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The Arctic middle atmosphere was affected by major sudden stratospheric warmings (SSW) in February 2018 and January 2019, respectively. In this article, we report for the first time the impact of these two events on the middle atmospheric nitric oxide (NO) abundance. The study is based on measurements obtained during two dedicated observation campaigns, using the Sub-Millimetre Radiometer (SMR) aboard the Odin satellite, measuring NO globally since 2003. The SSW of February 2018 was similar to other, more dynamically quiet, Arctic winters in term of NO downward transport from the upper mesosphere–lower thermosphere to lower altitudes (referred to as energetic particle precipitation indirect effect EPP-IE). On the contrary, the event of January 2019 led to one of the strongest EPP-IE cases observed within the Odin operational period. Important positive NO anomalies were indeed observed in the lower mesosphere–upper stratosphere during the three months following the SSW onset, corresponding to NO volume mixing ratios more than 50 times higher than the climatological values. These different consequences on the middle atmospheric composition are explained by very different dynamical characteristics of these two SSW events.
Elsevier
2021
2021
Method for high resolution emission estimations from construction sites. Phase I: Mapping input data
Denne rapporten presenterer resultatene fra analyse av tilgjengelige inngangsdata for å utvikle en modell for estimering av luftforurensende stoffer og klimagassutslipp basert på en «bottom-up»-tilnærming, inkludert både eksos- og ikke-eksosutslipp. Tilgjengeligheten av pålitelige inngangsdata er den begrensende faktoren og den mest kritiske delen av utformingen av en slik «bottom-up»-tilnærming. I denne studien har vi fokusert på å vurdere inngangsdata som gjør det mulig å definere; i) den nøyaktige plasseringen og området som påvirkes under bygging og konstruksjon, ii) start- og sluttdatoer; iii) typen byggeaktivitet; iv) aktiviteter med ikke-veigående mobile maskiner (NRMM) innen bygg og anlegg; v) veier i nærheten av byggeplasser.
NILU
2021
2021
Vurdering av CLEO for norske reindriftsutøvere
Denne rapporten er en evaluering av Local Environmental Observer (LEO) Network ved bruk av erfaringene fra pilottestene utført i perioden 2016-2020 av arktiske akademikere, urfolksinstitusjoner og samisk samfunn i Norge. Rapporten prøver å finne svar på hvordan man kan tilrettelegge for innrapportering av observasjoner på lokale miljøendringer blant norske reindriftsutøvere samt opprettholde en utstrakt bruk. Dette for å skape engasjement, bevisstgjøring, forsterke lokale stemmer og identifisere svar på viktige miljøutfordringer og mulige handlinger, og søke konstruktive og respektfulle måter å dele informasjon og samarbeid mellom ulike kunnskapssystemer.
Rapporten konkluderer med at for å gjøre det mulig for norske reindriftsutøvere å rapportere inn observasjoner av klimaendringer i miljøet, og legge til rette for en utstrakt og kontinuerlig bruk, bør det bygges en egen Sápmi løsning.
NILU
2021
An Advanced In vitro Respiratory Model for Genotoxicity Testing at the Air-Liquid Interface
Elsevier
2021
Integrated water vapor during rain and rain-free conditions above the Swiss Plateau
Water vapor column density, or vertically-integrated water vapor (IWV), is monitored by ground-based microwave radiometers (MWR) and ground-based receivers of the Global Navigation Satellite System (GNSS). For rain periods, the retrieval of IWV from GNSS Zenith Wet Delay (ZWD) neglects the atmospheric propagation delay of the GNSS signal by rain droplets. Similarly, it is difficult for ground-based dual-frequency single-polarisation microwave radiometers to separate the microwave emission of water vapor and cloud droplets from the rather strong microwave emission of rain. For ground-based microwave radiometry at Bern (Switzerland), we take the approach that IWV during rain is derived from linearly interpolated opacities before and after the rain period. The intermittent rain periods often appear as spikes in the time series of integrated liquid water (ILW) and are indicated by ILW ≥ 0.4 mm. In the present study, we assume that IWV measurements from radiosondes are not affected by rain. We intercompare the climatologies of IWV(rain), IWV(no rain), and IWV(all) obtained by radiosonde, ground-based GNSS atmosphere sounding, ground-based MWR, and ECMWF reanalysis (ERA5) at Payerne and Bern in Switzerland. In all seasons, IWV(rain) is 3.75 to 5.94 mm greater than IWV(no rain). The mean IWV differences between GNSS and radiosonde at Payerne are less than 0.26 mm. The datasets at Payerne show a better agreement than the datasets at Bern. However, the MWR at Bern agrees with the radiosonde at Payerne within 0.41 mm for IWV(rain) and 0.02 mm for IWV(no rain). Using the GNSS and rain gauge measurements at Payerne, we find that IWV(rain) increases with increase of the precipitation rate during summer as well as during winter. IWV(rain) above the Swiss Plateau is quite well estimated by GNSS and MWR though the standard retrievals are limited or hampered during rain periods.
