Ergebnisse der Spurengas-Messung auf dem Sonnblick (Ozon, Kohlenstoffmonoxid, Stickstoffoxide, Kohlenstoffdioxid) : Vergleich mit anderen Hintergrundstandorten : Umweltforschung im Hochgebirge - Ergebnisse von GAW-DACH und verwandten Projekten

1999

S. 65-70

3 Lit. Ang.

Unselbständiges Werk

200086914

Ozone measurements have been conducted by the Austrian Federal Environment Agency at the Sonnblick (sltitude 3106 m) since 1990. At this site, the highest annual mean concentration have been measured in Austria (between 0,092 and 0,102 mg/mß), proving a clear altitudinal dependence of mean concentrations. Temporal - both annually and daily - variations are very low compared to any other sites in Austria, due to a low amount both of local production and depletion of ozone. Air exchange with nearby valleys causes a minor decrease in ozone levels during daytime. At monitoring sites in mountainous regions of medium elevation, the daily variation becomes more pronounced due to local air exchange with valleys, ozone formation and depletion. In plains, nocturnal ozone depletion under a shallow inversion causes a strong decrease during night, vertical exchange in the morning and considerable ozone formation after noone give a characteristic daily variation. The concentration of carbon monoxide and nitrogen oxides (NOx) at the Sonnblick show a low diurnal and annual variation. During most time concentrations reflect the tropospheric conditions above the boundary layer; short-time concentration peaks indicate transport from the polluted boundary layer, in most cases from regions north of the Alps. Throughout Austria, carbon monoxide concentrations are rather uniform, influenced largely by a continental background level and only to a minor extent by local emissions. Backround NOx concentrations vary largely throughout Austria with highest values in extra-alpine plains, decreasing strongly with elevation and distance from large valleys. The daily variation of nitrogen monoxide (NO) and nitrogen dioxide (NO2) at Sonnblick, but also at other background sites, is largely determined by photolysis of NO2. Measured Carbon dioxide concentrations slowly increased during the last years from 357 ppm in 1992 to 370 ppm in 1998.