A Novel Adiabatic-Expansion-Type Cloud Simulation Chamber

Abstract

A new cloud simulation chamber was built at the Meteorological Research Institute (MRI) to investigate the details of the fundamental processes of cloud formation. The MRI cloud chamber was designed as an adiabatic-expansiontype cloud chamber covering temperatures from 30 to −100°C, pressures from 1030 to 30 hPa, and an evacuation rates corresponding to ascent rates from 0 to 30 m s −1. Improvements to the cooling system and cloud characterization instrumentation distinguish the new facility from past devices of this type that are no longer functional (e.g., the Colorado State University dynamic cloud chamber), and the capabilities exceed those of any other active facility (e.g., the Aerosol Interactions and Dynamics in the Atmosphere (AIDA) chamber) for covering a range of atmospheric conditions while reproducing approximately adiabatic parcel conditions. Results from the preliminary experiments demonstrate the accuracy of coordinated pressure and temperature controls to reproduce cloud formation processes (both dry and wet adiabatic expansion processes) and the ability of the chamberʼs instrumentation to measure aerosol, cloud droplet, and ice crystal characteristics. Performance tests demonstrate the chamberʼs usefulness as a facility to investigate cloud droplet and ice crystal formation processes through the activation of various types of aerosol particles.

A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of 17 ice nucleation measurement techniques

“…Therefore, it is an advantage of CECC that the parameterization derived from its experiments can be most readily extended to atmospheric conditions (Niemand et al, 2012). Development of large (up to 84 m 3 , i.e., AIDA) and/or temperature-controlled dynamic cloud simulation chambers (e.g., MRI-DCECC; Tajiri et al, 2013, a design which follows from DeMott Figure 8. T -binned n s ,geo (a) and n s ,BET (b).…”

Cloud Condensation Nuclei and Immersion Freezing Abilities of Al₂O₃ and Fe₂O₃ Particles Measured with the Meteorological Research Institute's Cloud Simulation Chamber

“…In this study, the abilities of two metal oxides (Al 2 O 3 and Fe 2 O 3 ) to act as CCN and INPs were measured using an array of instruments. These included the MRI's cloud simulation chamber (Tajiri et al 2013), the MRI's CFDC-type INC (Saito et al 2011), a CCN counter (CCNC, model CCN-200; DMT Inc.), and other aerosol measuring instruments. Measurements to assess the ability to act as CCN were performed twice for each material (Section 2.2).…”

“…The inner chamber could be cooled to any temperature between 30°C and −100°C. A detailed description can be found in the paper by Tajiri et al (2013). Table 3 shows the aerosol types, particle concentrations, total surface areas, examined temperature range, initial dewpoint temperature, temperature at the lifting condensation level, maximum cloud droplet concentration, maximum ice crystal concentration, and maximum INAS density for the seven cloud chamber experiments.…”

“…In this study, the CCN and INP abilities of Al 2 O 3 and Fe 2 O 3 particles were examined at higher temperatures to determine their role in mixed-phase cloud processes. A cluster of aerosol instruments and a CCN counter were used to measure the CCN ability (hygroscopicity), and the cloud simulation chamber of the Meteorological Research Institute (MRI) (Tajiri et al 2013) and the MRI's CFDC-type INC (Saito et al 2011) were used to measure the INP ability. Additionally, a cross-instrument comparison was conducted and the sensitivities of the metal oxides to nucleation events and experimental conditions were evaluated.…”

“…The MRI's cloud simulation chamber was used previously to investigate the ability of surrogates of atmospheric dust and biological aerosols to act as INPs (Tajiri et al 2013;Hiranuma et al 2015a, b) and to investigate the abilities of hygroscopic and glaciogenic seeding materials (hygroscopic flare, salt micropowder, and AgI particles) to act as CCN and INPs, along with their effects on the initial microphysical structures of clouds (Tajiri et al 2015). The MRI's CFDC-type INC has been used to investigate the ability of surrogates of atmospheric dust particles to act as INPs (Saito et al 2011;Tajiri et al 2013) as well as the seasonal variation and vertical distributions of atmospheric INPs (Murakami et al 2012;Yamashita et al 2014;Orikasa et al 2016).…”