This thesis examines the variability of the Hadley Circulation in the north-west Atlantic (NWAHC) and links with precipitation over Trinidad and the Tropical North-West Atlantic (TNWA), and representation by climate model simulations. Variability of the NWAHC is investigated in the ERA-Interim reanalysis dataset and the HadGEM2 climate modeL Precipitation is assessed using satellite and gauge-based observations, including the Trinidad gauge network, the ERA-Interim reanalysis and HadGEM2 climate model. Analyses of the recent variability of the NWAHC in the HadGEM2 simulations indicate an overestimation of intensity by up to -10x1010 kg/so There is anomalous southward displacement of the equatorward edge with concomitant anomalous widths in the model, by up to -12°. The reanalysis precipitation is excessive, simulating around twice as much precipitation as the observations during both the wet season Gune to December) and dry season Ganuary to May), throughout the Tl\.'WA. Interannual precipitation variability is influenced by SST anomalies in the tropical Atlantic (TA) and Equatorial Eastern Pacific (EEP), which produce changes in the atmospheric circulation. In the EEP positive SST anomalies result in precipitation decreases during both seasons in the TNWA. Positive SST anomalies in the west TA and the north TA result in precipitation increases in the CAR and SCA region. A relationship, consistent across all the datasets, was found between the location of the March-April-May (MAM) West-Atlantic Intertropical Convergence Zone (WAlTCZ) and precipitation patterns during the dry season in the CAR and SCA regions, where northward movement of the WAITCZ results in precipitation increases. In comparison to observations, the HadGEM2 model simulates excessive precipitation in the CAR region by up to 80% and underestimates precipitation by up to 50% in the SCA region. For Trinidad, dry season precipitation in the model is underestimated by up to 90% in comparison to gauge observations, however, interannual variability has a correlation of 0.6, whereas during the wet season interannual variability has a low correlation of 0.2. For HadGEM2 projections of the NWAHC over the period 2070-2099, there is a weakening in December to August by -5x1010 kg/s and a strengthening in September to November by -10x1010 kg/s. This is associated with a projected decline in precipitation for the SCA, CAR and over Trinidad by 8%, 23%, 18% during the wet season and 10%,22% 33% during the dry season.

This thesis explores the potential application of subseasonal weather forecasts for the energy industry. Power contracts that energy companies buy and sell are subject to price and volume risk. A significant component of these risks is driven by weather variability. Accurate weather forecasts can help increase profits whilst reducing price and volume risk. However, meteorological research to date (in relation to the energy sector) has focused on forecasting up to 10 days ahead, as weather forecasts were traditionally considered to have limited to no skill thereafter. The aim of this research is therefore to show that meteorological forecasts can be used to make quantitative skillful predictions that can reduce risk within the energy sector at the subseasonal timescale. Although there is a large body of literature using NWP model output at lead times up to 10 days, there appears to be no prior research investigating the potential for subseasonal weather forecasts on the energy sector. A three step process was pursued in order to achieve this. Firstly, the forecast skill of wind speed and temperature (two key meteorological variables for the energy industry) was evaluated. Then wind power, demand and power price models were developed allowing the explicit incorporation of weather into the power price. This allowed quantification of the weather related skill and impacts on the power price and subsequent evaluation of applications that are contingent on the power price. These applications were evaluated using the forecasts to inform trading strategies in an effort to increase profits and reduce risk. The first section of research demonstrates that there is forecast skill of wind speed and temperature within the ECMWF monthly forecast model up to week 3 weeks ahead (Le. a weekly average over a lead time of day 14-21). The ECMWF model demonstrated cor¬relations of approximately 0.6 for the operational forecast and 0.3 for the hindcasts when forecasting week 3 UK winds speeds. Similar results were found for temperatures. By using the weather information from the ECMWF monthly forecast, skillful predictions of UK wind power, demand and electricity price were obtained for week 3 during the winter period over the years 2008 to 2014. Anomaly correlations in the range of 0.5-0.6 and CRPS skill scores of 0.10-0.16 were obtained for all three of these variables when comparing the subseasonal forecast with a forecast based on climatological weather in¬formation. The added value of using the subseasonal weather forecast information for a number of trading strategies was evaluated. A speculative trading strategy using the subseasonal weather forecast to value futures contracts demonstrated that positive re¬turns were achieved when systematically trading over 5 winters. When choosing the volume of power to buy in order to hedge retail demand risk, it was found that in some instances the subseasonal forecast outperforms the version using climatological weather to hedge the risk. The final conclusion is that skillful subseasonal forecasts of the meteorological variables exist and this skill propagates through to the energy system variables (wind power, demand and price) which should allow a range applications within the energy sector to potentially reduce risk.

