Surface albedo is one of the critical parameters required by studies of surface energy balance and climate models. Albedo is defined as the ratio of outgoing radiances to incoming irradiances over hemispherical view-illumination geometry. Remotely sensed albedo is usually based on multiple view angle observations and a Bidirectional Reflectance Distribution Function (BRDF) model. The accuracy of remotely sensed albedo depends on a variety of factors of which the main ones are the accuracy of atmospherically corrected observations, the reliability of observations, and the validity of the applied BRDF model. Fine spatial resolution airborne and satellite data are valuable for the validation of coarse spatial resolution satellite albedos as they may be validated using field measurements with higher reliability. In this study, a variety of remote sensing data and field measurements were used to estimate, validate and analyse albedo at different spatial resolutions. The main aim was to validate the MODIS albedo product under UK conditions using the methods of direct and indirect comparisons with other available data. The source of the fine spatial resolution data used was the NCAVEO Field Campaign 2006 that took place at the Chilbolton calibration test site in southern England. The CHRIS/PROBA albedo was used as a fine spatial resolution (34 m) albedo map to investigate the spatial variation of albedo. The results of this investigation provided valuable information about the possibility of the extension of the obtained albedo map from CHRIS/PROBA data. The MODIS albedo product with a coarser spatial resolution (500 m), relative to the NCAVEO datasets, was compared with the CHRIS/PROBA albedo map to examine the effect of spatial scale on the accuracy of albedo (direct comparison). The uncertainties in the obtained albedo maps, from both MODIS and CHRIS/PROBA, were mainly examined by testing the accuracy of the input reflectance data and the applied BRDF model (indirect comparison). The results showed the accuracy of the MODIS albedo product inferior to that claimed by the MODIS team.

Seabirds are long-lived, diverse and behaviourally complex marine top predators that are capable of traversing large areas of the global oceans. Consequently, this group are at risk from the wide and persistent range of anthropogenic activities working in this environment. Understanding the consistency with which individuals and populations use the marine environment over space and time, and the mechanisms underlying at-sea behaviour is therefore vital for interpreting population dynamics and developing appropriate and long-standing conservation strategies. This thesis utilises a combination of state-of-the-art tracking technologies and biogeochemical analyses to provide a better understanding of the at-sea movements, ecology and behaviour of a critically endangered seabird: the Balearic shearwater Puffinus mauretanicus. This species is the most threatened seabird in Europe and is undergoing continued population declines, believed to be largely associated with at-sea mortality from fisheries bycatch and predation on land. Despite intensive study during the breeding season, knowledge of the at-sea ecology of Balearic shearwaters during key phases of the annual cycle remains poor. Year-round tracking from colonies on the Balearic Islands yielded new insights into migration strategies of individuals and populations. Most individuals remained faithful to non-breeding areas over the course of the five-year study, although some plasticity in migration behaviour was also detected, indicating capacity for change. Patterns of differential migration were persistent in the main study population, and were linked to sex-based (and potential life stage-based) differences in migratory behaviour, which are most likely associated with varying ties to the breeding grounds. Links between reproductive performance and non-breeding behaviour were also detected, demonstrating an importance of carry-over effects in this species, with potential implications for population dynamics. Furthermore, behavioural differentiation was found between island populations. Migration strategies, use of foraging habitat and phenology differed between a potential Balearic/Yelkouan shearwater hybrid population on Menorca and a neighbouring colony of Balearic shearwaters on Mallorca, providing insights into the relatedness of Puffinus species in the Mediterranean, and emphasising the need to identify units for management that are both ecologically and evolutionarily relevant. Combined geolocation, isotope and feather moult data further identified use of a diversity of foraging tactics in northeast Atlantic waters, and spatial differences in non-breeding dietary behaviour. These findings implicate a role of both forage fish and fisheries in shaping patterns of at-sea distribution during the non-breeding season, and may prove useful for future assessment of seabird responses to anthropogenic and environmental change. During the breeding season, persistent use of highly productive coastal habitats was identified, indicating exploitation of predictable resources. Such movements emphasise the vulnerability of the Balearic shearwater to anthropogenic activity, but also highlight the potential of area-based management approaches for species protection, when combined with management of human activities throughout the species’ distribution range. Together, the findings of this research provide urgently needed information on the at-sea behaviour and ecology of the Balearic shearwater, which should contribute to improved management efforts aimed at increasing population viability. In addition, this thesis contributes to a wider understanding of individual behaviours and inter-seasonal interactions in seabirds, and identifies the need to establish the movement behaviour of a wider range of life stages and populations across distinct seasons.

