A custom-built ice nucleation chamber is available to EMSL users to study the ice nucleating properties of atmospheric particles or aerosols in situ, under user-defined conditions. These conditions are designed to simulate mixed-phase and cirrus clouds and generate data to reduce the related uncertainty in predicting the Earth’s radiation budget and climate. Increasing our scientific understanding of Earth systems is part of EMSL’s broader goal to inform models of ecosystem processes and land-atmosphere interactions at larger scales.
The chamber provides online measurements of ice nucleation. The sample flow rate is 1 to 2 SLPM. The ice nucleation chamber is field-deployable, and access to it can be combined with other EMSL capabilities for enhanced research results.
The unique features of the chamber allow EMSL users to
- Measure the ice nucleation efficiency of aerosol particles for developing and/or constraining ice nucleation parameterizations
- Understand the importance of pre-activation toward ice nucleation ability by connecting two ice nucleation chambers in series
- Investigate the role of time dependence (stochastic hypothesis) and particle characteristics (singular hypothesis) in ice nucleation
- Assess the relative importance of multiple ice nucleation mechanisms (deposition, immersion, homogenous) in real time
- Extract ice and supercooled droplet residues for compositional and morphological analysis
- Determine ice onset for different aerosol types (SOA, soil and mineral dust, soot, biological, internally and externally mixed particles, etc.).
These resources support the Terrestrial-Atmosphere Processes Integrated Research Platform by enabling studies of aerosol properties and their interactions with other environmental components—key knowledge that can help us refine global biogeochemical models and improve accuracy of predicted ecosystem responses to environmental perturbations.
Tips for success
- Users have the option of connecting an aerosol concentrator to enhance the submicron aerosol population and the impactor to remove large supermicron aerosols upstream of the sampling inlet.
- In the laboratory, bulk samples can be dry dispersed and solution samples can be atomized to generate monodisperse or polydisperse aerosol particles. Various types of aerosols then can be investigated in immersion and deposition mode of ice nucleation from -15 to -60oC and 30 to 120% saturation conditions.
- Attaching a pumped flow virtual impactor expands the capability to separate particles into ice-nucleating and non-nucleating fractions.
- Forwarding ice residues to collect them on filter impactor and/or to an online spectroscopy technique further enhances their research capabilities.