Number-concentration size spectra of ambient aerosol were measured from a container laboratory (~2 m a.s.l.) on the R/V Tangaroa in February/March 2018. The voyage departed and returned to Wellington, New Zealand, spending the majority of the sampling period in the Ross Sea. Raw spectral measurements were made using a PCASP-100X spectrometer. The raw spectra were corrected according to size-dependent losses through the inlet line (Brockman, 2001). A modal analysis was then used to constrain the concentration of sea spray from these corrected spectra (Modini et al., 2015; Quinn et al., 2017).Relative wind speeds were measured using a Gill WindSonic anemometer. These were corrected according to acceleration factors over the ship's hull (Popinet et al., 2004) and then translated according to the ship's heading and velocity to derive the true wind speed and direction. Finally, the true velocities were adjusted from the measurement height (22.5 m) to the 10-m reference level according to the local stability and logarithmic wind profile (COARE3.5; Edson et al. 2013).Hourly averages were only included in the following data set, if: the ambient relative humidity was less than 98%; the accumulated precipitation was less than 1 mm; CO2 measured by a Picarro was less than 405 ppm; and, the influence of continental aerosol (excluding Antarctica) was negligible as determined by back-trajectory analysis.