Peatlands which are valued for their long-term carbon storage are subject to climate change impacts. Many of the mechanisms regulating carbon flux in peatlands are not well understood. Studies have hypothesized that spatial heterogeneity and patchiness of vegetation associated with micro-topography and hydrological gradients within peatlands play an important role in controlling trace gas exchange. Following this hypothesis, the objectives of my research is to characterize the spatial distribution of vegetation properties and water table level linked to hummock and hollow structures using ground data and remote sensing at the Mer Bleue peatland in Ontario. As well as determine whether these two methods will provide the same information with respect to the spatial patterns of vegetation. A hierarchically nested cyclic sampling scheme of leaf area index (LAI), percent vegetation cover and water table level provided concrete measures of peatland properties for spatial analysis. However, ground surveys covering large areas are time-consuming, expensive, and can damage peatland vegetation through trampling and repetitive sampling. Therefore, this research combined localized ground verification surveys with broad multi-spectral high resolution (2.44m) QuickBird satellite information to quantify spatial heterogeneity. Geostatistical analysis was performed on data from each of these sources to explore the spatial dependence of ground data and spectral reflectance. For the ground data, these analyses produced ground survey range results that mainly varied between 2 and 4m. These were interpreted to represent groupings of multiple 1m hummock structures or lawn (a flatter, wider hummock) structures observed in the field. The sill height demonstrated a linear relation to vegetation cover. The relative nugget error (RNE) showed variability occurring at scales finer than 1m likely due to the individual hummock structure, canopy layering and vegetation niche range. The remotely / Les tourbières qui sont valorisées pour leurs capacités à accumuler le carbone à long terme, sont exposées au changement climatique. Les théories sur les mécanismes qui régularisent l'échange carbonique ne sont pas encore bien établies et comprises. Les hypothèses de certaines études suggèrent que l'échange de gaz présent à l'état de trace est principalement contrôlé par l'hétérogénéité spatiale et la répartition clairsemée de la végétation en association avec les structures micro-topographiques et le gradient hydrologique à l'intérieur des tourbières. En me basant sur cette hypothèse, les objectifs de ma recherche sont de caractériser la distribution spatiale des propriétés de la végétation et de la nappe phréatique en relation avec les structures de hummocks et de creux en utilisant une combinaison de donnés de terrain et de télédétection à la tourbière de Mer Bleue en Ontario. De plus, il y a l'objectif de déterminer si les deux méthodes peuvent produire des résultats semblables sur les patrons spatiaux. Un schéma d'échantillonnage hiérarchique et emboîté comprenant des mesures d'indice de surface foliaire (LAI), le pourcentage de recouvrement pour chaque type de végétation et le niveau de la nappe phréatique fournissaient des mesures concrètes de propriétés relier à des tourbières pour l'analyse spatiale. Cependant la collection de donnés pour de grande surface s'avère laborieux en terme de temps, coûteuse et peut causer des dommages par la répétition de prélèvement d'échantillons et le piétinement. Pour cet effet, cette recherche combine des donnés de terrain local et des donnés de télédétection du satellite QuickBird à haute résolution (2.44m) à plus large échelle pour quantifié l'hétérogénéité spatiale. Une analyse géostatistique a été appliquée pour une série de donnés prise approximativement dans la même région de la tourbière par des mesures sur le terrain et

Icebergs offshore Newfoundland represent hazards to both ships and constructed facilities, such as off-shore oil production facilities. Collision with icebergs represent hazards for both surface and sub-surface facilities. In the latter case, hazards are associated with seabed scouring by the iceberg keel. In both cases, hazard analysis requires estimation of the flux of icebergs and their size distribution. Estimates of the flux of icebergs can be achieved by obtaining separate estimates of iceberg densities and of drift patterns of iceberg velocities. The objective of this thesis is to develop and apply estimation procedures for the density of icebergs using presently available data sets. The most comprehensive of these data sets is compiled by the International Ice Patrol (IIP), starting in 1960. The IIP database comprises data from several sources and for icebergs of varying sizes. In addition, the spatial coverage of surveys does not appear to be uniform throughout the year. Several non-parametric density estimation procedures are investigated. The objective is to eliminate any apparent high densities in the estimates due to the non-uniform coverage of the region during surveys and retain statistically significant features in the spatial variation of densities. / Several kernel estimators are examined: (1) a uniform square kernel, (2) a uniform circular kernel, (3) a Normal kernel, and (4) an adaptive kernel. Uniform kernels have the advantage of computational efficiency, however, they do not account for spatial variations in the densities and produce over-smoothing in regions of peak iceberg densities and under-smoothing in regions of low iceberg densities. The adaptive kernel is computationally more demanding, but appears to fulfill all the desired requirements for preserving significant features and eliminating erratic estimates.

