Document Type
Article
Publication Date
12-2016
Abstract
A detailed understanding of interactions of aerosols, cloud droplets/ice crystals, and trace gases within the atmosphere is of prime importance for an accurate understanding of Earth’s weather and climate. One aspect that remains especially vexing is that clouds are ubiquitously turbulent, and therefore thermodynamic and compositional variables, such as water vapor supersaturation, fluctuate in space and time. With these problems in mind, a multiphase, turbulent reaction chamber—called the Π chamber because of the internal volume of 3.14 m3 with the cylindrical insert installed—has been developed. It is capable of pressures ranging from 1,000 to –60 hPa and can sustain temperatures of –55° to 55°C, thereby spanning much of the range of tropospheric clouds. To control the relative humidity in the chamber, it can be operated with a stable, unstable, or neutral temperature difference between the top and bottom surfaces, with or without expansion. A negative temperature difference induces turbulent Rayleigh–Bénard convection and associated supersaturation generation through isobaric mixing. Supporting instrumentation includes a suite of aerosol generation and characterization techniques; temperature, pressure, and humidity sensors; and a phase Doppler interferometer. Initial characterization experiments demonstrate the ability to sustain steady-state turbulent cloud conditions for times greater than 1 day, with droplet diameters typically in the range of 5–40 µm. Typical turbulence has root-mean-square velocity fluctuations on the order of 10 cm s–1 and kinetic energy dissipation rates of 1 × 10–3 W kg–1.
Publication Title
Bulletin of the American Meteorological Society
Recommended Citation
Chang, K.,
Bench, J.,
Brege, M.,
Cantrell, W.,
Chandrakar, K.,
Ciochetto, D.,
Mazzoleni, C.,
Mazzoleni, L.,
Niedermeier, D.,
&
Shaw, R. A.
(2016).
A laboratory facility to study gas-aerosol-cloud interactions in a turbulent environment: The Π Chamber.
Bulletin of the American Meteorological Society,
97(12), 2343-2358.
http://doi.org/10.1175/BAMS-D-15-00203.1
Retrieved from: https://digitalcommons.mtu.edu/physics-fp/97
Version
Publisher's PDF
Publisher's Statement
©2016 American Meteorological Society. Article deposited here in compliance with publisher policies. Publisher's version of record: https://doi.org/10.1175/BAMS-D-15-00203.1
Supplemental video files used in writing this article can be viewed on Digital Commons @ Michigan Tech:
Turbulent mixing cloud in the Pi Chamber
Colliding plumes in a turbulent mixing cloud