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Arctic sea ice variations from the point of view of the global climate change
Škopan, Viktor ; Huth, Radan (advisor) ; Šobr, Miroslav (referee)
The Arctic is one of the regions of the Earth most vulnerable to climate change. Temperatures in the Arctic have risen by more than twice the global average over the past few decades and are roughly 4 řC above the temperature at the start of the Industrial Revolution, which occurred in the late 18th century. It is highly likely that anthropogenic activity is responsible for such a dramatic change. The Arctic sea ice responds to these changes by decreasing in area, thickness, age and other parameters. The most significant decline has been recorded in the summer months, when the area of the sea ice is shrinking at an average rate of 12.8 % per decade. There has also been a significant decline in the age of sea ice. Forty years ago, sea ice older than four years accounted for 30 % of the total area covered by sea ice, whereas today such old ice accounts for only 2 %. Positive climate feedbacks are contributing significantly to the rapid warming of the Arctic and increased sea ice melt. An example is the decreasing albedo (reflectivity) of the Arctic Ocean, which reflects much less solar radiation due to the shrinking sea ice, contributing to the faster warming of the region and higher sea ice melt. Models show that the warming of the Arctic will continue in the future, and temperatures in the Arctic...
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Long-term changes in Arctic sea ice
Lysenko, Anastasia ; Huth, Radan (advisor) ; Margold, Martin (referee)
The thesis summarizes the knowledge of sea ice in the Arctic, its properties, conditions and the process of formation. It also describes the Arctic climate and its changes since the early 20th century. The work shows how and why Arctic sea ice is important for the climate of our entire planet and that the climate system is highly interconnected. This means that if, for example, there are fundamental changes in the sea ice cover or climate, then the impact of these changes may manifest itself in a completely different area, which is a manifestation of the so- called cascading tipping point. Therefore, this work also touches on the topic of feedback and shows that determining the amount and type of sea ice in the Arctic Ocean is essential to improve our knowledge and understanding of polar weather and long-term climate fuctuations. Key words: climatic change, sea ice, temperature, Arctic
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Mapping of sea ice extent by the help of remote sensing methods
Suchá, Renáta ; Potůčková, Markéta (advisor) ; Štefanová, Eva (referee)
Mapping of sea ice extent by help of remote sensing methods Abstract The aim of this thesis is to show utilization of remote sensing methods for monitoring of sea ice by way of an example of Beaufort Sea. In first part of this thesis resulting from the available information in the literature. A short principle of remote sensing is introduced. Some of observation satelites are mentioned, above all Envisat ASAR, whose data are used in the second part of this thesis. Further, some researches concerning the monitoring of sea ice are analysed. The applied visual and radar data are described in detail for monitoring of polar areas. The advantages and limit sof these data are mentioned. In the conclusion of this first part, the researches monitoring the sea ice in Beaufort sea are mentioned. The second part of this thesis is demonstrativ the extend of sea ice in two chosen areas in Beaufort sea. On the basis of eleven radar Picture provided for free from an European space agency, a classification of two type sof sea ice (first-year sea ice, ice floes/multiyear sea ice) was effected. In the watched areas, there was noted a larger extent of sea ice in 2003 than in 2009. The minimum of the ice area in both years was in the month of September. In the Picture, there is a perceptible progres of ice floes which is...
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