Electron Spin Resonance (ESR) dating has many potential applications in the fields of archaeology and Quaternary geomorphology. In particular, it offers a useful addition to more established techniques for dating speleothems, which not only have relevance to Quaternary geomorphology but may also carry palaeomagnetic and palaeoclimatic data. This work consolidates the method of ESR dating, with special reference to calcite speleothems, and contributes to several important aspects of the methodology. Using a low energy nuclear accelerator as a source of alpha particles of various energies, it is shown that the effectiveness of alpha radiation in producing paramagnetic defects is energy dependent, and approximately linearly related to the range of the incident alpha; the implications for dose rate calculations are discussed, and ranges are calculated for alpha particles of different energies for various dating materials for use in applying the above finding. The alpha/gamma effectiveness ratio, k, is experimentally determined for 18 calcite speleothems as k$/sb[/rm av]$ = 0.052 $/pm$ 0.006, which is significantly less than most previous estimates. The k-value for a coral sample is 0.055. By examining the Th-230/Po-210 ratios of 19 speleothem samples it is shown that for almost all speleothems, radon is retained within the sample until its decay; thus the full radionuclide decay chains should be used in dose rate calculations. Analysis of 'typical' calcite spectra confirms that interference between peaks of different origins and stability affects the estimate of accumulated dose (AD), and provides a rational basis for decisions on different sample preparation methods and analytical procedures. The effect of these on age estimates is examined and routine experimental methods recommended. The effect of different ESR spectrometer operating parameters is also evaluated and it is shown that the use of high microwave power avoids potentially serious underestimation of the accumulated dose (AD). A straight-forward statistical method is developed; this enables confidence limits to be derived for AD and provides a test for equivalence of AD estimates, using standard linear hypothesis techniques. A robust Geiger Muller instrument sufficiently sensitive to give estimates of relative gamma dose rates in a few minutes is developed specifically for cave dosimetry. It has the potential, with further development and cross-calibration, to become a viable method for measuring absolute environmental gamma dose rates. Serious discrepancies between two 'absolute' dosimetry methods are revealed; this and other problems of environmental gamma dosimetry are discussed. The evaluation of gamma dose rates in calcite (with respect to both laboratory and field dosimetry) and the form of the dose response curve (including the possibility of supra-linearity and non-thermal instability) are identified as areas requiring further research.

Electron Spin Resonance (ESR) dating has many potential applications in the fields of archaeology and Quaternary geomorphology. In particular, it offers a useful addition to more established techniques for dating speleothems, which not only have relevance to Quaternary geomorphology but may also carry palaeomagnetic and palaeoclimatic data. This work consolidates the method of ESR dating, with special reference to calcite speleothems, and contributes to several important aspects of the methodology. Using a low energy nuclear accelerator as a source of alpha particles of various energies, it is shown that the effectiveness of alpha radiation in producing paramagnetic defects is energy dependent, and approximately linearly related to the range of the incident alpha; the implications for dose rate calculations are discussed, and ranges are calculated for alpha particles of different energies for various dating materials for use in applying the above finding. The alpha/gamma effectiveness ratio, k, is experimentally determined for 18 calcite speleothems as k$/sb[/rm av]$ = 0.052 $/pm$ 0.006, which is significantly less than most previous estimates. The k-value for a coral sample is 0.055. By examining the Th-230/Po-210 ratios of 19 speleothem samples it is shown that for almost all speleothems, radon is retained within the sample until its decay; thus the full radionuclide decay chains should be used in dose rate calculations. Analysis of 'typical' calcite spectra confirms that interference between peaks of different origins and stability affects the estimate of accumulated dose (AD), and provides a rational basis for decisions on different sample preparation methods and analytical procedures. The effect of these on age estimates is examined and routine experimental methods recommended. The effect of different ESR spectrometer operating parameters is also evaluated and it is shown that the use of high microwave power avoids potentially serious underestimation of the accumulated dose (AD). A straight-forward statistical method is developed; this enables confidence limits to be derived for AD and provides a test for equivalence of AD estimates, using standard linear hypothesis techniques. A robust Geiger Muller instrument sufficiently sensitive to give estimates of relative gamma dose rates in a few minutes is developed specifically for cave dosimetry. It has the potential, with further development and cross-calibration, to become a viable method for measuring absolute environmental gamma dose rates. Serious discrepancies between two 'absolute' dosimetry methods are revealed; this and other problems of environmental gamma dosimetry are discussed. The evaluation of gamma dose rates in calcite (with respect to both laboratory and field dosimetry) and the form of the dose response curve (including the possibility of supra-linearity and non-thermal instability) are identified as areas requiring further research.