Britain’s national rail system was ‘privatised’ as a result of the 1993 Railways Act, with most of the organisational and ownership changes implemented by 1997. This thesis examines the long term impacts of the privatisation initiative on the passenger rail service. A key issue when examining long term changes is that of the counterfactual – what would have happened if the changes had not occurred? A simple econometric model of the demand for passenger rail services was developed and used in conjunction with extrapolative methods for key variables such as fares, train kms and GDP to determine demand-side counterfactuals. Extrapolative methods were also used to determine counterfactual infrastructure and train operation costs. Although since privatisation rail demand has grown strongly, the analysis indicates that transitional disruptions suppressed demand by around 4% over a prolonged period (1994/95 to 2005/6), whilst the Hatfield accident reduced demand by about 5%, albeit over a short period (2000/1 to 2005/6). A welfare analysis indicates that although consumers gained as a result of privatisation, for most years this has been offset by increases in costs. An exception is provided by the two years immediately before the Hatfield accident. Overall the loss in welfare since the reforms were introduced far exceeds the net receipts from the sale of rail businesses. It is found that although the reforms have had advantages in terms of lower fares and better service levels than otherwise would have been the case, this has been offset by adverse transitional effects and high costs, which in turn may be linked with higher transaction costs.

Developed and developing countries need electricity, and this usage is increasing everyday. This constant increase cannot be satisfied with the current ways of electricity generation that have shown themselves to be out of phase with environmental concerns. Oceans yield great amount of energy that could be converted into electricity and the current research deals with one portion of ocean energy, wave energy. The wave energy converter studied in this thesis is a bottom-mounted, liquid-filled rectangular duct, covered with a rubber membrane and aligned head to the waves propagation direction. Two types of membrane were tested. The behaviour of this device beneath waves was investigated with two configurations: one with both its ends closed, the other one with a power take-off connected at its stern. The pressure at both ends was characterised by means of pressure transducers and the pressure inside the duct by means of laser sensors measuring the membrane displacement. Results from experiments carried out on the closed version of the duct pointed out a resonant behaviour of the system for wave frequencies at which bulges, propagating in the rubber membrane, could travel an integer number of times along the duct’s length. This resonance was characterised by pressure magnitudes at the stern up to 2.8 times that acting on the membrane from the incident wave. Moreover, the membrane displacement was for the first time mapped and the profile obtained showed characteristic nodes and antinodes. The performance of this device in harnessing wave power was evaluated by connecting a linear dashpot at its stern. Capture widths of up to 2.2 times the device width were obtained and the bandwidth of maximum power capture not limited to a single frequency. The pressure behaviour in both configurations was explained with a one dimensional theory of bulges propagating in distensible tubes with good agreement for the thicker tested membrane. On the contrary, this was not the case for the thinner membrane, suggesting that this model could not be used for configurations where bulge wavelengths are much shorter than that of the incoming wave.

