Title: Studying middle atmosphere solar effects using SCIAMACHY limb observations

Abstract:

The Earth's middle atmosphere is affected by variability - originating in many different processes from below and above - covering a wide
range of spatial and temporal scales. Particularly in terms of short-term solar variability at the 27-day time scale, the atmospheric
response is generally not well understood. Solar-driven 27-day signatures in atmospheric parameters are often fairly straightforward
to identify, but the attribution of the observed effects to potential photochemical or dynamical causes is usually complex.  We have been
using SCIAMACHY/Envisat limb-scatter and limb-emission observations in the optical spectral range to investigate solar 27-day signatures in a
variety of atmospheric parameters including temperature, noctilucent clouds/polar mesospheric clouds, OH and OI airglow emissions,
stratospheric aerosols and tropospheric cloud top altitude. This talk will provide an overview of the current scientific understanding of
solar 27-day signatures in atmospheric parameters - illustrated with many science results - and discuss gaps in our understanding. In addition to solar effects, lunar gravitational effects on the Earth's upper atmosphere will be discussed briefly.