Fant 9759 publikasjoner. Viser side 288 av 391:
2018
2018
2018
Interim Annual Assessment Report for 2017. European air quality in 2017.
Copernicus Atmosphere Monitoring Service
2018
2018
2018
2018
Water column distribution of mercury species in permanently stratified aqueous environments
Biogeochemical structures of three permanently stratified waterbodies were studied: a sea water basin (the Black Sea), an estuary (Hunnbunn fjord), and a freshwater lake (Nordbytjernet), with focus on the distributions of methylmercury (MeHg) and total mercury (THg). THg concentrations were similar in the sea water basin (0.2–1.8 ng/L) and the freshwater lake (0.8–1.2 ng/L), but significantly higher in the estuary (0.6–9.4 ng/L). An increase in the MeHg concentration and MeHg/THg ratio were found in the redox zone in all three basins, indicating bacterial production of MeHg in the aqueous phase. In the lake and estuary, the maximum MeHg concentration and MeHg/THg ratio were found in samples located closest to the bottom sediments, likely due to the formation of MeHg in surface sediments and subsequent diffusion to the overlying waters.
Springer
2018
2018
2018
Model development for high-resolution emissions from residential wood combustion
I denne rapporten beskriver vi MetVed-modellen. Denne modellen estimerer vedfyringsutslipp med høy oppløsning. Metved-modellen kombinerer nedskalering med bottom-up prinsipper for å estimere vedfyringspotensiale i modellgrid. Den baserer seg på boligtyper, størrelse, oppvarmingsteknologi, energibehov og utendørs temperatur. Modellen baserer seg på å kombinere flere databaser med høyt detaljert informasjon. Databasene inneholder boligtall og boligtyper med 250 meters romlig oppløsning, statistikk av energibruk i husholdninger, plassering av ildsteder som punktkilder, og geografisk posisjon av boliger med informasjon om boligtyper og tilgjengelige teknologier for oppvarming i husholdningene. Databasene blir i MetVed-modellen kombinert og forhold mellom ulike variabler analysert. MetVed-modellen inkluderer en tidsvarisjon av vedforbruket som baserer seg på oppvarmingsgradkonseptet kombinert med tidsvariasjon fra forbrukerstatistikk. Vertikalfordeling av utslippene baserer seg på vedforbruk fordelt på leiligheter og hus (enebolig, tomannsbolig og rekkehus). Resultater fra spredningsmodellberegninger viser at utslippsdata fra MetVed-modellen gir bedre samsvar med målinger enn spredningsberegninger basert på utslipp fra tidligere metoder for å estimere vedfyringsutslipp.
NILU
2018
In this study we apply two methods for data collection that are relatively new in the field of atmospheric science. The two developed methods are designed to collect essential geo-localized information to be used as input data for a high resolution emission inventory for residential wood combustion (RWC). The first method is a webcrawler that extracts openly online available real estate data in a systematic way, and thereafter structures them for analysis. The webcrawler reads online Norwegian real estate advertisements and it collects the geo-position of the dwellings. Dwellings are classified according to the type (e.g., apartment, detached house) they belong to and the heating systems they are equipped with. The second method is a model trained for image recognition and classification based on machine learning techniques. The images from the real estate advertisements are collected and processed to identify wood burning installations, which are automatically classified according to the three classes used in official statistics, i.e., open fireplaces, stoves produced before 1998 and stoves produced after 1998. The model recognizes and classifies the wood appliances with a precision of 81%, 85% and 91% for open fireplaces, old stoves and new stoves, respectively. Emission factors are heavily dependent on technology and this information is therefore essential for determining accurate emissions. The collected data are compared with existing information from the statistical register at county and national level in Norway. The comparison shows good agreement for the proportion of residential heating systems between the webcrawled data and the official statistics. The high resolution and level of detail of the extracted data show the value of open data to improve emission inventories. With the increased amount and availability of data, the techniques presented here add significant value to emission accuracy and potential applications should also be considered across all emission sectors.
2018