Fant 9850 publikasjoner. Viser side 114 av 394:
Energetic electrons from the magnetosphere deposit their energy in the atmosphere and lead to production of nitric oxide (NO) in the mesosphere and lower thermosphere. We study the atmospheric NO response to a geomagnetic storm in April 2010 with WACCM (Whole Atmosphere Community Climate Model). Modeled NO is compared to observations by Solar Occultation For Ice Experiment/Aeronomy of Ice in the Mesosphere at 72–82°S latitudes. We investigate the modeled NOs sensitivity to changes in energy and chemistry. The electron energy model input is either a parameterization of auroral electrons or a full range energy spectrum (1–750 keV) from National Oceanic and Atmospheric Administration/Polar Orbiting Environmental Satellites and European Organisation for the Exploitation of Meteorological Satellites/Meteorological Operational satellites. To study the importance of ion chemistry for the production of NO, WACCM‐D, which has more complex ion chemistry, is used. Both standard WACCM and WACCM‐D underestimate the storm time NO increase in the main production region (90–110 km), using both electron energy inputs. At and below 80 km, including medium‐energy electrons (>30 keV) is important both for NO directly produced at this altitude region and for NO transported from other regions (indirect effect). By using WACCM‐D the direct NO production is improved, while the indirect effects on NO suffer from the downward propagating deficiency above. In conclusion, both a full range energy spectrum and ion chemistry is needed throughout the mesosphere and lower thermosphere region to increase the direct and indirect contribution from electrons on NO.
American Geophysical Union (AGU)
2018
Polarized response of East Asian winter temperature extremes in the era of Arctic warming
American Meteorological Society
2018
2018
American Meteorological Society
2018
2018
2018
2018
American Geophysical Union (AGU)
2018
2018
Modeling the Time-Variant Dietary Exposure of PCBs in China over the Period 1930 to 2100
This study aimed for the first time to reconstruct historical exposure profiles for PCBs to the Chinese population, by examining the combined effect of changing temporal emissions and dietary transition. A long-term (1930–2100) dynamic simulation of human exposure using realistic emission scenarios, including primary emissions, unintentional emissions, and emissions from e-waste, combined with dietary transition trends was conducted by a multimedia fate model (BETR-Global) linked to a bioaccumulation model (ACC-HUMAN). The model predicted an approximate 30-year delay of peak body burden for PCB-153 in a 30-year-old Chinese female, compared to their European counterpart. This was mainly attributed to a combination of change in diet and divergent emission patterns in China. A fish-based diet was predicted to result in up to 8 times higher body burden than a vegetable-based diet (2010–2100). During the production period, a worst-case scenario assuming only consumption of imported food from a region with more extensive production and usage of PCBs would result in up to 4 times higher body burden compared to consumption of only locally produced food. However, such differences gradually diminished after cessation of production. Therefore, emission reductions in China alone may not be sufficient to protect human health from PCB-like chemicals, particularly during the period of mass production. The results from this study illustrate that human exposure is also likely to be dictated by inflows of PCBs via the environment, waste, and food.
2018
Målet er å belyse hvilke kvalitetskrav som bør stilles til luftkvalitetsberegninger, kart og data til ulike bruksformål slik disse er formulert i norsk regelverk, herunder Forurensningsloven, Folkehelseloven, Plan- og bygningsloven, Retningslinje for behandling av luftkvalitet i arealplanlegging (T1520) m.fl. Miljødirektoratet ønsker å sikre god, enhetlig og sammenlignbar kvalitet og praksis på utredninger av luftkvalitet og har bedt om anbefalinger i form av denne rapporten.
For å få et best mulig grunnlag for å vurdere behovet for veiledning og kvalitetskriterier for ulike anvendelser, har det vært fokus på å innhente informasjon og innspill fra ulike brukergrupper og fagmiljøer. Det er gjennomført en spørreundersøkelse og det er arrangert flere møter og åpne kommentarrunder med ulike brukergrupper og fagmiljøer. Siden eventuelle kvalitetskrav vil kunne ha betydning for konkurranse i markedet og påvirke ressursbruken både hos private aktører og myndigheter, har brukermedvirkning vært et viktig element i dette arbeidet etter ønske fra oppdragsgiver.
NILU
2018