Although much emphasis has been given to the analysis of continuous forest conversion in tropical regions, our understanding in detecting, mapping and interpreting the spatial pattern of woodland deforestation and degradation is still limited. This thesis focuses on two factors contributing to this limitation: uncertainties in retrieving woodland change from remote sensing imagery, and the complex processes that may cause woodland deforestation and degradation. Firstly, I investigate approaches to minimising uncertainty in ALOS PALSAR-derived biomass maps by modifying a widely used processing chain, with the aim of provide recommendations for producing radar-based biomass maps with reduced uncertainty. Secondly, to further improve the retrieval of woody biomass from ALOS PALSAR imagery, the semi-empirical Water Cloud Model (WCM) is introduced to account for backscattering from soil. In wooded areas with low canopy (such as the miombo woodland which dominates the study area) the effect from soil moisture on the received backscattered signal is critical. Thirdly, based on the biomass maps retrieved from the refined radar-remote-sensing-based methodology discussed above, the influence of driving variables of the woodland deforestation and degradation, and how they alter the spatial patterns of these two processes, are analysed. The threshold for defining woodland deforestation and degradation in terms of biomass loss intensity is generated through integration of radar-based biomass loss maps, an optical forest cover change map and fieldwork investigation. Multi-linear model simulations of the spatial variation of deforestation and degradation events were constructed at a district and 1 km resolution respectively to rank the relative importance of driving variables. Results suggest that biomass-backscatter relationships based on plots of approximately 1 ha, and processed with high resolution DEMs, are needed for low uncertainty biomass maps using ALOS PALSAR data. Although plots sizes of 0.1 - 0.5 ha lead to large uncertainties, aggregating 0.1 ha plots into larger calibration sites shows some promise even in hilly terrain, potentially opening up the use of common forest inventory data to calibrate remote-sensing-based biomass retrieval models. Such relationships appear to hold across the miombo woodland ecoregion, which implies that there is a consistent relationship at least in the miombo woodland. From this I infer that random error, different processing methods and fitting techniques, and data from small plots are the source of the differences in the savanna biomass-backscatter relationships seen in the literature. The interpreted WCM presented in this study for L-band backscatter at HV polarisation improves biomass retrieval for areas with a biomass value less than 15 tC/ha (or 0.025 m2/m2 in backscatter). Use of the WCM also results in better quality regional biomass mosaics. This is because the WCM helped to improve the correlation of biomass estimation for overlay areas by reducing bias between adjacent paths, especially the bias introduced by changes in soil moisture conditions between different acquisition dates for different paths. Result shows that active and combined soil moisture datasets (from the Climate Change Initiative Soil Moisture Dataset) can be used as effective soil moisture proxies in the WCM for biomass retrieval. This quantitative analysis on the driving variables of woodland deforestation and degradation suggests that large uncertainty exists in modelling the occurrence of deforestation and degradation, especially at a 1 km scale. The spatial patterns of woodland deforestation and degradation differ in terms of shape, size, intensity, and location. Agriculture-related driving variables account for most of the explained variance in deforestation, whereas for degradation, distance to settlements also plays an important role. Deforestation happens regardless of the original biomass levels, while degradation is likely to happen at high biomass areas. The sizes of degradation events are significantly smaller than those of deforestation events, with 90% of deforestation events sharing boundaries with degradation events. This thesis concludes by outlining the importance and difficulties in integrating 'distal' (underlying) drivers in modelling the spatial dynamics of deforestation and degradation. Further work on the causal connection between deforestation and degradation is also needed. The processing chain and biomass retrieval models presented in this study could be used to support monitoring and analysis of biomass change elsewhere in the tropics, and should be compatible with data derived from ALOS-2 and the future SAOCOM and BIOMASS satellite missions.

