Dissertations / Theses on the topic 'Surface elevations'

The thesis addresses a longstanding cartographic problem, of how to visualise the Earth's surface relief in an effective and meaningful way. The problem is narrowed to relief defined by digital elevation data and visualised as a static, orthographic representation. It is approached in three steps: firstly research focuses on determining the most useful form of graphical representation to be pursued; secondly the theoretical basis of computer visualisation is investigated through a three-model framework, prompting a number of directions where solutions might be developed; and thirdly the development and engineering of a system is reported which models and renders widely available elevation data, and which provides flexibility in its input variables. The developed system is then applied to specific cases of relief visualisation, and new graphical forms are developed. The investigation of past and current approaches to relief representation, and a review of computer-graphic rendering of simpler geometrically defined objects, have revealed some limitations in commonly used relief visualisation systems, but have established the simulation of light and shade as still the most promising line of development. Analysis of the component variables of surface visualisation and rendering has led to the visualisation paradigm of three parametric models - of elevation, illumination and reflectance. Some attractive qualities, including widespread availability, of the contour elevation model have been identified, and a system has been developed which reconstructs surfaces from this data structure in a more effective way than typical current approaches. The system is also designed to support more complex illumination and surface reflectance models than the somewhat simplistic scenarios commonly available. The thesis reports the application of the system to generate surfaces from contour data, and experimentation with multiple coloured light sources and varying degrees of surface specularity. Evaluation of system implementation, and of the qualities of a representative set of graphical products, is addressed through six design criteria within a context defined by a typical mapping application. This has led to conclusions that the system and the new graphical forms have a number of virtues, including close fidelity with the source data, and significant improvements in visualisation.

Wave energy is an energy source of great interest due to it being the most concentrated form of renewable energy. A profitable method for wave energy extraction is however yet to be found and this project aims to contribute to the progress. A method for making short-term predictions of the ocean surface elevation has been suggested for improved efficiency and such a method is presented here. The project is carried out in two dimensions on the numeric platform MATLAB. Simulations of a Wave Energy Converter show that the power output seems to increase when the developed prediction method is utilized.

Thesis (M.A.)--Boston University PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
Loss of surface elevation makes salt marshes more susceptible to impacts from accelerated sea level rise, such as vegetation drowning, die-off, and conversion of marsh to open water. The ultimate degradation of the salt marsh system is disastrous with ramifications ranging from loss of critical habitat to loss of an important buffer for coastal communities from storm surges. Effectively, a more comprehensive understanding of the mechanisms driving surface elevation loss in anthropogenically altered and degraded marshes is key to engineering successful marsh restoration projects, in an effort to reverse this trend. This study aims to achieve that goal in an area of a northern Massachusetts salt marsh with high man-made ditch density, through comparison of the hydrologic, sedimentary, and vegetative conditions to a non-ditched, reference portion of salt marsh. It was hypothesized that a decrease in subsurface hydroperiod through increased drainage, characteristic of areas of high ditch density, would allow for increased oxygen diffusion into the subsurface causing belowground decomposition rates to increase. This ultimately would lead to a reduction in organic matter, and without compensation from an inorganic sediment supply, marsh subsidence would occur. Water table levels, belowground biomass, bulk density data, and percent organic content data all supported this hypothesis, but direct analysis of the belowground litterbag component of this study did not demonstrate significant differences in decomposition rates between the ditched and non-ditched sites. Further study of belowground conditions, resulted in a live root turnover rate about twenty percent slower in the ditched marsh than in the non-ditched marsh. This suggests that turnover rates, not decomposition rates, may ultimately be the mechanism behind surface elevation loss in ditched marshes.

Dans cette thèse, nous présentons des méthodes pour construire une surface géologique optimal à partir d’une quantité énorme de points 3D extraits de cubes sismiques. Appliquer le processus à l’ensemble des points induit un risque important de contraction de la surface de sorte que l’extraction de la frontière initiale est une étape importante permettant une simplification à l’intérieur de la surface. La forme globale de la surface sera alors mieux respectée pour la reconstruction de la surface triangulaire finale. Nos propositions sont basées sur la régularité des données qui permet, même si des données sont manquantes, d’obtenir facilement les informations de voisinage. Tout d’abord, nous présentons une nouvelle méthode pour extraire et simplifier la frontière d’une surface d’élévation définie par un ensemble de voxels dans un grand volume 3D où des données sont manquantes. Deuxièmement, une méthode pour simplifier la surface à l’intérieur de sa frontière est présentée. Elle comprend une étape de simplification grossière optionnelle suivie par une étape plus fine basée sur l’étude des courbures. Nous tenons également compte du fait que la densité de données doit changer graduellement afin de recevoir à la dernière étape d’une surface triangulée avec de meilleurs triangles. Troisièmement, nous avons proposé une nouvelle méthode rapide pour trianguler la surface après simplification
Reconstructing surfaces with data coming from an automatic acquisition technique always entails the problem of mass of data. This implies that the usual processes cannot be applied directly. Therefore, it leads to a mandatory data reduction process. An effective algorithm for a rapid processing while keeping the original model is a valuable tool for constructing an optimal surface and managing the complex data.In this dissertation, we present methods for building an optimal geological surface from a huge amount of 3D points extracted from seismic cubes. Applying the process to the whole set of points induces an important risk of surface shrinking so that the initial boundary extraction is an important step permitting a simplification inside the surface. The global surface shape will then be better kept for the reconstruction of the final triangular surface. Our proposals are based on the regularity of data which permits, even if data are missing, to easily obtain the neighboring information. Firstly, we present a new method to extract and simplify the boundary of an elevation surface given as voxels in a large 3D volume having the characteristics to be sparse. Secondly, a method for simplifying the surface inside its boundary is presented with a rough optional simplification step followed by a finer one based on curvatures. We also keep into consideration that the density of data must gradually change in order to receive in the last step a triangulated surface with better triangles. Thirdly, we have proposed a new and fast method for triangulating the surface after simplification

Evapotranspiration from a forest clearcut was measured over two growing seasons as part of a larger study of the microclimate of forest clearcuts and microclimate modification by site preparation. Pinegrass is the dominant species on clearcuts in the dry southern interior and is the major competitor with coniferous seedlings. This paper examines the water use of a pinegrass dominated clearcut and the response of surface conductance to environmental variables. Evapotranspiration was derived from eddy correlation measurements of sensible heat flux and measurements of net radiation and soil heat flux. 419 hours of daytime energy balance data from the summers of 1987 and 1988 were analyzed. A rearranged form of the Penman-Monteith equation was used to calculate hourly mean surface conductances for the clearcut. Leaf area measurements were used to calculate stomatal conductance from surface conductances. Stomatal conductance was modelled using boundary-line and non-linear optimization techniques. The most successful model (R² = 0.71) was obtained using non-linear optimization with stomatal conductance as a non-linear function of saturation deficit at the leaf surface (D₀) and solar irradiance. D₀ was calculated from measured evapotranspiration and surface conductance. Response of stomata to saturation deficit would be expected to be better correlated to D₀ than D measured at a reference height above the canopy. Stomatal conductance was also modelled as a function of D (measured at 1.3 m) and solar irradiance. The resulting model (R² = 0.50) was poor compared to that based on D₀. Saturation deficit and temperature were found to be highly correlated both at 1.3 m above the canopy and at the leaf surface. Use of air temperature in the conductance model caused R² to decrease. No relationship between stomatal conductance and volumetric soil water content was found. Hourly evapotranspiration rates calculated using modelled surface conductances agreed well with measured rates.(R² = 0.89). Evapotranspiration was also modelled using the Priestley-Taylor approach. The mean hourly a for all daylight data was found to be 0.81. This simple model was found to give comparable results to the stomatal conductance based model (R² = 0.85).
Land and Food Systems, Faculty of
Graduate

Between 1977 and 2007, the Kaskawulsh Glacier underwent an overall decrease in volume of between 2.76 km3 water equivalent (we) and 4.60 km3 we, and a decrease in area of 2.27%. Volume losses are consistent with changes observed at most glaciers in the Yukon/Alaska region which are thinning and/or retreating (Arendt et al. 2006; Chen et al. 2006a; Larsen et al. 2007; Molnia 2007). The rate of volume change over the periods 1977-1995 and 1995-2007 remained constant at -0.52 km3 yr-1 we, while between 2000 and 2007 the glacier gained volume at a rate of 1.04 km3 yr-1 we. Gains in the recent 2000-2007 period result from prominent thickening in the accumulation area above 1989 m (+16.9 m) and minor thickening in the ablation area (+0.5 m). The observed thickening pattern is similar to patterns observed in Greenland (Chen et al. 2006b; Johannessen et al. 2005; Luthcke et al. 2008b), Antarctica (Davis et al. 2005), the Karakoram Himalaya (Hewitt 2005), New Zealand (Chinn 1999; Hooker and Fitzharris 1999), Scandinavia (Bamber et al. 2004; Chinn et al. 2005, Nesje et al. 2000), and Alaska (Arendt et al. 2008; Muskett et al. 2(03). Between 1956 and 2007, the glacier terminus retreated by an average of 655 m (13 m yr-1). No scaling ratio between terminus retreat and volume change could be established for the Kaskawulsh Glacier for the period 1977-2007.

