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Cold Environment Simulator Building and annex

@Many atmospheric phenomena occur at sub-zero temperatures, and even at temperatures well below -40‹C. The Cold Environment Simulator Building consists of two cold rooms and a cloud simulation chamber, and is widely used for experiments to investigate cloud formation and other atmospheric phenomena as well as to develop measuring devices and test their performance in low-temperature conditions.

@Cold rooms A and B are used for various experiments at temperatures as low as -40‹C and -90‹C, respectively. Air temperatures in these rooms are separately regulated using programmable control units. Temporal changes in air temperature (e.g., diurnal variations) can be represented within the cooling capacity of the refrigeration system. Using a vertical wind tunnel in cold room A, experiments on the growth of snowflakes, graupel and hailstones can also be carried out.

@The cloud simulation unit takes the form of an adiabatic-expansion-type chamber that can be used to simultaneously control the wall temperature and air pressure in the experimental volume to simulate natural cloud formation processes (adiabatic expansion). It can reproduce cloud formation processes (both dry and wet adiabatic expansion) in the temperature range of 30 to -100‹C, pressures ranging from 1,030 to 30 hPa, and an evacuation rate range corresponding to ascent velocities of 0 to 30 m s-1.

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MRI Cloud Simulation Chamber

@MRI cloud simulation chamber is used to seize cloud droplet formation / ice initiation and subsequent growth scenes for a variety of aerosol particles and atmospheric circumstances, and to quantify the activated fraction. In the MRI chamber experiment, test aerosols stored in the buffer tank were introduced into the cloud chamber (1.4m3 experimental volume) to attain a desired concentration followed by preconditioning of sample air in terms of temperature and humidity. Pre-set parameters such as the initial pressure, temperature and dewpoint temperature can be determined arbitrarily. The cloud formation experiments are performed on the principle of adiabatic expansions by synchronously controlling air pressure and wall temperature. It covers a temperature range of 30 to -100 ‹C, a pressure range of 1030 to 30 hPa, and an evacuation rate range corresponding to an ascent rate range of 0 to 30 m s-1.

@It is equipped with pressure transducers, thermocouples and two chilled mirror hygrometers for measuring thermodynamic condition and with laser imaging and scattering devices for sensing cloud droplet and ice crystal formation and properly measuring size distributions, shapes, and asphericity of aerosol and cloud particles from sub-?m to a few mm in size. The onset of cloud formation is also easily identified by means of a "view" laser. The laser light scattered by cloud droplets and ice crystals can be seen through the viewing window.

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