Volume 16, No. 3, March 2016, Pages 801-815 PDF(1.59 MB)
Supplementary MaterialPDF (724 KB)
Seasonal and Diurnal Variation of Formaldehyde and its Meteorological Drivers at the GAW Site Zugspitze
Michael Leuchner1,3, Homa Ghasemifard1, Marvin Lüpke1, Ludwig Ries2, Christian Schunk1, Annette Menzel1,3
1 Professur für Ökoklimatologie, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany
2 GAW Global Observatory Zugspitze/Hohenpeissenberg, Umweltbundesamt, II 4.5, Messnetz, Zugspitze 5, D-82475 Zugspitze, Germany
3 Institute for Advanced Study, Technische Universität München, Lichtenbergstraße 2a, D-85748 Garching, Germany
- One year of continuous formaldehyde measurements at the GAW site Zugspitze.
- Variability of HCHO mainly due to photochemistry and frequency of PBL influence.
- Large impact of cyclonality and flow direction on HCHO levels was observed.
- Two case studies of the HCHO winter and summer maximum were investigated.
Continuous formaldehyde measurements were performed at the high-altitude GAW site Environmental Research Station Schneefernerhaus for more than one year. This unique dataset was analyzed for daily and seasonal variation and for the influence of large-scale synoptic conditions and air-mass origin on the observed concentrations. The average daily course exhibited maxima in the afternoon and minima at night, however differing between seasons. The general strong seasonal variation with average values for winter, spring, summer, and fall of 0.350, 0.529, 0.986, 0.429 ppbv, respectively, could be well explained by secondary production following photochemical activity. The large variability of formaldehyde mixing ratios within the seasons was shown to be influenced by different factors in this complex topography such as mixing of air masses from the planetary boundary layer and the free troposphere, advection of differently aged air from various source regions, and local meteorological conditions. An analysis of the impact of large-scale weather types, cyclonality, and flow directions revealed that the cleanest air masses were advected from westerly directions in particular under cyclonic conditions while southerly cyclonic and northerly/northwesterly anticyclonic conditions led to the highest formaldehyde levels.
Formaldehyde; Remote site; Trajectories; Large-scale weather types.