Global ETD Search

61	The Unquantified Mass Loss and Changes of Northern Hemisphere Marine-Terminating Glaciers Kochtitzky, William 24 August 2022 (has links) Most of the glacier-caused sea level rise to date has been sourced from melt and icebergs from marine-terminating glaciers. Marine-terminating glaciers drain nearly all the Greenland and Antarctic ice sheets and many polar ice caps, ice fields, and mountain glaciers. However, we previously did not know how much solid mass, or frontal ablation, was lost by these glaciers, a key component of glacier mass balance. This thesis quantifies the area change and mass loss of marine-terminating glaciers in the Northern Hemisphere from 2000 to 2020 by quantifying glacier retreat, advance, and frontal ablation. In total, the 1704 marine-terminating glaciers in the Northern Hemisphere lost an average of 389.7 ± 1.6 km² a⁻¹ of their terminus from 2000 to 2020, for a total of 7527 ± 31 km², with 123 glaciers ceasing to be marine-terminating over this period. Overall, 85.3% of glaciers retreated, 2.5% advanced, and the remaining 12.3% did not change outside of uncertainty limits. Frontal ablation of marine-terminating glaciers, not including the Greenland Ice Sheet, contributed an average of 44.47 ± 6.23 Gt a⁻¹ of ice to the ocean from 2000 to 2010, and 51.98 ± 4.62 Gt a⁻¹ from 2010 to 2020. Ice discharge from 2000 to 2020 was equivalent to 2.10 ± 0.22 mm of sea-level rise and comprised approximately 79% of frontal ablation, with the remainder from terminus retreat. In Greenland, frontal ablation totaled 522.00 ± 17.38 Gt a⁻¹ for 2000-2010 and 559.05 ± 12.59 Gt a⁻¹ for 2010-2020. Ice discharge comprised ~90% of frontal ablation during both periods, while volume loss due to terminus retreat comprised the remainder. In total, Greenland accounted for 90% of northern hemisphere frontal ablation from 2000 to 2020. When combined with climatic-basal mass balance estimates this allows for the first estimate of complete Northern Hemisphere glacier mass budgets, which shows that Arctic Russia, Greenland, and Svalbard have positive climatic-basal balances. For the first time, this thesis provides complete frontal ablation estimates for the entire Northern Hemisphere of 522.0 ± 17.4 Gt a⁻¹ for 2000-2010 and 559.1 ± 12.6 Gt a⁻¹ for 2010-2020. glacier Alaska Canada Greenland Svalbard Iceland Russia climate change remote sensing icebergs ocean frontal ablation satellites calving Landsat Sentinel GIS tidewater glacier
62	Förnybar energi på Svalbard Andreasson, Tobias, Lindh, Emelia January 2018 (has links) This degree thesis investigates the possibilities of producing food inside a container at Svalbard, using renewable energy and energy storage. The idea was to be able to place the container at remote places without the need of being connected to the grid. We chose Svalbard, where it is cold and the sun is shining 24 hours a day at summertime. In the winter the opposite occurs and the sun is absent from the sky. The work is divided into theoretical studies and results based on different calculations. Such as economical evaluations (LCOE), and simulations using the computer programs Matlab and PVsyst. We have investigated if solar power and wind power is suitable as energy sources. Options for storage were batteries, grid and hydrogen storage. Different cases with Photovoltaics- and wind power plants, with batteries or grid, were compared against each other. It is not possible to use the grid as storage. This resulted in different sizing of our cases, with no excess energy production. The result showed that a 5 kWp photvoltaic plant with dual axis tracking system, was the most profitable. The Pay off would be 14 years and the total profit 63 453 SEK. If it will become possible in the future to use the grid at Svalbard as storage, it will open up opportunites for bigger systems. This will lead to higher profit than with smaller ones. Our results show that it is now most profitable with solar power. off grid container food renewable energy storage batteries Futufarm AB Leafy Green Machine Svalbard photovoltaics windpower PVsyst Matlab future Förnybar energi Svalbard solceller vindkraft kallt klimat odling hydroponisk tracking midnattssol polarnatt Longyearbyen container hållbar hybrid elnät framtid Futufarm AB självförsörjande energikällor energilagring batterilagring effektutjämning PVsyst Matlab Energy Systems Energisystem
63	Korelace abiotických proxy v holocenních jezerních sedimentech peri-Atlantské Arktidy / Correlation of abiotic proxies in Holocene lacustrine sediments of Peri-Atlantic Arctic Roman, Matěj January 2017 (has links) The peri-Atlantic Arctic, one of the most sensitive components of the Earth climate system, experienced pronounced climatic fluctuations during the Holocene. Several external forcings were considered responsible for these variations, including decline of insolation on the Northern Hemisphere, changes in distribution of land ice mass, explosive volcanism, or changes in atmospheric and oceanic circulation. In order to explore the driving mechanisms of the peri-Atlantic Arctic environmental variability, three sites located in different parts of the region were selected for palaeoenvironmental reconstructions with focus on extracting the climatic information. With this intention, sedimentary cores from i) Lake Garmaksla, Central Svalbard, ii) Jarfjorden, northeastern Norway, and iii) Kobbefjord area, southwestern Greenland, were retrieved and subjected to multi-proxy investigation. The absolute chronostratigraphic framework was established by comprehensive radiocarbon (14 C) and short-lived radioisotopes (210 Pb, 137 Cs) dating. Further analyses include measurements of magnetic susceptibility, grain size distribution, element composition by means of X-ray fluorescence (XRF), and elements bound to organic matter, i.e. organic carbon, nitrogen, sulphur and biogenic silica. The relationships between the...

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