Mesoscale dynamics and boundary-layer structure in topographically forced low-level jets

Two types of mesoscale wind-speed jet and their effects on boundary-layer structure were studied. The first is a coastal jet off the northern California coast, and the second is a katabatic jet over Vatnajökull, Iceland. Coastal regions are highly populated, and studies of coastal meteorology are of general interest for environmental protection, fishing industry, and for air and sea transportation. Not so many people live in direct contact with glaciers but properties of katabatic flows are important for understanding glacier response to climatic changes. Hence, the two jets can potentially influence a vast number of people. Flow response to terrain forcing, transient behavior in time and space, and adherence to simplified theoretical models were examined. The turbulence structure in these stably stratified boundary layers was also investigated. Numerical modeling is the main tool in this thesis; observations are used primarily to ensure a realistic model behavior. Simple shallow-water theory provides a useful framework for analyzing high-velocity flows along mountainous coastlines, but for an unexpected reason. Waves are trapped in the inversion by the curvature of the wind-speed profile, rather than by an infinite stability in the inversion separating two neutral layers, as assumed in the theory. In the absence of blocking terrain, observations of steady-state supercritical flows are not likely, due to the diurnal variation of flow criticality. In many simplified models, non-local processes are neglected. In the flows studied here, we showed that this is not always a valid approximation. Discrepancies between simulated katabatic flow and that predicted by an analytical model are hypothesized to be due to non-local effects, such as surface inhomogeneity and slope geometry, neglected in the theory. On a different scale, a reason for variations in the shape of local similarity scaling functions between studies is suggested to be differences in non-local contributions to the velocity variance budgets.

'You Never Truly Feel at Home': Students' Perceptions of their Multilingualism and its Role in their Identity Construction : - A Study Performed in a Suburb Located in a Socially Vulnerable Area

A relevant subject in our globalized world concerns the relationship between language and identity, specifically amongst migrant youngsters’ experience of group belonging. This study therefore focused on how adolescents born to foreign parents in Sweden, perceived their multilingualism as part of their identity formation. I also aimed to include how socio-economic aspects could affect the process of identity construction. Thus, the investigation was performed with seventh grade students at a primary school located in the Stockholm suburb Bredäng. The methods consisted of a questionnaire, which was completed by the entire class and a group interview where six students participated. The results revealed that students adapted their language use based on the context, but Swedish was used most habitually. The informants viewed their multilingualism as beneficial but yet fully aware of the linguistic ideologies functioning in society. By combining their minority and majority language, the students were left with different ethnic identities and had diverse interpretations of what it meant to be Swedish. Even though all of them perceived themselves to have multiple ethnic identities, this was not solely seen positively. The issue of belonging was raised and the students claimed to be outcasts everywhere. However, the results differed depending on whether the students were born in Sweden or not. Also, most of them struggled with the process of assumed and ascribed identities, since they perceived themselves to be Swedish but experienced that society valued them as immigrants. Lastly, the study revealed that there were connections between their multilingualism and social mobility as the relationship towards the motherland was highly prioritized even with low levels of economic capital.