NORCE Research Archive
Not a member yet
3811 research outputs found
Sort by
Bayesian model evaluation for multiple scenarios
Get PDFTraditional uncertainty analysis for subsurface models is typically based on a single dynamic model with a number of uncertain parameters. Improved and more robust forecasting can be obtained by combining several models in a Bayesian setting using model averaging. The traditional Bayesian Model Averaging (BMA), however, suffers from several drawbacks, such as too large sensitivity to prior model assumptions and instability with respect to measurement perturbations, especially when the number of measurements is large. We suggest a modified version of BMA (MBMA) where the calculations are stabilized using an ensemble of measurements. Bayesian stacking (BS) is a method that is directly focused on the performance of the combined predictive distribution of several models. The original version of BS (BSLOO) is based on leave-one-out cross-validation and requires a Bayesian inversion for each data point which may be very time consuming. We suggest a modified version of stacking (MBS) that requires only a single history match and uses an ensemble of measurements. MBS may be used with either prior (MBS-pri) or posterior (MBS-post) predictive distributions. The behavior of the methods is illustrated using three synthetic, linear examples. One is a simple mixture model. The other two are inspired by 4D seismic data. The results with MBS-pri are very similar to the results with MBMA. The results with MBS-post are similar to those of BSLOO when the data are uncorrelated. MBS can take into account correlated data or measurement errors, while correlations are neglected in the BSLOO weight calculations.publishedVersio
Geologi, jordsmonn og botaniske undersøkelser på Lisle Lyngøy (delrapport 1)
No full textLisle Lyngøya ligger i nordspissen av Øygarden kommune, som geologisk sett er en del av den norske strandflaten. Strandflaten er karakterisert av nederodert lavland, og strekker seg langs hele norskekysten med unntak av områder i Stad, Lofoten og Finnmark (hvor det er klippekyst). Kjennetegnet på strandflaten er mye skrinne vegetasjonsfattige og karrige områder med mye øyer, viker og skjær. Viker vendt mot sørvest fører marint materiale, deriblant makroplast opp i strandsonen i såkalt stormpåvirkede driftsvoller. Disse akkumulasjonspunktene er typisk i viker som er vendt mot sørvest altså mot dominerende vindretning. I en tidligere studie (Bastesen 2019), ble hele Øygarden kartlagt. Det ble funnet opp imot 800 potensielle viker med plast. Lisla Lyngøya er spesiell da den, basert på vår kunnskap, ikke har vært ryddet nevneverdig siden 1960, og dermed representer et område hvor plast og natur har sameksistert lenge.Geologi, jordsmonn og botaniske undersøkelser på Lisle Lyngøy (delrapport 1)publishedVersio
The dissolution of a miscible drop rising or falling in another liquid at low Reynolds number
Get PDF“A basic and basically unsolved problem in fluid dynamics is to determine the evolution of rising bubbles and falling drops of one miscible liquid in another” [D. D. Joseph and Y. Y. Renardy, Fundamentals of Two-Fluid Dynamics: Part II: Lubricated Transport, Drops and Miscible Liquids (Springer Science & Business Media, 2013), Vol. 4.]. Here, we address this important literature gap and present the first theory predicting the velocity, volume, and composition of such drops at low Reynolds numbers. For the case where the diffusion out of the drop is negligible, we obtain a universal scaling law. For the more general case where diffusion occurs into and out of the drop, the full dynamics is governed by a parameter-free first-order ordinary differential equation, whose closed form solution exists and only depends on the initial condition. Our analysis depends primarily on “drop-scale” effective parameters for the diffusivity through the interfacial boundary layer. We validate our results against experimental data for water drops suspended in syrup, corresponding to certain regimes of the mass exchange ratio between water and syrup, and by this explicitly identify the drop-scale parameters of the theory.The dissolution of a miscible drop rising or falling in another liquid at low Reynolds numberacceptedVersio
Carbon capture and storage - Publics in five countries around the north sea prefer to do it on their own territory