Cirrus clouds play an important role in radiative transfer, and thus have impact on the energy balance of the atmosphere and the climate of the Earth. Furthermore, they occur often and cover large areas globally at any time. Nevertheless, cirrus clouds are poorly studied, especially in the polar regions. Cirrus clouds are present in a large amount of the 14 years of data produced by the lidar at the Swedish Institude of Space Physics (IRF), but has not been studied to a large extent. A lidar is an active remote sensing instrument using a laser. This master's thesis develops and improves programs for analysis of cirrus clouds from this lidar data. It also performs analysis of six case studies chosen from the available data, and statistics of these six cases. The parameters calculated for each date are the cloud top, base and mean altitude, the geometrical thickness, the depolarisation ratio, the backscatter ratio (BSR), the backscatter coefficient, the extinction coefficient, the optical thickness and the number of cloud layers. No clear correlation between the optical thickness and the cloud top, base or mean altitude was found. There seems to be a weak correlation between increased optical thickness and increased geometrical thickness, which is not unreasonable. The mean cloud layer top altitude was 11.82 km and the mean cloud base was 10.36 km. The mean optical thickness for a cloud layer was 1.46 km, and the average of the cloud layer mean altitude was 11.09 km. It should be noted that the statistical analysis is based on only six cases with a total observation time of no more than 37 hours. A far larger dataset is needed in order to obtain any statistically signicant conclusions. The effect of averaging is studied, and it is concluded that averaging over altitude reduced the noise and facilitated the interpolation more than averaging over time did. Different approaches to obtain the molecular backscatter coefficient are compared, as well as the effect on the simulated molecular signal. Two of these approaches calculate the molecular backscatter coeffcient with input of the temperature and pressure either as continuously measured ground vales from the weather station at IRF or as radiosonde profiles for a specific time. In the other two, the molecular backscatter coeffcient is obtained from ECMWF data and from the standard atmosphere. Differences in the range 12-35% between the methods are found. Different approaches to calculate the backscatter ratio (BSR) are also compared. At cirrus altitudes, the decrease in the signal due to the molecular cloudfree part of the atmosphere is still strong, and finding the top and base separately by comparison with the standard deviation of the signal is proven a better method than interpolating between the point where the signal starts to increase and the point where it reaches the same signal value again. Height-normalising the signal provides a more robust method. For thin cirrus, the signal is not significantly attenuated above the cloud layer, and it is found that a method based on the ratios between the measured signal and the simulated molecular signal at cloud top and base did not produce reliable results for the optical thickness. In addition to analysing data and data processing methods, new data processing tools in MATLAB have been developed and existing functions have been improved. These will be valuable for continued studies with the IRF lidar, for cirrus as well as PSCs and thick and/or low-altitude clouds.

Estimation of biomass has high importance for economic, ecologic and climatic reasons due to the multiple ecosystem services offered by forested landscapes. Measurements that are taken in the field incur personal and economic costs. Nevertheless, biomass surveying based on remote sensing techniques offer efficiency thanks to covering large areas. The European Space Agency (ESA) Sentinel-1 satellite offers promising capabilities for above-ground biomass (AGB) estimation through synthetic aperture radar (SAR) based microwave remote sensing. In this study, experimental AGB estimations based on Sentinel-1 C-band data were produced over the Remingstorp estate (Västergötland County, Sweden) to analyze its performance over boreal productive forests. The obtained measurements were compared against reference values obtained by combining photogrammetric, aerial laser scanning (ALS) and field measurements. Thus, a reference high-resolution canopy height model (CHM) was produced from the difference between photogrammetric digital surface model (DSM) values and ALS digital terrain model (DTM) values. The comparison of CHM observations against diameter at breast height (DBH) field measurements revealed the existence of a vegetation height - vegetation volume relationship for the study species (Pinus Sylvestris and Picea Abbies), which allowed bole volume estimation based on vegetation height values. SAR-based AGB estimates were produced by defining statistical relationships between backscatter intensity and interferometric coherence measurements against reference CHM values. Additionally, evaluation of biomass estimation through interferometric (InSAR) height was possible by comparing against reference photogrammetric DSM. Backscatter signal saturation of C-band at low biomass volumes prevented quantification of biomass but permitted differentiation between forested and non-forested surfaces. Estimation of AGB through interferometric coherence was possible through modeling volumetric decorrelation, which on the contrary prevented biomass retrieval from InSAR height. Due to the given frequency properties at C-band, HV cross-polarized channel was used in all cases for better detection of the canopy layer. Image acquisition under stable conditions was a priority to avoid noise derived from variable dielectric properties, acquisition geometry effects and temporal decorrelation. Hence, image acquisitions under stable hydrometeorological conditions (i. e. stable frozen or dry) and for the lowest repeat-pass interval (i. e. 6-days) were prioritized.

