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The Antarctic Peninsula (AP) is one of the fastest-warming regions on Earth. To assess whether this warming is part of the natural variability in the climate system, palaeoclimate archives are used to document the character of past climate changes and constrain predictions for the future. This investigation integrates a suite of radiocarbon dated marine sediment records from the continental shelf of the AP to provide a critical assessment of the distribution, timing, magnitude and forcing of Holocene climatic events. Sedimentary logs, diatom assemblages, stable isotopes and pigments were used as proxies to reconstruct AP ice sheet retreat, fluctuations in sea ice extent, changes in water mass circulation and ice shelf collapse events. This has revealed the spatial and temporal heterogeneity of climate events through the Holocene. The marine environment of the western AP (WAP) experienced deglaciation onset of the Mid Holocene climatic optimum and climatic deterioration into the Late Holocene considerably earlier than the marine environment of the eastern AP (EAP) and AP terrestrial records. These differences suggest that the climate of the WAP has been more closely connected with the SE Pacific, through coupled ocean-atmosphere interactions (such as the position of Southern Westerlies and El Nino Southern Oscillation frequency), whereas the EAP displayed a closer affinity with AP terrestrial records and the cryospheric influences of the Weddell Sea. This investigation has emphasised the complexity of the climate system of the AP on a range of spatial and temporal scales and highlighted that no single record can adequately represent regional palaeoclimate records must be developed from the oceans and continents and then interpreted as an assemblage.

Measurements of Atmospheric Electricity have been made in the unpolluted air of Weardale during conditions of precipitation and in fair weather. An automatic recording system has been built to digitize instrument outputs on paper-tape for subsequent computer analysis. The system ivas installed and run at Lanehead Field Centre and was also used to process magnetic tape recordings from the LandRover mobile station. The system was expanded to include an 1-hour smoothing and sampling action for recording aveiaged values of fair weather Atmospheric Electricity. At times of electrically quiet precipitation, measurements have been made of potential gradient, precipitation current density, space charge density and both polar conductivities. A new method of compensation for displacement currents has been used. Conductivity measurements have revealed a charge separation process close to the ground in rain, but not in snow. Techniques of variance spectrum analysis have been adopted for the precipitation work. Coherency spectra of potential gradient with precipitation current have indicated electrical 'cells' in nimbostratus and their relevance to weather forecasting is discussed. The phase spectra for these two parameters have been examined to measure the height of electrical activity and this is found to coincide with the melting level, and an estimate is made of the conductivity of the charging region of the cloud. Digital filtering of records has disclosed a mechanical-transfer current of space charges, to an exposed rain receiver, opposite to the precipitation current. The diurnal variation of potential gradient at Lanehead has been refined with a further year's continuous observations in fair weather and seasonal differences in the diurnal variations of potential gradient, air- earth -current density and space charge density have been explained by increased convection in summer. The conduction current has been estimated, by the indirect method and the difference between this and the total air-earth current to an exposed plate is attributed to a mechanical-transfer current of space charges. Measurements in light winds have evinced the influence of the electrode effect.

Simultaneous records of precipitation current density, potential gradient and wind speed have been obtained with mobile equipment mounted on a Land-Rover and with fixed equipment located at a field station in the Pennines. Measurements were made in quiet precipitation with the two sets of equipment separated by horizontal distances of up to 8 km in a direction in line with the cloud movement. Maximum cross-correlation between the precipitation current density records at the two stations was usually for time lags corresponding to the time of travel of the clouds between the stations. On one occasion of low wind speed, simultaneous precipitation current correlation was obtained at the two stations when separated by 5 km. It was deduced that the time variations of electrical parameters observed at a ground station would normally be the result of movement of the cloud system rather than its electrical development. Analysis of the effects of wind speed has shown that rain electrification is more intense at sites more exposed to the wind and that the effects may be due to a process operating from ground level up to a height of several hundred metres. The persistence of potential gradient and of precipitation current density has been shown to be inversely proportional to cloud speed. The horizontal dimensions of cloud across which persistence exists at a given point in time has been shown to be independent of wind speed and to be of the order of several kilometres. It is suggested that these dimensions may be a characteristic of cloud type and may be used as a criterion for their identification. A theoretical model to explain the electrical structure of nimbostratus clouds has been proposed, and it has been shown to be consistent with observations. The model satisfactorily explains the inverse relation between precipitation current density and potential gradient and it explains observed differences in phase between precipitation current-time and potential gradient-time curves in terms of the periodicity of the electrical changes within the cloud.

