Nearshore wave forecasting and hindcasting by dynamical and statistical downscaling

A high-resolution nested WAM/SWAN wave model suite aimed at rapidly establishing nearshore wave forecasts as well as a climatology and return values of the local wave conditions with Rapid Enviromental Assessment (REA) in mind is described. The system is targeted at regions where local wave growth and partial exposure to complex open-ocean wave conditions makes diagnostic wave modelling difficult. SWAN is set up on 500 m resolution and is nested in a 10 km version of WAM. A model integration of more than one year is carried out to map the spatial distribution of the wave field. The model correlates well with wave buoy observations (0.96) but overestimates the wave height somewhat (18%, bias 0.29 m). To estimate wave height return values a much longer time series is required and running SWAN for such a period is unrealistic in a REA setting. Instead we establish a direction-dependent transfer function between an already existing coarse open-ocean hindcast dataset and the high-resolution nested SWAN model. Return values are estimated using ensemble estimates of two different extreme-value distributions based on the full 52 years of statistically downscaled hindcast data. We find good agreement between downscaled wave height and wave buoy observations. The cost of generating the statistically downscaled hindcast time series is negligible and can be redone for arbitrary locations within the SWAN domain, although the sectors must be carefully chosen for each new location. The method is found to be well suited to rapidly providing detailed wave forecasts as well as hindcasts and return values estimates of partly sheltered coastal regions.Comment: 20 pages, 7 figures and 2 tables, MREA07 special issue on Marine rapid environmental assessmen

Coping before, during and after a stay at a family treatment centre : A qualitative study based on conversations with former clients at Rachel Grepp Heimen

Denne studien er utført som en del av masterstudiet i sosialt arbeid ved Høgskolen i Oslo. Tema for studien er mestring hos tidligere beboere ved Rachel Grepp Heimen. Målet er å belyse og få kunnskap om hva de vektlegger som betydningsfullt ved oppholdet på institusjonen, og hvordan de opplever en endring av mestring. Dette blir belyst ut fra teori om mestring med fokus på såkalte mestringsressurser (selvopplevelse, nettverk og rammer som bolig, jobb, skole, jobb og penger). Jeg ønsker å bidra til å få frem denne kunnskapen og dermed øke forståelsen rundt tilbud som Rachel Grepp Heimen og bevisstheten rundt mestringsressurser som betydningsfullt for å kunne tilpasse seg sin livssituasjon. Denne studien er skrevet med utgangspunkt i fem kvalitative intervjuer av kvinner som har vært bosatt på institusjonen. De har til felles at de i en periode av livet befant seg i en vanskelig livssituasjon hvor de har hatt behov for hjelp fra profesjonelle. Studien er basert på deres opplevelse og erfaring og min (teoretiske) forståelse og drøfting av dette. Funnene er presentert i tema før, under og etter oppholdet som omhandler opplevelsen av: 1. Utfordringer før oppholdet 2. Oppholdet på institusjonen 3. Endring av mestringsressurser og oppholdets mulige bidrag til disse endringene Mine funn synes å vise at informantene finner betydning av oppholdet på institusjonen. Selv om ikke alle opplevde at oppholdet direkte bidro til at de endret livssituasjonen, finner jeg at informantene fremhever fellesskap, håp og at personalet alltid var der som en støtte når de skulle trenge det, som spesielt betydningsfullt. Min teoretiske forståelse er at mestring henger nært sammen med hvilke ressurser den enkelte har tilgjengelig. Hvilke mestringsressurser som synes å bli mest styrket under oppholdet varierer. Samtlige av informantene virket til å ha mangelfulle eller problemskapende nettverk før de flyttet til institusjonen. Det kommer ikke frem om dette var noe som ble direkte jobbet med under oppholdet, men jeg synes å se at endringer i deres selvopplevelse og studier/jobb tilknytning påvirker hvordan den enkelte samhandler og skaper seg nye nettverk. Jeg synes å se at mestringsressursene påvirker hverandre gjensidig positivt når de er tilstede. Funnene i undersøkelsen kan overføres til andre i lignende livssituasjon og er et bidrag til økt forståelse og kunnskap.This paper is part of the Master’s Program in Social Work at Oslo University College. The topic of the study is how former clients at the institution Rachel Grepp Heimen copes, aiming to get knowledge about what they see as the most important aspects of the stay at the institution, and how this has affected their own impression of ability to cope. Basis for the discussion is coping theory, focusing on coping resources (self-image, network, monetary and material resources). The author wishes to contribute to the understanding of change processes experienced at institutions as Rachel Grepp Heimen. The study is based on five qualitative interviews with women that are former clients of Rachel Grepp Heimen, having in common a former need for professional assistance due to difficult life situations. The discussion will be based on their own experiences before, during and after the stay, and the author’s (theoretical) understanding and analysis. The findings are presented thematically as their experience of : 1. Challenges before the stay 2. The actual stay 3. Change in coping resources and possible contributions related to the stay The findings in the study seem to indicate that the informants value the stay at the institution. Even if not all the informants attributed changes in their life situation directly to the stay, they all emphasize a heightened sense of community and hope, and the continuous support from the social workers as particularly valuable. The author’s theoretical understanding is that coping is closely connected to the resources being made available to the individual. What coping resources are strengthened during the stay seems to vary. All the informants seem to experience lacking or problematic social networks before moving to the institution. The study does not seem to show that the network aspect was specifically targeted during the stay, but the changes in the self-experience and social context (work/school) seems to improve the ability to interact and establish new social networks. This might indicate that coping resources (when present) have a mutual strengthening aspect. The findings may be applied to other individuals in similar life situations, and contributes to increased understanding and knowledge.Master i sosialt arbei