<p>The goal of this work has been to evaluate the different experimental techniques used for quantitative analysis of multi-phase materials systems. </p><p>Powder based specimens containing two-phases, austenite and ferrite , were fabricated and quantified. The volume fraction of ferrite varied from 2 Vol% to 50 Vol%. </p><p>X ray powder diffraction (XRD) measurements were based on two peak analysis. Computer based software Topas was used for quantitative analysis, which is believed to be the most advanced in this field. XRD results were found within the absolute limit of +/- 4% of given ferrite volume fraction. Volume fraction as low as 2 Vol% was successfully detected and quantified using XRD. However, high statistical error was observed in case of low volume fraction, such as 2 Vol% and 5 Vol% ferrite volume fraction. </p><p>Magnetic balance (MB) measurements were performed to determine the volume fraction of magnetic phase, ferrite. MB results were found in good agreement with given volume fractions. As low as 2 Vol% volume fraction was detected and quantified with MB. MB results were within the absolute limit of +/- 4% of given ferrite volume fraction. </p><p>Image analysis (IA) was performed after proper sample preparation as required by electron backscatter diffraction (EBSD) mode of Scanning electron microscopy (SEM). IM results were found within the absolute limit of +/- 2 % of given ferrite volume fraction. However, high statistical error was observed in case of 2 Vol% volume fraction.</p>

Plagioclase is the most abundant mineral in the lower crust and it is thus important to constrain the behaviour of plagioclase during deformation. Anorthosites, which are plagioclase-rich rocks, are common in Archaean cratons but their origin and rheological importance is still debated. The aims of this thesis are to 1) describe a newly discovered Archaean anorthosite complex (Naajat Kuuat, SW Greenland), investigate its origin and a possible genetic relationship between the anorthosite and associated mafic-ultramafic rocks and 2) to study the rheology and deformation mechanisms in plagioclase-rich rocks. The main focus of this thesis is on the deformation studies. (1) Geochemical whole-rock analyses from the Naajat Kuuat complex are indicative for an origin near a subduction zone setting. A genetic link by crystal fractionation between the anorthosite and associated mafic-ultramafic units is inferred. (2) Deformation behaviour of plagioclase is assessed from analyses of three anorthosite units deformed during different conditions. Samples were analysed using the electron backscatter diffraction technique (EBSD) in combination with optical and chemical analyses. All three case studies show significant strain localisation related to grain size reduction. A wet anorthosite deformed at dry conditions (T ~675-700°C) was dynamically recrystallised. Continuous bands of recrystallised grains developed a texture yet display microstructures and grain relationships indicative for grain size sensitive creep, suggesting that the rheology followed a Newtonian flow law. In the other two studies, samples with initially dry and wet composition, respectively, have experienced deformation during fluid present conditions at T ~550-620°C. These two samples show that fluids effectively caused reactions, replacements and aided strain localisation during deformation at mid crustal conditions. / At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 1: Manuscript; Paper 2 Manuscript; Paper 3 Manuscript.