Ground level ozone is one of the six criteria primary pollutants that is monitored by the United States Environmental Protection Agency. Statistical methods are increasingly being used to model ground level ozone concentration data. This thesis is motivated by the need to perform practical data analysis, and to develop methods for modelling of ozone concentration data observed over a vast study region in the eastern United States (US). For the purposes of analysis, we use two space-time modelling strategies: the dynamic linear models (DLM) and the auto-regressive (AR) models and obtain predictions and forecasts for set aside validation data. These methods are developed under the Bayesian paradigm and MCMC sampling techniques are used to explore the posterior and predictive distributions. Particularly, for analysis, we use a subset data set from the state of New York to illustrate the methods. Both the DLM and AR modelling approaches are compared in detail using the predictive and forecast distributions induced by them. The comparisons are facilitated by a number of theoretical results. These show better properties for the AR models under some conditions, which have been shown to hold for the real life example that we considered. To address the challenge of modelling large dimensional spatio-temporal ozone concentration data, we adopt Gaussian predictive processes (GPP) technique and propose a rich hierarchical spatio-temporal AR model. The important utility of this method lies in the ability to predict the primary ozone standard at any given location for the modelled period from 1997-2006 in the eastern US. Different sensitivity analyses are performed, and, in addition, hold-out data sets are used for model validation. Specifically, this new modelling approach has been illustrated for evaluating meteorologically adjusted trends in the primary ozone standard in the eastern US over the 10 year period. This helps in understanding spatial patterns and trends in ozone levels, which in turn will help in evaluating emission reduction policies that directly affect many industries. Forecasting of ozone levels is also an important problem in air pollution monitoring. We compare different spatio-temporal models for their forecasting abilities. The GPP based models provide the best forecast for set aside validation data. In addition, in this thesis we use computer simulation model output as an explanatory variable for modelling the observed ozone data. Thus, the proposed methods can also be seen as a spatio-temporal downscaler model for incorporating output from numerical models, where the grid-level output from numerical models is used as a covariate in the point level model for observed data. This type of space and time varying covariate information enriches the regression settings like the methods used in this thesis. Currently there is no package available that can fit space-time environmental data using Bayesian hierarchical spatio-temporal models. In this thesis we, therefore, develop a software package named spTimer in R. The spTimer package with its ability to fit, predict and forecast using a number of Bayesian hierarchical space-time models can be used for modelling a wide variety of large space-time environmental data. This package is built in C language to be computationally efficient. However, this C-code is hidden from the user and the methods can be implemented by anyone familiar with the R language. This thesis can be extended in several ways for example, for multivariate data, for non-Gaussian first stage data, and for data observed in environmental monitoring of stream networks.

Under the current climate there is significant spatial variation in the yield and water-use of bioenergy crops such as poplar short rotation coppice (SRC). Marked changes in patterns of precipitation and temperature are predicted globally as a result of anthropogenic climate change. This is likely to significantly impact on the yield and transpiration of poplar SRC. The response of poplar SRC to future climate change is unknown and represents a significant knowledge gap in the path to a sustainable future. This thesis used a land-surface scheme, JULES, to investigate the response of poplar SRC yield and transpiration to the interaction between changes in atmospheric CO2 concentration and changes in climate. Empirical work generated poplar SRC specific parameter values for use JULES. It was found that Vmax, a key model photosynthetic parameter, was significantly lower when estimated under the assumption of infinite leaf internal conductance to CO2. This invalidated the assumption that internal CO2 transfer has a negligible impact on the drawdown of CO2 from ci to cc. The photosynthesis model in JULES is based on this assumption; however, inclusion of this additional CO2 transfer pathway in the model did not impact on the accuracy of the simulated carbon assimilation, because the value of Vmax used in the model compensated for the presence/absence of this pathway. It was concluded that, given the model’s high sensitivity to Vmax, it is essential to calibrate the model with a parameter value estimated under assumptions appropriate for the model. Further modification, calibration and validation enabled JULES to simulate the dynamic growth and water-use of poplar under a managed SRC cycle, which is a novel application for the model. Changes in climate were simulated using an ensemble of GCM anomalies and atmospheric CO2 concentration was simulated using the SRES A1B emissions scenario. Results of this work highlighted the influence of climate in modifying the yield and transpiration responses to elevated concentrations of atmospheric CO2. Additionally, for a future climate scenario, these simulations indicated higher yields but also higher water-use of poplar SRC, although the magnitude and direction of response was highly spatially variable.

Over the past decade within the renewable energy sector a strong research and development focus has resulted in the growth of an embryonic tidal stream energy industry. Previous assessments of the tidal stream resource appear to have neglected shallow tidal flows. This resource located in water depths of 10-30m is significant because it is generally more accessible for energy extraction than deeper offshore tidal sites and hence a good location for first generation tidal stream arrays or fences. The close proximity to shore may lead to improvements in construction feasibility and economic prospects. The objective of this project is to investigate several aspects concerning the exploitation of shallow tidal flows for energy extraction. Fundamental to this project is the importance of developing research alongside and in conjunction with industrial shallow water prototype projects. The key objectives are: (1) The development and understanding of the use of artificial flow constraint structures in the form of specifically-shaped foundations (herein described as “rampfoundations”) that constrain the flow leading to an increase in the magnitude and quality of power from marine current energy convertors (MCEC) operating in shallow tidal flows. (2) The investigation of seabed and free-surface proximity effects on the downstream wake structure of a MCEC. (3) Commercial shallow water device optimisation; utilising project results to aid with the design and development of full-scale commercial demonstrators. Through theoretical and scaled experimental modelling, and commercial collaboration the project has concluded ramp foundations could be utilised to locally increase tidal flow velocities and increase MCEC output across a tidal cycle in shallow flows. Predicted power benefits are in the region of 5-22% depending on lateral and vertical ramp channel blockage ratios. The ramp width or overall array width must therefore be tuned to the channel width to maximise power benefits. Rampfoundations will thus only be technically viable in relatively narrow channels or ideally in MCEC arrays or tidal fences. Results have shown that the downstream wake length is dependent on and varies with the vertical flow constraint and it is critical that the downstream array spacing of MCECs are tuned to the local flow depth. An optimum device height to flow depth ratio to minimise wake length has been identified. It is hoped that this ramp-foundation concept and the relationship between boundary proximity and wake length will continue to help with the development of a niche shallow tidal energy market

