Person: Ries, Ludwig
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Veröffentlichung The underestimated role of stratosphere-to-troposphere transport on tropospheric ozone(2018) Trickl, Thomas; Ries, Ludwig; Vogelmann, HannesThe 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 summit station Zugspitze (2962 m a.s.l., Garmisch-Partenkirchen, Germany) between the mid-seventies and 2005, roughly from 11 ppb to 23 ppb (43 %). Systematic efforts for identifying and quantifying this influence have been made since the late 1990s. Meanwhile, routine lidar measurements of ozone and water vapour carried out since 2007, combined with in-situ and radiosonde data and trajectory calculations, have revealed the presence of stratospheric intrusion layers on 84 % of the yearly measurement days. The seasonal cycle for deep intrusions with a pronounced summer minimum seen at Alpine summit stations disappears if one looks at the entire free troposphere. The seasonal cycle previously obtained for the Zugspitze summit is rather well reproduced by the lidar data. The mid- and upper-tropospheric intrusion layers seem to be dominated by very long downward transport up to a full tour around the northern hemisphere in an altitude range starting at about 4.5 km a.s.l. Unless there is a strong perturbation, these layers remain considerably dry, typically with RHVeröffentlichung Very high stratospheric influence observed in the free troposphere over the Northern Alps - just a local phenomenon?(2020) Trickl, Thomas; Ries, Ludwig; Vogelmann, HannesThe atmospheric composition is strongly influenced by a change in atmospheric dynamics, which is potentially related to climate change. A prominent example is the doubling of the stratospheric ozone component at the summit station Zugspitze (2962 m a.s.l., Garmisch-Partenkirchen, Germany) between the mid-seventies 15 and 2005, roughly from 11 ppb to 23 ppb (43 %). Systematic efforts for identifying and quantifying this influence have been made since the late 1990s. Meanwhile, routine lidar measurements of ozone and water vapour carried out at Garmisch-Partenkirchen (German Alps) since 2007, combined with in-situ and radiosonde data and trajectory calculations, have revealed that stratospheric intrusion layers are present on 84 % of the yearly measurement days. At Alpine summit stations the frequency of intrusions exhibits a seasonal cycle with a 20 pronounced summer minimum that is reproduced by the lidar measurements. The summer minimum disappears if one looks at the free troposphere as a whole. The mid- and upper-tropospheric intrusion layers seem to be dominated by very long descent on up to hemispheric scale in an altitude range starting at about 4.5 km a.s.l. Without interfering air flows, these layers remain very dry, typically with RH =< 5 % at the centre of the intrusion. Pronounced ozone maxima observed above Garmisch-Partenkirchen have been mostly related to a 25 stratospheric origin rather than to long-range transport from remote boundary layers. Our findings and results for other latitudes seem to support the idea of a rather high contribution of ozone import from the stratosphere to tropospheric ozone. Copyright: Author(s) 2019. CC BY 4.0 License