# Effects of Wind Speed on Water Uptake, Phase State, and Viscosity of Sea Spray Aerosols

## TL;DR

This study shows how wind speed affects the physical and chemical properties of sea spray aerosols, such as their water content, phase state, and viscosity.

## Contribution

The study reveals how wind speed influences the physicochemical properties of sea spray aerosols by altering the sea surface microlayer.

## Key findings

- At 19 m/s, core−shell aerosol shells were largely liquid, while at 10 m/s they were mostly semisolid or liquid with higher viscosities.
- Rounded aerosols were predominantly liquid or semisolid at 60% RH, with similar viscosities across both wind speeds.
- Higher wind speeds increased water uptake in core−shell aerosols and disrupted the sea surface microlayer structure.

## Abstract

This study investigates the effects of wind speed on
physicochemical
properties such as water uptake, phase state, and viscosity at varying
relative humidity (RH) of individual nascent sea spray aerosols (SSAs).
We examined SSA sized within 0.1−0.6 μm generated from
a wind-wave channel at two wind speeds: 10 m/s representing a wind
lull scenario over the ocean and 19 m/s corresponding to wind speeds
encountered in stormy conditions. Atomic force microscopy (AFM) was
utilized to study two predominant SSA morphologies: core−shell
and rounded. AFM phase state measurements at 60% RH revealed that
shells of core−shells at 19 m/s were largely liquid, while
those at 10 m/s were mostly semisolid or liquid with similar proportions,
where semisolid shells exhibited higher viscosities at lower wind
speed. Rounded SSAs were predominantly liquid or semisolid at 60%
RH, with similar semisolid viscosities for both wind speeds. Increased
water uptake was observed for core−shells at 19 m/s, while
rounded SSA had similar hygroscopicity between the two wind conditions.
Collectively, we observed a variation in the physicochemical properties
of SSA generated at two wind speeds, which can be attributed to the
impact of elevated wind speed on disrupting the sea surface microlayer
film structure and composition.