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Abstract:
The satellite spectrometer SCIAMACHY aboard ENVISAT is a unique instrument that covers at a moderately high spectral resolution the entire optical range from the near UV (230 nm) to the near IR (2.4 \mum) with some gaps above 1.7 \mu. This broad spectral range allows not only the retrieval of several atmospheric trace gases (among them ozone), cloud and aerosol parameters, but also regular daily measurements of the spectral solar irradiance (SSI) with an unprecedented spectral coverage. The following studies were carried out with irradiance and ozone data from SCIAMACHY: a) SCIAMACHY SSI was compared to other solar data from space and ground as well as with SIM/SORCE (Solar Irradiance Monitor, the only other satellite instrument daily measuring the visible and near IR), in order to verify the quality of the SCIAMACHY measurements, b) an empirical solar proxy model, in short the SCIA proxy model, was developed that permits expressing the SCIAMACHY SSI variations by fitting solar proxies for faculae brightening and sunspot darkening, which then allows investigation of solar variability on time scales beyond the instrument life time, e.g. 11-year solar cycle, c) solar cycle SSI variations derived from empirical models (Lean2000, SATIRE, SCIA proxy) and different observations (SBUV composite, SUSIM) were compared for the three most recent solar cycles 21--23, and d) SCIAMACHY ozone limb profiles were analyzed to derive signatures of the 27-day solar rotation on stratospheric ozone. Our studies were complemented by investigations of daytime variations in mesospheric ozone (here data from SABER/TIMED), which were compared to results from the HAMMONIA chemistry climate model.