This thesis is concerned with the effects of climate change on ocean heat content in recent decades and the 21st century. We examine whether significant changes in ocean temperature can be detected in recent decades and attributed to anthropogenic or other factors, and we consider the recent and future pattern of sea level change due to ocean density change, which is dominated by temperature change. We compare ocean temperature change for 1960-2005 in four observational datasets and in historical simulations by atmosphere-ocean general circulation models (AOGCMs) from the Coupled Model Intercomparison Project phase 5 (CM1P5). Observations and CMIP5 models show that the upper 2000m have warmed and the signal gradually propagates to deeper layers over time with a defined geographical pattern determined by the regional processes of ocean heat uptake. Greenhouse gas forcing has contributed most to increase the temperature of the ocean which has been offset by anthropogenic aerosols, and volcanic eruptions cause episodic cooling. Using optimal fingerprinting, we show that observed changes may be attributed to greenhouse-gas, other anthropogenic and natural (mainly volcanic) forcings, with all three of these being detectable. Multi-model mean fingerprints are constructed using the time-depth structure of the warming by considering multiple depth levels, which decreases the uncertainty of the results. Limiting the observations and model fields to locations where there are observations benefits the detection of signals. By comparison of historical and pre-industrial control simulations using the AOGCMs of the CMIP5 project, we conclude that the observed geographical pattern for 1993-2012 of sea level change due to ocean dynamics and density changes is generally dominated by unforced (internal generated) variability, although some regions, especially in the Southern Ocean, may already show an externally forced response. Applying the method of pattern scaling to projections of sea level change we show that it gives accurate estimates of future local sea level change in response to anthropogenic forcing as simulated by the AOGCMs under RCP scenarios, and determine that the forced signal will be detectable above the noise of unforced internal variability within the next decade globally and may already be detectable in the tropical Atlantic. This work points to the need to continue developing AOGCMs in order to improve their simulations of past ocean temperature and sea level change and reduce their uncertainty in projections of the future.

TCs have caused death and great economic loss every year across the coastal area of the western North Pacific (WNP). Therefore it is important to improve the understanding of the climatology of TCs over this region and their modulation by natural climate variability and large-scale circulation systems. It is also important to improve our ability to predict possible changes in TC activity over the WNP under climate change conditions. The most appropriate approach to study this is to use numerical models. However, high model resolution is required to resolve the complex physical structure of TCs so that realistic climatologies of TCs can be produced. In this thesis, regional climate model (RCM) simulations, from the Unified Model of the UK Met Office (MetUM) with resolutions of 25 and 12km and two different dynamical cores, are used to project the future change in TC activity over Vietnam, Philippines and the South China Sea (SCS). These simulations are driven by data from the ERA-Interim reanalysis for the period 1990-2005 and the HadGEM2-ES global climate model covering the historical period (1961-2005) and a future period (2069-2099) under two IPCC greenhouse gas emission scenarios (RCP4.5 and RCP8.5) to investigate the impact of anthropogenic warming on TCs in the study region. An objective algorithm is used to identify and track the simulated TCs. First, the ability of the RCM to simulate TCs and their associated large-scale environments, for a current climate period of 1990-2005, with different model resolutions is evaluated. For the period of 1961-2005, the downscaled HadGEM2-ES simulations are also used to evaluate the model's ability to reproduce the modulation of TC activity associated with El Nino/Southern Oscillation (ENSO). Both the 25 km and 12 km models can reasonably simulate the TC activity over the SCS compared with the observed TCs. The associated large-scale environments are found to be simulated correctly compared with the ERA-Interim reanalysis. The observed weakened TC activity during El Nino events is also captured by the downscaled HadGEM2-ES. Compared with the 25 km model, the 12 km model has a better ability to simulate the large-scale environments and generally improves the simulation of the spatial distribution and structure of TCs. Improved simulated TC-ENSO response (in terms of TC frequency, track density, intensity, structure and associated large-scale environments) is also found in the 12 km model. However, the 12 km model does not produce stronger 10-m maximum wind speeds of TCs compared with the 25km model. For the projections towards the end of the 21st century, the downscaled HadGEM2-ES at both 25 km and 12 km resolution present an insignificant decrease in TC frequency with rates of -0.001 per year and -0.007 per year for RCP4.5 and RCP8.5 respectively. The Had2-25km projection shows a more than 3% increase of the intense (10 m wind speed >35 mS-1) TCs over the South China Sea, while weak TCs (wind speed >25 ms-1) decrease by 10% under RCP8.5. Also, both the RCMs simulate a seasonal shift of TC activity in a warming climate, with an increase in TCs during winter related to the more favourable large-scale conditions and a decrease in TCs is projected in summer.

