Comparison of strato-mesospheric CO measured by Odin and KIMRA
U. Raffalski(1), G Hochschild(2), G. Kopp(3) and J. Urban(4)
(1) Institute of Space Physics, -, Kiruna, Sweden
(2) Forschungszentrum und Universität Karlsruhe, Institute of Meteorology and Climate Research, Karlsruhe, Germany
(3) Now at NDT Systems & Services AG, -, Stutensee, Germany
(4) Chalmers University of Technology, -, Gothenburg, Sweden
The location of IRF Kiruna above the polar circle (67.8N/20.4E) allows
for investigation of strato-mesospheric carbon monoxide. The variation
of mesospheric CO is controlled by middle atmosphere dynamics since its
photochemical lifetime is comparable to the time constants associated
with transport processes. The strong positive gradient in latitude from
the summer to the winter pole makes CO a very good tracer for poleward
transport from lower latitudes. The mixing ratio of CO between 40 and 80
km increases rapidly therefore CO can as well be used as a good tracer
for high- altitude vertical transport such as vortex-related dynamics.
The ground-based millimeter wave radiometer KIMRA is equipped with a
high-resolution Fast-Fourier-Transform spectrometer which enables
observation up to approximately 80 km. However, the very low pressure
broadening at that altitude of the CO line at 230 GHz leaves us with a
relatively coarse height resolution.
The Kimra measurements and results over the course of the winter
2007/2008 are compared with one year of CO data from the Odin satellite.
As additional reference the Odin water vapor data will be used in order
to compare the subsidence in the middle atmosphere.