Ocean circulation and storm surge models have neglected mass contributions from precipitation and can have a systematic bias in sea surface height (SSH). Here, a new rainfall scheme has been set up in the ocean circulation model Regional Ocean Modelling System (ROMS) to incorporate the effects of precipitation mass. When precipitation is added to the sea surface, it spreads out via surface gravity waves that increase in propagation speed with increasing water depth. Over several days, the increase in SSH due to the precipitation mass added created a geostrophic adjustment, generating clockwise-rotating geostrophic currents around the SSH increase. The transfer of momentum from precipitation to the sea surface, or rain stress, is investigated in ROMS. An error in the existing implementation of rain stress has been uncovered and corrected. The existing ROMS code generated an error in the direction of rain stress by up to 45° and systematically overestimated its magnitude by 41%. The SSH response to wind stress is examined. Positive and negative surges are generally generated by onshore and offshore winds respectively. While positive surges are widely studied, negative surges are less well understood. Negative surges are larger in magnitude and extend further across the coastline than positive surges. It is shown for the first time that the alongshore component of the wind stress is the main contributor to the asymmetrical surge response. Without this component, the ratio of negative to positive surge can decrease by more than half. This asymmetry also increases with increasing latitude and decreasing depth. In the case study of a real tropical cyclone, Monica, the effect of incorporating precipitation mass is compared with other processes affecting storm surge: surface wind, inverse barometer effect and rain stress. The maximum SSH response is 170.6 cm for the wind effect, 61.5 cm for the inverse barometer effect, 7.5 cm for the effect of rain stress and 6.4 cm for the effect of rain mass. Each process has been shown to have different spatial influences. The effect of rain mass has a strong remote influence compared to the inverse barometer effect and the effect of rain stress. This is particularly seen in semi-enclosed bays.

The analysis of visibility between two points on the earthâ s terrain is a common use of GIS software. Most commercial GIS software packages include the ability to generate a viewshed, or a map of terrain surrounding a particular location that would be visible to an observer. Viewsheds are often generated using â bare-earthâ Digital Elevation Models (DEMs) derived from the process of photogrammetry. More detailed models, known as Digital Surface Models (DSMs), are often generated using Light Detection and Ranging (LIDAR) which uses an airborne laser to scan the terrain. In addition to having greater accuracy than photogrammetric DEMs, LIDAR DSMs include surface features such as buildings and trees. This project used a visibility algorithm to predict visibility between observer and target locations using both photogrammetric DEMs and LIDAR DSMs of varying resolution. A field survey of the locations was conducted to determine the accuracy of the visibility predictions and to gauge the extent to which the presence of surface features in the DSMs affected the accuracy. The use of different resolution terrain models allowed for the analysis of the relationship between accuracy and optimal grid size. Additionally, a series of visibility predictions were made using Monte Carlo methods to add random error to the terrain elevation to estimate the probability of a targetâ s being visible. Finally, the LIDAR DSMs were used to determine the linear distance of terrain along the lines-of-sight between the observer and targets that were obscured by trees or bushes. A logistic regression was performed between that distance and the visibility of the target to determine the extent to which a greater amount of vegetation along the line-of-sight impacted the targetâ s visibility.
Master of Science

Modern day cars are often equipped with a variety of sensors that collect information about the car and its surroundings. The stereo camera is an example of a sensor that in addition to regular images also provides distances to points in its environment. This information can, for example, be used for detecting approaching obstacles and warn the driver if a collision is imminent or even automatically brake the vehicle. Objects that constitute a potential danger are usually located on the road in front of the vehicle which makes the road surface a suitable reference level from which to measure the object's heights. This Master's thesis describes how an estimate of the road surface can be found to in order to make these height measurements. The thesis describes how the large amount of data generated by the stereo camera can be scaled down to a more effective representation in the form of an elevation map. The report discusses a method for relating data from different instances in time using information from the vehicle's motion sensors and shows how this method can be used for temporal filtering of the elevation map. For estimating the road surface two different methods are compared, one that uses a RANSAC-approach to iterate for a good surface model fit and one that uses conditional random fields for modeling the probability of different parts of the elevation map to be part of the road. A way to detect curb lines and how to use them to improve the road surface estimate is shown. Both methods for road classification show good results with a few differences that are discussed towards the end of the report. An example of how the road surface estimate can be used to detect obstacles is also included.

Thesis (M.A.)-Wilfrid Laurier University, 1996.
Includes bibliographical references (l.174-182). Issued also online via the World Wide Web; files in PDF format available to WLU users. Available in microfiche format.

Previous studies investigating the velocity and elevation change records of the Greenland Ice Sheet (GrIS) revealed rapid and complex changes. It is therefore imperative to determine changes with both high spatial and temporal resolutions. By fusing multiple laser altimetry data sets, the Surface Elevation Reconstruction and Change (SERAC) program is capable of reconstructing surface elevation changes with high spatial and temporal resolution over the entire GrIS. The input data include observations from NASA’s Ice, Cloud and land Elevation Satellite (ICESat) mission (2003-2009) as well as data collected by NASA’s Airborne Topographic Mapper (ATM) (1993-2013) and Land, Vegetation and Ice Sensor (LVIS) (2007-2012) airborne laser altimetry systems. This study extends the record of surface elevation changes over the GrIS by adding 2012 and 2013 laser altimetry data to the previous 1993-2011 record. Extending the record leads to a new, more accurate and detailed altimetry record for 1993-2013.

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Digital Elevation Models (DEMs) are fused with laser altimetry data over Zachariæ Isstrøm, northeast Greenland to analyze surface elevation changes and associated thinning rates during 1978-2014. Little to no elevation change occurred over Zachariæ Isstrøm from 1978-1999, however, from 1999-2014 elevation changes near the calving front became increasingly negative and accelerated. Calving front position showed steady retreat and grounding line position has been retreating towards the interior of the ice sheet at an increasing rate from 2010-2014 when compared to the 1996-2010 period. The measured elevation changes near the calving front have brought a large portion of the glacier close to the height of flotation. If the current thinning trend continues this portion of the glacier will reach flotation within the next 2-5 years allowing for further retreat and increased vulnerability to retreat for sections of the glacier further upstream.

Hyporheic exchange is an ecologically and biogeochemically essential function of rivers and streams. One important driver of hydrostatic (hyporheic) exchange is gra- dients in the hydrostatic hydraulic head at the streambed. This thesis investigates the impact of discharge on hydrostatic exchange in two stream reaches in Uppland, Sweden, with different geomorphological characteristics. By comparing 1D approx- imations of hydrostatic head variations along different longitudinal profiles across the streams, the use of a 2D hydraulic model for defining such variations is evaluated. Channel topography and discharge data have been obtained through field surveys in the two streams and form the basis for the setup of two HEC-RAS 2D models. The models have been calibrated against stream-depth measurements, validated against stream depth and stream velocity, and used for simulation of a range of discharges in both reaches. Water surface elevations, obtained for the different discharges in three profiles along each reach, have been used as input in a spectral model evaluating flow across streambed area; average hyporheic exchange velocity W. The results show that W , and thereby the hydrostatic exchange, decreases with increasing dis- charge and varies between different longitudinal profiles in the reach with the most complex geomorphology. For the reach with simpler geomorphology, the effects of discharge, as well as variations across the streams, are negligible. This implies that a 1D approximation of the hydrostatic head variations at the streambed can be sat- isfactory for a stream with simple geomorphology, whereas a 2D evaluation is more accurate for a stream with a complex geomorphology.
Denna uppsats handlar om hur ett vattendrags geomorfologi (form och geologi) och vattenföring påverkar hyporheiskt utbyte. Hyporheiskt utbyte är en process där ytvat- ten tränger igenom vattendragets botten, flödar i den så kallade hyporheiska zonen och blandas med grundvatten för att sedan återvända till vattendraget. Det är en vik- tig funktion på grund av dess påverkan på ekologi och biogeokemiska reaktioner, exempelvis genom syresättning av botten. Hyporheiskt utbyte påverkas bland annat av variationer i vattnets energinivå (hydrau- lisk tryckhöjd) vid bottnen. Den hydrauliska tryckhöjden varierar med vattenytans höjd, som är summan av bottnens topografi och vattnets djup. Målet med studien var att undersöka vattenföringens påverkan på hydrostatiskt, hyporheiskt utbyte i två vattendrag med olika geomorfologiska egenskaper. Endimensionella (1D) approx- imationer av hydraulisk tryckhöjd används ibland vid modellering av hyporheiskt utbyte. Därför var ytterligare ett mål att utvärdera flera endimensionella (1D) ap- proximationer av hydraulisk tryckhöjd vid botten, för att på så sätt undersöka om tvådimensionell (2D) modellering tillför mer information. För att uppnå målen genomfördes fältstudier vid två vattendrag i Uppland, vid vilka topografimätningar och spårämnesförsök gjordes. Dessa lade grunden för uppbygg- nad av 2D-modeller över vattendragen i modelleringsverktyget HEC-RAS. Model- lerna kalibrerades mot uppmätta djupdata och användes sedan för simulering av ett antal olika vattenföringar. Longitudinella profiler placerades i mitten samt till vänster respektive höger om mitten i vattendragen. Längs dessa profiler, för de olika vatten- föringarna, erhölls vattenytans höjd, som blev indata till en spektral modell. Utifrån topografi och vattenytans höjd längs en profil beskriver den spektrala modellen hur den hydrauliska trycknivån varierar med hjälp av en Fourier-serie. Den spektrala modellen beräknar det hyporheiska utbytets medelhastighet W , vil- ken är ett mått på hur stor volym vatten som genomtränger bottenarea per tid. Re- sultaten visar att för vattendraget med mest komplex geomorfologi minskar W med ökande vattenföring, och W varierar också mellan de olika longitudinella profilerna. För det andra vattendraget, som har en enklare geomorfologi, syns inga betydande skillnader, varken mellan olika vattenföringar eller profiler. Därutöver är W mind- re för vattendraget med enklare geomorfologi jämfört med vattendraget med kom- plex geomorfologi. Resultaten antyder därmed att 1D-approximationer av hydraulisk tryckhöjd vid bottnen är tillräckliga för vattendrag med enkel geomorfologi, medan 2D-modellering tillför information för ett vattendrag med komplex geomorfologi.

