No description available.

No description available.

The relationship between the Arctic and sub-Arctic sea-ice concentration (SIC) anomalies, particularly those associated with the Greenland and Labrador Seas' "Ice and Salinity Anomalies (ISAs)" occurring during the 1960s/1970s, 1970s/1980s, and 1980s/1990s, and the overlying atmospheric circulation (SLP) fluctuations is investigated using the Empirical Orthogonal Function (EOF) and Singular Value Decomposition (SVD) analysis methods. The data used are monthly SIC and SLP anomalies, which cover the Northern Hemisphere north of 450 and extend over the 38-year period 1954--1991. / One goal of the thesis is to describe the spatial and temporal variability of SIC and atmospheric circulation on interannual and decadal timescales. Another goal is to investigate the nature and strength of the air-ice interactions. The air-ice interactions are investigated in detail in the first SVD mode of the coupled variability, which is characterized by decadal-to-interdecadal timescales. Subsequently, the nature and strength of the air-ice interactions are studied in the second SVD mode, which shows a long-term trend. The interactions in the third SVD mode which has an interannual timescale are briefly mentioned. (Abstract shortened by UMI.)

<p> Natural disasters can be very devastating to the public during their impact phase. After a natural disaster impacts a region, the response and recovery phases begin immediately. Weather conditions may interrupt emergency response and recovery in the days following the disaster. This study analyzes the climatology of weather conditions during the response and recovery phases of hurricanes and tornadoes to understand how weather may impact both environment and societal needs. Using specific criteria, 66 tornadoes and 16 hurricane cases were defined. National Weather Service (NWS) recognized weather stations were used to provide temperature, precipitation, snowfall, relative humidity, wind speed, and wind direction data. Regional and temporal groups were defined for tornado cases, but only one group was defined for hurricanes. By applying statistical analysis to weather observations taken in the week following the disasters, a climatology was developed for the response and recovery phase. Tornado and hurricane post-disaster climate closely mimicked their synoptic climatology with cooler and drier weather prevailing in days 2-4 after a disaster until the next weather system arrived about 5 days later. Winter tornadoes trended to occur in the Southeast and were associated with more extreme temperature differences than in other regions and season. The results of this study may help governmental and non-governmental organizations prepare for weather conditions during the post-disaster phase.</p>

This thesis presents results from a large-scale dynamic restoration program implemented by Parks Canada Agency (PCA) to remove invasive marram grasses (Ammophila spp.) from a foredune-transgressive dune complex in Pacific Rim National Park, British Columbia, Canada. The program goal is to restore habitat for endangered Pink sandverbena (Abronia umbellate var breviflora) as required by the Canadian Species at Risk Act (SARA). Three sites were restored by PCA via mechanical removal of invasive marram grasses (Ammophila spp.) in September 2009. This study documents geomorphic and sediment mass exchange responses at one of these sites as derived from detailed Digital Elevation Model (DEM) surveys of a 10 320 m2 study area that spans three discrete geomorphic units (beach, foredune, and transgressive dune complex). Subsequent approximately bi-monthly total station surveys for the first year post-restoration are compared to a pre-restoration baseline Light Detection and Ranging (LiDAR) survey (August 2009) to quantify and describe morphodynamic responses and volumetric changes. Two different methodologies were utilized for post processing of volumetric change DEMs in order to filter out non-statistically significant change. The first filter used software developed for fluvial geomorphology and was tested using the student’s t distribution. This approach, while novel in the field of coastal geomorphology, was less complex than the second which was based on spatial statistical procedures popular in the ecological sciences. This filter was based on local Moran’s Ii, which was used to generate 1.5m and 5m distance thresholds of statistically significant geomorphic change. These thresholds were specified to simulate the outer limit of saltating grains and the dimensions of landform development, respectively. Results show that the beach receives appreciable sediment supply via bar welding and berm development in the winter, much of which is transported to the foredune and transgressive dune complex units in the spring. This promotes rapid redevelopment of incipient dunes in the backshore, rebuilding of the seaward slope of the foredune following wave scarping, and localized extension of depositional lobes in the transgressive dune complex fed by sediment from the beach and foredune stoss (only shown in local Moran’s Ii results). The results of this study suggest that the foredune-transgressive dune complex at Wickaninnish Dunes has experienced enhanced aeolian activity and positive sediment volume changes over the first year following mechanical restoration. In addition, comparison of the two methodologies show that spatial statistics were found to provide both more realistic calculated volumes at a smaller threshold distance (e.g., – 0.012m3 m-2 in the foredune after devegetation; only +0.015m3 m-2 in the transgressive dune complex in the year following restoration) and better highlighting of important spatial processes at a larger threshold distance (e.g., foredune stoss erosion; feature highlighting) than the volumetric change calculations based on a simpler statistical threshold. / Graduate

