Fant 9747 publikasjoner. Viser side 349 av 390:
2013
The MEMORI technology - an innovative tool for the protection of movable cultural assets. Lecture Notes in Computer Science, 7616
2012
We present here emissions estimated from a newly developed emission model for residential wood combustion (RWC) at high spatial and temporal resolution, which we name the MetVed model. The model estimates hourly emissions resolved on a 250 m grid resolution for several compounds, including particulate matter (PM), black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) in Norway for a 12-year period. The model uses novel input data and calculation methods that combine databases built with an unprecedented high level of detail and near-national coverage. The model establishes wood burning potential at the grid based on the dependencies between variables that influence emissions: i.e. outdoor temperature, number of and type and size of dwellings, type of available heating technologies, distribution of wood-based heating installations and their associated emission factors. RWC activity with a 1 h temporal profile was produced by combining heating degree day and hourly and weekday activity profiles reported by wood consumers in official statistics. This approach results in an improved characterisation of the spatio-temporal distribution of wood use, and subsequently of emissions, required for urban air quality assessments. Whereas most variables are calculated based on bottom-up approaches on a 250 m spatial grid, the MetVed model is set up to use official wood consumption at the county level and then distributes consumption to individual grids proportional to the physical traits of the residences within it. MetVed combines consumption with official emission factors that makes the emissions also upward scalable from the 250 m grid to the national level.
The MetVed spatial distribution obtained was compared at the urban scale to other existing emissions at the same scale. The annual urban emissions, developed according to different spatial proxies, were found to have differences up to an order of magnitude. The MetVed total annual PM2.5 emissions in the urban domains compare well to emissions adjusted based on concentration measurements. In addition, hourly PM2.5 concentrations estimated by an Eulerian dispersion model using MetVed emissions were compared to measurements at air quality stations. Both hourly daily profiles and the seasonality of PM2.5 show a slight overestimation of PM2.5 levels. However, a comparison with black carbon from biomass burning and benzo(a)pyrene measurements indicates higher emissions during winter than that obtained by MetVed. The accuracy of urban emissions from RWC relies on the accuracy of the wood consumption (activity data), emission factors and the spatio-temporal distribution. While there are still knowledge gaps regarding emissions, MetVed represents a vast improvement in the spatial and temporal distribution of RWC.
2019
2021
2019
The miniaturized enzyme-modified comet assay for genotoxicity testing of nanomaterials
The in vitro comet assay is a widely applied method for investigating genotoxicity of chemicals including engineered nanomaterials (NMs). A big challenge in hazard assessment of NMs is possible interference between the NMs and reagents or read-out of the test assay, leading to a risk of biased results. Here, we describe both the standard alkaline version of the in vitro comet assay with 12 mini-gels per slide for detection of DNA strand breaks and the enzyme-modified version that allows detection of oxidized DNA bases by applying lesion-specific endonucleases (e.g., formamidopyrimidine DNA glycosylase or endonuclease III). We highlight critical points that need to be taken into consideration when assessing the genotoxicity of NMs, as well as basic methodological considerations, such as the importance of carrying out physicochemical characterization of the NMs and investigating uptake and cytotoxicity. Also, experimental design—including treatment conditions, cell number, cell culture, format and volume of medium on the plate—is crucial and can have an impact on the results, especially when testing NMs. Toxicity of NMs depends upon physicochemical properties that change depending on the environment. To facilitate testing of numerous NMs with distinct modifications, the higher throughput miniaturized version of the comet assay is essential.
Frontiers Media S.A.