Get PDFCarbon Capture and Storage (CCS) has been identified as an essential part of the lowest-cost path toward reaching the goals of the Paris Agreement. In Europe, an accelerated pace of CCS development indicates that a CO2 transport and storage system could be established by 2030. However, we know little about how the public views the market for transport and storage of CO2 currently under development in Europe. In early 2023, we conducted an experimental comparative survey to study public opinions on cross-border CO2 trade for storage in Denmark, Germany, the Netherlands, Norway and the UK. The share of respondents that perceive CCS as somewhat positive or very positive varies considerably between the countries; we find the highest share in Denmark (69%), followed by the UK (68%), Norway (67%), the Netherlands (57%) and the lowest share in Germany (49%). Especially concerns about environmental risks and costs lead to more negative views, while perceptions of job creation and economic opportunities lead to more positive evaluations. The experimental results show that importing CO2 for storage is among the least preferred options in all countries, while the storage of CO2 that has been captured in the own country is the most preferred option; the gap in the share of positive evaluations is substantial and amounts to up to 20 percentage points in the UK. Respondents who feel that countries are responsible for reducing national greenhouse gas emissions and storing their own captured CO2 drive the pattern of a more positive evaluation of a domestic CCS value chain and a more negative evaluation of importing CO2.Carbon capture and storage - Publics in five countries around the north sea prefer to do it on their own territorypublishedVersio
Uformelle tilleggstenester og fråverande politisk interesserepresentasjon? Frivillige organisasjonar sine relasjonar til kommunar innan helse- og omsorg i Noreg
Get PDFFrivillige organisasjonar er hevda å kunne bidra i velferdsproduksjon på måtar offentlege og kommersielle aktørar ikkje kan. Overordna kan ein skilje mellom bidrag i form av politisk interesserepresentasjon i utviklinga av velferdstenester og i form av sjølve produksjonen av velferdstenester. Med utgangspunkt i manglande kunnskap om utbreiing av dei to ulike typane velferdsbidrag frå frivillige organisasjonar i Noreg drøftar og undersøker eg empirisk i denne artikkelen i kva grad frivillige organisasjonar innan helse- og omsorgsfeltet har relasjonar til kommunar som omhandlar tenesteproduksjon og politisk interessepresentasjon, i kva grad relasjonar er formaliserte og institusjonaliserte, og kven som har definisjonsmakt og styringskontroll i relasjonane. Kvantitative analyser av data frå ei spørjeundersøking blant 465 frivillige helse- og omsorgsorganisasjonar syner her at organisasjonar sine relasjonar til kommunar i relativt stor grad handlar om formell interesserepresentasjon og til ein viss grad om samarbeid om kommunal tenesteyting, men er dominert av mindre institusjonalisert enkeltsakssamarbeid. Det ligg her eit potensial til å betre dra nytte av frivillig sektor sine særbidrag i utviklinga av og i produksjonen av velferdstenester i Noreg. For å få til dette kan ei forbetring av dei grunnleggande rammevilkåra for frivillige organisasjonar innan helse og omsorg vere ein viktig faktor.publishedVersio
Nitrogen fixation rates in the Guinea Dome and the equatorial upwelling regions in the Atlantic Ocean
Get PDFBiological nitrogen fixation is a key process balancing the loss of combined nitrogen in the marine nitrogen cycle. Its relevance in upwelling or high nutrient regions is still unclear, with the few available studies in these regions of the ocean reporting rates that vary widely from below detection limit to > 100 nmol N L−1 d−1. In the eastern tropical Atlantic Ocean, two open ocean upwelling systems are active in boreal summer. One is the seasonal equatorial upwelling, where the residual phosphorus associated with aged upwelled waters is suggested to enhance nitrogen fixation in this season. The other is the Guinea Dome, a thermal upwelling dome. We conducted two surveys along 23° W across the Guinea Dome and the Equator from 15° N to 5° S in September 2015 and August–September 2016 with high latitudinal resolution (20–60 nm between stations). The abundance of Trichodesmium colonies was characterized by an Underwater Vision Profiler 5 and the total biological nitrogen fixation in the euphotic layer was measured using the 15N2 technique. The highest abundances of Trichodesmium colonies were found in the area of the Guinea Dome (9°–15° N) with a