Beyond velocity and acceleration: Jerk, snap and higher derivatives

© 2016 IOP Publishing Ltd. The higher derivatives of motion are rarely discussed in the teaching of classical mechanics of rigid bodies; nevertheless, we experience the effect not only of acceleration, but also of jerk and snap. In this paper we will discuss the third and higher order derivatives of displacement with respect to time, using the trampolines and theme park roller coasters to illustrate this concept. We will also discuss the effects on the human body of different types of acceleration, jerk, snap and higher derivatives, and how they can be used in physics education to further enhance the learning and thus the understanding of classical mechanics concepts

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Direct application of geothermal energy

An overall treatment of direct geothermal applications is presented with an emphasis on the above-ground engineering. The types of geothermal resources and their general extent in the US are described. The potential market that may be served with geothermal energy is considered briefly. The evaluation considerations, special design aspects, and application approaches for geothermal energy use in each of the applications are considered. The present applications in the US are summarized and a bibliography of recent studies and applications is provided. (MHR

Modulation of Magnetospheric Substorm Frequency: Dipole Tilt and IMF By Effects

Substorm activity is heavily influenced by the Interplanetary Magnetic Field (IMF) Bz component and magnetospheric substorms occur most frequently when Bz is strongly negative. The substorm occurrence rate is also affected by the magnitude of the By component, but it is usually presumed that this contribution is independent of the sign of By. Using five independent substorm onset lists, we show that substorm activity does depend on the sign of By near the solstices. Specifically, we show that substorms occur more frequently when By and the dipole tilt angle Ψ have different signs as opposed to when they have the same sign. These results confirm that the magnetosphere exhibits an explicit dependence on the polarity of By for nonzero Ψ, as other recent studies have suggested, and imply variation in the dayside reconnection rate and/or the magnetotail response. On the other hand, we find no clear relationship between substorm intensity and By regardless of Ψ. Last, for the onset list based on identifying negative bays at auroral latitudes, we observe an overall trend of more frequent onsets for positive By, regardless of season. However, substorm frequency in the other four substorm lists does not exhibit an overall preference for positive By. We show that this phenomenon is very likely a consequence of the particular substorm identification method (i.e., identification of negative bays), which is affected by local ionospheric conditions that depend on By and Ψ.publishedVersio