Aims: This study uses radiological and clinical evaluations of the healing of endosseous titanium implants presented with different surface characteristics in the clinical situation (paper I-III) and experimentally to describe the early bone healing in maxillary sinus membrane elevation with and without the use of grafting material (paper IV). Material and methods: In paper I, 136 patients were treated with 394 dental implants – 199 were oxidized titanium implants (Nobel Biocare TiUnite) and 195 were turned titanium surface implants (Nobel Biocare Mark III). Implant survival rates were retrospectively investigated after a minimum of five months after functional loading of the implants. At the five-year follow-up (paper II), eight patients were deceased and 128 were invited. Twenty-five patients refrained from participating in the study. The remaining 103 patients (287 implants – 133 with a turned surface and 154 with an oxidized surface) were examined after at least five years of functional loading. Clinical examinations of bleeding on probing (BoP) and pocket depth (PD) were performed. Intraoral radiographs were used to assess marginal bone levels (MBLs). In paper III, 28 patients were subjected to autologous bone graft and delayed implant placement, with a total of 92 dental implants. Thirteen patients received 47 implants with a turned surface and 15 patients received 45 implants with an oxidized surface. After a minimum of five years of functional loading, all patients were clinically examined regarding PD and BoP. The MBL was measured in intraoral radiographs. Cone beam computed tomography (CBCT) was used to evaluate the apical bone level (ABL) of the implants and intra-sinus conditions. The experimental study (paper IV) used nine adult male tufted capuchin primates (Cebus apella). Eight animals were subjected to bilateral maxillary sinus membrane elevation using a lateral replaceable bone window technique. One oxidized dental implant was placed in the residual bone of the sinus floor, protruding into the maxillary sinus cavity on both sides. In four animals, one sinus was left without any additional treatment, while the contralateral sinus was filled with autologous bone grafts from the tibia. In two animals, the implants were inserted under the elevated sinus membrane on both sides. In two animals, the sinus membrane was totally removed bilaterally before placement of implants. The animals were euthanized after 10 (n=4) or 45 (n=4) days. One non-operated animal representing pristine tissue conditions served as the control. The maxillary sinuses with implants were retrieved and further processed to prepare light microscopic ground sections or decalcified sections for immunohistochemical analyses. Results: In paper I seven implants were lost in five patients – six in the maxilla and one in the mandible. All failed implants were Mark III turned implants. The overall implant survival rate was 98.2% with a survival rate of 96.4% for implants with turned surface after a minimum of five months after functional loading. In paper II, one additional oxidized implant failed, giving an overall cumulative survival rate of 94.7 and 99.4%, respectively, after at least five years of functional loading. There was no difference for BoP, PD, or MBL between turned and oxidized implants. A total of two implants, three oxidized and one turned, showed a PD > 3 mm, MBL > 4 mm, and BoP. However, none of these were associated with suppurative infection on examination. In paper III no difference was found between the two implants surfaces used in terms of PD, BoP, MBL, or ABL. Pathological reactions to the sinus membrane were seen in four of the patients (14%). Radiographic signs of sinus pathology were not correlated to either survival rate of the implants or any of the investigated parameters. In the experimental paper IV, bone formation started from the bottom of the sinus floor, sprouting into the granulation tissue along the implant surface under the elevated membrane irrespective of time and surgical technique. Bone formation was not seen in direct conjunction with the sinus membrane. A distinct expression of osteopontin was observed in the serous glands of deeper portion of the lamina propria in direct connection with the elevated sinus membrane and close to the implant within all groups. Conclusion: After more than five years of function in non-grafted patients, oxidized implants had a survival rate higher than turned implants, although this was not statistically significant. No difference was found in MBL, PD, or BoP. Grafting of the maxillary sinus floor with intra- orally harvested bone and delayed placement of either turned or oxidized implants resulted in equally high long-term survival rates, MBL, ABL, and BoP. Pathological findings in the maxillary sinus cavity, in terms of sinus membrane health, are few and not correlated to any of the other investigated parameters. In the experimental study bone formation after sinus membrane elevation with or without additional bone grafts started at the sinus floor and sprouted into the elevated space along the implant surface. Removal of the membrane resulted in less bone formation. The sinus membrane did not seem to present osteoinductive potential in sinus membrane elevation procedures.

River incision into a widespread, upland low-relief landscape, and related patterns of exhumation recorded by low-temperature thermochronology, together underpin geodynamic interpretations for crustal thickening and uplift of the eastern Tibetan Plateau. We report results from a suite of 11 (U-Th-Sm)/He cooling-age samples. Eight samples comprise a 1.2 km relief section collected from elevations up to 4800 m in the Jiulong Shan, an elevated, rugged region located in the hinterland of the Yalong-Longmen Shan Thrust Belt, and surrounded on three sides by upland low-relief landscape surfaces. Zircon and apatite cooling ages record two episodes of rapid exhumation in the early Oligocene and late Miocene, that were separated by a period of stability from similar to 30 to 15 Ma. The first episode is consistent with a similar pulse evident from the Longmen Shan. The second episode is ongoing, and when integrated with adjacent cooling-age data sets, shows that doming of the Jiulong Shan has resulted in 2 to 4 km of differential exhumation of the plateau interior. We show from a compilation of glacial landform-mapping that the elevation of the plateau surface closely tracks global last glacial maximum equilibrium line altitude. We hypothesize that smoothing of highlands by efficient glacial and periglacial erosion, coupled with potential river captures and conveyance of sediments via external drainage, can yield an apparently continuous low-relief plateau landscape formed diachronously at high elevation. (C) 2016 Elsevier B.V. All rights reserved.

Introduction: Computed electrocardiographic imaging (CEI) is a method that uses ST- segment deviations from the 12-lead electrocardiogram (ECG) and has been tested on a small number of patients.Aim: To extend the testing material of the CEI method and deduce a threshold using ECGs recorded pre- and during acute occlusion. The performance of the CEI and ST elevation myocardial infarction (STEMI) criteria will be compared. Method: Two CEI images were generated from each of 99 patients before and during complete occlusion in the left anterior descending (LAD), right coronary artery (RCA) and left circumflex coronary artery (LCx). Result: The sensitivity and specificity of STEMI criteria was 61% and 96% respectively for the whole occlusion group. The sensitivities and specificities were 74 %, 97% (LAD); 60%, 94% (RCA); 35%, 100% (LCx) respectively, for STEMI criteria. A threshold of 998 units was deduced from the CEI method. Conclusion: The CEI method has similar diagnostic performance of an occlusion as STEMI criteria.

Sediment accretion and elevation change in tidal forests, and the corresponding ability of these wetlands to keep pace with sea-level rise (SLR), represent data gaps in our understanding of wetland sustainability. Surface Elevation Tables and marker horizons were installed in three mature tidal forests and a restored tidal marsh, allowing us to measure elevation change, accretion, and subsidence. Additionally, we measured predictor variables to test for their significance in explaining accretion and elevation change rates. Mean accretion at our sites was 11.67 +/- 3.01 mm yr-1 and mean elevation change was -20.22 +/- 8.10 mm yr-1, suggesting subsidence occurring beneath the sites. Processes contributing to accretion and elevation change at our sites may be driven by hydrologic patterns. Comparing our elevation trends with SLR trends suggests that our study sites may not keep pace with SLR. However, we may be observing short-term oscillations that do not indicate true long-term trends.

Climate change in the Arctic and sub-Arctic has induced substantial changes in the inland cryosphere. The warming climate is causing a reduction in glacier size and extent and the average net mass balance for Arctic glaciers have been negative over the past 40 years. Relatively few studies have been conducted concerning the development of the thermal distribution in glaciers during extensive volume changes. There is a possible diversity in how the thermal structure might change with a changing climate. Storglaciären is losing the cold surface layer in the ablation area and progressively becomes more temperate, while Kårsaglaciären is losing the zone of temperate ice in the ablation area and consequently becoming colder. The overall objective of this study has been to improve the understanding of the thermal response of polythermal glaciers to climate change. The results from Pårteglaciären, northern Sweden, indicate a decrease in volume by 18% in the last 15 years with an expected decrease of 35% of its present size during the coming century. As a consequence of the prevailing climate and volume decrease Pårteglaciären is experiencing a thinning of the cold surface layer at an average rate of 1.13 m a-1. The volumetric and cold surface layer changes are in the same magnitude, which may indicate that the CTS adapts relatively rapidly to the present changes. Assuming a climatic effect similar to what has been observed on Storglaciären, it can be concluded that the thinning has influenced the thermal regime. But in contrast to Kårsaglaciären, the thermal distribution on Pårteglaciären has become more temperate as a result of the substantial mass loss.
Klimatförändringar i Arktis och subarktis har orsakat stora förändringar i kryosfären. Ett varmare klimat orsakar en minskning av glaciärers storlek och omfattning och nettomassbalansen för Arktiska glaciärer har varit negativ under de senaste 40 åren. Relativt få studier har genomförts angående utvecklingen av den termiska fördelningen i glaciärer under omfattande volymförändringar. Det finns en möjlig diversitet i hur den termiska strukturen kan ändras med ett förändrat klimat. Storglaciären förlorar det kalla ytskiktet i ablationsområdet och blir successivt mer tempererad, medan Kårsaglaciären förlorar zonen med tempererad is i ablationsområdet och blir därmed kallare. Syftet med den här studien har varit att öka förståelsen för den termiska reaktionen hos polytermala glaciärer till ett förändrat klimat. Resultaten från Pårteglaciären i norra Sverige visar en volymreducering med 18% under de senaste 15 åren med en förväntad minskning på 35% av den nuvarande storleken under det kommande århundradet. Som en följd av det rådande klimatet och den reducerade volymen genomgår det kalla ytskiktet på Pårteglaciären en förtunning med en genomsnittlig hastighet av 1.13 m a-1. Volymförändringarna och förändringarna i kalla ytskiktet är i samma storleksordning, vilket tyder på att CTS anpassas relativt snabbt till de nuvarande förändringarna. Förutsatt en klimatisk effekt liknande den som observerats på Storglaciären, kan slutsatsen dras att förtunningen har påverkat den termiska regimen. Men i motsats till Kårsaglaciären har den termiska fördelningen på Pårteglaciären blivit mer tempererad som ett resultat av den omfattande massförlusten.

This thesis analyzed the new parameter hydrodynamic demand representing the damage of tsunami waves on structures and coastlines,maximum positive amplitudes and current velocities occurred during tsunami inundation by using the numerical model TUNAMI-N2. Regular shaped basins were used with two different bottom slopes in analyses in order to understand the behaviour of tsunami wave and investigate the change of important tsunami parameters along different slopes during tsunami inundation. In application, different initial conditions were used for wave profiles such as solitary wave, leading elevation single sinusoidal wave and leading depression sinusoidal wave. Three different initial wave amplitudes were used in order to test the change of distribution of the hydrodynamic demand. The numerical results were compared and discussed with each other and with the results of existing analytical and experimental studies.

