Leipzig Aerosol Cloud Interaction Simulator (LACIS)
1. INSTITUTION IN CHARGE OF THE LABORATORY FACILITY The Leibniz Institute for Tropospheric Research (IfT) was founded in 1991 for the investigation of physical and chemical processes in the polluted troposphere. The institute comprises three different departments, i.e. Physics, Chemistry, and Modelling. 2. DESCRIPTION OF RESEARCH FACILITY LACIS consists of a laminar flow tube with thermostated walls. The length of the flow tube can vary from 0.5 up to 10 m. Residence times up to 60 s and temperatures down to -40 °C are feasible. Using high precision instruments, the thermodynamic conditions in the LACIS flow tube are controlled with extremely high accuracy. (Fig. 2 and 3) Particles to be investigated with respect to, e.g., their potential to act as cloud condensation and/or ice nuclei, are introduced into LACIS in form of a narrow 2 mm wide beam surrounded by particle free sheath air (see Fig. 4). Both, the particles and the sheath air flows are humidified using saturators the temperatures of which are controlled by thermostats. LACIS may be operated under both, sub-saturated and super-saturated conditions with respect to water and therefore combines the capabilities of measuring hygroscopic and dynamic post-activation growth in one instrument. Relative humidities up to 99% (sub-saturated) and super-saturations down to 2 0 can be adjusted reproducibly. An optical particle spectrometer which was designed and built for LACIS (see Fig. 5) can be mounted along the LACIS-tube and allows measuring of the particle/droplet sizes in-situ. From this, e.g. growth factors and growth rates and eventually hydrometeor phase can be determined. In the near future a number of these particle spectrometers will be available and mounted where needed. To describe the fluid flow, heat / mass transfer and particle/droplet dynamics in LACIS, a detailed process model has been developed. It combines the computational fluid dynamics (CFD) code FLUENT with a microphysical particle/droplet dynamics model, the so-called Fine Particle Model (FPM). Using this model, microphysical expressions to describe the microphysical process of interest (e.g., particle/droplet activation and ice nucleation) can be validated, and new expressions can be derived and tested. This model, together with extensive expertise in modelling of particle and droplet dynamics are available at the facility for the interpretation of experimental results gained with LACIS. The facility offers instruments and expertise regarding the production of well-defined multi-component, multiphase aerosol particles. For particle generation and coating, instruments such as atomizers, nucleation/condensation type generators and a spark generator are available. In addition to LACIS itself, the new LACIS building (see Fig. 1) offers laboratory space for setup, calibration, etc. of guest experiments and instruments. a) URL of facility: b) Policy in relation to data availability and data access: c) Access to the facility: d) Fee for using the facility: e) Scheduled scientific activities at the site:
f) Association to national, European and/or international networks: g) Indication on specific issues for which collaboration is sought:
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Project coordinator: Consiglio Nazionale delle Ricerche. coordinator@accent-network.org Project Office: Università di Urbino. project.office@accent-network.org Web-coordinator: Norwegian Institute for Air Research. mail@accent-network.org ACCENT Disclaimer |