Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 32 for “"Southern Annular Mode"”.
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Antarctic sea ice trends and its response to the Southern annular mode
Sea ice covers vast regions of the Southern Ocean and impacts on the climate as well as the plant and animal life of the region. The variability of sea ice in the Southern Ocean affects the entire food web of the region, from phytoplankton to Antarctic krill through to the apex predators such as …
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Revisiting the links between the Southern Annular Mode and rainfall over the Western Cape region of South Africa
… focus of this thesis is on the influence of the Southern Annular Mode (SAM) on rainfall over the region, the possible influence of El Niño Southern Oscillation (ENSO) is also considered. To achieve this, a correlation analysis was conducted using the Marshal (2003) SAM index and station rainfall …
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Exploring winter rainfall in western South Africa : connections, influences and the potential for statistical seasonal forecasting
… of relationships between SWC rainfall and the Southern Annular Mode (SAM), South Atlantic sea surface temperature (SST), Antarctic sea ice concentration (SIC), and the EI Nino-Southern Oscillation (ENSO) were explored using spatial and temporal correlations. Insight gained from the correlation …
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Variability of zooplankton and sea surface temperature in the Southern Ocean
… between physical and biological processes in the Southern Ocean have significant impacts on local ecosystems as well as on global climate. In this thesis, I present evidence that the Southern Ocean circulation affects the variability of zooplankton and sea surface temperature, both of which are …
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Low frequency variabilty of the Agulhas Current region in a numerical model
… the current using output from a regional ocean model. Validation of the model with in situ and satellite observed values for the temperature and SSH showed the modelled SSH results to be only marginally different from the satellite observed, while the temperature validation showed the modelled …
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Stratospheric ozone and Southern Hemisphere climate change : impacts and robustness in CMIP5 models
… to be the dominant cause of recent observed southern hemisphere (SH) circulation changes during austral summer, along with the consequential impacts on tropospheric climate conditions. Links between ozone depletion and the positive phase of the dominant mode of variability of the southern …
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An analysis of anomalously wet summers in the South Western Cape of South Africa
… patterns are found to be linked to a negative Southern Annular Mode pattern and in the late summer, also linked to ENSO and the zonal wave number 3 pattern. Overall, trends suggest decreases in rainfall days in the Greater Cape Town region and in the nearby mountain areas where most major dams …
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Decadal rainfall variability over Southern Africa
Southern Africa is a region of vulnerability, with high seasonal and interannual rainfall variability combined with rain-dependent agriculture. This variability is underpinned by influences from ENSO and other oceanic forcing, and known to exhibit quasi-decadal variability at 16-20 years (Tyson, …
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Reconstruction of the historical climate of the Southern Ocean from whaling ships’ logbooks
The estimated century-long trends in the Southern Ocean climate are uncertain, as the data used to estimate these changes are relatively short (~60 years) compared to possible long-term climate variability found in the region. Due to the lack of longer land-based meteorological records, logbooks of …
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Understanding the interannual variability of pCO2 in the sea-ice impacted Southern Ocean
… of oceanic pCO2 in the sea-ice-impacted Southern Ocean and identify their potential primary drivers, this thesis combines in situ observations with remotely sensed data and reanalysis models during the austral summer months. The region of focus is divided into three sections: the Southern …
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The role of the large-scale modes of climate variability in the Southern African wave climate
The wave energy flux along the southern African coastline regularly reaches extreme levels, seriously impacting coastal communities, infrastructure, as well as near-coast and offshore marine operations. Understanding the drivers behind past high wave energy events and their frequency is key to …
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High-Latitude Southern Hemisphere Climate Variability, Trends, and Tropical Forcing.
… aspects of climate variability in the Southern Hemisphere (SH) high-latitudes, with a focus on the time-varying behaviour and long-term trends in Antarctic sea ice and atmospheric circulation, as diagnosed from observations, reanalyses, and simulations using an Atmospheric General …
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Environmental change recorded in physical and geochemical proxies over the Last Glacial Cycle from two Northland, New Zealand dune lakes: Lake Kanono and Lake Kai Iwi
Lake sediment archives from Southern Hemisphere mid-latitude regions with maritime climates provide invaluable records of late Quaternary environmental change that are essential for the evaluation of inter-annual, decadal, centennial, and millennial-scale trends driven by shifting positions of the …
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Investigation of Wind Variability in the South Atlantic Sector of the Southern Ocean and the Influence on the Upper Ocean in a Numerical Ocean Model
… papers have linked climate variability in the Southern Ocean (SO) with the Southern Annular Mode (SAM), which has seen an increase in the positive phase since the mid-1960s, due to the Antarctic ozone depletion and emissions of greenhouse gases. The SAM is recognized as the main mode of …
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Dynamics of marine zooplankton : social behavior ecological interactions, and physically-induced variability
… social interactions between individuals. In the Southern Ocean, krill often assemble in swarms and schools, the dynamics of which have important ecological consequences. Mathematical and numerical models are employed to study the interplay of biological and physical processes that contribute to …
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Innovative water tracers and water isotopes enhance Antarctic research with climate models
… confounded by many influencing factors, climate models are instrumental in elucidating relevant processes. Here I aim to leverage climate models for Antarctic studies. Firstly, I developed innovative water tracing diagnostics in an isotope-enabled atmospheric general circulation model …
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An altimetry based examination of the path and variability of the Agulhas Return Current
… Dipole, both of which are associated with the Southern Annular Mode (SAM), illustrating the effects that southward shifts in the subtropical high pressure system have on regional and mesoscale climate modes. The combination of a stable, topographically forced flow path with observed EKE …
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Assessing dry spell and wet day frequencies over southern Africa during the summer rainy season
Rainfall over southern Africa experiences substantial temporal and spatial variability which heavily impacts poor rural populations in the region that rely on rainfed agriculture for their livelihoods. Instead of totals, seasonal rainfall is better characterised by wet and dry events occurring …
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Climate Drivers Compound Under Climate Change
… by three major climate drivers; the El Niño-Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and the Southern Annular Mode (SAM). Each climate driver has impacts upon seasonal rainfall, temperature and fire risk. In south-east Australia, there is some evidence that large scale fire …
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Climate Drivers Compound Under Climate Change
… by three major climate drivers; the El Niño-Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and the Southern Annular Mode (SAM). Each climate driver has impacts upon seasonal rainfall, temperature and fire risk. In south-east Australia, there is some evidence that large scale fire …
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