First Results of the SCIAMACHY Mission: Mesosphere

Limb measurements in the mesosphere

First detection of signatures from polar mesospheric clouds (PMC; noctilucent clouds) in the northern summer mesosphere (Dr. C. von Savigny, ife/UB) The size distribution and the thermodynamic phase of the PMCs will be determinable.

The retrieval of first mesospheric ozone results (Dr. C. v. Savigny) were done with SCIARAYS (Dr. J. Kaiser) in the Hartley bands using wavelengths between 240 and 300 nm. The CMAM data correspond to an August mean, i.e. also NH summer, this should be good enough for a rough comparion. At least we know the order of magnitude is correct.
There seems to be a slight altitude and/or concentration difference, but (a) we don't know yet what the expected errors of the retrieval are, and (b) CMAM (like all middle atmosphere models) has not been properly validated with real observations in this altitude range. CMAM is known to underestimate ozone densities in the upper stratosphere, i.e. above 35 km. This is most likely due to too much actice haligen species there. Since the upper stratosphere is too transparent for UV photons the model overshoots at ozone density peak altitudes (de Grandpre et al., JGR, 26,475-491, 2000). Units are molec/cm^3, of course.