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2021
2021
As the leading climate mode of wintertime climate variability over Europe, the North Atlantic Oscillation (NAO) has been extensively studied over the last decades. Recently, studies highlighted the state of the Eurasian cryosphere as a possible predictor for the wintertime NAO. However, missing correlation between snow cover and wintertime NAO in climate model experiments and strong non-stationarity of this link in reanalysis data are questioning the causality of this relationship.
Here we use the large ensemble of Atmospheric Seasonal Forecasts of the 20th Century (ASF-20C) with the European Centre for Medium-Range Weather Forecasts model, focusing on the winter season. Besides the main 110-year ensemble of 51 members, we investigate a second, perturbed ensemble of 21 members where initial (November) land conditions over the Northern Hemisphere are swapped from neighboring years. The Eurasian snow–NAO linkage is examined in terms of a longitudinal snow depth dipole across Eurasia. Subsampling the perturbed forecast ensemble and contrasting members with high and low initial snow dipole conditions, we found that their composite difference indicates more negative NAO states in the following winter (DJF) after positive west-to-east snow depth gradients at the beginning of November. Surface and atmospheric forecast anomalies through the troposphere and stratosphere associated with the anomalous positive snow dipole consist of colder early winter surface temperatures over eastern Eurasia, an enhanced Ural ridge and increased vertical energy fluxes into the stratosphere, with a subsequent negative NAO-like signature in the troposphere. We thus confirm the existence of a causal connection between autumn snow patterns and subsequent winter circulation in the ASF-20C forecasting system.
2021
2021
Long-term trends of air pollutants at national level 2005-2019
Trend calculations of air pollutants for the periods 2005-2019 have been applied. Sulphur dioxide shows the largest decrease of all pollutants with a reduction of the order of 60-70 %. The agreement between reported emission data and measured concentrations are quite good. For NO2, a mismatch between the trend in air concentrations and NOx emissions is found. While the overall NOx emissions are reported to be reduced by 45 %, the measured NO2 data indicate a decline of the order of 30 % although marked differences between the countries are found. This mismatch could not be explained by changes in meteorology as this is accounted for. Possible reasons for the mismatch could be the NO2/NOx ratio of the emissions, changes in baseline hemispheric ozone concentration and natural emissions. For PM data (PM10 and PM2.5) we find an opposite mismatch, meaning that the PM concentrations show stronger downward trends than the reported emissions. This is likely an effect of the importance of secondary aerosols which are mitigated by other activities than the direct PM emissions. An overall reduction in PM10 of the order of 30-38 % is found during 2005-2019 while the direct emissions give a reduction that is 5-10 percentage units smaller. Similar results are found for PM2.5, but these findings are uncertain due to the less amount of long-term data. For O3, our findings are in line with earlier studies noting that the annual mean ozone concentration has increased while the high peaks have been reduced. But the reduction of the peaks is now within only a few percent and non-significant, while for the 2000-2017 period it was significant and about 10%.
ETC/ATNI
2021
Ren luft for alle. ExtraStiftelsen project 2019/HE1-263918.
In 2019, in the framework of Oslo being European Green Capital, NILU invited students from elementary schools to
measure air pollution in their neighbourhood, using simple and affordable measuring methods based on paper and
Vaseline. The students prepared the measuring devices and selected the places where they wanted to monitor. After one
week, they retrieved the devices and used a scale to compare the amount of dust fastened to the Vaseline. All of the data
gathered by the students was uploaded by the teachers to a website (https://luftaforalle.nilu.no/), where a map showed all the results from the participating schools. The school campaign has helped researchers to get data on particulate matter from many places where data was not available, and has increased awareness among the children about the sustainability challenges cities are facing.
NILU
2021
Quality assurance and quality control procedure for national and Union GHG projections 2021
The quality assurance and quality control (QA/QC) procedure is an element of the QA/QC programme of the Union system for policies and measures and projections to be established in 2021 according to Article 39 of the Regulation on the Governance of the Energy Union and Climate Action (EU) 2018/1999. The European Environment Agency (EEA) is responsible for the annual implementation of the QA/QC procedures and is assisted by the European Topic Centre on Climate Change Mitigation and Energy (ETC/CME). The QA/QC procedure document describes QA/QC checks carried out at EU level on the national reported projections from Member States and on the compiled Union GHG projections. QA/QC procedures are performed at several different stages during the preparation of the national and Union GHG projections in order to aim to ensure the timeliness, transparency, accuracy, consistency, comparability and completeness of the reported information. The results of the 2021 QA/QC procedure are presented in the related paper ETC/CME Eionet Report 8/2021.
ETC/CME
2021
2021
DNA repair gene polymorphisms and chromosomal aberrations in healthy, nonsmoking population
Elsevier
2021
2021
2021
2021
Vurdering av utslipp til luft fra Wistingfeltet i Barentshavet. Underlag for konsekvensutredning.
NILU har vurdert miljøkonsekvensene av utslipp til luft fra fremtidig utbygging og drift av Wisting-feltet i Barentshavet. Utslipp av CO2, CH4, N2O og NMVOC er vurdert utfra bidrag til strålingspådriv/global oppvarming. Kraftforsyning fra land med sjøkabel vil sterkt redusere utslippene av CO2. Klimaeffekten av utslipp til luft fra produksjonen vil bli liten. Bidraget fra Wisting til eutrofiering og forsuring gjennom avsetning av NOx og SOx forventes å være lite og knapt målbart. Likeledes vil bidraget fra Wisting til ozonproduksjon være minimalt og knapt målbart. Klimaeffekten av BC-utslipp (Black Carbon) fra installasjonene på Wisting vil bli liten. Samtidig gir utslipp av BC i Arktis større effekt pr. utslippsenhet enn utslipp lenger sør. Det bør derfor være et mål å optimalisere faklingen fra Wisting slik at utslipp av BC blir redusert til et absolutt minimum.
NILU
2021
Transboundary particulate matter, photo-oxidants, acidifying and eutrophying components
Norwegian Meteorological Institute
2021
Why is the city's responsibility for its air pollution often underestimated? A focus on PM2.5
While the burden caused by air pollution in urban areas is well documented, the origin of this pollution and therefore the responsibility of the urban areas in generating this pollution are still a subject of scientific discussion. Source apportionment represents a useful technique to quantify the city's responsibility, but the approaches and applications are not harmonized and therefore not comparable, resulting in confusing and sometimes contradicting interpretations. In this work, we analyse how different source apportionment approaches apply to the urban scale and how their building elements and parameters are defined and set. We discuss in particular the options available in terms of indicator, receptor, source, and methodology. We show that different choices for these options lead to very large differences in terms of outcome. For the 150 large EU cities selected in our study, different choices made for the indicator, the receptor, and the source each lead to an average difference of a factor of 2 in terms of city contribution. We also show that temporal- and spatial-averaging processes applied to the air quality indicator, especially when diverging source apportionments are aggregated into a single number, lead to the favouring of strategies that target background sources while occulting actions that would be efficient in the city centre. We stress that methodological choices and assumptions most often lead to a systematic and important underestimation of the city's responsibility, with important implications. Indeed, if cities are seen as a minor actor, plans will target the background as a priority at the expense of potentially effective local actions.
2021
2021
2021
2021
2021