maximum of 3 colonies L−1 near the surface. By contrast, colonies were almost absent in the Equatorial band between 2° N and 5° S. The highest nitrogen fixation rate was measured at the northern edge of the Guinea Dome in 2016 (ca. 31 nmol N L−1 d−1). In this region, where diazotrophs thrived on a sufficient supply of both phosphorus and iron, a patchy distribution was unveiled by our increased spatial resolution scheme. In the Equatorial band, rates were considerably lower, ranging from below detection limit to ca. 4 nmol N L−1 d−1, with a clear difference in magnitude between 2015 (rates close to zero) and 2016 (average rates around 2 nmol N L−1 d−1). This difference seemed triggered by a contrasting supply of phosphorus between years. Our study stresses the importance of surveys with sampling at fine-scale spatial resolution, and shows unexpected high variability in the rates of nitrogen fixation in the Guinea Dome, a region where diazotrophy is a significant process supplying new nitrogen into the euphotic layer.publishedVersio
Family-like Relationships and Wellbeing of Young Refugees in Finland, Norway, and Scotland
Get PDFAbstract: In this article, we explore the role of family-like relationships in creating wellbeing for unaccompanied minor refugees (UMRs) to Europe. Our theoretical point of departure is a relational approach to wellbeing as conceptualized by Sarah C. White. The data comprises interviews with 51 settled UMRs in Finland, Norway, and Scotland, focused on their social networks, and a selection of paired interviews with young people alongside someone they defined as family-like and important for their wellbeing today. Findings illuminate the important role family-like relationships have in meeting the daily needs of young refugees. These relationships are ascribed meaning in the context of young people’s wider networks and ideas of ‘what family should do’. Family-like relationships gain particular importance for UMRs in two different ways: first, the physical absence of the family of origin enforces children and young people’s need to create trusted, reciprocal networks. Second, building family-like relationships is necessary in a new country where UMRs grow up and face new expectations, needs, and opportunities. We argue that relational wellbeing is built in a hybrid ‘third space’. A welfare state should support the wellbeing of UMRs by nurturing welcoming communities and providing UMRs help with building family-like relationships through formal and other support networks.Family-like Relationships and Wellbeing of Young Refugees in Finland, Norway, and ScotlandpublishedVersio
Arctic sea ice mass balance in a new coupled ice–ocean model using a brittle rheology framework
Get PDFSea ice is a key component of the Earth's climate system as it modulates the energy exchanges and associated feedback processes at the air–sea interface in polar regions. These exchanges have been suggested to strongly depend on openings in the sea ice cover, which are associated with fine-scale sea ice deformations, but the importance of these processes remains poorly understood as most numerical models struggle to represent these deformations without using very costly horizontal resolutions (≃ 5 km). In this study, we present results from a 12 km resolution ocean–sea ice coupled model, the first that uses a brittle rheology to represent the mechanical behaviour of sea ice. This rheology has been shown to reproduce observed characteristics and complexity of fine-scale sea ice deformations at relatively coarse resolutions. We evaluate and discuss the Arctic sea ice mass balance of this coupled model for the period 2000–2018. We first assess sea ice quantities relevant for climate (volume, extent, and drift) and find that they are consistent with satellite observations. We evaluate components of the mass balance for which observations are available, i.e. sea ice volume export through Fram Strait and winter mass balance in the Arctic marginal seas for the period 2003–2018. Model values show a good match with observations, remaining within the estimated uncertainty, and the interannual variability of the dynamic contribution to the winter mass balance is generally well captured. We discuss the relative contributions of dynamics and thermodynamics to the sea ice mass balance in the Arctic Basin for 2000–2018. Using the ability of the model to represent divergence motions at different scales, we investigate the role of leads and polynyas in ice production. We suggest a way to estimate the contribution of leads and polynyas to ice growth in winter, and we estimate this contribution to add up to 25 %–35 % of the total ice growth in pack ice from January to March. This contribution shows a significant increase over 2000–2018. This coupled framework opens up new opportunities to understand and quantify the interplay between small-scale sea ice dynamics and ocean properties.publishedVersio
