Fant 9890 publikasjoner. Viser side 110 av 396:
2018
A Lagrangian particle dispersion model, the FLEXible PARTicle dispersion chemical transport model (FLEXPART CTM), is used to simulate global three-dimensional fields of trace gas abundance. These fields are constrained with surface observation data through nudging, a data assimilation method, which relaxes model fields to observed values. Such fields are of interest to a variety of applications, such as inverse modelling, satellite retrievals, radiative forcing models and estimating global growth rates of greenhouse gases. Here, we apply this method to methane using 6 million model particles filling the global model domain. For each particle, methane mass tendencies due to emissions (based on several inventories) and loss by reaction with OH, Cl and O(1D), as well as observation data nudging were calculated. Model particles were transported by mean, turbulent and convective transport driven by 1∘×1∘ ERA-Interim meteorology. Nudging is applied at 79 surface stations, which are mostly included in the World Data Centre for Greenhouse Gases (WDCGG) database or the Japan–Russia Siberian Tall Tower Inland Observation Network (JR-STATION) in Siberia. For simulations of 1 year (2013), we perform a sensitivity analysis to show how nudging settings affect modelled concentration fields. These are evaluated with a set of independent surface observations and with vertical profiles in North America from the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL), and in Siberia from the Airborne Extensive Regional Observations in SIBeria (YAK-AEROSIB) and the National Institute for Environmental Studies (NIES). FLEXPART CTM results are also compared to simulations from the global Eulerian chemistry Transport Model version 5 (TM5) based on optimized fluxes. Results show that nudging strongly improves modelled methane near the surface, not only at the nudging locations but also at independent stations. Mean bias at all surface locations could be reduced from over 20 to less than 5 ppb through nudging. Near the surface, FLEXPART CTM, including nudging, appears better able to capture methane molar mixing ratios than TM5 with optimized fluxes, based on a larger bias of over 13 ppb in TM5 simulations. The vertical profiles indicate that nudging affects model methane at high altitudes, yet leads to little improvement in the model results there. Averaged from 19 aircraft profile locations in North America and Siberia, root mean square error (RMSE) changes only from 16.3 to 15.7 ppb through nudging, while the mean absolute bias increases from 5.3 to 8.2 ppb. The performance for vertical profiles is thereby similar to TM5 simulations based on TM5 optimized fluxes where we found a bias of 5 ppb and RMSE of 15.9 ppb. With this rather simple model setup, we thus provide three-dimensional methane fields suitable for use as boundary conditions in regional inverse modelling as a priori information for satellite retrievals and for more accurate estimation of mean mixing ratios and growth rates. The method is also applicable to other long-lived trace gases.
2018
This paper presents the results of BC inversions at high northern latitudes (>50°N) for the 2013–2015 period. A sensitivity analysis was performed to select the best representative species for BC and the best a priori emission dataset. The same model ensemble was used to assess the uncertainty of the a posteriori emissions of BC due to scavenging and removal and due to the use of different a priori emission inventory. A posteriori concentrations of BC simulated over Arctic regions were compared with independent observations from flight and ship campaigns showing, in all cases, smaller bias, which in turn witnesses the success of the inversion. The annual a posteriori emissions of BC at latitudes above 50°N were estimated as 560±171ktyr−1, significantly smaller than in ECLIPSEv5 (745ktyr−1), which was used and the a priori information in the inversions of BC. The average relative uncertainty of the inversions was estimated to be 30%.