Anthropogenic emissions of greenhouse gases and aerosols have led to climate change including changes in surface temperature and precipitation. The surface temperature response is better understood than the precipitation response as a result of observed data availability and the complexity of the physics governing hydrological cycle changes. The complex general climate models (GeMs) are computationally demanding and include many physical processes that contribute to the changing water cycle. It remains necessary to understand the main drivers of this change. In this thesis, the main aim is to understand the water cycle changes by examining the degree to which simple models can simulate global-average results emerging from GeMs. For this purpose, a simple atmospheric energy budget model is used to calculate the global mean precipitation changes for the historical period and future scenarios. The results are then compared with GeMs to understand the physical processes affecting the global precipitation changes. The original form of the simple atmospheric energy budget model does not take into account many different factors included in GeMs, such as regional temperature and precipitation changes, fast surface sensible heat flux changes, fast precipitation response of volcanic aerosols and inter-annual variability. This work examines whether it is possible to extend the simple model to include some of these factors or compare the idealised experiments with the results of complex models (Wu et al. 2010). The simple model does well in producing the total global precipitation anomalies compared with GeMs multi-model mean consistent with earlier studies. The results of the simple model for individual GeMs are in less good agreement and different reasons for this disagreement have been investigated. Substituting the temperature changes from each GeM and also normalising the radiative forcings of simple model to the adjusted GeM RFs lead to an increase in compatibility between the simple model and GeMs, indicating that the main differences are related to the temperature equation and RFs. Adding the fast response of volcanic aerosols also increased the correlation between the simple model and GeMs particularly in volcanic years. Using new results from (Precipitation Driver Response Model Intercomparison Project) PDRMIP, the effect of fast surface sensible heat changes has been investigated which shows a considerable contribution to atmospheric energy budget changes particularly for aerosols. The simple model has been modified by adding the fast sensible heat changes which leads to a small improvement in the simple model; however it is not possible to be certain how robust this improvement is. More data and more work is still required but generally it is concluded that the simple model performs well compared with complex models.

The primary cosmic ray electron flux has boon measured with a system composed of a cerenkov telescope and a scintillation detector separated by lead absorber. The sensitive energy range of the instrument was between 25 and 800 Mev.. A preliminary measurement with a modified detector has investigated the differential energy spectrum of the primary electrons. The results are taken from high altitude balloon flights which achieved a maximum altitude in excess of 5 gm/cm2. of residual atmosphere. Flights were made from Kiruna, Sweden (geomagnetic latitude 65°N) and Cardington, England (geomagnetic latitude 50°N) between 1964 and 1966. The flights at the lower latitude were used to correct those at the higher latitude for the influence of atmospheric secondary electrons. The Kiruna flights were also corrected independently using a theoretical estimate of the secondary flux.

