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UP: Fachverband Umweltphysik
UP 5: Atmosphere - trace gases, aerosols; Methods -measurement techniques
UP 5.2: Vortrag
Montag, 5. März 2018, 15:00–15:15, G 1.011
The underestimated role of stratosphere-to-troposphere transport on tropospheric ozone - Two decades of lidar vertical sounding — •Thomas Trickl1, Hannes Vogelmann1, Ludwig Ries2, Hans-Eckhart Scheel1, and Michael Sprenger3 — 1Karlsruher Institut für Technologie, IMK-IFU, Garmisch-Partenkirchen — 2Umweltbundesamt, Schneefernerhaus — 3ETH Zürich, Institut für Atmosphäre und Klima
The atmospheric composition is strongly influenced by changing atmospheric dynamics, in potential relation to climate change. A prominent example is the doubling of the stratospheric ozone component at the Zugspitze summit (2962 m) between the mid-seventies and 2005. We present lidar studies of stratospheric air intrusions since 1996, since 2007 based on routine measurements ozone, water vapour and aerosol. Combined with in-situ and sonde data as well as trajectory calculations, we identified stratospheric influence in the free troposphere on more than 80 % of the measurement days. The pronounced seasonal cycle at Alpine summit stations exhibiting a summer minimum disappears if one looks at the entire free troposphere. Very long downward transport up to a full tour around the northern hemisphere dominates the stratospheric contributions in an altitude range above 4.5 km. It is interesting to note that, in recent years, most pronounced ozone maxima have been related to a stratospheric origin rather than to long-range transport from remote boundary layers. This fact could be caused by improving air quality in the most relevant source regions or changing transport patterns.