A posteriori emissions of BC in North America are driven by anthropogenic sources, while biomass burning appeared to be less significant as it is also confirmed by satellite products. In northern Europe, a posteriori emissions were estimated to be half compared to the a priori ones, with the highest releases to be in megacities and due to biomass burning in eastern Europe. The largest emissions of BC in Siberia were calculated along the transect between Yekaterinsburg and Chelyabinsk. The optimised emissions of BC were high close to the gas flaring regions in Russia and in western Canada (Alberta), where numerous power and oil and gas production industries operate. Flaring emissions in Nenets–Komi oblast (Russia) were estimated to be much lower than in the a priori emissions, while in Khanty-Mansiysk (Russia) they remained the same after the inversions of BC. Increased emissions at the borders between Russia and Mongolia are probably due to biomass burning in villages along the Trans-Siberian Railway. The maximum BC emissions in high northern latitudes (>50°N) were calculated for summer months due to biomass burning and they are controlled by seasonal variations in Europe and Asia, while North America showed a much smaller variability.
2018
During an exceptionally warm September of 2016, the unique, stable weather conditions over Poland allowed for an extensive testing of the new algorithm developed to improve the Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI) aerosol optical depth (AOD) retrieval. The development was conducted in the frame of the ESA-ESRIN SAMIRA project. The new AOD algorithm aims at providing the aerosol optical depth maps over the territory of Poland with a high temporal resolution of 15 minutes. It was tested on the data set obtained between 11-16 September 2016, during which a day of relatively clean atmospheric background related to an Arctic airmass inflow was surrounded by a few days with well increased aerosol load of different origin. On the clean reference day, for estimating surface reflectance the AOD forecast available on-line via the Copernicus Atmosphere Monitoring Service (CAMS) was used. The obtained AOD maps were validated against AODs available within the Poland-AOD and AERONET networks, and with AOD values obtained from the PollyXT-UW lidar. of the University of Warsaw (UW).
EDP Sciences
2018
The PLASTOX project investigates the ingestion, food-web transfer, and ecotoxicological impact of microplastics (MPs), together with the persistent organic pollutants (POPs), metals and plastic additive chemicals associated with them, on key European marine species and ecosystems. PLASTOX combines field-based observations, laboratory tests and manipulative field experiments to study the ecological effects of MPs.
As part of a long-term field experiment conducted at marine locations across Europe (Mediterranean to Arctic), a range of different virgin polymer pellets, post-use polymers (LDPE, PP, PS and PET), as well as marine litter-derived microplastic particles, were deployed underwater for up to 12 months in the small boat harbour of Tromsø, Northern Norway. The deployment device consisted of an empty stainless steel SPMD canister, with the various plastic types placed in reusable, empty 'teabags' made of PP, placed separately in nylon netting. Sampling was conducted 1 week, 1 month, 3 months, 6 months and 12 months after deployment. Hydrophobic persistent organic pollutants such as PAHs, PCBs, DDTs, PBDEs and pesticides that had become associated with the plastic were measured and their adsorption kinetics in seawater under Arctic conditions established. Samples were extracted using ultrasound and non-polar solvents, followed by GPC and SPE clean up prior to chemical analysis and quantification by GC/MS/MS and GC/qMS. The release kinetics of common plastic additives, including phthalates, organophosphate esters, bisphenols and perfluorinated chemicals, were estimated from four types of post-industrial virgin pellets (LDPE, PS, PVC, PET) according to the same sampling protocol. Chemical analysis was performed using either GC/MS or LC-QTOF.
Results show that HCB and PCBs represented the dominant pollutant classes adsorbing to all of the different polymer types, but at concentrations that are more than 10-times lower than those previously reported. However, equilibrium between pollutants and the polymers was not reached during the deployment period, indicating that Arctic conditions may result in different sorption kinetics than observed in temperate regions.
2018
Impacts of the autumn Arctic sea ice on the intraseasonal reversal of the winter Siberian high
Science Press
2018
2018
NILU’s Environmental Management Report 2017
One of NILU’s main goals is to study the impact of pollution and supply decision-makers with a sound scientific platform for choosing measures to reduce the negative impacts. Furthermore, it is very important for the institute to have control of the impact the institute’s own activities may have on the environment and to reduce negative impacts as far as possible.
NILU has for many years been working to improve the status of the environment and to reduce negative impacts. In order to take this one step further, it was decided that the institute should restructure the work according to a relevant environmental standard and to seek certification according to the same standard.