The former Viking settlement Birka is located on Björkö Island in Lake Mälaren, the third largest lake in Sweden. Birka is a well-known archeological site that onshore has been carefully examined. The lake floor of the waters surrounding the island has been less investigated but has a great potential to host not yet discovered archeological objects from this former hub for seafarers. Therefore, a geophysical survey including multibeam sonar mapping and subbottom profiling was carried out mainly along the shores of western Björkö Island. Processing and analysis of these collected data form the basis of this thesis. The main aims of this study are to produce a suite of geological maps and stratigraphic profiles that are used to geologically interpret the uppermost sediment stratigraphy and the bathymetry of the area. In addition, the processed data are investigated for archeological objects. The result shows that the acoustic records of the sediment stratigraphy reaches back to glacial clay formed as a consequence of the retreat of the Late Weichselian ice sheet, and that the uppermost sediment units probably are from the time after the isolation of Lake Mälaren from the Baltic Sea. The bathymetry and backscatter results have revealed that this relatively shallow study area contains several objects that potentially could be of interest from an archeological point of view. These objects include several unidentified objects in the Björkö strait and two unregistered shipwrecks where ground truthing data need to be collected to determine their respective origin.

The goal of this work has been to evaluate the different experimental techniques used for quantitative analysis of multi-phase materials systems. Powder based specimens containing two-phases, austenite and ferrite , were fabricated and quantified. The volume fraction of ferrite varied from 2 Vol% to 50 Vol%. X ray powder diffraction (XRD) measurements were based on two peak analysis. Computer based software Topas was used for quantitative analysis, which is believed to be the most advanced in this field. XRD results were found within the absolute limit of +/- 4% of given ferrite volume fraction. Volume fraction as low as 2 Vol% was successfully detected and quantified using XRD. However, high statistical error was observed in case of low volume fraction, such as 2 Vol% and 5 Vol% ferrite volume fraction. Magnetic balance (MB) measurements were performed to determine the volume fraction of magnetic phase, ferrite. MB results were found in good agreement with given volume fractions. As low as 2 Vol% volume fraction was detected and quantified with MB. MB results were within the absolute limit of +/- 4% of given ferrite volume fraction. Image analysis (IA) was performed after proper sample preparation as required by electron backscatter diffraction (EBSD) mode of Scanning electron microscopy (SEM). IM results were found within the absolute limit of +/- 2 % of given ferrite volume fraction. However, high statistical error was observed in case of 2 Vol% volume fraction.

We have been actively involved in the research and management activities of European Co-Operation in the Field of Scientific and Technical Research (EU COST) actions such as COST 238 Prediction and Retrospective Ionospheric Modeling over Europe (PRIME), COST 251 Improved Quality of Service in Ionospheric Telecommunication System Planning and Operation, COST 271 Effects of the Upper Atmosphere on Terrestrial and Earth-Space Communications, COST 296 Mitigation of Ionospheric Effects on Radio Systems (MIERS) and COST 724 Developing the Scientific Basis for Monitoring, Modeling and Predicting Space Weather. In this thesis High Frequency (3-30 MHz) (HF) radar system under ionospheric disturbances has been identified globally and some operational suggestions have been presented. The use of HF radar system is considered from the identification of ionospheric propagation medium point of view. Doppler velocity is considered as the characteristic parameter of the propagation medium. ap index is chosen as the parameter for disturbance characterization due to geomagnetic storms in the ionosphere. The main difficulty is the scarcity of data, which is rare and confidential. Therefore semi-synthetic data are generated. Dependence of Doppler velocity and group range of the echo signal on ap index is examined and some details of dependence are studied and demonstrated. Thus, effects of space weather on the ionosphere and as a result on HF radar wave propagation are displayed. These results are examples of system identification. This can be used in communication system planning and operation.

