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Visar resultat 1 - 5 av 38 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Sulfur in polar ice and snow : Interpretations of past atmosphere and climate through glacial archives

   Författare :Ulf Jonsell; Margareta Hansson; Mark Curran; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ice cores; aerosols; sulfate; methanesulfonate; sulfur isotopes; climate; glacial cycles; Antarctica; Greenland; Physical geography; Naturgeografi;

   Sammanfattning : Snow contains information on the atmosphere it is deposited from. This information is stored in polar ice sheets (Antarctica and Greenland), which are unique geochronological archives of past climate and atmospheric composition. On time scales from annual to glacial cycles, this thesis deals with the signals of sulfur compounds in these archives. LÄS MER

3. 2. Subsurface fluxes of mass and energy at the accumulation zone of Lomonosovfonna ice cap, Svalbard

   Författare :Sergey Marchenko; Veijo Pohjola; Rickard Pettersson; Carleen Reijmer; Thomas Schuler; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; glacier; ice sheet; sea level; runoff; ice; firn; snow; stratigraphy; density; core; radar; thermistor; temperature; preferential water flow; thermal conductivity; water content; Geovetenskap med inriktning mot naturgeografi; Earth Science with specialization in Physical Geography;

   Sammanfattning : Glaciers cover ca 10% of the Earth's land and are found in the high altitudes and latitudes. They are important components of environmental systems due to the multiple feedbacks linking them with the atmosphere, hydrosphere and periglacial landscapes. LÄS MER

4. 3. Extreme solar particle storms and links to solar activity inferred from cosmogenic radionuclides in ice cores

   Författare :Chiara Paleari; MERGE: ModElling the Regional and Global Earth system; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ice cores; cosmogenic radionuclides; Solar storms; 10Be; 36Cl; Solar energetic particles;

   Sammanfattning : During solar storms, large amounts of solar energetic particles (SEP) are accelerated into the interplanetary medium and sometimes hit Earth. These events, known as SEP events, can have harmful impacts on our modern society by affecting spacecrafts and potentially astronauts in space. LÄS MER

5. 4. Nitrate stable isotopes and major ions in snow and ice from Svalbard

   Författare :Carmen Paulina Vega Riquelme; V. A. Pohjola; R. Pettersson; E. Isaksson; C. E. Bøggild; Kumiko Goto-Azuma; Uppsala universitet; []
   Nyckelord :nitrate stable isotopes; nitrate; NOx proxies; ice cores; percolation; ion relocation; Svalbard; stabila isotoper av nitrat; nitrat; indikator för kväveoxider; iskärnor; perkolation; joniska omlokalisering; Svalbard; Earth Science with specialization in Physical Geography; Geovetenskap med inriktning mot naturgeografi;

   Sammanfattning : Increasing atmospheric reactive nitrogen (Nr), as consequence of human activities, has generated accumulation of nitrate (NO3-) in Arctic regions. The Arctic has fragile nitrogen limited ecosystems that can be altered by increases of dry or wet deposition of Nr. LÄS MER

7. 5. Solar Activity Changes at the End of the Last Ice Age - Influences on Climate and Applications for Dating

   Författare :Florian Adolphi; BECC: Biodiversity and Ecosystem services in a Changing Climate; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solar Activity; 10Be; 14C; radiocarbon calibration; time scale; geochronology; paleoclimate; ice cores; tree rings; IntCal; cosmogenic radionuclides;

   Sammanfattning : Throughout its history Earth experienced a variety of natural climate changes. By investigating their spatial and temporal evolution we can increase the understanding of the mechanisms and dynamics underlying natural climate change and improve our general comprehension of the climate system. LÄS MER