This study analyzes the parameter &ldquo
hydrodynamic demand&rdquo
that is also defined by the square of Froude Number representing the damage of tsunami waves on structures and coastlines, and other hydrodynamic parameters, i.e., the distribution of instantaneous flow depths, runup values and the direction of maximum currents, occurred during tsunami inundation by using advanced numerical modeling. The analyses are performed on regular-shaped basins with different bottom slopes and real-shaped topographies using different wave shapes, wave periods and types. Various orientation and amount of coastal and land structures are used in simulations to have results for many different cases. This study provides the opportunity to define the damage of level in residential areas and to test the performance of coastal protection structures. The behavior of tsunami hydrodynamic parameters in shallow and inundation zone is investigated and a correlation is obtained between the average maximum values of square of Froude Number with the wave characteristics and sea bottom slope. After determining hydrodynamic parameters in regular shaped basins, a case study is applied by modeling the March 11, 2011 Great East Japan Tsunami with finer resolution in nested domains. The determination of hydrodynamic parameters in inundation zone during 2011 Japan event is performed in one of the most damaged coastal city Kamaishi.

Coastal erosion is an issue of concern for Louisiana, in the United States, and for all other coastal communities in the world. Among many coastal protection and restoration technologies, shoreline protection structures focus on wave reductions to prevent waves from hitting the coastal landforms directly. A novel technology called the Wave Suppression and Sediment Collection (WSSC) system focuses on solving the limitations of conventional shoreline protection structures regarding mobility, constructability, and sustainability. The primary goals of this study are to optimize the WSSC units for wave reduction and sediment transport and to verify the performance of this technology in an actual field environment. Computational Fluid Dynamics (CFD) simulations were carried out to optimize the designs of the units in terms of pipe diameters and face slope. Results have indicated that increasing pipe diameters decreases wave reduction and increases sediment transport ability of the units. Further, it was found that increasing the face slope decreases the wave reduction ability; however, no effect was found on the sediment transport efficiency. Parametric optimization suggested that a porosity (open-to-total area ratio) of 30% should yield satisfactory wave reduction and balanced sediment transport by the units. For better output from the units, the designs should be modified according to site-specific requirements. Field site investigations involved Surface Elevation Table (SET) surveying and marker clay experiments. SET surveys showed significant sediment accumulation over eleven months behind the units. Also, no significant change was observed at the control site over three months, which proves the effectiveness of the technology in stopping erosion and facilitating land building. Marker clay experiments validated the SET measurements and proved that there was a significant amount of sediment deposition over the white Feldspar clay layer over six months. This strengthens the conclusion that the WSSC units can be used successfully in a Louisiana marsh environment to battle coastal erosion and land loss.

Basal Temperature of Snow (BTS) measurements were used as the primary inputs to a high resolution (30 x 30 m grid cells) empirical-statistical regional permafrost probability model for the southern and central Yukon, and northernmost British Columbia (59° - 65°N). Data from seven individual study areas distributed across the region were combined using a blended distance decay technique, with an eighth area used for validation. The model predictions are reasonably consistent with previous permafrost maps for the area with some notable differences and a much higher level of detail. The modelling gives an overall permafrost probability of 52%. North of 62°N, permafrost becomes more extensive in the lowland areas whereas farther south permafrost is typically common only above treeline. Significant differences exist between the mountain environments of the Yukon and the Swiss Alps where the BTS method originated and as a result different modelling approaches had to be developed. This work therefore: (1) develops additional explanatory variables for permafrost probability modelling, the most notable of which is equivalent elevation, (2) confirms the use of ground truthing as a requirement for empirical-statistical modelling in the Yukon and (3) uses a combination of models for the region in order to spatially predict between study areas. The results of this thesis will be of use to linear infrastructure route-planning, geohazard assessment and climate change adaptation strategies. Future work employing the model will allow the effects of scenario-based climate warming to be examined.

An increase in the number of debris-covered glaciers and expansion of debris cover across many glaciers has been documented in many of the world’s major glacierised mountain ranges over the last 100 years. Debris cover has a profound impact on glacier mass balance with thick layers insulating the underlying ice and dramatically reducing ablation, while thin or patchy cover accelerates ablation through albedo reduction. Few debris-covered glaciers have been studied in comparison with ‘clean’ glaciers and their response to climatic change is uncertain. Remote sensing, integrated with field data, offers a powerful but as yet unrealised tool for studying and monitoring changes in debris-covered glaciers. Hence, this thesis focuses on two key aims: i) to test the utility of visible/near infrared satellite sensors, such as TERRA ASTER, for studying debris-covered glaciers; ii) to develop techniques to fully exploit the capability of these satellite sensors to extract useful information, and monitor changes over time. Research was focused on four interrelated studies at the Miage Glacier, in the Italian Alps. First, a new method of extracting debris-thickness patterns from ASTER thermal-band imagery was developed, based on a physical energy-balance model for a debris surface. The method was found to be more accurate than previous empirical approaches, when compared with field thickness measurements, and has the potential advantage of transferability to other sites. The high spatial variability of 2 m air temperature, which does not conform to a standard lapse rate, presents a difficulty for this approach and was identified as an important area for future research. Secondly, ASTER and Landsat TM data are used to map debris-cover extent and its change over time using several different methods. A number of problems were encountered in mapping debris extent including cloud cover and snow confusion, spatial resolution, and identifying the boundary between continuous and sporadic debris. Analysis of two images in late summer 1990 and 2004 revealed only a small up glacier increase in debris cover has occurred, confirming other work’s conclusions that the debris cover on Miage Glacier increased to its present extent prior to the 1990s. A third area of research used ASTER DEMs to monitor surface elevation changes of the Miage Glacier over time to update previous studies. Surface velocities on the glacier tongue were also calculated between 2004-2005 using feature-tracking of ASTER orthorectified visible band imagery and ASTER DEMs. However, ASTER DEMs were found to be rather poor for both applications due to large elevation errors in topographically rough parts of the glacier, which prevented a full analysis and comparison of results to previous surface elevation and velocity studies. Finally, the lithological units of the debris cover were mapped, based on the spectral differences of different rock types in the debris layer, providing information both on the location and concentration of different rock types on the surface. Therefore, the identification in the variation in emissivity throughout the glacier surface can be identified, which in turn has an impact upon calculated surface temperatures and ablation respectively. Overall, this research presents a significant contribution to understanding the impact of a debris layer on an alpine glacier, which is an area of key interest and current focus of many present glaciological studies. Since future glacial monitoring will increasingly have to consider supraglacial debris cover as a common occurrence, due to climate warming impacts of glacial retreat and permafrost melting. This contribution is achieved through the successful application of methods which utilise ASTER data to estimate debris thickness and debris extent, and the lithological mapping of debris cover. Therefore, the potential for incorporating these remote sensing techniques for debris-covered glaciers into current global glacier monitoring programs has been highlighted. However the utility of ASTER derived DEMs for surface elevation change analysis and surface velocity estimations in a study site of steep and varied terrain has been identified as questionable, due to issues of ASTER DEM accuracy in these regions.

This thesis is about using airborne laser scanning data for making maps for Orienteering. In this thesis were used altimetry data DMR 4G and DMR 5G. These data are provided by ČUZK. The control measuring was made in choosen area to verify the accuracy. In this thesis is described procedure of data collection and their treatment. The results of this thesis are two illustrations of the orienteering maps.

碩士
國立交通大學
土木工程學系
84
In the present study an empirical transfer function between the wave pressure and wave height,which was established by Kuo and Chiu(1994) ,was applied to predict the history signals of the free water surface elevation from the wave pressure beneath the still water level.The Fast Fourier Transform(FFT) method is used to calculate the power spectral and history signals of wave height.The FFT method is compared with LCM method developed by Nielsen(1986) in this paper.It is found that both of FFT method and LCM method are accurately calculated when the pressure gages are locatted near the still water level.However, when the distance between the pressure gage and the still water level is longer,the FFT method with the empirical transfer function is more efficient and accurate than the LCM method. Furtherwore,the present study has decided on the cutoff frequency range,the weak point of the power spectral analisis which was resolved in this paper. Furthermore,the present study used the physical model test to investigate the transfer function between the wave pressure and the wave height in shallow water. By the analysis from the experimental data, we can find the transfer function is concern with the wave frequency and pressure gage locations. In addition ,the transfer functions of each older nonlinear components seem to be the same.

碩士
國立海洋大學
河海工程學系
89
The purpose of this project is to measure and analyze wave field by imaging process in the laboratory. We get the idea from the use of radar and satellite remote control. The images of wave were caught by the infrared CCD remote sensing system. The images were measured in time series. We can measure gray value from the image by using software in order to analyze the relation between gray value and the water surface profile.This experiment aims to find the relation between gray value and wave height. The early stage of this experiment is to research on regular wave. The gray value of image is related to camera position, illuminant feature. First of all, we want to figure out an experimental transfer formula of wave height from the gray value. Second, to measure the variety of gray value with wave height, wave direction, and water depth in further research. If this project is practicable, we can replace the instrument to measure water surface profiles. Last but not least, we hope this method can be applied to practical ocean measurement in further research.

博士
國防大學理工學院
國防科學研究所
103
The fastest and most economical method of acquiring terrain images is aerial photography. The use of unmanned aerial vehicles (UAVs) has been investigated for this task. However, UAVs present a range of challenges such as flight altitude maintenance. This paper reports a method that combines skyline detection with a stereo vision algorithm to enable the flight altitude of UAVs to be maintained. A monocular camera is mounted on the downside of the aircraft’s nose to collect continuous ground images, and the relative altitude is obtained via a stereo vision algorithm from the velocity of the UAV. Image detection is used to obtain terrain images, and to measure the relative altitude from the ground to the UAV. The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images. A forward-looking camera is mounted on the upside of the aircraft’s nose. In combination with the skyline detection algorithm, this helps the aircraft to maintain a stable flight pattern. Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path. We use Microsoft Visual Studio 2013 to develop our image detecting system. First, real-time images were transmitted by cameras and video transmitters to ground control station. After the algorithms processed, the detected results were converted to voltage values to control the roll and pitch servo. From the test result, the skyline detection and fixed altitude flight systems processing time from image acquisition to voltage output are around 1 ms and 16 ms. It proves that the vision-based flight control applied to stable and fixed altitude flight is practicable.

