Dresden 2011 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 6: Dynamics

UP 6.1: Vortrag

Mittwoch, 16. März 2011, 18:15–18:30, HSZ 201

High-resolved turbulence observations in the stratosphere by the in-situ sensor LITOS — •Anne Theuerkauf, Michael Gerding, and Franz-Josef Lübken — Leibniz Institute of Atmospheric Physics (IAP) at the University of Rostock, Kühlungsborn, Germany

Even in the statically stable stratosphere gravity wave breaking and turbulence occur. The resulting energy dissipation in this altitude range modifies the energy transfer from the troposphere into the mesosphere. Moreover stratospheric turbulence is an important process in the vertical mixing of trace species. For the determination of precise energy dissipation rates (epsilon) the entire turbulence spectrum down to the viscous subrange has to be observed, i.e. sub-cm spatial resolution is required. Therefore we developed a balloon-borne payload LITOS (Leibniz-Institute Turbulence Observations in the Stratosphere) for wind and temperature soundings with a vertical resolution of 2.5 mm. LITOS has been launched several times from Kühlungsborn (54°N, 12°E), Kiruna (67°N, 21°E), and Sodankylä (67°N, 27°E).

We observed thin turbulent layers of 20-100 m thickness, partly up to 500 m, in a mainly non-turbulent stratosphere. The turbulent regions are separated by sharp boundaries from the non-turbulent regions. We will show examples of detected turbulent layers, altitude resolved epsilon-profiles and corresponding profiles of the turbulent heating rate and diffusion coefficient. We will discuss the occurrence of these layers and their relation to atmospheric background parameters.