The polar vortex is a large scale cyclone located in the middle atmosphere near to the planet’s geographic poles. These vortices form during the hemispheric winter and break down in the spring of the following year. They may also break down in mid winter, causing a sudden stratospheric warming event (SSW). The vortex is thought to be preconditioned leading up to these warming events, resulting in the breakdown of the vortex. Integral diagnostics are used to investigate the stripping of air from the vortex as part of this preconditioning. Contour diagnostics of mass and circulation are calculated using ERA-40 reanalysis data for the stratosphere. The edge of the vortex is easily identifiable in these diagnostics as a high gradient of Ertel’s potential vorticity (PV), and the warming events are also clearly visible. From these the amount of air removed from the vortex is determined from the balance equation of the mass integral. These terms show that there are significant amounts of air removed from the vortex, with several stripping events identifiable in them through the winter, especially in those during which a major sudden warming event occurred. These stripping events can be seen in corresponding PV maps, where tongues of PV can be seen to be stripped from the vortex and mixed into the surrounding surf zone of turbulent air. From the integral diagnostics a Lagrangian measure of the meridional circulation in the stratosphere is also calculated. In the final part of the thesis a shallow water model is used to investigate a quantitative link between forcing and the amount of stripping of the vortex. It is found that when the forcing is large enough there is significant stripping of mass from the vortex. This does not lead to SSWs in all cases, and the total amount of stripping is not found to be proportional to the maximum amplitude of the forcing.

Concerns regarding climate change are becoming a driver behind legislation at both UK and EU levels, and also on the wider, planetary scale. This is the case with emissions from landfills where the release of methane is being targeted for reduction. This thesis uses an integrative approach, incorporating concepts of hierarchy from systems theory, to model landfill as a complex biophysical technology. It assesses the contribution to carbon deposition and global warming of landfill through changes to that technology itself and through changes in the waste stream caused by potential waste policies. The thesis develops an holistic, conceptual model of the landfill system, mapping flows and transformations of carbon within that system. It further develops this conceptual model into a calculating model of landfill as a waste management technology incorporating measurements taken to provide new data and validate published data to calibrate the model. It thus applies modelling techniques to a biophysical technology, producing an integrated model of the landfill that allows the knowledge gained from other research to be used to explore engineering and operational decisions on landfills. The thesis includes results from measurements of the composition of household waste, and of the biochemical methane potential (BMP) of fractions of that waste. It includes measurements of the residual BMP in samples of excavated waste and measurements of gas flows. The main results suggest the following: • Early capping of landfilled waste is important in reducing the global warming impact; • If the rate of degradation of the waste is accelerated in the drive towards sustainability, capping should be carried out even earlier if the global impact is not to be increased; • Although recycling parts of the degradable elements of the waste stream has the effect of reducing the global impact, extensive recycling has implications for landfill engineering.

Thesis advisor: Jeremy Shakun / As recently measured amounts of global atmospheric carbon dioxide concentrations have risen 40% from pre-Industrial levels and will likely reach double by mid-century, climate scientists have expressed concern over the future state of the climate system, and have attempted to gauge the consequences of such a large forcing. The principal parameter for climate scientists is equilibrium climate sensitivity, which is the change in temperature following a doubling of atmospheric CO2 concentrations. Current estimates of climate sensitivity span too expansive of a range to provide a clear understanding of the magnitude of temperature changes one can expect. Therefore, I conduct many individual multivariate analyses as a means of narrowing these ranges of sensitivity and to investigate geographical distributions of sensitivity, at the very least. To do so, I analyze four major climate forcings: greenhouse gas, atmospheric dust, ice volume, and insolation. Using several multiple linear regressions, I calculate the relative weighting of each forcing in driving the temperature signal in 47 local temperature proxy records. The paleoclimate proxy records chosen span glacial cycles over the past 800 kyr. These results provide insight into the geographical distributions of the relative influences of each of the forcings, while working to constrain the range of sensitivity estimates through the weighting of the greenhouse gas forcing. Separating out the individual climate inputs allows me to conclude what percentage of climate change was caused by CO2 in the past, and by implication how much warming might be expected due to GHG forcing in the future. / Thesis (BS) — Boston College, 2015. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