M. Ing.
Digital Surface Models (DSM) are widely used in the earth sciences for research, visu- alizations, construction etc. In order to generate a DSM for a speci c area, specialized equipment and personnel are always required which leads to a costly and time consuming exercise. Image processing has become a viable processing technique to generate terrain models since the improvements of hardware provided adequate processing power to complete such a task. Digital Surface Models (DSM) can be generated from stereo imagery, usually obtained from a remote sensing platform. The core component of a DSM generating system is the image matching algorithm. Even though there are a variety of algorithms to date which can generate DSMs, it is a computationally complex calculation and does tend to take some time to complete. In order to achieve faster DSMs, an investigation into an alternative processing platform for the generation of terrain models has been done. The Graphics Processing Unit (GPU) is usually used in the gaming industry to manipulate display data and then render it to a computer screen. The architecture is designed to manipulate large amounts of oating point data. The scientic community has begun using the GPU processing power available for technical computing, hence the term, General Purpose computing on a Graphics Processing Unit (GPGPU). The GPU is investigated as alternative processing platform for the image matching procedure since the processing capability of the GPU is so much higher than the CPU but only for a conditioned set of input data. A matching algorithm, derived from the GC3 algorithm has been implemented on both a CPU platform and a GPU platform in order to investigate the viability of a GPU processing alternative. The algorithm makes use of a Normalized Cross Correlation similarity measurement and the geometry of the image acquisition contained in the sensor model to obtain conjugate point matches in the two source images. The results of the investigation indicated an improvement of up to 70% on the processing time required to generate a DSM. The improvements varied from 70% to some cases where the GPU has taken longer to generate the DSM. The accuracy of the automatic DSM generating system could not be clearly determined since only poor quality reference data was available. It is however shown the DSMs generated using both the CPU and GPU platforms relate to the reference data and correlate to each other. The discrepancies between the CPU and the GPU results are low enough to prove the GPU processing is bene cial with neglible drawbacks in terms of accuracy. The GPU will definitely provide superior processing capabilites for DSM generation above a CPU implementation if a matching algorithm is speci cally designed to cater for the bene ts and limitations of the GPU.

Light Detection and Ranging (Lidar) is a remote sensing technique that provides high resolution range measurements between the laser scanner and Earth’s topography. These range measurements are mapped as 3D point cloud with high accuracy (< 0.1 meters). Depending on the geometry of the illuminated surfaces on earth one or more backscattered echoes are recorded for every pulse emitted by the laser scanner. Lidar has the advantage of being able to create elevation surfaces in 3D, while also having information about the intensity of the returned pulse at each point, thus it can be treated as a spatial and as a spectral data system. The 3D elevation attributes of Lidar data are used in this study to identify possible water surface points quickly and efficiently. The approach incorporates the use of Laplacian curvature computed via wavelets where the wavelets are the first and second order derivatives of a Gaussian kernel. In computer science, a kd-tree is a space-partitioning data structure used for organizing points in a k dimensional space. The 3D point cloud is segmented by using a kd-tree and following this segmentation the neighborhood of each point is identified and Laplacian curvature is computed at each point record. A combination of positive curvature values and elevation measures is used to determine the threshold for identifying possible water surface points in the point cloud. The efficiency and accurate localization of the extracted water surface points are demonstrated by using the Lidar data for Williamson County in Texas. Six different test sites are identified and the results are compared against high resolution imagery. The resulting point features mapped accurately on streams and other water surfaces in the test sites. The combination of curvature and elevation filtering allowed the procedure to omit roads and bridges in the test sites and only identify points that belonged to streams, small ponds and floodplains. This procedure shows the capability of Lidar data for water surface mapping thus providing valuable datasets for a number of applications in geomorphology, hydrology and hydraulics.
text

碩士
國立成功大學
水利及海洋工程學系
105
A shallow-water model (SWM) based on shallow water equations (SWEs) using surface elevation and fluxes (η, qx, qy) as variables (Wang and Connor, 1975) was developed. Theoretical formulation is performed on the basis of the depth-averaged SWEs. Least-squares method with eight-node quadrilateral finite-element for space interpolations and theta-method for time integration are used to develop the SWM. SWM was applied to the case of flow past a flat channel. Numerical results are fairly compared with results obtained by the SWM using surface elevation and depth-averaged velocities (η, u, v) as variables. Numerical results of SWM based on (η, qx, qy) apparently show better accuracy and flux conservation than those based on the variable (η, u, v) of SWM. The SWM is then utilized to study Green Island wakes induced by the Kuroshio. Characteristics of the downstream vortex, such as the aspect ratio and period, are examined and compared with results of obtained by the variable (η, u, v) of SWM in previous study. However we still need to fix the open boundary condition, the water depth is limited only in 10 m and velocity lower than 0.5 m/s, comparing to previous study setting that water depth is 360 m and velocity is 1.0 m/s. Finally we discuss the vortex street in the case of water depth 10 m and flux 5 m2/s.

碩士
淡江大學
建築學系碩士班
101
The main point of research is to simulate the physical environment and climate impact before renewing aged apartments. By using Ecotect to create digital designs of the architecture prototype model, much information will be provided. Given the hourly climate data taken from previous years and the creation of model residential areas in New Taipei City, 林口、五股、八里、新莊、與蘆洲, these five areas can be analyzed on Ecotect. Their materials used for facade , and the orientation in elevation facing, either to the south east, south, or southwest, will all be cross analyzed with the equinox and solstice. Ecotect will also simulate and analyze the facade design and its corresponding result of solar radiation and daylight exposure. The architectural design of the building can be changed accordingly to the response of these variables. Chapter 1: Research orientation and process, hypothesis, issues and topics, extent, contents and expected results. Chapter 2: literature and theory review related research. The physical formulae required and the regulated limitation and consideration of various cases. Chapter 3: architectural development and corresponding variables, and its practical operations and tests. Chapter 4: Building of architectural prototypes and design patterns, and the usage of Ecotect and Radiance on environmental factors. Chapter 5: The focus of prototype design and structure on the direction it faces, the equinox and solstice of year, its building materials, and the facade design in correspondence to solar radiation and daylight exposure. Chapter 6: The conclusion, design results, architectural industrialization, and analysis of possible development.

碩士
國立臺灣大學
牙醫學研究所
82
Lasers have been suggested for endodontic therapy because it had sterilazation effect on root canals and sealing effect on the inal tubules. The main problem is the heat generated by application of laser in the root canal. Will the heat generated by laser hurt the periradicular tissue? The purpose of this study was to evaluate the temperature elevation on root surface and morphological changes in root canal walls when laser was applied on root canal therapy. Results were with appropriate adjustment of the laser energy and power the heat generated by the laser would not destroy the periradicular tissue. By scanning electron microscopy, melting, recrystallization and even cracking of the irradiated canals were found when the energy of the ND:YAG laser was set at 100 mj/pulse and 20-30 pps. When the CO2 laser with the output power set at 4 W or above, melting on the top of the dentinal tubules" orifice at the inner surface of the root canal was found.

