Underestimated role of sea surface temperature in sea spray aerosol formation and climate effects

Abstract

The uncertainty regarding the correlation between sea spray aerosol (SSA) formation and sea surface temperature (SST) hinders the accurate estimation of SSA’s impact on global climate. Here, we developed a temperature-controlled plunging SSA simulation tank to investigate the impact of SST on SSA formation from two perspectives: SSA particle size distribution and organic enrichment. Our findings show that SSA particle size decreases with decreasing SST, as exhibited by an increase in SSA within Aitken mode and a decrease in SSA within accumulation and coarse modes. SST can significantly enhance organic enrichment in SSA particles, while the multiplicative increases vary from 2 to 10 times depending on the organic matter species and the SSA particle size. Based on our experimental results, it is predicted that SST reduction may lead to a significantly higher contribution of Aitken modal SSA-derived CCN in cold waters (0 °C) than in warm waters (30 °C). Additionally, we incorporate SST for the first time in estimating the global flux of dissolved organic carbon (DOC) emitted via SSA, yielding a value ranging from 23.45 to 55.78 Tg C yr −1 . Compared to previous works, our study reveals the crucial role of SST in influencing both cloud formation and the atmospheric organic burden of SSA.