The standard model of headland formation assumes a coastline with discordant geology, where the less resistant rock is eroded at a higher rate than the more resistant geology. The indentation of the coastline will continue to increase until variations in wave energy due to refraction balance with the variation in rock strength and beach volume. On soft cliff coasts, where no systematic variations in cliff lithology or strength exist subtle headlands are still seen. Several examples of this can be seen on the southwest coast of the Isle of Wight, a coastline of complex interbedded soft rock lithology. Its relatively straight planform is punctuated by three established and one potentially emerging headland. All of these headlands are fronted by locally elevated intertidal shore platforms. It was hypothesised that these platform potentially act in three ways. Firstly by reducing the amount of wave energy reaching the cliff base, thus reducing local cliff recession rates. The second may counteract the first by increasing the wave energy directed at the cliff base due to refraction, the balance between these two effects will determine if a headland will grow, be maintained or decline. Thirdly by blocking longshore transport of beach sediment, building a protective beach up-drift, while starving the downdrift coast of sediment, potentially accelerating erosion in that area. To test these three possible mechanisms, investigation into the geological and geotechnical properties of the cliff and platform, beach volumes and sediment budget, wave refraction, and historical recession rates was undertaken. The elevation of the shore platform is controlled by their resistance to erosion, which is related to aspects of their lithology and structural geology. These include clay content, mass properties, dip and strike in relation to the orientation of the coastline and the strength of the surrounding beds. Although two of the established headlands, Hanover and Atherfield Points act as a partial barrier to sediment transport the sediment volumes along the coastline were insufficient to significantly influence recession rates. The results of the sediment budget indicate that the low sediment volumes observed are likely to have been consistent over time due to the low inputs of beach grade sediment. Wave refraction modelling revealed that concentration of wave energy occurs towards the established headlands of Hanover and Atherfield Points this is reflected in the higher than average recession rates seen at these headlands. It is concluded that the major control of the formation and evolution of headlands on the southwest coast is the geological and geotechnical properties of the intertidal platforms. Once established these headlands exist in a state of dynamic equilibrium controlled by the persistence of the platform forming beds and the balance between refraction and attenuation of wave energy across the platform surface. These results may have widespread implications on soft cliffed sediment-starved coasts where similar processes are dominant.

No description available.

According to current climate change predictions for the UK, summers are expected to become dryer and hotter in the future. This has potentially serious implications for overheating of naturally ventilated office buildings, many of which already fail to perform under current heatwave conditions. This thesis addresses the summer performance of such buildings under current and future climates by means of building performance simulation. Current industry standard weather datasets for building performance simulation are not however, suited to the assessment of the potential impacts of a changing climate. This work describes the integration of future climate scenarios into widely used weather file formats and critically assesses the resulting weather datasets. Simulations of a case study building at the University of Southampton highlight the potential impact of climate change on future summer overheating inside naturally ventilated buildings. The results of these simulations are compared to monitored data from the case study building during an extended heatwave period in the summer of 2006. It is shown that the present day performance of a naturally ventilated building under an extended heatwave period can give an indication of its likely performance during a projected typical hot summer in the 2050’s under a medium-high emissions scenario. A second case study building serves to highlight that building designs and building services solutions which are suitable for retaining acceptable indoor comfort levels during current heatwave periods, are likely to be suitable to alleviate summer overheating under the predicted warmer future climates. Further simulations, encompassing various locations throughout the UK emphasize the need for timely refurbishment of naturally ventilated office buildings within the next few decades to avoid increasing numbers of existing buildings failing to perform under the predicted future summer conditions.