In der vorliegenden Dissertation wird gezeigt, dass es möglich ist mittels öffentlich zugänglicher Daten der Landesämter Paläooberflächen im Zentrum einer Großstadt zu modellieren. Auf der Suche nach dem anthropogen unbeeinflussten Georelief des heutigen Stadtgebietes Leipzigs ist nicht nur die Rekonstruktion ursprünglicher, natürlicher Gegeben-heiten das Ziel, sondern auch die Auseinandersetzung damit, wie der Mensch seine Umwelt in diesem Gebiet bis heute formte und strukturierte. Die Thematik vereint verschiedene geographische Disziplinen, wie z. B. Geomorphologie, Geoarchäologie und Geoinformatik, indem das verbindende Element der Untersuchungsraum in der Innenstadt von Leipzig ist. Zur Rekonstruktion der Erdoberfläche als Digitales Geländemodell (DGM) vor etwa 1.000 Jahren (DGM 1015) und 11.000 Jahren (DGM BASIS) sind hauptsächlich Daten des Sächsischen Landesamtes für Archäologie und des Sächsischen Landesamtes für Umwelt, Landwirtschaft und Geologie ausgewertet worden. Um die heterogenen Ausgangsdaten mit Hilfe von Leitprofilen verarbeiten zu können, erfolgt vorab das Aufstellen von Arbeitshypothesen. Alle Daten sind so aufbereitet, dass sie in einer Gesamtdatenbank zusammengefasst dargestellt und in einem Geographischen Informationssystem (GIS) auswertbar sind. Ausgehend von der Gesamtdatenbank fand auf Grundlage der Arbeitshypothesen die Generierung von Teildatenbanken statt. Demnach entspricht der Aufschlussansatzpunkt dem rezenten Relief (DGM HEUTE) und die erste anthropogen unbeeinflusste Sedimentschicht bzw. die Schicht mit den ältesten Siedlungsspuren dem Paläorelief vor ca. 1.000 Jahren (DGM 1015ROH bzw. DGM 1015). Des Weiteren präsentiert die Basis der holozänen Sedimente das Paläorelief vor ca. 11.000 Jahren (DGM BASIS). Basierend auf den Modellen DGM 1015ROH und DGM HEUTE findet eine Evaluierung der Datengrundlagen und der Methodik statt. Dafür erfolgt eine Gegenüberstellung des DGM HEUTE mit dem auf LiDAR-Daten basierendem DGM 2 des Staatsbetriebes Geobasisinformation und Vermessung Sachsen. Denn es besteht in der vorliegenden Dissertation die Annahme, dass es möglich ist, ein DGM 1015 bzw. DGM BASIS zu erstellen, wenn es gelingt mit denselben Daten das DGM 2 annähernd zu reproduzieren. Nach der »Observed vs. Predicted Analyse« besteht offensichtlich ein von der Datenherkunft unabhängiger, signifikanter, monotoner Zusammenhang, zwischen dem DGM HEUTE und dem DGM 2, welcher nicht zufällig ist. Folglich ist es möglich, mit den Daten und der Methodik auch ein DGM 1015 bzw. DGM BASIS zu erstellen. Weiterhin konnte mit Hilfe von multivariater Statistik nachgewiesen werden, dass die Heterogenität der Datengrundlagen in Bezug auf das Jahr der Datenerhebung und die Art der Koordinatenbestimmung (xi, yi, zi) einen vernachlässigbaren Einfluss auf die Abweichung zwischen dem DGM HEUTE und dem DGM 2 im Testdatensatz haben. Nachdem die Datengrundlagen evaluiert und teilweise u. a. mit Hilfe der Leitprofile, historischen Aufnahmen und dem DGM 2 an umgebende Profile angepasst wurden, findet die Extraktion der finalen Teildatenbanken DGM 1015 und DGM BASIS aus dem Gesamtdatensatz statt. Der Vorteil dieses für Leipzig entwickelten Untersuchungsdesigns liegt darin, dass durch den Vergleich zwischen dem DGM HEUTE und dem DGM 2 eine Evaluierung der Datengrundlagen messbar wird und nicht ausschließlich auf qualitative Kriterien zurückzuführen ist. Es wird somit auch quantitativ bewiesen, dass diese Methodik zur Paläoreliefmodellierung für die Innenstadt von Leipzig sehr gut angewendet werden kann. Prinzipiell ist es nicht möglich abschließend eine Realität der interpolierten Paläooberflächen zu präsentieren, sondern es können lediglich verschiedene Realitäten und deren Wahrscheinlichkeiten vorgestellt werden. Neben geostatistischen Methoden kommen auch deterministische Interpolationsverfahren zum Einsatz. Zur Quantifizierung der Ergebnisse erfolgt u. a. eine Kreuzvalidierung, auf deren Grundlage die Auswahl der finalen Interpolationsdarstellungen stattfindet. Das DGM BASIS und DGM 1015 stellen die Ausgangssituation der Reliefverhältnisse bei der Siedlungsgründung Leipzigs dar. Grundsätzlich ist es mit der vorliegenden Arbeit gelungen eine neue, fundierte Perspektive zur kritischen Diskussion der Landschafts- und Siedlungsgenese im Untersuchungsgebiet bereitzustellen. Neben einer detailgetreuen Abbildung der geomorphologischen und geologischen Gegebenheiten im heutigen Zentrum Leipzigs im Jahr 1015 und zu Beginn des Holozäns, ist es möglich, den Flurabstand zwischen den DGM zu bestimmen, um Veränderungen zu quantifizieren. In diesem Kontext ist es weiterhin möglich natürliche von anthropogenen Prozessen zu trennen und diese zeitlich aufzuschlüsseln. Auf dieser Basis können detailliertere Aussagen zum Relief zwischen Weiße Elster- und Parthetal um das Jahr 1015 gemacht werden. Des Weiteren lassen die Paläomodelle Rückschlüsse auf die raumbezogenen Gunstfaktoren bei der Siedlungsplatzwahl und -gestaltung zu. Zudem existiert das Potenzial zur Entwicklung einer visuell reizvollen Grundlage, um geowissenschaftliche und geoarchäologische Sachverhalte im Bildungsbereich für die Öffentlichkeit zu nutzen. Die Thematik hat durch den Charakter einer Fallstudie zunächst einen lokalen Bezug zu Leipzig (Sachsen). Das dabei entwickelte Untersuchungsdesign eröffnet jedoch eine neue, fundierte und transparente Möglichkeit zur Paläoreliefrekonstruktion in weiteren Untersuchungsgebieten.:Bibliografische Daten I Zitat II Danksagung III Zusammenfassung IV Abstract VI Abbildungs- & Tabellenverzeichnis XII Abkürzungsverzeichnis XVIII 1. Einleitung 1 1.1 Fragestellung und Zielführung 1 1.2 Abgrenzung des Untersuchungsgebietes 3 1.3 Grundlagen 7 1.3.1 Fachliche Einordnung der Thematik 7 1.3.2 Begriffe und Definitionen 9 1.3.2.1 »Natürlich gewachsener Boden« 9 1.3.2.2 Zeitangaben 9 1.3.2.3 Digitale Erdoberflächenmodelle 12 1.3.2.4 Lage- und Höhenbezugssystem 13 1.3.2.5 Unsicherheiten und Fehler 13 1.4 Forschungsgeschichtlicher Überblick 16 1.5 Ähnliche Forschungen außerhalb Leipzigs 24 2. Stand des Wissens im Untersuchungsgebiet 26 2.1 Naturräumliche Einordnung 26 2.1.1 Klima 29 2.1.2 Geologie 31 2.1.2.1 Leitprofil der Leipziger Tieflandsbucht 31 2.1.2.2 Geologischer Aufbau des Untersuchungsgebietes 34 2.1.3 Boden 36 2.1.4 Vegetation 40 2.1.5 Gewässernetz 41 2.1.5.1 Auengenese der Weißen Elster 43 2.1.5.2 Auengenese der Parthe 47 2.1.5.3 Zusammenfluß der Weißen Elster und Parthe 49 2.2 Siedlungsgeschichtliche Einordnung 50 2.2.1 Allgemeiner Überblick 51 2.2.2 Die im Jahr 1015 erwähnte »urbs Libzi« 56 2.2.3 Die Zwillingssiedlung der »urbs Libzi« 59 2.2.4 Wasserbauliche Einschnitte im Untersuchungsgebiet 63 3. Methodik 67 3.1 Generierung der Datenbasis 71 3.1.1 Formulieren der Arbeitshypothesen 72 3.1.2 Datengrundlagen und deren Aufbereitung 75 3.1.3 Zusammenfassung: Gesamtdatenbank 77 3.2 Zwischenergebnisse »DGM 1015ROH« und »DGM HEUTE« 78 3.2.1 Generierung der Teildatenbanken 78 3.2.2 Interpolation und qualitative Auswertung der Zwischenergebnisse 78 3.2.3 Definition von Teiluntersuchungsgebieten 82 3.3 Evaluation der Methodik 82 3.3.1 Deskriptive Statistik 83 3.3.2 »Observed vs. predicted Analyse« 84 3.3.3 Multivariate Statistik 86 3.3.4 Validation der Methodik 91 3.4 Evaluation der Datengrundlagen und Generierung der finalen Teildatenbanken 92 3.4.1 Evaluation der Datengrundlagen 94 3.4.2 Finale Teildatenbanken »DGM 1015« und »DGM BASIS« 95 3.4.3 Interpolation und qualitative Auswertung der Ergebnisse 95 3.4.4 Validation der Datengrundlage 96 3.5 Geostatistische Auswertung des »DGM 1015« und »DGM BASIS« 96 3.5.1 Objektive Auswahl der Rasterzellengröße 98 3.5.2 Simulation und Analyse der Paläooberflächen 102 3.5.3 Simulation und Analyse der Fließgewässer 104 3.5.4 Evaluation der vorhergesagten Unsicherheiten 105 3.6 Abschließende Interpolation und räumliche Validierung 106 3.6.1 Weitere Interpolationsmöglichkeiten und finale Modelle 106 3.6.2 Flurabstandsberechnungen zwischen den DGM 110 3.6.3 Anstehende geologische Substrate der finalen DGM 111 4. Ergebnisse und Diskussion 114 4.1 Generierung der Datenbasis 114 4.1.1 Arbeitshypothesen 114 4.1.2 Datengrundlagen 114 4.1.2.1 Höhenfestpunkte 114 4.1.2.2 LiDAR Daten 118 4.1.2.3 Historische Archive 120 4.1.2.4 Leitprofile 123 4.1.2.5 Geologische Aufschlüsse 126 4.1.2.6 Archäologische Dokumentationen 131 4.1.3 Zusammenfassung: Gesamtdatenbank 141 4.2 Zwischenergebnisse »DGM 1015ROH« und »DGM HEUTE« 143 4.2.1 Generierung der Teildatenbanken 143 4.2.2 Interpolation und qualitative Auswertung der Zwischenergebnisse 144 4.2.3 Definition von Teiluntersuchungsgebieten 150 4.3. Evaluierung der Methodik 152 4.3.1 Deskriptive Statistik 152 4.3.2 »Observed vs. Predicted Analyse« 154 4.3.3 Multivariate Statistik 157 4.3.4 Validation der Methodik 163 4.4. Evaluierung der Datengrundlagen 166 4.4.1 Evaluation und ggf. Anpassung der Datengrundlagen 168 4.4.1.1 Geologische Aufschlüsse 168 4.4.1.2 Archäologische Dokumentationen 169 4.4.1.3 Fallbeispiel: Teiluntersuchungsgebiet Matthäikirchhof 173 4.4.2 Finale Teildatenbanken »DGM 1015« und »DGM BASIS« 176 4.4.3 Interpolation und qualitative Auswertung der Ergebnisse 179 4.4.4 Validation der Datengrundlage 182 4.5 Geostatistische Auswertung des »DGM 1015« und »DGM BASIS« 184 4.5.1 Objektive Auswahl der Rasterzellengröße 184 4.5.2 Simulation und Analyse der Paläooberflächen 186 4.5.3 Simulation und Analyse der Fließgewässer 193 4.5.4 Evaluation der vorhergesagten Unsicherheiten 197 4.6 Abschließende Interpolation und räumliche Validierung 198 4.6.1 Weitere Interpolationsmöglichkeiten und finale Modelle 199 4.6.2 Flurabstandsberechnungen zwischen den DGM 207 4.6.3 Anstehende geologische Substrate der finalen DGM 210 4.7 Landschafts- und Siedlungsgenetische Interpretation der Paläomodelle 218 5. Synthese und Ausblick 233 6. Literaturverzeichnis 248 7. Anlagen i
