Sökning: "climate reconstructions"
Visar resultat 21 - 25 av 59 avhandlingar innehållade orden climate reconstructions.
21. Arctic Ocean benthic foraminifera preservation and Mg/Ca ratios : Implications for bottom water palaeothermometry
Sammanfattning : Reconstructions of Arctic Ocean palaeotemperatures are needed to disentangle natural variability from anthropogenic changes and understand the role of ocean heat transport in forcing or providing feedbacks on Arctic climate change. Despite known complications with calcareous microfossil preservation in Arctic Ocean sediments, calcareous benthic foraminifera can be common in interglacial sequences. LÄS MER
22. Summer Climate Variability during the Past 1200 Years in Central Scandinavia – A Tree-Ring Perspective
Sammanfattning : To set the current 20th century warming in a long-term context, significant efforts have been made to reconstruct hemispheric-to-global temperatures beyond the instrumental period. Tree-rings, which have annual resolution and can be precisely dated, have been widely used to infer past climate variability. LÄS MER
23. The Ups and Downs of the Holocene: Exploring Relationships between Global CO2 and Climate Variability in the North Atlantic Region
Sammanfattning : This thesis aimed to examine the relationship between climate and atmospheric CO2 concentrations through rapid climate changes during the Holocene. Climate was reconstructed using high-resolution, radiocarbon dated, lake sediment geochemical proxies (magnetic susceptibility, loss-on-ignition, total carbon/nitrogen/sulphur determinations and biogenic silica), vegetational reconstruction (pollen analysis) and stomatal frequency based CO2 reconstructions. LÄS MER
24. High-resolution simulations of two cold palaeo climates in Europe : MIS 3 and LGM
Sammanfattning : The study of past climate is important because it increases our understanding of how the climate system works. Past climate is often reconstructed by using proxies (that is observations of things that tell something about past climate, for example tree rings, pollen in lake sediments and fossils). LÄS MER
25. Urban and rural environments from Iron Age to Medieval time in northern Europe : Evidence from fossil insect remains from South-Eastern Sweden and Novgorod, Russia
Sammanfattning : This thesis presents and discusses results from studies in of subfossil insect remains of natural and cultural origin. Samples were obtained by coring in sediments or by collection during archaeological excavations. The aim was to reconstruct local environment and climate in rural and early urban situations from Iron Age to medieval time. LÄS MER
