The understanding of alpine groundwater dynamics and the interactions with surface stream water is crucial for water resources research and management in mountain regions. In order to characterize local spring and stream water systems, samples at 8 springs, 5 stream gauges and bulk samples of precipitation at 4 sites were regularly collected between January 2012 and January 2016 in the Berchtesgaden Alps for stable water isotope analysis. The sampled hydro-systems are characterized by very different dynamics of the stable isotope signatures. To quantify those differences, we analyzed the stable isotope time series and calculated mean transit times (MTT) and young water fractions (YWF) of the sampled systems. Based on the data analysis, two groups of spring systems could be identified: one group with relatively short MTT (and high YWF) and another group with long MTT (and low YWF). The MTT and the YWF of the sampled streams were intermediate, respectively. The reaction of the sampled spring and stream systems to precipitation input was studied by lag time analysis. The average lag times revealed the influence of snow and ice melt for the hydrology in the study region. It was not possible to determine the recharge elevation of the spring and stream systems due to a lack of altitude effect in the precipitation data. For two catchments, the influence of the spring water stable isotopic composition on the streamflow was shown, highlighting the importance of the spring water for the river network in the study area. 相似文献
Landslides triggered by rainfall are the cause of thousands of deaths worldwide every year. One possible approach to limit the socioeconomic consequences of such events is the development of climatic thresholds for landslide initiation. In this paper, we propose a method that incorporates antecedent rainfall and streamflow data to develop a landslide initiation threshold for the North Shore Mountains of Vancouver, British Columbia. Hydroclimatic data were gathered for 18 storms that triggered landslides and 18 storms that did not. Discriminant function analysis separated the landslide-triggering storms from those storms that did not trigger landslides and selected the most meaningful variables that allow this separation. Discriminant functions were also developed for the landslide-triggering and nonlandslide-triggering storms. The difference of the discriminant scores, ΔCS, for both groups is a measure of landslide susceptibility during a storm. The variables identified that optimize the separation of the two storm groups are 4-week rainfall prior to a significant storm, 6-h rainfall during a storm, and the number of hours 1 m3/s discharge was exceeded at Mackay Creek during a storm. Three thresholds were identified. The Landslide Warning Threshold (LWT) is reached when ΔCS is −1. The Conditional Landslide Initiation Threshold (CTLI) is reached when ΔCS is zero, and it implies that landslides are likely if 4 mm/h rainfall intensity is exceeded at which point the Imminent Landslide Initiation Threshold (ITLI) is reached. The LWT allows time for the issuance of a landslide advisory and to move personnel out of hazardous areas. The methodology proposed in this paper can be transferred to other regions worldwide where type and quality of data are appropriate for this type of analysis. 相似文献
The development and age of the present geomorphology and superficial material of the Coloradofjella plateau, Spitsbergen, have been investigated through field surveying and laboratory sediment analyses. The focus was specifically on the role of glacial erosion and periglacial processes. The summit plain is deeply incised with large V-shaped valleys. Extensive networks of ice wedge polygons indicate that the fine-grained regolith is at least a few metres thick. An abundance of coarse-grained gabbroid erratics, clearly derived from sources further to the east, are distributed over parts of the summit plain. A vertical-walled dolerite dyke protruding up to 4 m above the adjacent surface shows no sign of glacial erosion. Our findings confirm that the present bedrock geomorphology and regolith in the summit plain survived at least the Late Weichselian glaciation. This is best explained by the ice sheet having been cold-based throughout its existence on the summit plain. Cold-based conditions imply that permafrost survived the last glacial cover. Based on the geomorphic evidence and estimates of Late Cenozoic erosion, we suggest that the present summit plains roughly represent the remains of a preglacial surface. 相似文献