The charges and masses of individual raindrops were measured in different conditions of rainfall at two different sites. An apparatus was developed to measure raindrop parameters and display their values in the form of a spot whose vertical and horizontal positions on an oscilloscope screen represent the mass and charge respectively. Photographic records, each of a number of successive spots, were made for periods of between half-a-minute and twenty-five minutes during twenty-four separate periods of rainfall which covered many meteorological conditions between thunderstorms and fine drizzle. The photographic results are analysed in terms of the weather conditions applying at the times of measurement. It is shown that stratus and cumulus clouds produce distinct charge/mass patterns on the exposures, and that these patterns can be related to known factors about the nature of the different clouds. The methods of charge measurement by electrostatic induction, and of mass measurement by registering the impacts of drops- on to a detector plate are described. Suggestions are made for future work and improvements to the equipment.

Fine weather ionic conduction and convection currents near the Earth's surface have been studied. Air-earth current density, potential gradient, electric space char^ density, number density of ions of either sign have been measured. It has been confirmed that raised earthed antennas can also be used for air-earth current measurements. Air-earth current measurements with a wire and a plate antenna, show- that within the first few metres of the atmosphere the transfer of electric space charge by moving air masses produces currents comparable to the conduction current. The term 'advection current' has been used to denote those currents produced by the horizontal movements of air masses containing electric space charge. An experiment performed in a low-speed wind tunnel shows that ions in moving air streams are not likely to be controlled by potential gradients less than 1000 V m"\Electric space charge measurements show pulses lasting about a-5minute. They usually lie between 10 and 20 pCm(^-3). A qualitative explanation is given by solving the continuity equation. A theoretical account of the movement of ions in the atmosphere is also given. Analysis of the measured parameters using a computer programme suggests the existence of a layer of positive space charge, a few millimetres thick, close to the Earth's surface. Occurrence of extensive air showers has been recorded to see if there is any unobserved relationship with atmospheric electric elements. Measurements did not show much evidence; however, these are by no means conclusive. Simple calculation shows that only showers corresponding to primary energies of 10(^19)eV or 10(^20) eV can give measurable changes in the air-earth current density. The difficulties of measuring separately the two components of the conduction current by the direct method at any point above the Earth's surface is also discussed.

The thesis is based on research carried out in Sierra Leone over a period of several years. An asymmetric field mill and a 'wide-angle' shielded receiver have been developed for the measurement of electric field and precipitation current in tropical thunderstorms. A detailed field-mill theory is presented which analyses the effects of leakage currents, inadequate grounding, contact potentials, conduction current, 'pick-up' of fluctuating electric fields and noise in the amplifier. Principles are deduced for the optimum design of a precision field mill using either a phase sensitive detector or an asymmetric signal. Measurements of precipitation current and its response to step changes in the field show that turbulent diffusion of splash droplets probably constitutes an important, even dominant, electrical process in heavy rain. The response of precipitation current to a lightning flash, averaged over many flashes, is large and has a delay of a few seconds. From the analysis of various models considered as a mechanism to explain the results it is deduced that charge carried on splash droplets is being diffused upwards by turbulence, transported by wind and is itself precipitating into the rain receiver. An experiment was performed to measure the electric current due to evaporation. The results show that the current due to evaporation in the presence of an electric field is much smaller than that due to conduction in air. The observation of a 'warm' thunderstorm cloud is reported. A project was developed to make visual and electrical measurements simultaneously on the same cloud. A time lapse film of tropical clouds, together with some electric field measurements beneath them, are used to discuss the flow pattern associated with a tropical thunderstorm and the mechanism by which it becomes charged. Appendices include an analysis of the shielding effect of a vertical rod at ground potential, the description of some further instrumentation, including a data processing system designed by the author which uses a novel but effective method of detecting the occurrence of the peak of a signal, more detailed mathematical derivations of equations used in the main text and a filming schedule for the time-lapse photography.

