Gå til innhold
  • Send

  • Kategori

  • Sorter etter

  • Antall per side

Fant 2640 publikasjoner. Viser side 80 av 264:

Publikasjon  
År  
Kategori

Temporal variability in surface water pCO2 in Adventfjorden (West Spitsbergen) with emphasis on physical and biogeochemical drivers

Ericson, Ylva; Falck, Eva; Chierici, Melissa; Fransson, Agneta Ingrid; Kristiansen, Svein; Platt, Stephen Matthew; Hermansen, Ove; Myhre, Cathrine Lund

American Geophysical Union (AGU)

2018

Polychlorinated biphenyls (PCBs) as sentinels for the elucidation of Arctic environmental change processes: a comprehensive review combined with ArcRisk project results

Carlsson, Pernilla; Breivik, Knut; Brorström-Lundén, Eva; Cousins, Ian; Christensen, Jesper; Grimalt, Joan O.; Halsall, Crispin; Kallenborn, Roland; Abass, Khaled; Lammel, Gerhard; Munthe, John; MacLeod, Matthew; Odland, Jon Øyvind; Pawlak, Janet; Rautio, Arja; Reiersen, Lars-Otto; Schlabach, Martin; Stemmler, Irene; Wilson, Simon; Wöhrnschimmel, Henry

Polychlorinated biphenyls (PCBs) can be used as chemical sentinels for the assessment of anthropogenic influences on Arctic environmental change. We present an overview of studies on PCBs in the Arctic and combine these with the findings from ArcRisk—a major European Union-funded project aimed at examining the effects of climate change on the transport of contaminants to and their behaviour of in the Arctic—to provide a case study on the behaviour and impact of PCBs over time in the Arctic. PCBs in the Arctic have shown declining trends in the environment over the last few decades. Atmospheric long-range transport from secondary and primary sources is the major input of PCBs to the Arctic region. Modelling of the atmospheric PCB composition and behaviour showed some increases in environmental concentrations in a warmerArctic, but the general decline in
PCB levels is still the most prominent feature. ‘Within-Arctic’ processing of PCBs will be affected by climate change-related processes such as changing wet deposition. These in turn will influence biological exposure and uptake of PCBs. The pan-Arctic rivers draining large Arctic/sub-Arctic catchments provide a significant source of PCBs to the Arctic Ocean, although changes in hydrology/sediment transport combined with a changing marine environment remain areas of uncertainty with regard to PCB fate. Indirect effects of climate change on human exposure, such as a changing diet will influence and possibly reduce PCB
exposure for indigenous peoples. Body burdens of PCBs have declined since the 1980s and are predicted to decline further.

2018

Nitric oxide response to the April 2010 electron precipitation event: Using WACCM and WACCM-D with and without medium-energy electrons

Smith-Johnsen, Christine; Marsh, Daniel R.; Orsolini, Yvan; Tyssøy, Hilde Nesse; Hendrickx, Koen; Sandanger, Marit Irene J.; Ødegaard, Linn-Kristine Glesnes; Stordal, Frode

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

Ma, Shuangmei; Zhu, Congwen; Liu, Boqi; Zhou, Tianjun; Ding, Yihui; Orsolini, Yvan

American Meteorological Society

2018

The Global N2O model Intercomparison Project (NMIP): Objectives, simulation protocol and expected products

Tian, Hanqin; Yang, Jia; Lu, Chaoqun; Xu, Rongting; Canadell, Josep G.; Jackson, Robert; Arneth, Almut; Chang, Jinfeng; Chen, Guangsheng; Ciais, Philippe; Gerber, Stefan; Ito, Akihiko; Huang, Yuanyuan; Joos, Fortunat; Lienert, Sebastian; Messina, Palmira; Olin, Stefan; Pan, Shufen; Peng, Changhui; Saikawa, Eri; Thompson, Rona Louise; Vuichard, Nicolas; Winiwarter, Wilfried; Zaehle, Sönke; Zhang, Bowen; Zhang, Kerou; Zhu, Qiuan

American Meteorological Society

2018

Ash metrics for European and trans‐atlantic air routes during the Eyjafjallajökull eruption 14 April to 23 May 2010

Prata, A. J.; Kristiansen, Nina Iren; Thomas, Helen E.; Stohl, Andreas

American Geophysical Union (AGU)

2018

Modeling the Time-Variant Dietary Exposure of PCBs in China over the Period 1930 to 2100

Zhao, Shizhen; Breivik, Knut; Jones, Kevin C; Sweetman, Andrew J

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

Adapting to urban challenges in the Amazon: flood risk and infrastructure deficiencies in Belém, Brazil

Mansur, Andressa V.; Brondizio, Eduardo S.; Roy, Samapriya; Soares, Pedro Paulo de Miranda Araújo; Newton, Alice

2018

Influence of solar wind energy flux on the interannual variability of ENSO in the subsequent year

He, Shengping; Wang, Hui-Jun; Gao, Yongqi; Li, Fei; Li, Hui; Wang, Chi

Science Press

2018

Publikasjon
År
Kategori