Hot-wire anemometry for simultaneous droplet and turbulent measurements

This work proposes a new application of hot-wire anemometry (HWA) beyond velocity measurements in fog droplet size sampling, with initial field deployment highlighting its ability to measure both droplet size and turbulence data simultaneously. Traditional methods often rely on separate, non-collocated tools to measure droplet microphysics and turbulence, which prevents direct assessment of droplet-turbulence interactions. In contrast, the HWA collects simultaneous, high-frequency data on the droplet size distribution (DSD) and fine-scale turbulence properties, such as the turbulent kinetic energy dissipation rate. This feature is essential for testing theories of droplet growth in turbulent environments and addressing the ongoing challenge of parameterizing microphysical processes in numerical models. According to the results, as compared to a conventional optical instrument, our HWA set-up offers higher resolution and potentially a wider detection range for smaller droplets. This study positions HWA as an alternate method in fog measurement techniques, and provides a new tool for understanding the intricate interactions between fog microphysics and turbulent dynamics.