Effects of temperature and salinity on sea-spray-aerosol formation simulated with a bubble-generating chamber

Abstract. A new bubble-generating glass chamber design with an extensive set of aerosol production experiments is presented. Compared to the experiments described in the literature, current setup is among the medium-sized installations allowing precise control over the air discharge, water temperature and salinity. The size and material of the chamber offer variety of applications due to its portability, measurement setup adjustability and sterilization option. The experiments have been conducted in a cylindrical bubbling tank of 10 l volume filled by ~30–40 % with water of controlled salt content and temperature and covered with a hermetic lid. The chamber was used to study the characteristics of the aerosols produced by bursting bubbles under different conditions. In line with previous findings, the sea spray aerosol production was shown to depend linearly on the surface area covered by the bubbles, which in turn is a near-linear function of the air discharge through the water. Observed dependencies of the aerosol size spectra and particle fluxes on water salinity and temperature, being qualitatively comparable with the previous experiments, substantially refined the existing parameterizations. In particular, the bubble size was practically independent from the air discharge through the water body, except for very small flows. Also, the dependence of aerosol spectrum and amount on salinity was much weaker than suggested in some previous experiments. The temperature dependence, to the contrary, was significant and consistent, with a transition in the spectrum shape at ~10 °C. Theoretical analysis based on the basic conservation laws supported the main results of the experiments but also highlighted the need of better understanding of the aerosol production from a cold water surface.