Browsing by Subject "Finland"

Diurnal temperature range (DTR), defined as the difference between daily maximum and minimum temperatures, is an important variable in ecosystem dynamics. Human-induced climate change, which has increased mean temperatures worldwide, has been noted to cause global changes in DTR. In this thesis, the changes in daily maximum and minimum temperatures, as well as diurnal temperature range, were studied between the climatological periods of 1961–1990 and 1991–2020 from twenty weather observation stations in Finland. Student’s t-test was utilized to assess the statistical significance of the differences between period mean values. The results show that daily maximum and minimum temperatures have risen significantly across Finland in all seasons. The differences between 1961–1990 and 1991–2020 mean values were +1.26 °C and +1.51 °C for daily maximum and minimum temperatures, respectively. Both daily maximum and minimum temperatures have risen most notably in winter (DJF), with daily extreme temperatures increasing asymmetrically. The increase in temperatures was more pronounced for daily minimum temperatures, rising by approximately 3 °C in winter, nearly one degree more than daily maximum temperatures during the same season. Annually averaged diurnal temperature range has generally decreased in Finland from 1961–1990 to 1991–2020. The decrease in DTR was statistically significant in the northern part of Finland, and overall, the country experienced a statistically significant decrease of −0.25 °C. The decreases in annual mean DTR exhibited a latitudinal pattern, with the largest decrease observed in northern Finland and smallest in southern Finland. The majority of the decrease in DTR occurred during winter across the country, whereas changes in the other seasons were smaller and varied in direction. A decrease in DTR in Finland has been reported by other studies, although the results in this thesis (−0.09 °C/decade trend) are larger in amplitude compared to other estimates. The decrease in winter DTR was attempted to be explained by changes in air mass advection, which substantially influences diurnal temperature range in addition to influencing day-to-day variations in temperature. It was concluded that changes in air mass advection have substantially influenced the changes in winter DTR, but they may not necessarily explain all of the observed changes. Cloud cover changes were examined using ERA5 reanalysis data, but these changes were judged to be unimportant for the decrease in winter DTR. However, asymmetrical cloud cover changes in the other seasons could have potentially contributed to the differing direction of DTR change observed in spring, summer and autumn across the country.

Finland and Estonia form a cross-border region in Europe. Unlike other cross-border regions, which share a land border with their neighbor, Finland and Estonia are separated by the Gulf of Finland. The distance is close enough to facilitate regular travel by ferry on a weekly or monthly basis, but for Estonian immigrants living in Finland, daily commutes are unlikely. Given that Finland is the top migration destination for Estonians, the cross-border region of Estonia-Finland poses an interesting case study. In this thesis, the integration and transnationalism of Estonians living in Finland are studied through a spatial mobility lens. First, a theoretical framework is proposed to facilitate empirical research. The framework jointly examines integration and transnationalism by partitioning them into separate domains: social, structural, cultural, civic & political, identity, and spatial. The aim of the framework is to narrow the socio-spatial gap in migration literature, by focusing on the interwoven nature of the social and spatial perspectives. Using data from a comprehensive survey about Estonian immigrants living in Finland, the proposed theoretical framework is operationalized for multiple correspondence analysis (MCA). Three MCA analyses are performed: 1) social integration with host society (Finland), 2) social transnationalism with the sending society (Estonia), and 3) spatial transnationalism between the host society (Finland) and the sending society (Estonia). MCA results show that transnationalism and integration vary both across and within domains. MCA results are connected to one another using correlation analysis and general linear model (GLM) analyses. Correlation analysis and GLM demonstrate that for the study population, integration in the host society and transnationalism with the sending society are inversely associated. This inverse relationship carries over into the spatial domain and can be seen based on which country an immigrant does certain activities (e.g., visiting family, working, accessing healthcare, enjoying leisure time). Immigrants with strong social connections to the host society are more likely to do activities in Finland whereas immigrants with strong social connections to the sending society are more likely to do activities in Estonia. Some immigrants exhibit a multilocal mobility pattern, in which they do activities equally in both Estonia and Finland.

Cobalt is a strategic metal whose production is dominated by a handful of countries and mines. The Terrafame (formerly known as Talvivaara) black-shale hosted Ni-Cu-Zn-Co deposit in North-Eastern Finland is a globally significant deposit for cobalt containing 1 453 Mt of ore averaging 0.02% Co. The enrichment of cobalt has likely taken place during multiple phases throughout the geological history of the deposit with both the depositional phase and the orogeny phase having a key effect on concentrating cobalt. Scanning electron microscope based automated mineralogy (SEM-AM) and electron probe microanalyses (EPMA) were applied to study the mineralogy of 15 thin sections from Kuusilampi ore body. The results from SEM-AM were further enhanced by applying a python programming language-based data processing procedure that was created specifically for this study. The main Co-containing sulfide minerals at Terrafame are pyrite, pyrrhotite and pentlandite. The Co concentration in pyrite is controlled by the grain type, with pyrites that exsolved from the monosulfide solid solution having the highest average Co concentration. The Co concentration in pentlandite appears to be controlled by the host rock with Mn-rich calc-silicate rocks having an average of 2.77 wt.% Co and black shales 0.47 wt.% Co in pentlandite. Co-rich, with up to 27 wt.% Co sulfarsenide group minerals also occur in the deposit, but their abundances were calculated to be too low to be considered a major contributor to the bulk cobalt concentration at the Terrafame deposit.

Studies of the last ice age have been made in Finland since the early 20th century. The result is a wealth of information on activities related to the continental ice sheet and the location of the ice margins. The purpose of this thesis was to find out the usefulness of animations when visualizing research results. Animations have the advantage of sharing a large amount of information in a short time and they often are easier to comprehend compared to texts and images. In addition to this the aim was to visualize dynamics of the ice sheet and its ice margin positions. The materials from different studies that were used in visualization contain visual materials from ice sheet in northern Europe and more precisely from Finland. The animations were created by using ArcGis program and Blender 3D graphics software. In ArcGis the GIS-database was modified for suitable format to be used in Blender. Based on the visual materials, objects were formed in Blender from polygons that reflect the geometry of the ice sheet and its environment. The movements and other events were modelled by animating them and their visual look was formed by assigning different materials for different objects. Lastly, the animation was post-processed through composite and then rendered out of the program in the desired format. The results of the study were two animations about the activities related to the continental ice sheet in Northern Europe and Finland. The animation of Northern Europe is a general overview of growth and retreat of the ice sheet between 34–10 ka. The main result of the study is an animation of retreat of the ice sheet during deglaciation in Finland between 14–10 ka. The animation of the Finnish area visualizes ice lobes and stagnant ice areas between them. In addition to the ice sheet the animation also visualizes ice lakes, terminal moraines and calving of the ice sheet, as well as the sub-aquatic and supra-aquatic regions in Finland. The study can be further refined by adding all existing research data of ice margin positions and ice sheet dynamics. The animation regarding the ice sheet dynamics of Finland could be further expanded and refined towards areas in Norway, Sweden and Russia. In addition to that, one could add an elevation model and the development model of Baltic Sea and other water bodies to create a more diverse work. Based on the study, the usability of the animation in glacial geologic studies is significant when it is based on extensive research data and up-to-date glacial geological knowledge. The applications of animations are numerous and they can be used to generalize geological events.