The distribution of Cenozoic subsidence across Northeast Atlantic volcanic margins have been evaluated to define the width of the rift zone and magnitude of extensional deformation. The subsidence profiles are corrected for the effects of lower-crustal magmatic bodies emplaced during continental break-up. The dimensions of the bodies have been derived from the crustal velocity structure. The width of the Late Cretaceous-Paleocene Northeast Atlantic rift zone was more than 300 km, and the lithospheric extension factor increases gradually towards the line of continental separation. A large number of high-quality seismic reflection data tied to scientific and commercial wells reveals that the initiation of extensional deformation preceded continental separation by ˜ 18 m.y. on the Vøring margin, off Norway. These results show that the Northeast Atlantic volcanic margins, commonly considered as typical volcanic margins indeed, have similar dimensions as non-volcanic margins, and as continental rifts. Thus, these margins contrast significantly with previously suggested evolutionary models based on narrow rift zones and formation during rapid lithospheric failure. The wide rift is compatible with volume of igneous rocks observed along these margins, and with a thermal anomaly similar to that associated with production of Northeast Atlantic oceanic lithosphere. 相似文献
Observations of water surface elevation (WSE) and bathymetry of the lagoons and cenotes of the Yucatán Peninsula (YP) in southeast Mexico are of hydrogeological interest. Observations of WSE (orthometric water height above mean sea level, amsl) are required to inform hydrological models, to estimate hydraulic gradients and groundwater flow directions. Measurements of bathymetry and water depth (elevation of the water surface above the bed of the water body) improve current knowledge on how lagoons and cenotes connect through the complicated submerged cave systems and the diffuse flow in the rock matrix. A novel approach is described that uses unmanned aerial vehicles (UAVs) to monitor WSE and bathymetry of the inland water bodies on the YP. UAV-borne WSE observations were retrieved using a radar and a global navigation satellite system on-board a multi-copter platform. Water depth was measured using a tethered floating sonar controlled by the UAV. This sonar provides depth measurements also in deep and turbid water. Bathymetry (wet-bed elevation amsl) can be computed by subtracting water depth from WSE. Accuracy of the WSE measurements is better than 5–7 cm and accuracy of the water depth measurements is estimated to be ~3.8% of the actual water depth. The technology provided accurate measurements of WSE and bathymetry in both wetlands (lagoons) and cenotes. UAV-borne technology is shown to be a more flexible and lower cost alternative to manned aircrafts. UAVs allow monitoring of remote areas located in the jungle of the YP, which are difficult to access by human operators. 相似文献
Limiting global warming to ‘well below’ 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase even further to 1.5°C is an integral part of the 2015 Paris Agreement. To achieve these aims, cumulative global carbon emissions after 2016 should not exceed 940 – 390?Gt of CO2 (for the 2°C target) and 167 – ?48?Gt of CO2 (for the 1.5°C target) by the end of the century. This paper analyses the EU’s cumulative carbon emissions in different models and scenarios (global models, EU-focused models and national carbon mitigation scenarios). Due to the higher reductions in energy use and carbon intensity of the end-use sectors in the national scenarios, we identify an additional mitigation potential of 26–37 Gt cumulative CO2 emissions up to 2050 compared to what is currently included in global or EU scenarios. These additional reductions could help to both reduce the need for carbon dioxide removals and bring cumulative emissions in global and EU scenarios in line with a fairness-based domestic EU budget for a 2°C target, while still remaining way above the budget for 1.5°C.Key policy insights
Models used for policy advice such as global integrated assessment models or EU models fail to consider certain mitigation potential available at the level of sectors.
Global and EU models assume significant levels of CO2 emission reductions from carbon capture and storage to reach the 1.5°C target but also to reach the 2°C target.
Global and EU model scenarios are not compatible with a fair domestic EU share in the global carbon budget either for 2°C or for 1.5°C.
Integrating additional sectoral mitigation potential from detailed national models can help bring down cumulative emissions in global and EU models to a level comparable to a fairness-based domestic EU share compatible with the 2°C target, but not the 1.5°C aspiration.
AbstractFinding the shortest path through open spaces is a well-known challenge for pedestrian routing engines. A common solution is routing on the open space boundary, which causes in most cases an unnecessarily long route. A possible alternative is to create a subgraph within the open space. This paper assesses this approach and investigates its implications for routing engines. A number of algorithms (Grid, Spider-Grid, Visibility, Delaunay, Voronoi, Skeleton) have been evaluated by four different criteria: (i) Number of additional created graph edges, (ii) additional graph creation time, (iii) route computation time, (iv) routing quality. We show that each algorithm has advantages and disadvantages depending on the use case. We identify the algorithms Visibility with a reduced number of edges in the subgraph and Spider-Grid with a large grid size to be a good compromise in many scenarios. 相似文献