Sea spray aerosols (SSAs) are produced via bubble burst on the interface of atmosphere and ocean. These are an important component in the Earth’s climate system which constitute a major source of uncertainty in predicting future climate.
The SSA source function is a fundamental input parameter in many global atmospheric transport models. It has been suggested that SSAs contribute a small fraction to cloud condensation nuclei (CCN) in the global ocean because of the low number concentration of SSAs.
Scientists from Institute of Earth Environment of the Chinese Academy of Sciences and National University of Ireland Galway have found that the contribution of SSA to CCN was largely overlooked on a global scale. The study was published in Nature Geoscience.
Scientists proposed a new method of deriving SSA number size distribution by using the ultra-high hygroscopicity signature of the sea salt. The major component of SSA over North Atlantic during winter time.
The SSA number size distribution versus meteorological conditions were parameterized based on more than five-year semi-continuous on-line measurement. The newly proposed SSA size-resolved source function used four unconstrained log-normal modes fitting. The relationship between SSA number and wind speed varied for different SSA modes.
Scientists found a large contribution of Aitken mode SSA number, based on the hygroscopicity measurement. The conventional way to describe SSA number size distribution utilized a very broad lognormal distribution by extrapolating the number size distribution of large particles. The mode diameter was constrained to the sea spray laboratory experiments. The broad distribution aimed to encapsulate multiple unspecified sea spray production mechanisms.