Techniques for seabed habitat mapping have developed considerably over the past 10 years, principally through advances in acoustic technologies and tools for improved spatial analysis. The increasing need for information on the distribution and structure of seabed habitats in coastal waters (< 50 m deep) has developed in Australia due to increasing pressures from development and exploitation. A clear understanding of the uncertainties in creating spatial information from marine data is required within seabed mapping projects, particularly those using acoustic methods that vary in coverage and resolution. This thesis investigates methods to explore spatial uncertainty in the techniques used to characterise shallow water seabed habitats using local and regional scale case studies ranging from interpolation of sediment cores to classifying digital elevation models generated from multi-beam acoustic data. Uncertainties are investigated in a multidiscipliary approach to habitat mapping. Broad-scale and fine-scale mapping of marine seabed habitats can provide considerable information on patterns of physical seafloor structuring and this is now achievable given recent technological advances in echosounders and backscatter analysis, digital underwater video, differential GPS and Geographic Information Systems (GIS). The uncertainties in classifying single beam acoustic data are examined by comparing data visually classified into habitat classes in real time compared to those defined through post-processing in the laboratory. The influence of a range of transect spacings on qualitative knowledge-based interpolation of shallow rocky reef acoustic data is assessed. Parameters of physical reef characteristics from single beam acoustic data are investigated which aid in improving kriging interpolation techniques. A fuzzy classification method is applied to sediment core data collected over 100s of kms in order to map the distribution of unconsolidated sediments. This technique is tested on Australia's SeaScapes data. The SeaScapes layer was recreated with classes derived from an unsupervised fuzzy clustering algorithm. A sensitivity analysis was performed which explores the optimal number of clusters and clearly shows where classes overlap, highlighting confusion and therefore potential classification errors in the data. Conditional simulation was utilised to explore uncertainty in the interpolated data layers and animations produced which provided an advanced way of visualising the surfaces. Image segmentation techniques are applied at various values of splitting and merging thresholds to identify objects in sidescan sonar imagery. Grey Level Co-occurrence Matrices (GLCM) texture measures are integrated with segmentation to identify homogeneous texture regions in an image. The segmentation and object oriented classification provide good classification results in 10-40 m water depth with accuracy values of >80 % when classifying two classes and >60% when classifying three classes. This section of research focuses on the analysis of seabed habitats through the use of algorithmic calculations at multiple scales to quantitatively delineate distinct seabed regions based on texture parameters. The textural characteristics of three habitat classes are explored and tested onsidescan sonar data in two case studies. Segmentation results are validated using underwater video transects and statistical techniques. The classified sidescan acoustic images are spatially characterised using fragmentation statistics. These results are a leap forward providing a methodology and a terminology to describe the distribution of shallow rocky reef, combined with a classified map and an uncertainty map generated by the object oriented technique. Fuzzy classification techniques are used to characterise the two dimensional structure of shallow rocky reefs from multi-beam bathymetric data. The results from two morphometric classification techniques are contrasted and compared. Many physical and biological processes acting on the seabed are highly correlated with bathymetric features, such as ridges and channels. Examples of these include the selection of habitat by many commercially fished species, such as rock lobster, abalone and reef associated fish species. These physical attributes can therefore often be key predictors of habitat uitability, community composition and species distribution and abundance. These methods greatly improve insight into classification and related uncertainties of morphometric classification. There are many potential applications of seabed habitat mapping for which estimates of uncertainty will provide additional crucial information. As habitat mapping becomes more common in Australian coastal waters and datasets build up over time, compatibility between different sets of information will be essential. Monitoring and change detection analysis requires detailed baseline data with uncertainty estimates to ensure that features that display change are reliably detected. The accuracy of marine habitat maps and their associated levels of uncertainty are extremely hard to convey visually or to quantify with existing methodologies. The new techniques developed in this research provide a rigorous alternative to current practices. The methods used in this research integrate existing techniques in a novel way to improve insight into classification and related uncertainty for seabed habitat maps which will progress and improve resource management for Australian coastal waters.