This thesis explores how and by whom climate change is written. Although climate change has the potential to impact all ways of life, not all have the power to determine its meaning. In order to identify the actors with the symbolic power to name climate change, the basis of this authority and the activities through which shared environmental problems are named, this thesis examines one of the central sites of meaning production: the Intergovernmental Panel on Climate Change (IPCC). Deploying the sociological approach and thinking tools of Pierre Bourdieu, the IPCC is positioned at the centre of the international political struggle over climate change. It is from within this social location that the thesis re-constructs the actors, activities and forms of authority constituting the IPCC’s assessments of climate change as a practice of writing. In order to determine the forces structuring the IPCC’s writing of climate change the thesis identifies the actors that make up the organisation and follows the assessment report along the pathway of its formation. Documenting the report’s construction from the panel’s decision to repeat the assessment process to government approval of the final product reveals the interrelationship and reinforcing nature of scientific, political, economic, and organisational order in the IPCC’s assessment activities. As a result of these forces and the actors they empower, the meaning of climate change is being written in and through the order that generated the problem.

This thesis is a critique of the technological optimism of climate change economics, the basis for climate change policies world-wide. It utilises a Foucauldian genealogy – a form of critique that deploys history strategically – to show how the “truth” of the present was produced under very particular circumstances, circumstances not at all in conformity with the notion of progressive, scientific discovery. Using this methodology, I am able to chart the process by which economists became experts on technological change. I show how, in Adam Smith, technological change first became predictable, and locate the cause in Smith’s pantheistic theology. The subject Smith creates, homo oeconomicus, is rendered entirely knowable, as is her ingenuity. She acts in ways uniformly predictable and positive, as long as she is left free from government interference. This motors the vision of harmonious progress that thereafter becomes the rationality of the discipline, what I call negative progress. Moreover, it is this subject, translated into two growth theories, that lies at the heart of climate change economics. The major conclusions and contributions of the thesis are, firstly, that an underlying metaphysics is in fact what allows economists to speak “truth” about the future of technological change; and secondly, that the optimism of the resulting projections is made possible only as a result of the divine essence at the heart of economic man.

Weather observations form a crucial part of meteorological forecasts and are also used as input to climate models and for monitoring long-term climate trends and changes. But coverage at sea is much less dense spatially and temporally, especially at high latitudes. Passive underwater acoustics has been established for several decades as a good and reliable tool to monitor the weather. The frequency spectra of different weather types have been well documented and acoustic disdrometers have been developed in several research environments. Nevertheless, many questions remain about the validity of some of these measurements, the best analysis approaches and the combination of different weather processes. This is particularly true in polar regions, where the loud and complex acoustics of ice-related processes adds to the difficulty of the task. This thesis focuses on the analysis of a broadband dataset acquired in an Arctic fjord (Kongsfjord, Svalbard), in summer 2007. Taken at 6 locations from the mouth of the fjord to the glaciers at its termination, measurements cover the combination of varying levels of rain (from none to light rain), wind (from none to 11 km/h), ice (from none to growlers and bergy bits), shipping (from none to a large cruise ship) and animal activity (including whales and diving seabirds). The recordings covered frequencies from 100 Hz to 48 kHz. Principal-Components Analysis identified 3 distinct frequency bands mostly related to noise from wind, rain and ice. Laboratory-based tank experiments were conducted to assess the physical sources of these components (from 100 Hz to 100 kHz), confirming the acoustic role of ice and the relevance of the frequency bands identified by Principal-Component Analysis. These experiments also identified for the first time the role of higher (up to 45 kHz) acoustic frequencies in the identification of ice-related processes such as scraping, colliding and melting. Principal-Component Analysis is shown to be a valuable and rigorous tool for identifying weather processes at sea, especially in complex combinations of wind, rain, ice and other factors. Analyses at frequencies higher than generally used also offer the potential of identifying specific processes associated to the melting of glaciers and icebergs. This has paved the way for field measurements at glaciers around Svalbard in summer 2009. The approach presented here is now considered by the Meteorological Office (UK) for inclusion on operational present-weather sensors attached to moored or drifting buoys in polar and high-latitude regions in general.

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