Global impacts of COVID-19 pandemic on sexual and reproductive health services: An international comparative study on primary care from the INTRePID Consortium
Get PDFObjective To understand how the COVID-19 pandemic has impacted sexual and reproductive health (SRH) visits. Design An ecological study comparing SRH services volume in different countries before and after the onset of the COVID-19 pandemic. Setting Seven countries from the INTernational ConsoRtium of Primary Care BIg Data Researchers (INTRePID) across four continents. Population Over 3.8 million SRH visits to primary care physicians in Australia, China, Canada, Norway, Singapore, Sweden and the USA. Methods Difference in average SRH monthly visits before and during the pandemic, with negative binomial regression modelling to compare predicted and observed number of visits during the pandemic for SRH visits. Main outcome measures Monthly number of visits to primary care physicians from 2018 to 2021. Results During the pandemic, the average volume of monthly SRH visits increased in Canada (15.6%, 99% CI 8.1–23.0%) where virtual care was pronounced. China, Singapore, Sweden and the USA experienced a decline (−56.5%, 99% CI −74.5 to −38.5%; −22.7%, 99% CI −38.8 to −6.5%; −19.4%, 99% CI −28.3 to −10.6%; and −22.7%, 99% CI −38.8 to −6.5%, respectively); while Australia and Norway showed insignificant changes (6.5%, 99% CI −0.7 to –13.8% and 1.7%, 99% CI −6.4 to –9.8%). The countries that maintained (Australia, Norway) or surpassed (Canada) pre-pandemic visit rates had the greatest use of virtual care. Conclusions In-person SRH visits to primary care decreased during the pandemic. Virtual care seemed to counterbalance that decline. Although cervical cancer screening appeared insensitive to virtual care, strategies such as incorporating self-collected samples for HPV testing may provide a solution in a future pandemic.publishedVersio
Regional water cycle sensitivity to afforestation: synthetic numerical experiments for tropical Africa
Get PDFAfforestation as a climate change mitigation option has been the subject of intense debate and study over the last few decades, particularly in the tropics where agricultural activity is expanding. However, the impact of such landcover changes on the surface energy budget, temperature, and precipitation remains unclear as feedbacks between various components are difficult to resolve and interpret. Contributing to this scientific debate, regional climate models of varying complexity can be used to test how regional climate reacts to afforestation. In this study, the focus is on the gauged Nzoia basin (12,700 km2) located in a heavily farmed region of tropical Africa. A reanalysis product is dynamically downscaled with a coupled atmospheric-hydrological model (WRF-Hydro) to finely resolve the land-atmosphere system in the Nzoia region. To overcome the problem of Nzoia river flooding over its banks we enhance WRF-Hydro with an overbank flow routing option, which improves the representation of daily discharge based on the Nash-Sutcliffe efficiency and Kling-Gupta efficiency (from −2.69 to 0.30, and −0.36 to 0.63, respectively). Changing grassland and cropland areas to savannas, woody savannas, and evergreen broadleaf forest in three synthetic numerical experiments allows the assessment of potential regional climate impacts of three afforestation strategies. In all three cases, the afforestation-induced decrease in soil evaporation is larger than the afforestation-induced increase in plant transpiration, thus increasing sensible heat flux and triggering a localized negative feedback process leading to more precipitation and more runoff. This effect is more pronounced with the woody savannas experiment, with 7% less evapotranspiration, but 13% more precipitation, 8% more surface runoff, and 12% more underground runoff predicted in the Nzoia basin. This study demonstrates a potentially large impact of afforestation on regional water resources, which should be investigated in more detail for policy making purposes.publishedVersio