Ocean, Ice, Atmosphere Seminar

The European ENVISAT satellite carries the SCIAMACHY instrument (Scanning Imaging Absorption SpectroMeter for Atmospheric CHartographY) to monitor the atmosphere since February 2002. SCIAMACHY covers the wavelength range from 220 to 2380 nm with a spectral resolution of 0.2 to 1.5 nm and provides nadir, limb and occultation viewing modes [Noel et al., 1998]. The limb viewing mode covers altitude levels from 0 to 100 km, whereas the nadir mode provides total columns ranging from ground to the exosphere. The objective of the proposed study is to identify and locate emission signals of metal species in the upper stratosphere, mesosphere and lower thermosphere (50-100 km altitude). Attention is turned as well to neutral species as to ionized ones. Dependent on the signal strength, Fe, Fe+, Mg, Mg+, Si, Na and Cr are examined. Thus essentially emissions in the UV are monitored. Nevertheless it will be glanced at emissions in the visible spectral range originating e.g. from the well-known Na.

The excitation process is modelled and included in a retrieval algorithm to obtain concentration profiles in height as well as horizontal variability. Since a large part of the mesospheric metals is considered to be of meteroic origin, special events like meteoric showers are taken into particular consideration.