Electron Spin Resonance (ESR) dating has many potential applications in the fields of archaeology and Quaternary geomorphology. In particular, it offers a useful addition to more established techniques for dating speleothems, which not only have relevance to Quaternary geomorphology but may also carry palaeomagnetic and palaeoclimatic data. This work consolidates the method of ESR dating, with special reference to calcite speleothems, and contributes to several important aspects of the methodology. Using a low energy nuclear accelerator as a source of alpha particles of various energies, it is shown that the effectiveness of alpha radiation in producing paramagnetic defects is energy dependent, and approximately linearly related to the range of the incident alpha; the implications for dose rate calculations are discussed, and ranges are calculated for alpha particles of different energies for various dating materials for use in applying the above finding. The alpha/gamma effectiveness ratio, k, is experimentally determined for 18 calcite speleothems as k$/sb[/rm av]$ = 0.052 $/pm$ 0.006, which is significantly less than most previous estimates. The k-value for a coral sample is 0.055. By examining the Th-230/Po-210 ratios of 19 speleothem samples it is shown that for almost all speleothems, radon is retained within the sample until its decay; thus the full radionuclide decay chains should be used in dose rate calculations. Analysis of 'typical' calcite spectra confirms that interference between peaks of different origins and stability affects the estimate of accumulated dose (AD), and provides a rational basis for decisions on different sample preparation methods and analytical procedures. The effect of these on age estimates is examined and routine experimental methods recommended. The effect of different ESR spectrometer operating parameters is also evaluated and it is shown that the use of high microwave power avoids potentially serious underestimation of the accumulated dose (AD). A straight-forward statistical method is developed; this enables confidence limits to be derived for AD and provides a test for equivalence of AD estimates, using standard linear hypothesis techniques. A robust Geiger Muller instrument sufficiently sensitive to give estimates of relative gamma dose rates in a few minutes is developed specifically for cave dosimetry. It has the potential, with further development and cross-calibration, to become a viable method for measuring absolute environmental gamma dose rates. Serious discrepancies between two 'absolute' dosimetry methods are revealed; this and other problems of environmental gamma dosimetry are discussed. The evaluation of gamma dose rates in calcite (with respect to both laboratory and field dosimetry) and the form of the dose response curve (including the possibility of supra-linearity and non-thermal instability) are identified as areas requiring further research.

Electron Spin Resonance (ESR) dating has many potential applications in the fields of archaeology and Quaternary geomorphology. In particular, it offers a useful addition to more established techniques for dating speleothems, which not only have relevance to Quaternary geomorphology but may also carry palaeomagnetic and palaeoclimatic data. This work consolidates the method of ESR dating, with special reference to calcite speleothems, and contributes to several important aspects of the methodology. Using a low energy nuclear accelerator as a source of alpha particles of various energies, it is shown that the effectiveness of alpha radiation in producing paramagnetic defects is energy dependent, and approximately linearly related to the range of the incident alpha; the implications for dose rate calculations are discussed, and ranges are calculated for alpha particles of different energies for various dating materials for use in applying the above finding. The alpha/gamma effectiveness ratio, k, is experimentally determined for 18 calcite speleothems as k$/sb[/rm av]$ = 0.052 $/pm$ 0.006, which is significantly less than most previous estimates. The k-value for a coral sample is 0.055. By examining the Th-230/Po-210 ratios of 19 speleothem samples it is shown that for almost all speleothems, radon is retained within the sample until its decay; thus the full radionuclide decay chains should be used in dose rate calculations. Analysis of 'typical' calcite spectra confirms that interference between peaks of different origins and stability affects the estimate of accumulated dose (AD), and provides a rational basis for decisions on different sample preparation methods and analytical procedures. The effect of these on age estimates is examined and routine experimental methods recommended. The effect of different ESR spectrometer operating parameters is also evaluated and it is shown that the use of high microwave power avoids potentially serious underestimation of the accumulated dose (AD). A straight-forward statistical method is developed; this enables confidence limits to be derived for AD and provides a test for equivalence of AD estimates, using standard linear hypothesis techniques. A robust Geiger Muller instrument sufficiently sensitive to give estimates of relative gamma dose rates in a few minutes is developed specifically for cave dosimetry. It has the potential, with further development and cross-calibration, to become a viable method for measuring absolute environmental gamma dose rates. Serious discrepancies between two 'absolute' dosimetry methods are revealed; this and other problems of environmental gamma dosimetry are discussed. The evaluation of gamma dose rates in calcite (with respect to both laboratory and field dosimetry) and the form of the dose response curve (including the possibility of supra-linearity and non-thermal instability) are identified as areas requiring further research.

Thesis (Ph. D.)--University of Chicago, 1914. / "Private edition, distributed by the University of Chicago Libraries, Chicago, Illinois." "Reprinted from South Dakota State Geological Survey, Bulletin no. 8, July, 1918." Original title page has subtitle: A detailed discussion of the surface, resources, climate, plants, animals, and human geography, including the history of the area. A study in regional geography. "A bibliography of the literature cited": p. 163-168. Also available on the Internet.

Thesis (Ph.D.)--University of Massachusetts Amherst, 2006. / (UMI)AAI3216942. Adviser: Raymond S. Bradley. Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2440.

Thesis (B.A.)--University of Hong Kong, 1969. / Includes bibliographical references (p. 70-82)