scostep 2010 (stp12) - Leibniz-Institut für Atmosphärenphysik an der ...

STP12 Abstracts
Berlin, 12 - 16 July 2010
SCOSTEP Symposium 2010
Variation of the Mesospheric Ozone above the Arctic caused by solar influence observed
by ground-based millimeterwave radiometry
Palm Mathias, Wieters Nadine, Hoffmann Christoph, Sinnhuber Miriam, Golchert Sven, Notholt
Justus
We present measurements of strato- and mesospheric O3 with a time resolution of 1 hour and
an altitude range from 25 to 90 km. The instrument is located in the high Arctic at 79N.
Ground based millimeterwave radiometry offers the opportunity to measure O3 at a narrow
and well defined spot in the mesosphere. Because of the slowly moving sun in the high
Arctic, the state of the mesosphere regarding to solar illumination can be assumed to be
constant throughout the measuring time of about 1 hour.
The measurements are compared to the model output of a 3D chemical-transport model which
is developed at the IUP. The model is appended using mesospheric chemistry and includes
solar forcing of the atmosphere.
The VMR of O3 strongly depends on the solar illumination. The strongest variation is due to
the equilibrium reaction O3 + nu O + O2, which creates the diurnal variation. There are,
however, other variations which do not follow this scheme and are less well understood.
The qualitative agreement of the model and the measurement is good, the quantitative
agreement ranges from excellent to rather poor. It is assumed that variation of the O3 content
in the mesosphere due to solar illumination strength is not well represented. Possible sources
for the observed variation and the underlying mechanisms are discussed and quantitavely
studied.