirect unit weight estimation. The
average ratio of measured to theoretically-predicted overburden pressure was 0.6, indicating that on average the pressure
cells underestimated the load. The overburden pressure measured near the toe of the landfill was greater than that predicted
by the unit weight of landfilled material, while most of the overburden pressure measurements further inside the landfill
were less than predicted. Several possible causes for this phenomenon are discussed, including the uneven distribution of
forces resulting from the heterogeneous nature of the waste and cover soil. The earth pressure cells were capable of detecting
the placement of individual waste lifts. 相似文献
10.
Juan F. García-Quijano Gaby Deckmyn Reinhart Ceulemans Jos van Orshoven Bart Muys 《Climatic change》2008,86(3-4):397-424
There is a gap between the increased scientific understanding of carbon pools and fluxes at individual trees/stand and that
of forested landscape with complex structures (i.e. variety of species, age classes, site characteristic and management practices).
The question about how results generated from a simulated physiologically distinct individual(s)/stands grown at a particular
location (scale) can be extrapolated (scaling) across a diverse population in time and space with diverse environments, has
been troubling scientists for many years. Scale and scaling present three problems in common: (a) spatial heterogeneity, (b)
non-linearity in response and (c) disturbance regimes. Scale, in particular, presents other three problems: (d) threshold
scale for processes, (e) dominant processes with scales and (f) emerging properties of the system. Scaling presents problems
with (g) feedbacks between plants and environment and (h) plant interactions. The present study proposes a modeling framework
linking a process-based model SECRETS – to overcome some of the scale and scaling problems (a, b, c, d and g) – to a C accounting
model GORCAM – to integrate the effects of C stock in wood products and from fossil fuel substitution. The capabilities of
the modeling framework are tested against three theoretical complex forested landscapes that combine some of the five following
scenarios: existing multifunctional forest under (1) actual and (2) changing environmental conditions, and afforestation of
an agricultural area with (3) a new multifunctional forest or with (4) a short rotation coppice (poplar) or with (5) an agricultural
crop (miscanthus) for bioenergy production. Forest reserves calculations are included for completeness of the landscape C
balance and as reference. Results, on the one hand, suggest that the framework is able to simulate C sequestration and stock
in ecosystem pools, wood products and fossil fuel substitution of the scenarios under actual environmental conditions. However,
comparison of results under changing environmental conditions, against specific plant literature suggest SECRETS formulation
must be improved with recent development in photosynthesis, stomatal conductance and N balances. On the other hand, results
also suggest that under actual environmental conditions, the optimum landscape scenario to sequester C and avoid fossil emissions
to the atmosphere is composed by existing multifunctional forest, reserves and afforestation with short rotation coppice for
bioenergy production. 相似文献