In search of the anthropogenically undisturbed palaeo-surface of the city of Leipzig, the main goals are the reconstruction of the specific natural conditions during the Holocene and a deduction about how the environment has been shaped and structured by humans in this area over the last 1,000 years. In the present doctoral thesis, the possibility to model palaeo-surfaces for the central part of a big city by means of publicly accessible data of the state offices is demonstrated. The topic combines various geographical disciplines with a focus on the interface between Geosciences and Archaeology (often termed Geoarchaeology). For the reconstruction of the earth's surface as a Digital Elevation Model (DEM) about 1,000 years ago (DEM 1015) and 11,000 years ago (DEM BASIS) mainly data from the Archaeological Heritage Office Saxony and the Saxon State Office for Environment, Agriculture and Geology have been evaluated. The qualitative data are linked by using GIS through surveying techniques. To be able to process the heterogeneous data, working hypotheses are established in advance. According to them, the elevation of the top of a geological drill or archaeological excavation represents the current surface (DEM HEUTE). In addition, the first anthropogenically undisturbed layer of a geological drill or the layer with the oldest settlement trace of an archaeological excavation represents the data basis for the DEM 1015ROH and the DEM 1015, respectively. Furthermore, the basis in transition to Holocene sediments represents the palaeo-relief approximately 11,000 years ago (DEM BASIS). All data are summarized in an overall database. Hence, the data can be analyzed in a Geographical Information System (GIS). Based on the models DEM 1015ROH and DEM HEUTE the data basis and the methodology are evaluated. For this purpose, a comparison between the DEM HEUTE and another recent DEM, which was generated with LiDAR data provided by the State Operation Geobasisinformation and Surveying Saxony (DEM 2), is conducted. Therefore, it is assumed that it is possible to create a DEM 1015 or DEM BASIS, if it is possible to reproduce approximately the DEM 2 with the same data. The Observed vs. Predicted Analysis shows, that between the DEM HEUTE and the DEM 2 a non-data-independent, significant, monotonic relationship exists, which is not random. Consequently, based on the mentioned assumption above, it is possible to use the data and methodology to create a DEM 1015 or DEM BASIS. Furthermore, the multivariate statistic for the data set demonstrated, that the heterogeneity of the data bases in relation to the year of data collection and the type of coordinate determination (xi, yi, zi) had a negligible influence on the deviation between the DEM HEUTE and the DEM 2. Nevertheless, a check and, if necessary, a correction of the original data is necessary. If there are anomalies, the correction of the original data will be adapted to the surroundings by means of representative soil profiles, historical recordings and the DEM 2. After the data basis and methodology are validated the final sub databases DEM 1015 and DEM BASIS are extracted from the overall database. By means of the developed investigation design the comparison between the DEM HEUTE and the DEM 2 can be based on a quantitative evaluation of the data basis and not exclusively to qualitative criteria. Thus, it is also proved quantitatively that the methodology to model the palaeo-surface works very well for the inner city of Leipzig. However, models represent only a limited picture of reality. In principle, there is no unique interpolation result. That´s why, it is mandatory to present different realities of the palaeo-surfaces and their probabilities. Therefore, in addition to geostatistical interpolation methods, deterministic methods are also used. To quantify the results, among other things, a cross validation is performed. On this basis the selection of the most likely interpolation for the final representation takes place. The DGM BASIS and DGM 1015 show the highest possible approximation of the palaeo-surfaces. In general, the present dissertation has succeeded in providing a new, well-founded perspective for the critical discussion of landscape and settlement genesis in the study area. In addition to a detailed mapping of the geomorphological and geological conditions in the center of Leipzig at the time of 1015 and at the beginning of the Holocene, it is possible to determine the differences between the DEMs to quantify changes. In this context, it was also possible to separate natural from anthropogenic processes and to date the changes. On that basis, more detailed statements about the relief between the river valleys of Weiße Elster and Parthe around the year 1015 can now be made. In addition, the palaeo-models allow conclusions on the space-related favorable factors in settlement site selection and design. Finally, there is the possibility to represent the palaeo-surfaces as a visually appealing basis for geoarchaeological questions in public education. Due to its´ nature of being a case study, the topic has a local connection to Leipzig (Saxony). However, the developed investigation design will open new, well-founded, transparent options for the reconstruction of palaeo-reliefs in further study areas.:Bibliografische Daten I Zitat II Danksagung III Zusammenfassung IV Abstract VI Abbildungs- & Tabellenverzeichnis XII Abkürzungsverzeichnis XVIII 1. Einleitung 1 1.1 Fragestellung und Zielführung 1 1.2 Abgrenzung des Untersuchungsgebietes 3 1.3 Grundlagen 7 1.3.1 Fachliche Einordnung der Thematik 7 1.3.2 Begriffe und Definitionen 9 1.3.2.1 »Natürlich gewachsener Boden« 9 1.3.2.2 Zeitangaben 9 1.3.2.3 Digitale Erdoberflächenmodelle 12 1.3.2.4 Lage- und Höhenbezugssystem 13 1.3.2.5 Unsicherheiten und Fehler 13 1.4 Forschungsgeschichtlicher Überblick 16 1.5 Ähnliche Forschungen außerhalb Leipzigs 24 2. Stand des Wissens im Untersuchungsgebiet 26 2.1 Naturräumliche Einordnung 26 2.1.1 Klima 29 2.1.2 Geologie 31 2.1.2.1 Leitprofil der Leipziger Tieflandsbucht 31 2.1.2.2 Geologischer Aufbau des Untersuchungsgebietes 34 2.1.3 Boden 36 2.1.4 Vegetation 40 2.1.5 Gewässernetz 41 2.1.5.1 Auengenese der Weißen Elster 43 2.1.5.2 Auengenese der Parthe 47 2.1.5.3 Zusammenfluß der Weißen Elster und Parthe 49 2.2 Siedlungsgeschichtliche Einordnung 50 2.2.1 Allgemeiner Überblick 51 2.2.2 Die im Jahr 1015 erwähnte »urbs Libzi« 56 2.2.3 Die Zwillingssiedlung der »urbs Libzi« 59 2.2.4 Wasserbauliche Einschnitte im Untersuchungsgebiet 63 3. Methodik 67 3.1 Generierung der Datenbasis 71 3.1.1 Formulieren der Arbeitshypothesen 72 3.1.2 Datengrundlagen und deren Aufbereitung 75 3.1.3 Zusammenfassung: Gesamtdatenbank 77 3.2 Zwischenergebnisse »DGM 1015ROH« und »DGM HEUTE« 78 3.2.1 Generierung der Teildatenbanken 78 3.2.2 Interpolation und qualitative Auswertung der Zwischenergebnisse 78 3.2.3 Definition von Teiluntersuchungsgebieten 82 3.3 Evaluation der Methodik 82 3.3.1 Deskriptive Statistik 83 3.3.2 »Observed vs. predicted Analyse« 84 3.3.3 Multivariate Statistik 86 3.3.4 Validation der Methodik 91 3.4 Evaluation der Datengrundlagen und Generierung der finalen Teildatenbanken 92 3.4.1 Evaluation der Datengrundlagen 94 3.4.2 Finale Teildatenbanken »DGM 1015« und »DGM BASIS« 95 3.4.3 Interpolation und qualitative Auswertung der Ergebnisse 95 3.4.4 Validation der Datengrundlage 96 3.5 Geostatistische Auswertung des »DGM 1015« und »DGM BASIS« 96 3.5.1 Objektive Auswahl der Rasterzellengröße 98 3.5.2 Simulation und Analyse der Paläooberflächen 102 3.5.3 Simulation und Analyse der Fließgewässer 104 3.5.4 Evaluation der vorhergesagten Unsicherheiten 105 3.6 Abschließende Interpolation und räumliche Validierung 106 3.6.1 Weitere Interpolationsmöglichkeiten und finale Modelle 106 3.6.2 Flurabstandsberechnungen zwischen den DGM 110 3.6.3 Anstehende geologische Substrate der finalen DGM 111 4. Ergebnisse und Diskussion 114 4.1 Generierung der Datenbasis 114 4.1.1 Arbeitshypothesen 114 4.1.2 Datengrundlagen 114 4.1.2.1 Höhenfestpunkte 114 4.1.2.2 LiDAR Daten 118 4.1.2.3 Historische Archive 120 4.1.2.4 Leitprofile 123 4.1.2.5 Geologische Aufschlüsse 126 4.1.2.6 Archäologische Dokumentationen 131 4.1.3 Zusammenfassung: Gesamtdatenbank 141 4.2 Zwischenergebnisse »DGM 1015ROH« und »DGM HEUTE« 143 4.2.1 Generierung der Teildatenbanken 143 4.2.2 Interpolation und qualitative Auswertung der Zwischenergebnisse 144 4.2.3 Definition von Teiluntersuchungsgebieten 150 4.3. Evaluierung der Methodik 152 4.3.1 Deskriptive Statistik 152 4.3.2 »Observed vs. Predicted Analyse« 154 4.3.3 Multivariate Statistik 157 4.3.4 Validation der Methodik 163 4.4. Evaluierung der Datengrundlagen 166 4.4.1 Evaluation und ggf. Anpassung der Datengrundlagen 168 4.4.1.1 Geologische Aufschlüsse 168 4.4.1.2 Archäologische Dokumentationen 169 4.4.1.3 Fallbeispiel: Teiluntersuchungsgebiet Matthäikirchhof 173 4.4.2 Finale Teildatenbanken »DGM 1015« und »DGM BASIS« 176 4.4.3 Interpolation und qualitative Auswertung der Ergebnisse 179 4.4.4 Validation der Datengrundlage 182 4.5 Geostatistische Auswertung des »DGM 1015« und »DGM BASIS« 184 4.5.1 Objektive Auswahl der Rasterzellengröße 184 4.5.2 Simulation und Analyse der Paläooberflächen 186 4.5.3 Simulation und Analyse der Fließgewässer 193 4.5.4 Evaluation der vorhergesagten Unsicherheiten 197 4.6 Abschließende Interpolation und räumliche Validierung 198 4.6.1 Weitere Interpolationsmöglichkeiten und finale Modelle 199 4.6.2 Flurabstandsberechnungen zwischen den DGM 207 4.6.3 Anstehende geologische Substrate der finalen DGM 210 4.7 Landschafts- und Siedlungsgenetische Interpretation der Paläomodelle 218 5. Synthese und Ausblick 233 6. Literaturverzeichnis 248 7. Anlagen i

