1. has in-depth knowledge about the composition of the atmosphere, including the role of various atmospheric trace compounds
2. understands and is able to solve simple models that describe the earth's short+long wave energy balance and the role of atmospheric species in this  balance
3. has in-depth knowledge about the chemical processes underlying photochemical ozone production and ozone smog in the atmosphere
4. has in-depth knowledge about both the large scale atmospheric carbon cycle (CO₂)
5. knows the physical processes underlying the use of isotopes as paleoclimate proxy and can apply simple isotope approaches to identify sources and sink processes from exemplary datasets
6. has in-depth knowledge about the physics and dynamics of stratospheric ozone and stratospheric tracers
7. is acquainted with sources and characteristics of aerosols in the atmosphere

This course aims at providing in-depth knowledge on processes that control the chemical composition of the atmosphere. Some attention will be given to experimental and theoretical techniques. The course focuses around two themes: (i) atmospheric gasphase chemistry, and (ii) aerosol and clouds. Atmospheric gasphase chemistry: Good knowledge of stratospheric and tropospheric air chemistry is the key to understanding global environmental problems such as stratospheric ozone depletion or greenhouse warming. Most trace gases are emitted into the atmosphere by the vegetation. Physicochemical processes in the air eventually transfer these species back into the biosphere, lithosphere, or the oceans. Land use change (i.e. transferring natural ecosystems into agricultural areas or into cities and highways) and air pollution (fossil fuel burning, traffic and industrial exhaust) are the major impacts on the natural system of atmospheric chemistry. Besides changing the total primary emission of trace gases these anthropogenic impacts also change chemical pathways in the air. Anthropogenic activity thus exhibits a strong climate forcing because it feeds back to concentrations of greenhouse gasses and the formation of aerosols and clouds. Aerosol and clouds: Aerosols act as condensation nuclei for cloud formation, and co-determine the micro-physical and optical properties of clouds. Further, aerosols play an important role in the multiphase chemistry of the troposphere and the stratosphere, e.g., in the formation and destruction of ozone. Anthropogenic activities have caused a substantial increase in atmospheric aerosol abundances, which influences solar and terrestrial radiation in several ways. In this part the sources, microphysics, transformations and removal of aerosols will be examined. We will explore the impact of the changing aerosol characteristics on climate, e.g., through the use of numerical models. Attention will be given to the measurement of aerosol and cloud properties with emphasis on remote sensing techniques.