The impacts of extreme temperatures on human health and morbidity have been well documented in many studies. In literature, changes in the trends of extreme temperatures have been studied using percentiles, indicators and climate modeling. The aim of this study is to determine if the trend exhibited in the literature of statistically significant increases in extreme minimum temperatures, is also exhibited in the Greater Toronto Area during the 1971 to 2000 timeframe. A methodological approach using counts is the basis for the analysis. Statistical significance is determined through the use of Spearman’s Rank, Kendal-Tau and T-tests. A total of five stations are analysed, three being urban and two representing the surrounding suburban areas. The results indicate that statistically significant decline in extreme minimum temperature counts have occurred. In agreement with the literature, statistically significant increases in extreme maximum temperature counts can not be determined.

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.

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.

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.

Increasing wind penetration adds to the importance of enhancing the reliability of wind, to mitigate the magnitude and frequency of changes in electricity generation. This work addresses how improvements can be made to reliability through the geographic dispersal of wind farms in Ontario, Canada, using modeled North American Regional Reanalysis data. Optimal configurations of wind farm locations are determined according to two criteria. The first selects combinations of wind farms that follow temporal demand patterns, by maximizing the difference between the energy price and the cost of electricity. The second attempts to select combinations of wind farms that minimize the coefficient of variation in the aggregate output. It is found that there are no wind regimes in Ontario that match demand sufficiently for a viable development strategy, but that combinations of as few as three locations can reduce the coefficient of variation by over 30%, compared to a single region.

Increasing wind penetration adds to the importance of enhancing the reliability of wind, to mitigate the magnitude and frequency of changes in electricity generation. This work addresses how improvements can be made to reliability through the geographic dispersal of wind farms in Ontario, Canada, using modeled North American Regional Reanalysis data. Optimal configurations of wind farm locations are determined according to two criteria. The first selects combinations of wind farms that follow temporal demand patterns, by maximizing the difference between the energy price and the cost of electricity. The second attempts to select combinations of wind farms that minimize the coefficient of variation in the aggregate output. It is found that there are no wind regimes in Ontario that match demand sufficiently for a viable development strategy, but that combinations of as few as three locations can reduce the coefficient of variation by over 30%, compared to a single region.

The seasonal asymmetry in coastal temperatures on Hudson Bay was explored and evaluated as a proxy to hindcast sea ice conditions prior to 1972. Various indices of air temperature difference (∆T) between Churchill, MB and Inukjuak, QC were tested for linear correlations with spatially averaged sea ice concentration (SIC) and ice-free season length (IFS). A multiple regression equation employing a 31-day average of peak ∆T and a 61-day average of temperature during freeze-up reproduced the IFS record with an average error of 8.1 days. This equation was employed to extend the IFS record by 28 years. The resulting 68-year time series revealed a significant increasing trend most pronounced from 1985 to 2011. Hindcast data helped eliminate low-frequency climate oscillations of periodicity <68 years as a source of this trend, lending further evidence to the growing consensus of a declining sea ice being the result of anthropogenic climate forcing.

Remote sensing provides methods to infer vegetation information over large areas at a variety of spatial and temporal resolutions that is of great use for terrestrial carbon cycle modeling. Understory vegetation and foliage clumping in forests present a challenge for accurate estimates of vegetation structural information. Multi-angle remote sensing was used to derive and refine new information about the vegetation structure for the purpose of improving global leaf area index mapping. A field experiment with multi-angle, high resolution airborne observations over modified and natural backgrounds (understory, moss, litter, soil) was conducted in 2007 near Sudbury, Ontario to test a methodology for the background reflectivity retrieval. The experiment showed that it is feasible to retrieve the background information, especially over the crucial low to intermediate canopy density range where the effect of the understory vegetation is the largest. The tested methodology was then applied to background reflectivity mapping over conterminous United States, Canada, Mexico, and Caribbean land mass using space-borne Multi-angle Imaging SpectroRadiometer (MISR) data. Important seasonal development of the forest background vegetation was observed across a wide longitudinal and latitudinal span of the study area. The previous first ever global mapping of the vegetation clumping index with a limited eight-month multi-angular POLDER 1 dataset was expanded by integrating new, complete year-round observations from POLDER 3. A simple topographic compensation function was devised to correct negative bias in the data set cause by topographic effects. The clumping index reductions can reach up to 30% from the topographically non-compensated values, depending on terrain complexity and land cover type. The new global clumping index map is compared with an assembled set of field measurements, covering four continents and diverse biomes. Finally, inclusion of the new vegetation structural information, including background reflectivity and clumping index, gained from the multi-angle remote sensing was then shown to improve the performance of LAI retrieval algorithms over forests.