MDPI
2021
Implementing Citizen Science in Primary Schools: Engaging Young Children in Monitoring Air Pollution
Frontiers Media S.A.
2021
2021
This report analyses evolution and trends of air quality in Europe, based on a 15-year time series of spatial data fusion maps for the years 2005-2019. The analysis has been performed for PM10 annual average, the ozone indicator SOMO35 and NO2 annual average. For the purpose of the Eionet Report - ETC/ATNI 2021/11 trend analysis, a consistent reconstruction of the full 15-year time series of air quality maps has been performed, based on a consistent mapping methodology and input data. For the reconstruction, the Regression – Interpolation – Merging Mapping (RIMM) methodology as routinely used in the regular European-wide annual mapping has been applied.
The trend analysis has been performed based on time series of the aggregated data for individual countries, for large European regions and for the entire mapping area, both for spatial and population-weighted aggregations. In addition, maps of trends have been constructed based on the trend estimates for all grid cells of a map.
For the European-wide aggregations across the whole mapping area, statistically significant downward trend have been estimated for PM10 and NO2, while no significant trend was detected in the case of ozone.
ETC/ATNI
2021
NILU – Norsk institutt for luftforskning og Ingenia AS har på oppdrag fra Statens vegvesen kartlagt effekten ventilasjonstårnene i Ekeberg- og Bjørvikatunnelen har med hensyn til å redusere luftforurensning fra dagsonen på Sørenga. Prosjektet besto av et omfangsrikt måleprogram i og rundt Operatunnelen i Bjørvika, en vurdering av ventilasjonstårnenes effekt basert på målingene og forslag til prinsipper for et nytt styringsregime.
Drift av ventilasjonstårnene ble funnet å ha en tydelig effekt på PM10- og NO2-konsentrasjonen i dagsonen og på bakkenivå utenfor dagsonen fra trinn 3 (av 4). Forslaget til nytt styringsregime fokuserer på ventilasjonstårndrift i piggdekksesongen og avhengighet av ytre forhold.
NILU
2021
2021
Aerosol particles are a complex component of the atmospheric system which influence climate directly by interacting with solar radiation, and indirectly by contributing to cloud formation. The variety of their sources, as well as the multiple transformations they may undergo during their transport (including wet and dry deposition), result in significant spatial and temporal variability of their properties. Documenting this variability is essential to provide a proper representation of aerosols and cloud condensation nuclei (CCN) in climate models. Using measurements conducted in 2016 or 2017 at 62 ground-based stations around the world, this study provides the most up-to-date picture of the spatial distribution of particle number concentration (Ntot) and number size distribution (PNSD, from 39 sites). A sensitivity study was first performed to assess the impact of data availability on Ntot's annual and seasonal statistics, as well as on the analysis of its diel cycle. Thresholds of 50 % and 60 % were set at the seasonal and annual scale, respectively, for the study of the corresponding statistics, and a slightly higher coverage (75 %) was required to document the diel cycle.
Although some observations are common to a majority of sites, the variety of environments characterizing these stations made it possible to highlight contrasting findings, which, among other factors, seem to be significantly related to the level of anthropogenic influence. The concentrations measured at polar sites are the lowest (∼ 102 cm−3) and show a clear seasonality, which is also visible in the shape of the PNSD, while diel cycles are in general less evident, due notably to the absence of a regular day–night cycle in some seasons. In contrast, the concentrations characteristic of urban environments are the highest (∼ 103–104 cm−3) and do not show pronounced seasonal variations, whereas diel cycles tend to be very regular over the year at these stations. The remaining sites, including mountain and non-urban continental and coastal stations, do not exhibit as obvious common behaviour as polar and urban sites and display, on average, intermediate Ntot (∼ 102–103 cm−3). Particle concentrations measured at mountain sites, however, are generally lower compared to nearby lowland sites, and tend to exhibit somewhat more pronounced seasonal variations as a likely result of the strong impact of the atmospheric boundary layer (ABL) influence in connection with the topography of the sites. ABL dynamics also likely contribute to the diel cycle of Ntot observed at these stations. Based on available PNSD measurements, CCN-sized particles (considered here as either >50 nm or >100 nm) can represent from a few percent to almost all of Ntot, corresponding to seasonal medians on the order of ∼ 10 to 1000 cm−3, with seasonal patterns and a hierarchy of the site types broadly similar to those observed for Ntot.
Overall, this work illustrates the importance of in situ measurements, in particular for the study of aerosol physical properties, and thus strongly supports the development of a broad global network of near surface observatories to increase and homogenize the spatial coverage of the measurements, and guarantee as well data availability and quality. The results of this study also provide a valuable, freely available and easy to use support for model comparison and validation, with the ultimate goal of contributing to improvement of the representation of aerosol–cloud interactions in models, and, therefore, of the evaluation of the impact of aerosol particles on climate.
2021
2021
American Geophysical Union (AGU)
2021
2021
2021