Jena 2013 – wissenschaftliches Programm
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SYES: Symposium Einfluss der Sonne auf das Klima der Erde
SYES 1: Einfluss der Sonne auf das Klima der Erde
SYES 1.3: Hauptvortrag
Donnerstag, 28. Februar 2013, 15:00–15:30, HS 2
NOx - the energetic particle - climate connection? — •Thomas Reddmann — KIT Karlsruhe
In addition to the variability of the solar spectrum in the UV and VIS part, and the modulation of cosmic galactic radiation with the solar cycle, the solar wind impresses the signs of solar activity to the upper parts of the Earth’s atmosphere. Energetic particles as protons in the MeV range from eruptive processes on the Sun’s surface, or electrons accelerated within the magnetosphere of the Earth, sometimes to relativistic energies, ultimately reach the lower thermosphere and mesophere. This particle precipitation causes local ionization and subsequently reactive gases as NOx and HOx are produced. Observations from satellites during the last decade, for example from the atmospheric instruments MIPAS and SCIAMACHY on the European ENVISAT satellite, have shown that following solar eruptive events or geomagnetic storms the concentration of the reactive gases can reach considerable amounts. During polar winter when NOx is long-lived, downward transport of NOx can bring it even to the stratosphere and to the ozone layer where it causes additional ozone loss. For the middle atmosphere, where ozone essentially determines the radiative heating rate, the dynamical state of the middle atmosphere is therefore somehow coupled to the precipitation of the particles, and via stratosphere-troposphere coupling this may even propagate to the surface and impact climate. On the other hand, the strength of the downward transport itself strongly depends on the dynamical state of the middle atmosphere. This chemical dynamical coupling and the role of energetic particles is a topic of current research. Recent results of observations and model simulations will be presented and open questions of this mechanism will be discussed.