Abstract
Sea spray aerosol (SSA) formation have a major role in the climate system, but measurements at a global-scale of this micro-scale process are highly challenging. We measured high-resolution temporal patterns of SSA number concentration over the Atlantic Ocean, Caribbean Sea, and the Pacific Ocean covering over 42,000 km. We discovered a ubiquitous 24-hour rhythm to the SSA number concentration, with concentrations increasing after sunrise, remaining higher during the day, and returning to predawn values after sunset. The presence of dominating continental aerosol transport can mask the SSA cycle. We did not find significant links between the diel cycle of SSA number concentration and diel variations of surface winds, atmospheric physical properties, radiation, pollution, nor oceanic physical properties. However, the daily mean sea surface temperature positively correlated with the magnitude of the day-to-nighttime increase in SSA concentration. Parallel diel patterns in particle sizes were also detected in near-surface waters attributed to variations in the size of particles smaller than ~1 µm. These variations may point to microbial day-to-night modulation of bubble-bursting dynamics as a possible cause of the SSA cycle.
Highlights
Sea spray aerosol (SSA) formation have a major role in the climate system, but measurements at a global-scale of this micro-scale process are highly challenging
Where NLRT is the number concentration of long-range continental transport, NSOA is the number concentration from aerosols formed from gas-to-particle conversion mechanisms, and NSE refers to the number concentration from ship emissions
To distinguish between different aerosol sources, it is common to discuss the different aerosol types and properties according to their sizes, where different regimes of the aerosol size distribution belong to different aerosol types and processes[5]
Summary
Sea spray aerosol (SSA) formation have a major role in the climate system, but measurements at a global-scale of this micro-scale process are highly challenging. To evaluate the interplay between the diel cycle, the wind speed, and the influence of long-range continental transport, we explored the relationship between the DNR of NSSA ≥ 0.58 μm, and the total aerosol concentration (taken as the concentration for Dop ≥ 0.25 μm during daytime) at different wind speed regimes (Fig. 5).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have