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 19 of 19 for “"polar ice"”.
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Radar Altimetric Studies of Polar Ice
… provide valuable information regarding snow and ice surfaces in the polar regions, where darkness and cloud cover prevail. Here, data collected in the Arctic by a Ku-band microwave radar altimeter, designed and constructed in the UK, are analysed. The two main components of this study comprise …
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Radio-echo layering in polar ice sheets
… observed in the Antarctic and Greenland ice sheets during radio-echo sounding. It describes in detail layering seen with 60 and 300 MHz equipment _in the Antarctic ice sheet during three field seasons betwe~n 1974 and 1979, and discusses the effects of glaciological and equipment factors, …
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Prediction under uncertainty : from models for marine-terminating glaciers to Bayesian computation
The polar ice sheets have enormous potential impact on future global mean sea level rise. Recent observations suggest they are losing mass to the ocean at an accelerated rate. Skillful prediction of the ice sheets' future mass loss remains difficult, however; observations of key variables are …
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Feasibility of acoustic neutrino detection with the South Pole Acoustic Test Setup
… to find them in sufficient numbers. Antarctic polar ice has turned out to be an ideal medium for detecting neutrinos. It is exceptionally pure, transparent and free of radioactivity. The density of detectors in such large neutrino telescopes is dictated by the attenuation length of the …
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Late Jurassic to Early Cretaceous stable isotope and geochemical records from the northern high latitudes: implications for palaeoclimate
… conditions with elevated CO2 levels and warm polar regions. Although much compelling evidence to support this idea of global warmth exists, some recent studies propose that the greenhouse climate may at times have been punctuated by sub-freezing polar conditions and the presence of limited …
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Fabrication of an Apparatus for All-Optical Production of Metastable Krypton
… Analysis (ATTA) has made radiokrypton dating of polar ice and groundwater samples a possibility for scientists all over the world, allowing them to date samples further back in time and more accurately than other methods. However, this technique is hampered by the 36-hour cleaning process …
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Stratigraphic and Geochemical Expression of Early Cretaceous Environmental Change in Arctic Svalbard
… show evidence that they were rafted by glacial ice (e.g. surface striations), although could have been rafted by seasonal sea-ice. The results show that regionally widespread cold water conditions were the most likely control on ikaite formation and glendonite preservation. This counters recent …
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On the meridional heat transport and its partition between the atmosphere and oceans
… calculations using a coupled atmosphere-ocean-ice model in which idealized ocean basins impose various geometrical constraints on ocean circulation. A wide range of ocean heat transports and heat transport partitions are found, but with more modest variations in the total heat transport. …
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Aquatecture: Architectural Adaptation to Rising Sea Levels
… relating to climate change is that as the polar ice caps continue to melt, rising water will invade our coastal cities around the world. In accordance with sea level projection maps, sea levels will rise 20 feet1, and major cities like Miami, Shanghai, Calcutta, and Manhattan will be …
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A New Method for Melt Detection on Antarctic Ice-Shelves and Scatterometer Calibration Verification
<p>Ku-band dual-polarization radar backscatter measurements from the SeaWinds on QuikScat scatterometer and microwave radiometer measurements from the Special Sensor Microwave/Imager (SSM/I) are used to determine periods of surface melt and freeze in the Antarctic ice-shelves. The normalized radar …
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Detailed thermal analysis of a thin-shell, spherical radiometer in Earth orbit
… the earth radiation field is not diffuse. The polar ice caps were found to reflect incident solar radiant flux specularly to the spherical detector. The absorptance of the earth-'reflected solar component as a function of incident angle is important and responded to the specularly reflected …
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High-precision isotope ratio measurements of uranium and plutonium in the environment
… at Harpenden (Hertfordshire, UK) and an Alpine ice core from Dome du Gouter, Mont Blanc, French Alps. Activity concentrations for 137Cs and 239,240Pu and the 238U/235U atomic ratio were also determined in the same samples. The activity concentrations clearly reflect the yearly yields of …
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An altimeter waveform model for combined surface and volume scattering
… same altimeters have recorded data from over the polar ice sheets, where the scattering processes cannot in general be limited to surface properties. Radar pulse penetration, which gives rise to volume scattering, must also be accounted for in these return waveforms. This pulse penetration affects …
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The Determinants of Climate Change Risk Practice and Disclosure: An Analysis of Institutional Investors in the UK Using a Mixed Method Approach
… dwindling water resources, intense wildfires, polar ice melt, rising sea levels, flooding, loss of biodiversity, and extreme weather events (United Nations, 2024). As key players at the top of the investment value chain, institutional investors hold a pivotal role in mitigating and disclosing …
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Evolution of the Geohydrologic Cycle During the Past 700 Million Years
… includes the atmosphere, cryosphere (glacial and polar ice), the biosphere, surface water, groundwater, and the oceans. The amounts of water in these various reservoirs of the hydrologic cycle have likely varied significantly over the past 700 Ma, with the cryosphere and continental biosphere …
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Using the fossil charcoal and pollen records from Elands Bay Cave and Boomplaas Cave, South Africa, to reconstruct variability in local hydroclimate and seasonality
… predominantly by benthic ocean sediment and ice cores. These records are characterized by cyclical variation, suggesting changing polar ice volumes from glacial to interglacial conditions, driven by Milankovich cycles and greenhouse gas concentration feedbacks. While these records have …
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The Evolution of Massive Young Stellar Objects in the Large Magellanic Cloud
… the 277 YSOs we collected spectra for, 41 have ice absorption features, indicating they are surrounded by cold ice-bearing dust particles. We have decomposed the shape of the ice features to probe the composition and thermal history of the ice. We find that most the CO2 ice is embedded a polar …
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Foraminiferal and stable isotope investigation of the Cenomanian-Turonian extinction and oceanic anoxic event
… leading to periods of high sea level and no polar ice. This had great effects on the ocean's structure, chemistry and circulation, and led to both extinction and diversification of biota. At the time of the CTB a number of events occurred. Particularly well researched is the oceanic anoxic …
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Multisensor Microwave Remote Sensing in the Cryosphere
… be a useful tool in estimating sea and glacial ice surface characteristics with both scatterometers and radiometers exhibiting high sensitivity to important ice properties. This dissertation presents an array of studies focused on extracting key surface features from multisensor microwave data …