2022
The Modeled Seasonal Cycles of Surface N2O Fluxes and Atmospheric N2O
Nitrous oxide (N2O) is a greenhouse gas and stratospheric ozone-depleting substance with large and growing anthropogenic emissions. Previous studies identified the influx of N2O-depleted air from the stratosphere to partly cause the seasonality in tropospheric N2O (aN2O), but other contributions remain unclear. Here, we combine surface fluxes from eight land and four ocean models from phase 2 of the Nitrogen/N2O Model Intercomparison Project with tropospheric transport modeling to simulate aN2O at eight remote air sampling sites for modern and pre-industrial periods. Models show general agreement on the seasonal phasing of zonal-average N2O fluxes for most sites, but seasonal peak-to-peak amplitudes differ several-fold across models. The modeled seasonal amplitude of surface aN2O ranges from 0.25 to 0.80 ppb (interquartile ranges 21%–52% of median) for land, 0.14–0.25 ppb (17%–68%) for ocean, and 0.28–0.77 ppb (23%–52%) for combined flux contributions. The observed seasonal amplitude ranges from 0.34 to 1.08 ppb for these sites. The stratospheric contributions to aN2O, inferred by the difference between the surface-troposphere model and observations, show 16%–126% larger amplitudes and minima delayed by ∼1 month compared to Northern Hemisphere site observations. Land fluxes and their seasonal amplitude have increased since the pre-industrial era and are projected to grow further under anthropogenic activities. Our results demonstrate the increasing importance of land fluxes for aN2O seasonality. Considering the large model spread, in situ aN2O observations and atmospheric transport-chemistry models will provide opportunities for constraining terrestrial and oceanic biosphere models, critical for projecting carbon-nitrogen cycles under ongoing global warming.
American Geophysical Union (AGU)
2024
2021
2018
2008
Antarctica and the Southern Ocean are important parts of the Earth system. The physical and biological properties here to a large degree control and shape other parts of the Earth through atmospheric, cryospheric and oceanic connections. The Troll Observing Network – TONe - is a new comprehensive infrastructure centered around the Norwegian Troll Research Station in Dronning Maud Land. It will be an important contribution to global research efforts in this part of Antarctica, closing data gaps in Antarctic environmental observations and providing key data required to respond to the fundamental societal challenges and uncertainties facing the world today. The Norwegian and international partner consortium in TONe is in the process to develop the state-of-the-art, multi-platform, multi-disciplinary observatory network for environmental observations, and a remotely piloted aerial system (RPAS) services to collect data for studying and monitoring the atmosphere, terrestrial and marine environment. The observatory network consists of 8 observatories: an integrated cloud observatory, an atmosphere composition observatory, an infrasound array, an ionospheric observatory, a seismic array, an ice-shelf observatory, a multidisciplinary open ocean moored observatory and a sea-bird observatory. The key aspect of TONe is to ensure wide and free access to the data from the observatories and the RPAS services to the entire national and international research community. TONe as a whole will be implemented and fully operational from 2027, while single parts of the infrastructure will be available before that.
2023
The NextGEOSS Cold Region pilot: Improved discoverability and access to polar data
GEO Cold Regions coordinates global efforts to provide Earth Observation (EO) products and services to science, decision- and policy-makers with a vested interest in the cryosphere (in particular) and the environment (in general) of polar regions and mountain areas around the world. The NextGEOSS Cold Regions Pilot focuses on three areas: (1) the Arctic/Svalbard region, (2) Antarctica, and (3) the Himalayan glaciers, linking together satellite and in situ data from the targeted regions, including the atmospheric, marine, and terrestrial domains, and making them available in the NextGEOSS Data Hub and the NextGEOSS Cold Regions Community Portal. The pilot liaise with ongoing initiatives such as SIOS, GEOCRI, WMO GCW, as well as national programs in Antarctica. The products resulting from the Cold Regions pilot can be used to develop Information Services for the Cold Regions Initiative, using the NextGEOSS system and making use of existing interoperability standards. This presentation will introduce the first version of the Cold Regions Community Portal, aiming to make polar data relevant for Cold Regions more easily discoverable and accessible for users.
2021
The NILU aircraft plume model: A technical description. NILU TR
En plume-modell som beskriver kjemisk og fysisk utvikling av eksosen fra fly er utviklet. Denne rapporten gir en detaljert beskrivelse av plume-spredningen, diffusjonen i plumen og det kjemiske skjemaet som er inkludert i modellen.
1999
2006