München 2004 – wissenschaftliches Programm

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UP: Umweltphysik

UP 4: Satelliten und Anwendungen I

UP 4.5: Fachvortrag

Montag, 22. März 2004, 15:15–15:30, HS 225

Remote Sensing of Frost Flowers — •Lars Kaleschke and Georg Heygster — Institute of Environmental Physics (iup) and Remote Sensing (ife), Dept. of Physics and Electrical Engineering, FB 1, University of Bremen, Otto-Hahn-Allee 1, D-28359 Bremen, Germany

Frost flowers are a common feature on Arctic and Antarctic sea ice during the cold seasons and can be found on almost any newly frozen lead. These large ice crystals grow from a supersaturated atmospheric boundary layer on young sea ice. Frost flowers exhibit very high salinities. Bromide concentrations in frost flowers are around three times higher than in sea water. It has been speculated that frost flowers could play an important role in tropospheric chemistry. Heterogeneous mechanisms can increase exponentially the reactive gas phase bromine (Bromine Explosion). Severe tropospheric ozone depletion events in the Arctic and Antarctica during springtime are associated with enhanced bromine oxide (BrO) occurance. As a potential source of sea salt aerosol, frost flowers are also important for the interpretation of ice core data. Frost flowers protude a few centimeters above the surface and increase the surface roughness. The surface roughness can be measured with radar systems. We present a new project with the aim to develop methods for the mapping of frost flower coverage with satellite microwave sensors.