Brown algae are an important group of organisms inhabiting coastal ecosystems worldwide. Because of their sessile nature, they are exposed to natural abiotic stresses such as high and low irradiances, desiccation, thermal fluctuations and mechanical stress, as well as anthropogenic-derived stresses such as chemical pollution. While the impacts of metal pollution affect brown algae on a local scale, there is growing concern on the potential interactions between pollutants and abiotic pressures resulting from global climate change. The main objective of this study was to determine the nature of the interactions (synergistic, additive or antagonistic) of different concentrations of copper in combination with increased temperatures in controlled laboratory experiments using the model brown alga Ectocarpus siliculosus as a proxy for brown seaweeds, which are globally important primary producers and bioengineers of near-shore waters. The responses in E. siliculosus were evaluated at different levels of biological organisation. At the whole organism level Cu or temperature affected growth but no interactions occurred. Antagonistic interactions occurred between stressors in the photosynthetic efficiency response (measured as chlorophyll a fluorescence), being less affected by Cu at higher temperatures. The bioaccumulation of Cu ions showed and antagonistic response to temperature as less Cu ions were accumulated at elevated temperature. The concentrations of H2O2 and lipid peroxides (TBARS), which are indicators of oxidative stress, were synergistically affected by interactions of stressors. In contrast, the concentrations of antioxidants ascorbate and glutathione reflected both additive and antagonistic interactions respectively. This also occurred in the activity of antioxidant 8 enzymes (superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase) and the expression of related genes. Finally, the results of the biochemical and physiological tests were integrated with the whole transcriptome response to temperature and Cu stress. These results showed that interactions between temperatures and Cu stress could be highly complex, but also lead to the discovery of potential stress markers such as light harvesting complex proteins and several transporters. This research provides new insights into the responses of brown macroalgae to metal and thermal stress. Those responses indicate that synergistic or antagonistic interactions can occur at different levels of organisation, being the regulation of antioxidant metabolism, photosynthetic physiology and related gene expression, the most important mechanisms involved. This information will aid to understand potential effects of climate change on the toxicity of metals for macroalgae in estuaries and coasts affected by pollution.

This thesis provides highlights of the atmospheric research conducted during the program of studies 2003-07. The theme is variability of the winds at mesospheric heights (60-100 km) due to Planetary Waves (PW, 2-30 days) over middle and high latitudes. Considerable energy and momentum are transported by atmospheric waves, and their global characteristics are required to understand many phenomena and explain coupling processes within the atmosphere. The vertical propagation of PW from the upper troposphere to the mesosphere is investigated by applying the Morlet wavelet and wave number analysis to the MetO (United Kingdom Meteorological Office) stratospheric assimilated fields, TOMS total (column) ozone, and Medium Frequency (MFR) and Meteor Wind (MWR) radar measurements. The results show that large-scale eastward propagating PW dominate at tropopause and low stratospheric heights, while westward PW become comparable or even stronger in the upper stratosphere and above during months other than summer. There are also strong seasonal dependences of the PW activity in each of the stratospheric and mesospheric regions, which are attributed, at least partially, to the influence of the background wind on PW propagation. Longitudinal variations in PW activity are explained by longitudinal variations in these winds.<p>During summer (westward zonal winds) PW activity is reduced in the stratosphere and only relatively fast westward propagating PW, such as quasi 2-day wave (Q2DW), are able to reach mesospheric heights from below. The results obtained using 14 years of MFR data at Saskatoon provide a unique climatology (70-100 km) of this wave: in addition to summer activity the Q2DW is also present at low mesospheric heights in winter, especially when the eastward winds are weak; there are significant interannual variations in Q2DW activity in both seasons. Strong latitudinal and longitudinal differences in Q2DW occurrence and amplitude are shown from the comparisons of wind data at several stations.<p>During winter, when zonal winds are eastward, the PW coupling between stratosphere and mesosphere is stronger than during other seasons. Detailed data analysis has been performed for the Arctic winter of 2004/05, for which the stratospheric state is described using conventional zonal mean parameters as well as the newer Q-diagnostic. Spectral analyses for this winter show relatively weak PW activity at stratospheric and mesospheric heights and strong latitudinal and longitudinal differences of mean winds and PW characteristics consistent with the form and location of the polar vortex. <p>In addition to the vertical coupling it has also been shown that weaker horizontal inter-hemispheric coupling occurs during equinoctial months, when eastward winds dominate globally. It is demonstrated that with favorable conditions, planetary waves with 10, 16 and 25 day periods penetrate to the opposite hemisphere.

This study investigates how the estimated thickening of the active layer will affectthe soil organic carbon in permafrost soils. The focus lies on estimating how muchof the upper permafrost soil organic carbon will be affected by the active layerdeepening due to global warming, on what timescale the deepening will take placeand if the estimated changes differ depending on the extent of permafrost in theregion. A model made in a Geographic Information System (GIS) combines datasetsfrom The Northern Circumpolar Soil Carbon Database, field data of soil organiccarbon content (SOCC) in different permafrost soil horizons in the Usa basin anddata of recent and future active layer depth from a spatially distributed permafrostdynamics model in the Pechora River Basin. The model shows that in 1980, 75% ofthe available 0–100 cm Gelisol soil organic carbon mass (SOCM) has affected byseasonal thawing. In 2050 the proportion is increased to 86% and by 2090 almostthe whole study area has an active layer deeper than 1 meter (98%). This indicatesan increase from approximately 0.64% to 0.84% of the total 1–100 cm SOCM in thenorthern permafrost region. The change is more gradual in the isolated and thesporadic permafrost zones and more abrupt in the continuous and discontinuous regions.