The wireless transfer of power is the enabling technology for realizing a true internet-of-things. Broad sensor networks capable of monitoring environmental pollutants, health-related biological data, and building utility usage are just a small fraction of the myriad of applications which are part of an ever evolving ubiquitous lifestyle. Realizing these systems requires a means of powering their electronics sans batteries. Removing the batteries from the billions or trillions of these envisioned devices not only reduces their size and lowers their cost, but also avoids an ecological catastrophe. Increasing the efficiency of microwave-to-DC power conversion in energy-harvesting circuits extends the range and reliability of passive sensor networks. Multi-frequency waveforms are one technique that assists in overcoming the energy-harvesting circuit diode voltage threshold which limit the energy-conversion efficiency at low RF input powers typically encountered by sensors at the fringe of their coverage area. This thesis discusses a systematic optimization approach to the design of energy-conversion circuits along with multi-frequency waveform excitation. Using this methodology, a low-power 5.8 GHz rectenna showed an output power improvement of over 20 dB at -20 dBm input power using a 3-POW (power-optimized waveform) compared to continuous waveforms (CW). The resultant efficiency is the highest reported efficiency for low-power 5.8 GHz energy harvesters. Additionally, new theoretical models help to predict the maximum possible range of the next generation of passive electronics based upon trends in the semiconductor industry. These models predict improvements in diode turn-on power of over 20 dB using modern Schottky diodes. This improvement in turn-on power includes an improvement in output power of hundreds of dB when compared to CW.

The goal of this thesis was to detail spatial and temporal organic particulate dynamics at an integrated multi-trophic aquaculture (IMTA) site on the west coast of Vancouver Island, Canada. To accomplish this goal, in-situ optical measurements of particulate scattering (bp), particulate backscattering (bbp) and the particulate backscattering ratio (bbp:bp) were collected in conjunction with discrete sampling for particulate organic carbon (POC) and chlorophyll a (chl a) concentrations. These measurements were performed over three seasons (autumn, winter and summer) at reference sites and at sites within and directly adjacent to the fish component of the IMTA system. Chapter 2 of this thesis focused on the examination of bio-optical relationships over various timescales (seasonally, daily and within-day) to describe temporal and vertical particulate variability and to assess the effectiveness of bio-optical methods for environmental monitoring. Autumn showed low bio-optical magnitudes with distinct lower cage increases possibly attributable to aquaculture derived wastes. In spring, sampling was performed over diatom bloom conditions, dominating the bio-optical measurements. During summer, an Emiliania Huxleyi bloom likely occurred, strongly enhancing bbp and bbp:bp magnitudes in the thermally stratified upper water column. Throughout these conditions, bp was predominantly influenced by chl a suggesting sensitivity to phytoplankton concentrations. While bbp was conditioned by chl a during the diatom bloom, it was also highly sensitive to the presence of inorganic and likely detrital materials. Finally, bbp:bp was sensitive to particulate compositions, showing low values (< 0.010) in diatom dominated waters and high values when refractive coccoliths were likely present. Notably, in autumn, bbp:bp was conditioned by detrital particles and along with bbp, showed post-feeding lower cage increases suggesting that these parameters could be useful candidates for particulate waste tracking during low ambient particle conditions. In chapter 3, the temporal, vertical and horizontal dispersion of the aquaculture derived particulate wastes are detailed. Autumn was the only period to show waste signals, likely due to their quick dilution into the particulate rich fields in spring/summer. During this period, post-feeding particulate waste increases were focused at the bottom of the cage with possible vertical sinking towards the seafloor. Minimal horizontal dispersion towards the scallop portion of the system was observed; however, more comprehensive sampling over differing hydrographic regimes is necessary to characterize waste dispersion. Based on our temporally limited autumn results, the most appropriate placement of uptake species for waste assimilation would be directly below the studied cage. Our results highlight the need for high spatial and temporal resolution methods for particulate monitoring within IMTA settings as discrete sampling may miss “patchy” waste dispersal streams. The bio-optical measurements performed during this study could fill this need as they can provide high resolution information on particulate concentrations and compositions not achievable solely through the use of discrete water sampling. With further research, optical instrumentation could be incorporated into IMTA systems allowing for the near real time and continuous collection of data on particulate dynamics. This knowledge could greatly aid in the design and implementation of systems optimized for waste removal by uptake species. / Graduate / 0792 / 0768 / 0752 / jdelbel@uvic.ca