An attempt has been made to see whether there is a basic charge separation process which operates between ice and water when they are moving relative to one another. Measurements have also been made on the potential differences produced between ice and water under a variety of different conditions and the effect on the potential differences of having air bubbles within the ice/water interface has been studied. Apparatus is described for the measurement of the electrical effects on freezing and melting bulk samples of water. No evidence has been found for a charge separation process which operates only when water moves relative to ice at the freezing point However, the results show that at freezing rates of 10 µm s(^-1) and above that the mechanism proposed by Workman and Reynolds (1950) is responsible for the majority of the net charge separated, whereas, at very low freezing rates or on melting, the Temperature Gradient Mechanism, proposed by Latham and Mason(1961) predominates. The relevance of the electrification of ice and water to the origin of electrical charges in clouds is discussed, and explanations of the results of earlier work on simulations of conditions in clouds are put forward, in the light of the results obtained during the experiments with bulk water samples.

Investigations of the current from an earth-connected point 0.002 cm in diameter, supported by masts at heights of 20m, 27m end 34m are described. Simultaneous measurements of the potential gradient at the ground to windward of the point, and wind speed at the point, indicate that the current can be represented by the equation I = K(W + C) (F - M) where I is the point discharge current in mioroamps W the wind speed in metres per second F the potential gradient in volts per metre M the onset value of the potential gradient (200 v/m at 20m, 135 v/m at 27m, l00 v/m at 34m) C and K are constants (C = 4 m/s and K = 2.56 x 10(^-4)µa per v/m per m/s at 27m) The general equation still holds when the potential gradient is measured 7m below the 34m mast but at 2m below the 20m point the equation is I = A(W + D) (F - M)(^n) where A and D are constants is dependent on wind speed. Measurements of point discharge currents down the trunk of a tree indicate that these are somewhat lower than those through a single point of corresponding height in similar conditions. The results are compared with those of previous workers and discrepancies are attributed to wind speed and wind direction effects, whilst good agreement is found between the present findings and the theoretical work of Chalmers and Mapleson (1955) and Chapman (1956). A reassessment of the Alti-Electrograph results of Simpson and scrase (1937) is made and suggests that the potential gradients measured by this means immediately below thunderclouds are of the earns order of magnitude as those measured by observers in aircraft (Gunnl953).

The principal aim of this thesis is to reconstruct East Asian Monsoon (EAM) variability during the mid-Holocene, developing a relatively new proxy of bulk organic carbon isotopic signature (δ13C). C/N ratios and trace elements are also employed to conduct a multi-proxy case study from the Pearl River estuary, southern China. Sources of sediments within an estuary include river-derived terrestrial/freshwater input, in situ brackish-water suspended sediment and tide-derived marine input. This study assumes the three proxies can help differentiate sources of sediments relating to monsoon-driven freshwater flux and help reconstruct monsoonal precipitation history during the mid-Holocene when the sea level was relatively stable. To achieve the aims of this thesis a range of modern samples were collected from terrestrial areas, including plants and soil samples, through to estuarine areas, including seasonal estuarine suspended organic matter (SOM) and surface sediment. Results suggest that bulk organic δ13C and C/N ratios can successfully identify sources of the organic component of the estuarine sediment, and thus can be used to infer relative changes in monsoon-driven freshwater flux to the estuary. For example, more negative δ13C values reflect a greater level of contribution of freshwater organic carbon, i.e. stronger monsoonal freshwater discharge. Results also show that a combination of selected metals, such as the terrigenous metals (Fe, Mn, Co and As), can be useful for indicating sediment sources and sedimentary environment. Analysis of an estuarine core (UV1) shows that freshwater discharge from the Pearl River catchment gradually declined from 6400 to 2000 cal. years BP, suggesting a gradual weakening of summer monsoon precipitation, responding to the weakening insolation controlled by the orbital-driven precession cycle. Superimposed on this are wet/dry intervals, ranging from centennial- to millennial- scale, driven by solar activity. Changes in ENSO and high-latitude cooling events might be responsible for dry/wet events at centennial- to decadal- scale, identified during the mid-Holocene. This study also suggests that the coupling of thermal and moist conditions of the EAM might only have become stable after 4500 cal. yr BP. A sudden shift in the geochemical signature indicates agricultural activity in the Pearl River delta intensified from 2000 cal. yr BP.