Suchergebnisse

Hitze ist für viele Menschen und insbesondere für bestimmte Bevölkerungsgruppen eine große Belastung. Daneben können gleichzeitig die schädliche ultraviolette (UV) Strahlung sowie die Ozonkonzentration erhöhte Werte annehmen. Das zeitliche Auftreten dieser Faktoren und deren Abhängigkeit untereinander werden näher betrachtet und für den Zeitraum von 2010 bis 2014 statistisch ausgewertet. Als Messstationen dienen zwei an der Ostsee gelegene Küstenstationen (Barth und Zingst) sowie zwei Mittelgebirgsstationen im Südschwarzwald (Schauinsland und Feldberg). Für das troposphärische Ozon wird für jeden Tag der maximale 8-h-Mittelwert errechnet. Zur Beurteilung der Hitzebelastung wird der thermische Index der gefühlten Temperatur (GT) im Zeitraum von 10 bis 17 h UTC berechnet und die UV-Strahlung hinzugezogen. Die statistische Auswertung der Korrelation nach Pearson zeigt schließlich die Abhängigkeit im Auftreten der thermischen Indizes und des Ozons bzw. der UV-Strahlung, jeweils nach Jahren und Jahreszeiten getrennt. Die Ergebnisse können für die untersuchten Stationen keine direkte lineare Abhängigkeit aufzeigen. Die Wintermonate weisen für alle Parameter ein sehr schwaches Bestimmtheitsmaß (R²) auf. Potenziell höhere Werte werden für den Sommer ermittelt, ausgenommen für den Zusammenhang zwischen der GT und UV an den Küstenstationen, und erreicht Werte bis zu 0. In den Übergangsjahreszeiten sind sowohl höhere als auch niedrigere R² gegeben.

National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996–2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant ( p <0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54 %, 52 % and 45 % of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11 %, 12 % and 12 % of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and south-western extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in observed ozone mean (0.16±0.02 ppbv yr −1 (2σ error)), 5th (0.13±0.02 ppbv yr −1 ) and 95th (0.16±0.03 ppbv yr −1 ) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O 3 concentrations for the period 1996–2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13±0.01 ppbv yr −1 ) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (−0.03±0.02 ppbv yr −1 ) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O 3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NO x and VOC reductions have a substantial effect on observed annual mean O 3 trends in the rest of Europe. On a ten year time-scale presented in this study, O 3 trends related to anthropogenic NO x and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996–2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54 %, 52 % and 45 % of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11 %, 12 % and 12 % of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and south-western extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in observed ozone mean (0.16±0.02 ppbv yr−1 (2σ error)), 5th (0.13±0.02 ppbv yr−1) and 95th (0.16±0.03 ppbv yr−1) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O3 concentrations for the period 1996–2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13±0.01 ppbv yr−1) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (−0.03±0.02 ppbv yr−1) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O3 trends in the rest of Europe. On a ten year time-scale presented in this study, O3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O-3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 +/- 0.01 ppbv yr(-1)) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 +/- 0.02 ppbv yr(-1)) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O-3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O-3 trends in the rest of Europe. On a ten year time-scale presented in this study, O-3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.