This thesis provides highlights of the atmospheric research conducted during the program of studies 2003-07. The theme is variability of the winds at mesospheric heights (60-100 km) due to Planetary Waves (PW, 2-30 days) over middle and high latitudes. Considerable energy and momentum are transported by atmospheric waves, and their global characteristics are required to understand many phenomena and explain coupling processes within the atmosphere. The vertical propagation of PW from the upper troposphere to the mesosphere is investigated by applying the Morlet wavelet and wave number analysis to the MetO (United Kingdom Meteorological Office) stratospheric assimilated fields, TOMS total (column) ozone, and Medium Frequency (MFR) and Meteor Wind (MWR) radar measurements. The results show that large-scale eastward propagating PW dominate at tropopause and low stratospheric heights, while westward PW become comparable or even stronger in the upper stratosphere and above during months other than summer. There are also strong seasonal dependences of the PW activity in each of the stratospheric and mesospheric regions, which are attributed, at least partially, to the influence of the background wind on PW propagation. Longitudinal variations in PW activity are explained by longitudinal variations in these winds.<p>During summer (westward zonal winds) PW activity is reduced in the stratosphere and only relatively fast westward propagating PW, such as quasi 2-day wave (Q2DW), are able to reach mesospheric heights from below. The results obtained using 14 years of MFR data at Saskatoon provide a unique climatology (70-100 km) of this wave: in addition to summer activity the Q2DW is also present at low mesospheric heights in winter, especially when the eastward winds are weak; there are significant interannual variations in Q2DW activity in both seasons. Strong latitudinal and longitudinal differences in Q2DW occurrence and amplitude are shown from the comparisons of wind data at several stations.<p>During winter, when zonal winds are eastward, the PW coupling between stratosphere and mesosphere is stronger than during other seasons. Detailed data analysis has been performed for the Arctic winter of 2004/05, for which the stratospheric state is described using conventional zonal mean parameters as well as the newer Q-diagnostic. Spectral analyses for this winter show relatively weak PW activity at stratospheric and mesospheric heights and strong latitudinal and longitudinal differences of mean winds and PW characteristics consistent with the form and location of the polar vortex. <p>In addition to the vertical coupling it has also been shown that weaker horizontal inter-hemispheric coupling occurs during equinoctial months, when eastward winds dominate globally. It is demonstrated that with favorable conditions, planetary waves with 10, 16 and 25 day periods penetrate to the opposite hemisphere.

Coral bleaching and mortality caused by ocean warming is the largest threaten to modern coral reefs. Understanding the change and acclimatization of coral communities to warming temperature is urgent for management and conservation. Using transect photo-surveys and monitoring of natural substratum quadrats with fluorescence technique, we compare the community structure and recruitment of corals between a reef artificially heated by thermal outfall of a nuclear power plant for more than 25 years (Outlet) and a nearby natural reef (Hobihu) in Nanwan Bay, southern Taiwan. Both reefs are influenced by intermittent upwelling induced by internal wave. Abundance of hard corals in Outlet was significant higher than in Hobihu, while soft corals showed an opposite pattern. Coverages of corals such as Montipora spp., Porites spp., Galaxea spp. and Favia spp. were significant higher, but Seriatopora spp. and Stylophora spp. were significant lower in Outlet than in Hobihu. Coral recruitment rates were higher in Hobihu than in Outlet with Hobihu having more Pocilloporidae recruits while Outlet having more Euphylliidae, majorly Galaxea recruits. Coral recruitment rates and their survivorship were significant higher in spring/summer season than in autumn/winter season. These results suggest that elevated seawater temperature with other contrasting environmental conditions (different exposure and current) may change the structure of coral community by influencing differently on various life stages. Massive and encrusting corals may be more resilient to ocean warming.

Thesis (M.A.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 105-111).

Climate change is a topic of social and political commentary and controversy, and is a topic that will continue to be addressed by future scientists and laypersons alike. This report contains information and laboratory exercises for use in a greenhouse gas (GHG) and global warming potential (GWP) learning module, to be employed in secondary or entry level university engineering and environmental science curricula. Exercises include a hands-on experience with the greenhouse effect and calculations of GWP for 20-year and 100-year timeframes. / text