Fant 9758 publikasjoner. Viser side 229 av 391:
2015
On the coupling between polar and tropical regions during springtime: variability of tropical intrusion and Frozen In Anticyclones. Poster P-1108-04
Abstract : Recent observational and modeling transport studies of Arctic stratospheric final warming have shown that tropical/subtropical air masses can be transported to high latitudes and remain confined within a long-lived ¿frozen- in¿ anticyclone (FriaC), embedded in the summer easterlies for several months. We first present a climatology of these sporadic events over the period 1960-2011 using era-40 and era interim reanalyses. this study highlights stratospheric favorable preconditioning for FrIACs occurrence, that is: i) early and abrupt final warming, ii) no stratospheric major warming during the previous winter, and iii) east phase of the Quasi-Biennial Oscillation. We will present in detail the FriaC in spring 2011, which was the largest ever recorded. Our climatology further suggests that the frequency of occurrence of FriaCs has increased over the last decade (among the nine cases detected over the period 1960- 2011, five occurred between 2002 and 2011). A chemistry climate model is then used for the first time to investigate FriaCs characteristics and variability. simulations were performed with the nCar¿s Community earth system Model (CesM, version 1.0.2), a coupled model system including the Whole Atmosphere Community Climate Model (WACCM). FrIACs characteristics (i.e. spatial extent and duration), are overall consistent by comparing with FriaCs detected era-40 meteorological reanalyses. Dynamical analysis reveals that FriaCs are associated with an abrupt and early winter-to-summer stratospheric circulation transition, characterized by an amplification of planetary wave activity. Furthermore, our model results confirm that FrIACs occur preferentially under the easterly phase of the QBO and in absence of MSW during the preceding
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Monitoring of the atmospheric ozone layer and natural ultraviolet radiation. Annual report 2014. NILU OR
Rapporten presenterer måledata for totalozon og UV-stråling over norske målestasjoner i 2014.
For Oslo, Andøya og Ny-Ålesund er trenden i totalozon beregnet for perioden 1979-2014.
Ozonlaget over Norge var relativt tynt våren 2014, men det tok seg opp i april/mai, og verdiene
var tilnærmet normale resten av året. Den klare reduksjonen av ozonlaget over Norge i perioden
1979-1997 stoppet opp i 1998, og ozonlaget over Norge ser nå ut til å ha stabilisert seg.
2015
Joint actions for air quality and climate mitigation in Europe. ETC/ACM Technical Paper, 2015/7
2015
Spredningsberegninger for utslipp fra tunnelmunninger i Hammerfest. NILU OR
Spredningsberegninger for tunnelmunninger i Hammerfest. Det er beregnet maksimale konsentrasjoner av PM10,og NOX i tunnelene ved ugunstige trafikkforhold (rushtrafikk ettermiddag). Konsentrasjonsreduksjon som funksjon av avstand fra tunnelmunninger er vist i tabell, og konsentrasjonene er sammenlignet med Nasjonalt mål og grenseverdier for luftkvalitet.
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