Dresden 2020 – wissenschaftliches Programm
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UP 6.5: Vortrag
Mittwoch, 18. März 2020, 17:50–18:10, HSZ 105
Investigating the excitation mechansm of the sodium D-line emissions — •Julia Koch1, Landon Rieger2, Chris Roth2, Adam Bourassa2, Doug Degenstein2, and Christian von Savigny1 — 1Universität Greifswald, Greifswald, Germany — 2University of Saskatchewan, Saskatoon, Canada
The understanding of the excitation mechanism of the sodium D-line emission is important for all further investigations of atomic sodium in the upper mesosphere. In 1939 Chapman proposed a first scheme of the chemical reactions between sodium and ozone that were thought to lead to the yellow sodium line doublet. But after that it became clear that this mechanism could not explain the observed varability in the Na D-line ratio. That lead to a modified mechanism, known as the "modfied Chapman mechanism". However, it is well accepted that there is still a parameter that is not fully understood: the branching ratio f, that defines how many sodium atoms are produced (via the reaction Na + O3) in the excited Na(2P) state. Here we show sodium profiles retrieved from data measured with the OSIRIS instrument on the Odin satellite. And in combination with Lidar data from Logan, Utah we want to contribute to find a better value for the branching ratio.