The chosen standard is ISO 14001:2004 (Environmental management systems—Requirements with guidance for use) and NILU achieved certification according to this standard in October 2010. This report summarizes the results of the system in 2017.
NILU
2018
2018
Coral Reef Socio-Ecological Systems Analysis & Restoration
Restoration strategies for coral reefs are usually focused on the recovery of bio-physical characteristics. They seldom include an evaluation of the recovery of the socio-ecological and ecosystem services features of coral reef systems. This paper proposes a conceptual framework to address both the socio-ecological system features of coral reefs with the implementation of restoration activity for degraded coral reefs. Such a framework can lead to better societal outcomes from restoration activities while restoring bio-physical, social and ecosystem service features of such systems. We first developed a Socio Ecological System Analysis Framework, which combines the Ostrom Framework for analyzing socio-ecological systems and the Kittinger et al. human dimensions framework of coral reefs socio-ecological systems. We then constructed a Restoration of Coral Reef Framework, based on the most used and recent available coral reef restoration literature. These two frameworks were combined to present a Socio-Ecological Systems & Restoration Coral Reef Framework. These three frameworks can be used as a guide for managers, researchers and decision makers to analyze the needs of coral reef restoration in a way that addresses both socio-economic and ecological objectives to analyze, design, implement and monitor reef restoration programs.
MDPI
2018
Concentrations of organohalogenated contaminants (OHCs) can show significant temporal and spatial variation in the environment and wildlife. Most of the variation is due to changes in use and production, but environmental and biological factors may also contribute to the variation. Nestlings of top predators are exposed to maternally transferred OHCs in the egg and through their dietary intake after hatching. The present study investigated spatial and temporal variation of OHCs and the role of age and diet on these variations in plasma of Norwegian white-tailed eagle (Haliaeetus albicilla) nestlings. The nestlings were sampled at two locations, Smøla and Steigen, in 2015 and 2016. The age of the nestlings was recorded (range: 44 - 87 days old) and stable carbon and nitrogen isotopes (δ13C and δ15N) were applied as dietary proxies for carbon source and trophic position, respectively. In total, 14 polychlorinated biphenyls (PCBs, range: 0.82 - 59.05 ng/mL), 7 organochlorinated pesticides (OCPs, range: 0.89 - 52.19 ng/mL), 5 polybrominated diphenyl ethers (PBDEs, range: 0.03 - 2.64 ng/mL) and 8 perfluoroalkyl substances (PFASs, range: 4.58 - 52.94 ng/mL) were quantified in plasma samples from each location and year. The OHC concentrations, age and dietary proxies displayed temporal and spatial variations. The age of the nestlings was indicated as the most important predictor for OHC variation as the models displayed significantly decreasing plasma concentrations of PCBs, OCPs, and PBDEs with increasing age, while concentrations of PFASs were significantly increasing with age. Together with age, the variations in PCB, OCP and PBDE concentrations were also explained by δ13C and indicated decreasing concentrations with a more marine diet. Our findings emphasise age and diet as important factors to consider when investigating variations in plasma OHC concentrations in nestlings.
Elsevier
2018
2018
Spesifikasjoner for sensorsystemer til måling av luftkvalitet. Anbefalinger ved anskaffelse.
Denne rapporten forklarer tekniske begrep knyttet til måleytelse, samt gir anbefalinger og krav i forbindelse med utarbeidelse av anbud. Rapporten går gjennom eksisterende instrumentering til luftkvalitetsmåling i Norge og gjeldende lovgivning rundt temaet. Den nevner mulige applikasjoner for ny sensorteknologi. En oversikt over metrologiske begrep sammen med forklaringer gir leseren grunnleggende kunnskap for å kunne tolke instrumentspesifikasjoner. Rapporten identifiserer noen viktige parametere knyttet til kvaliteten på sensorsystemer.
NILU
2018
2018