Die Anpassung von Küstenniederungen, Seemarschen und Inseln an klimatische Veränderungen und einen steigenden Meeresspiegel ist eine der großen Herausforderungen des 21. Jahrhunderts. Im Gegensatz zu eingedeichten Küstenmarschen und Inseln besitzen tidebeeinflusste Seemarschen ein natürliches Anpassungspotential an sich verändernde hydrologische Rahmenbedingungen. Überflutungsabhängige Sedimenteinträge führen zu einem Anwachsen der Marschoberfläche und kompensieren somit einen Anstieg des Meeresspiegels. Die 10 verbliebenen nordfriesischen Halligen (Schleswig-Holstein, Deutschland) (Kapitel 1) sind bewohnte Inselmarschen, welche aufgrund ihrer anthropogenen Überprägung von naturbelassenen Seemarschen unterschieden werden müssen. Diese umfasst z.B. den Bau von flachen Sommerdeichen und Sielanlagen. Inwiefern sich diese Veränderungen auf die Sedimentdynamik der Marschen auswirken, ist bislang unzureichend belegt, was eine fundierte Diskussion bezüglich zukünftiger Entwicklungsperspektiven der Halligmarschen verhindert. Die vorliegende Arbeit ist dazu angelegt, diese Wissenslücke zu schließen. Sie untersucht das vertikale Marschwachstum exemplarisch auf den Halligen Hooge, Langeneß und Nordstrandischmoor und beurteilt deren Anpassungsvermögen an einen steigenden Meeresspiegel. Darüber hinaus werden zukünftige Entwicklungsperspektiven diskutiert. Um Faktoren und Prozesse, welche maßgeblich die Sedimentdynamik der Halligen beeinflussen, messbar zu machen, musstengeeignete Methoden entwickelt und angewendet werden. Zur Berechnung jährlicher Überflutungshäufigkeiten wurden Pegelschwellenwerte für Überflutungsereignisse auf Basis von digitalen Geländemodellen (DGMs) und d-GPS (differential global positioning system) Messungen errechnet und auf die verfügbaren, regionalen Pegeldaten angewendet (Kapitel 2). Sedimentfallen, bestehend aus LDPE (low density polyethylene) Flaschen (1 Liter) und Kunstrasenmatten (20 x 30 cm), bilden die Grundlage einer dreijährigen (November 2010 – März 2013) Feld- und Laborstudie zur zeitlichen und räumlichen Erfassung der sturmflutabhängigen Sedimentdeposition (Kapitel 3). Durch die Verwendung regionaler bodenphysikalischer Parameter (Lagerungsdichte und Gehalt an organischer Bodensubstanz) können Depositionsraten in eine vertikale Wachstumskomponente transformiert werden. Dazu werden Ergebnisse einer Rammkernsondierung genutzt, welche 12 Sedimentkerne mit einer Länge von maximal 100 cm umfasst. Die Sedimentbohrkerne sind weiterhin die Grundlage für eine 137Cs- und 210Pb-Datierung. Die Kombination beider Datensätze (Kapitel 4) ermöglicht einen schlüssigen Vergleich der Marschentwicklung seit dem Jahr 1915 mit regionalen Pegeldaten und Projektionen des zukünftigen Meeresspiegelanstiegs. Die Analyse der verfügbaren Pegeldaten (Kapitel 2) zeigt eine hohe Variabilität der jährlichen Überflutungshäufigkeiten. Das zehnjährige Mittel eintretender Ereignisse beträgt 2 Überflutungen auf Hooge, 9 – 10 Überflutungen auf Langeneß und 15 Überflutungen auf Nordstrandischmoor. Aufgrund der künstlichen Überhöhung der Marschkante durch Sommerdeiche mit + 1.54 m ü. mittlerem Tidehochwasser (MThw) auf Hooge und + 0.98 m ü. MThw auf Langeneß werden die betreffenden Halligen lediglich bei selten eintretenden Sturmflutereignissen überflutet. Die Höhe des wasser- und sedimentundurchlässigen Steinpflasters auf Nordstrandischmoor beträgt lediglich + 0.7 m ü. MThw. Die methodischen Untersuchungen bezüglich der Nutzung von Sedimentfallen (Kapitel 3) zeigen, dass beide Typen von Sedimentfallen vergleichbare Ergebnisse liefern. Oberhalb einer Depositionsrate von ~ 2.0 kg/m2 sinkt das Rückhaltevermögen der Kunstrasenmatte im Vergleich zur LDPE Flasche deutlich ab. Die parallele Nutzung beider Fallentypen, insbesondere wenn die Depositionsraten den Schwellenwert (~ 2.0 kg/m2) nicht überschreiten, erlaubt: (1) Die Überprüfung, ob beide Datensätze konsistent sind. (2) Die Identifizierung von Ausreißern. (3) Eine Abschätzung, ob Sediment auf oder in der Sedimentfalle nach der Überflutung remobilisiert wird. Um die Sedimentdeposition in eine vertikale Wachstumsrate zu übersetzen, muss die mittlere Bodendichte als auch der Gehalt an organischer Bodensubstanz des Marschbodens berücksichtigt werden. Die Bohrkernuntersuchungen zeigen, dass diese bodenphysikalischen Parameter auf den unterschiedlichen Halligen stark variieren. Marschen, die häufig überflutet werden lagern weniger organisches Material im Oberboden ein als selten überflutete Marschen. Niedrige Gehalte an leichten organischen Materialien geringer Dichte resultieren wiederum in einer höheren Lagerungsdichte des Marschbodens (Hooge 0.64 g/cm3, Langeneß 0.67 g/cm3, Nordstrandischmoor 0.83 g/cm3). Autochthones organisches Material (welches primär von der Halligvegetation stammt) trägt mit einem Anteil von 9.0 ± 1.4 % (Hooge) bis 21.4 ± 6.6 % (Nordstrandischmoor) zum Marschwachstum bei. Die Ergebnisse der Sedimentfallenuntersuchungen als auch der Datierungen zeigen deutlich ein Ungleichgewicht zwischen Marschwachstum und Meeresspiegelanstieg seit Beginn des 20. Jahrhunderts. Die langjährigen Wachstumsraten, basierend auf der 210Pb-Datierung, liegen mit 1.0 ± 0.3 mm/a auf Hooge, 1.2 ± 0.3 mm/a auf Langeneß und 2.6 ± 0.9 mm/a auf Nordstrandischmoor deutlich unterhalb des MThw-Anstiegs von 5.0 ± 0.3 mm/a (1951 – 2011, Wyk auf Föhr). Projektionen des Meeresspiegelanstiegs bis zum Jahr 2100 (Berechnet durch das fwu, Siegen) weisen darauf hin, dass extreme Wasserstände (höchste, jährliche Tidehochwasserstände, HThw, 6.6 ± 3.8 mm/a) deutlich schneller ansteigen werden als das MThw oder der mittlere Meeresspiegel (2.6 ± 0.4 mm/a). Aufgrund dieser Beobachtungen ist von einem zukünftigen Anstieg des Gefährdungspotentials für die Halligen auszugehen, wenn es nicht gelingt, ein sedimentologisches Gelichgewicht zwischen Meeresspiegel und Marschwachstum herzu stellen. Der Anstieg der Wellenhöhe und Periode, aufgrund von steigender Wassertiefe und einer geringeren Wellentransmissionsrate an den Sommerdeichen, resultiert in einer steigenden hydrodynamischen Belastung der Warften und der Marschoberfläche. Das sedimentäre Ungleichgewicht, besonders auf Hooge und Langeneß, kann eindeutig auf das hydrologische Management der Halligen zurückgeführt werden. Aus sedimentologischer Sicht sind die beiden Hauptkritikpunkte (1) die geringe Anzahl an Überflutungen aufgrund der Deichanlagen und (2) der eingeschränkte Transport suspendierter Feststoffe über die Binnenpriele. Letzteres resultiert aus der Blockade der Binnenpriele durch Sielanlagen und führt zu einer Abnahme der Sedimentdeposition mit zunehmender Entfernung zur Uferlinie. Um dem Ungleichgewicht zwischen Marschwachstum und Meeresspiegelanstieg entgegenzuwirken, ist es dringend erforderlich, neue Managementstrategien für die Halligen zu entwickeln (Kapitel 6), welche sedimentologische/geomorphologische Aspekte sowie die speziellen Bedürfnisse der Halligbevölkerung gleichermaßen berücksichtigen. Letztere beinhalten die Minimierung ökonomischer Schäden wie etwa Einschränkungen der landwirtschaftlichen Nutzung oder des Tourismus. Mögliche Szenarien können ein Abflachen der bestehenden Deiche oder deren Rückbau und Erneuerung durch wasser- und sedimentdurchlässige Rauhstreifen (z.B. Elastocoast®, BASF) beinhalten. Weiterhin erscheint die Reaktivierung der blockierten Binnenpriele eine plausible Maßnahme zu sein. Erste Freilandexperimente auf Hallig Langeneß (Kapitel 5) belegen einen erhöhten Sedimenttransport in die Binnenmarsch aufgrund geöffneter Sielanlagen in Verbindung mit Windstau (Thw-Ereignisse über Springtideniveau). Ob die generelle Umsetzung derartiger Maßnahmen möglich ist, ist in erster Linie davon abhängig, ob die Halligbevölkerung derartigen Veränderungen ihrer Umwelt aufgeschlossen gegenübersteht und diese lokalpolitisch getragen werden. Auf jeden Fall ist ein Umdenken dahingehend erforderlich, die halligtypischen Überflutungen (Land-Unter) nicht ausschließlich als Bedrohung zu verstehen. Sie sind ein natürliches Phänomen, welches notwendig ist, um das Gleichgewicht zwischen Meeresspiegelanstieg und Sedimentdeposition aufrechtzuerhalten.