The long term contamination of groundwater resources by dense non-aqueous phase liquids (DNAPLs) such as chlorinated solvents is an increasing problem being faced throughout the industrialised world. The transport and eventual fate of these compounds in the subsurface is controlled by the nature of the chemical spillage, the hydrogeological characteristics of the aquifer media and physiochemical properties of the particular contaminant. Geographic Information System (GIS) based risk assessment tools are developed for use with the UK’s Permo-Triassic Sandstone aquifer in order to assist stakeholders make informed decisions on the best use of groundwater in high risk areas and assess the value and management options for resources that are coming under increasing pressure from chlorinated solvent DNAPL contamination. Both semi-quantified and quantified probabilistic methods are presented with associated case studies using the best available data for regions of the UK where high densities of chlorinated solvent users industries combine with valuable groundwater resources. However, attempts at validation of the methodologies are hindered by availability of information on a regional scale, in particular the difficulties in collection and collation of historical land-use data is seen as a major hurdle to the accurate prediction of areas and resources at risk. Nevertheless the tools are potentially useful for guiding regulators and decision makers in the water industry to prioritisation of sites for site specific studies.

Morphological analysis and mapping of Loch Lomond Stadial moraines at five key sites, Torridon, Rannoch Moor, Tyndrum and Strath Fillan, the upper Forth Valley and the east Loch Lomond basin has allowed the genetic interpretation and inferences of climatic significance to made. Hummocky moraine is found at three of these sties, Torridon, Rannoch Moor and Tyndrum, where they are interpreted as polygenetic in origin. The spatial organisation and morphology of hummocky features investigated in Torridon allows the differentiation of cross-valley orientated marginal moraines and the more numerous streamlined features with a down-valley orientation interpreted as flutings. As the flutings are superimposed on the cross-valley moraines they are thought to post-date moraine formation. The spatial organisation of glacial landforms in Torridon therefore represents a palimpsest landscape. Mapping of moraines in the Rannoch Moor basin suggests that this was a major centre of ice convergence rather than accumulation during the Loch Lomond Stadial. Ice mainly accumulated in the corries in the mountains to the west of moor from where it flowed to coalesce as an upland icefield. Ice is thought to have reached a sufficient volume in the Rannoch Moor basin to flow down valleys as outlet glaciers. Hummocky features found at Tyndrum and Strath Fillan have a polygenetic origin and include the remnants of eskers, hummocks produced by local ice stagnation, marginal moraines, and lateral moraines which have been modified by paraglacial debris flow. Large terraces at this sites are interpreted as kame terraces with pitted and channelled surfaces. Local ice stagnation is thought to have occurred during a regional pattern of active deglaciation.

No description available.

A thermodynamic-dynamic sea ice model based on the granular material rheology of Tremblay and Mysak is used to study the interannual variability of the Arctic sea ice cover during the 41-year period 1958--1998. The sea ice model is coupled to both a mixed layer ocean model and a one-layer thermodynamic atmospheric model. The model is first run with monthly climatology for most of the thermodynamic and dynamic forcing components to obtain a stable periodic seasonal cycle. For the 41-year run, the monthly wind stress forcing is derived from analyzed sea level pressures from the National Centers for Environmental Prediction (NCEP Reanalysis) data. The atmospheric thermodynamic forcings are based on monthly climatology. / In this thesis we explore the high-latitude sea ice circulation and thickness changes due to year-to-year variations in the wind field. We focus our study on the interannual variability of the sea ice. volume in the Arctic Basin, and the subsequent changes in the export of sea ice from the Arctic Basin into the northern North Atlantic via Fram Strait. (Abstract shortened by UMI.)

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008. / Source: Dissertation Abstracts International, Volume: 69-05, Section: B, page: 3154. Adviser: Marcelo H. Garcia. Includes bibliographical references (leaves 118-130) Available on microfilm from Pro Quest Information and Learning.