Trends, seasonal cycles and synpotic scale episodes of halocarbons observed in Ny-Ålesund, Spitsbergen

A study of the important gases in the air at the Ny-Ålesund measuring station at Svalbard is presented in this thesis. The monitoring station is located 474 m a.s.l. at Mt. Zeppelin, a mountain ridge with steep rocky slopes and glaciers on all sides. SOGE is an integrated System for Observation of halogenated Greenhouse gases in Europe. A combination of observations and modeling is used to estimate regional emissions as well as global trends and impact on climate and the ozone layer. In situ observations at four background stations in Europe forms the back bone of SOGE. A wide range of halogenated greenhouse gases are measured in situ at these four background measurement stations. The four stations are Mt. Zeppelin at Svalbard in arctic Norway, Mace Head in Ireland, Jungfraujoch in Switzerland and Mt.Cimone in Italy. Measurements are performed with high frequency by the use of automated gas chromatographs with mass spectrometry detectors. Measurement data from the years 2001 - 2003 are analyzed in this thesis for trends and pollution events. Trends in background concentrations were also analyzed. Positive trends in the background concentrations were observed for substances which are used as CFC-substitutes (hydrofluorcarbons, hydroclorofluorcarbons). Background concentrations in the HFCs at Ny-Ålesund increased from January 2001 until December 2003 as follows: HFC-125 from 1.8 to 3.5 ppt, HFC-134a from 21 to 31 ppt, and HFC-152a from 2.8 to 4.3 ppt. All peak concentrations of the measured gases were significantly lower at Ny-Ålesund than other sites, due to the stations remote location. The peak events were analyzed separated to see if there were any trends in the pollution pattern. Events of polluted air masses were studied in combination with air mass trajectories from European, Atlantic, Russian and North American sectors to allocate specific source regions.