Automated Droplet Freezing Assay System: Investigating Soil and Biogenic Particle Ice Formation
NURUN NAHAR LATA, Gourihar Kulkarni, Sarah Williams, Mickey Rogers, Swarup China, Pacific Northwest National Laboratory
Abstract Number: 466
Working Group: Instrumentation and Methods
Abstract
In the atmosphere, ice nucleation (IN) is the process through which water vapor transforms into ice crystals within clouds, a fundamental yet intricate phenomenon with significant implications for weather and climate. IN influences cloud microphysics, precipitation, and climate dynamics, particularly in mixed-phase clouds containing both supercooled liquid water droplets and ice particles, which affect cloud lifetime and radiative properties. Clouds at warmer temperatures (> -15°C) are highly sensitive to the presence of ice nucleating particles (INP), such as complex soil dust or biogenic particles. Freezing assay systems are commonly used in the community to study warm temperature freezing. However, traditional droplet freezing assays rely on manual dispensing, introducing variability and large uncertainties in estimating heterogeneous ice nucleation rate coefficients (Jhet). We developed a novel system that integrates an automated droplet dispensing unit, Nanodroplet Processing in One Pot for Trace Samples (NanoPOTS) with a freezing assay system, achieving droplet volumes with 97% accuracy, by improving uncertainty estimation in Jhet. This system will measure the droplet freezing assay with high accuracy and seamlessly integrate with downstream analytical techniques, offering a powerful tool for researchers in atmospheric science and biogeochemistry. We will present preliminary results from this novel system to the IN properties of soil and biogenic particles. It enables subsequent multi-modal microscopy and mass spectrometry characterization of particles, enhancing our understanding of IN mechanisms and their impacts on weather and climate.