Sea2Cloud - Tangaroa - SSA - WIBS - Level 0

Sea spray was continuously generated with a plunging jet system, as described in detail in Sellegri et al. (2023) and previously used in Schwier et al. 2015 and 2017, Trueblood et al. 2021, Freney et al. 2021 and Sellegri et al. 2021. The 10 L tank was operated with a 10 cm seawater depth, so jet and film drops did not interact with the tank’s top locate 15 cm above the seawater level. Eight plunging jets were created by flushing seawater through 1 micrometer orifices that were equally spaced along a ¼” stainless steal tube, located at 5 cm below the tank’s top in the chamber diagonal. Jets penetrate the seawater volume at a depth of 7 cm, and therefore do not interact with the chamber bottom. The sea-spray generation system was operated at near constant jet flow rate, and reproduces sea-spray size distributions of similar shape to those reported for other plunging jet devices (Fuentes et al. 2010). The system was fed continuously with seawater sampled from a depth of ~6 m by the underway seawater supply. Once a day, the flow-through seawater system of the plunging jet system was switched from seawater directly coming from the ship underway seawater system to cooled seawater that had been stored in a 50 L temperature-controlled reservoir immediately before the temperature experiments start (filling time less than 5 min, Figure 1). Temperature gradients between 2°C and 15°C were applied to the seawater over approximately 1 hour, with an initial decreasing temperature ramp, followed by an increasing temperature ramp. The experiments were stopped when the temperature-controlled reservoir had emptied. Temperature experiments were performed every morning around 11 am from 18/03/20 to 26/03/20, with an additional experiment in the afternoon of 26/03/20.

Supermicron particles generated by the SSA generator were taken through a short 1/2 inch antistatic smoothly curved line to a Waveband Inte- grated Bioaerosol Sensor (WIBS) for diameters ranging from 500 nm up to 4500 nm.