Fant 10273 publikasjoner. Viser side 135 av 411:
2018
Rapporten viser overskridelser av tålegrenser for forsuring av vann og jord, samt overgjødslingseffekter på vegetasjon, med
avsetningsverdier for perioden 2012–2016. Det er kun en liten reduksjon i areal med overskridelse siden forrige periode: For
vann, ved bruk av SSWCoaa-modellen er 7% av Norges areal overskredet (8% i forrige periode). Bruk av FABoaa-modellen, som
forutsetter et mye større forsuringsbidrag fra nitrogen, gir en overskridelse på 19% av Norges areal (20% i forrige periode).
Overskredet areal for overgjødslingseffekter på vegetasjon er 20% (21% i forrige periode). Tålegrensene for forsuring av
skogsjord er ikke overskredet. Noen oppdateringer av tålegrensene har blitt gjort, primært for overgjødsling av vegetasjon. Det
er også benyttet en ny metode for beregning av avsetninger. Ingen av endringene gav store forskjeller i totalt overskredet areal,
men noen forskjeller i hvor man finner overskridelser og størrelsen på overskridelsene.
Norsk institutt for vannforskning (NIVA)
2018
Accurate gas velocity measurements in emission plumes are highly desirable for various atmospheric remote sensing applications. The imaging technique of UV SO2 cameras is commonly used to monitor SO2 emissions from volcanoes and anthropogenic sources (e.g. power plants, ships). The camera systems capture the emission plumes at high spatial and temporal resolution. This allows the gas velocities in the plume to be retrieved directly from the images. The latter can be measured at a pixel level using optical flow (OF) algorithms. This is particularly advantageous under turbulent plume conditions. However, OF algorithms intrinsically rely on contrast in the images and often fail to detect motion in low-contrast image areas. We present a new method to identify ill-constrained OF motion vectors and replace them using the local average velocity vector. The latter is derived based on histograms of the retrieved OF motion fields. The new method is applied to two example data sets recorded at Mt Etna (Italy) and Guallatiri (Chile). We show that in many cases, the uncorrected OF yields significantly underestimated SO2 emission rates. We further show that our proposed correction can account for this and that it significantly improves the reliability of optical-flow-based gas velocity retrievals.
In the case of Mt Etna, the SO2 emissions of the north-eastern crater are investigated. The corrected SO2 emission rates range between 4.8 and 10.7 kg s−1 (average of 7.1 ± 1.3 kg s−1) and are in good agreement with previously reported values. For the Guallatiri data, the emissions of the central crater and a fumarolic field are investigated. The retrieved SO2 emission rates are between 0.5 and 2.9 kg s−1 (average of 1.3 ± 0.5 kg s−1) and provide the first report of SO2 emissions from this remotely located and inaccessible volcano.
2018
2018
Signals from the south; humpback whales carry messages of Antarctic sea‐ice ecosystem variability
John Wiley & Sons
2018
Uptake and effects of 2, 4, 6 - trinitrotoluene (TNT) in juvenile Atlantic salmon (Salmo salar)
Elsevier
2018
2017
2017
2017
2017
2017