Atmospheric clouds are highly non-stationary, inhomogeneous and intermittent, and embody an enormous range of scales with strong couplings between turbulent fluid dynamics and microphysical processes. LACIS-T, the turbulent version of the Leipzig Aerosol Cloud Interaction Simulator (LACIS), which is a wind tunnel with precisely controlled turbulent temperature and humidity fields, allows detailed investigations of the interactions between cloud microphysical processes (e.g., cloud condensation nuclei activation, heteorogeneous ice nucleation) and turbulence under reproducible laboratory conditions. The results and knowledge to be gained are highly interesting on a fundamental process level, and will also help in interpreting the results from in-situ measurements in clouds. The investigations performed will significantly enhance our understanding concerning the interactions between cloud microphysics and turbulence, and consequently cloud processes in general. The project is financially supported by the Leibniz-society (WGL, SAW project: SAW-2013-IfT-2).

LACIS-T in the TROPOS cloud lab building Sketch: © Ingenieurbüro Mathias Lippold

Measuring section of LACIS-T.

LACIS-T itself is a closed loop wind tunnel (Göttingen type) with two separate flow branches with individual thermodynamical control (temperature, humidity, flow) are being turbulently mixed in the measuring section, which has a size of 2.0m x 0.8m x 0.2m. Due to the different temperature of the two flow branches supersaturation in generated. Additionally, aerosol particles can be injected into the turbulent mixing zone.