ClO in der arktischen Stratosphäre : Konsequenzen für das Verständnis von Wellen- und Mischungsprozessen im arktischen Polarwirbel aus einer Ballonmessung vom 11. Februar 1997 in Kiruna

• Main Author: Winkler, Ulf
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag 2004
• Subjects: Arktis*; Kiruna; Northern Finland; Northern Sweden; polar night
• Online Access: https://juser.fz-juelich.de/record/32552; https://juser.fz-juelich.de/search?p=id:%22PreJuSER-32552%22

On 11$^{th}$ February, 1997, the TRIPLE balloon was launched in Kiruna, Northern Sweden. It ascended into the lower stratosphere, reached a maximum altitude of 24.1 km and landed in Northern Finland after a 2.5-hour flight. Thanks to advantageous meteorological conditions the balloon passed through the edge region of the polar vortex. Moreover, the data of the TRIPLE flight show that on that day a wave event occurred. The edge region of the polar vortex is of interest because the phenomenon of the polar vortex is closely related to the springtime ozone loss, also known as the ozone hole. Under certain circumstances, the air inside the vortex is forced to remain under polar night conditions for a period of months. Due to the low temperatures reactive chlorine compounds are formed. After the return of sunlight in springtime especially the ClO radical acts as a catalyst of massive ozone depletion. The stability of the polar vortex and the action of the vortex edge as a transport barrier are decisive factors for the extent of ozone depletion. On the gondola of the TRIPLE balloon several instruments were mounted for the measurement of various molecules, among them the ClO/BrO instrument of Research Centre Jülich, an ozone sounding device from the University of Wyoming and the BONBON cryosampler from Johann Wolfgang von Goethe University, Frankfurt am Main. Consequently it was possible to simultaneously observe the wave event and its consequences for the chemistry in the air masses in question. The measured ClO profile thus acted as an indicator of the lowest temperature experienced by the respective air parcel during the event. As the most probable simultaneous explanation for the observed ClO, temperature and pressure profiles a wave standing perpendicular to the earth’s surface is suggested. Chemistry and transport calculations by means of the Chemical Lagrangian Model of the Stratosphere (CLaMS) support this assumption. A theoretical examination shows that such an event can cause horizontal mixing processes. ...