Climate-, Astro-, and Geo-Sciences

Molecular water in all its facets plays an outstanding role in a variety of planetary and interstellar processes. Ice polymorphs are essential for understanding atmospheric and astrochemical processes, including the radiative balance and hydrological cycle, as well as in the chemical dynamics of the Earth’s and other planets’ atmospheres. Molecular water ice grains are understood to be central for astrochemical processes, while their formation and the actual chemistry happening at their surfaces are not well explored yet. In the atmosphere, aerosols partially counteract the greenhouse effect by reflecting solar radiation, thus playing an immanent role for the habitability of the Earth. Here, in particular, the formation of aerosol particles but also their respective interface effects are yet to be fully understood. In the solid Earth, significant amounts of molecular water are stored in the crystalline structure of minerals and melts as H2O molecules, stoichiometric OH-groups or as defects. Cycling of this molecular water from the surface to the deep Earth is essential to plate tectonics, resulting in volcanism and earthquakes at convergent boundaries and the formation of continental crust.The presence of super-critical aqueous fluids in the crust is responsible for ore formation. Water ice and molecule/water ice mixtures are highly abundant in giant exoplanets such as Uranus or Neptune where high-pressure and -temperature polymorphs might cause magnetic field generation. Thus, molecular water isa key ingredient for many cosmic and planetary processes.

Speakers: Max Wilke (U Potsdam), Michael Steiger (U Hamburg), Melanie Schnell (DESY/CAU Kiel), Hans-Peter Liermann (DESY).