Abstract
Abstract. The Leipzig Aerosol Cloud Interaction Simulator (LACIS) was used to investigate the hygroscopic growth and activation of sea-salt particles which were generated from three different sea-water samples. The measurements showed that the sea-salt particles exhibit a slightly reduced hygroscopic growth compared to pure NaCl particles. Köhler theory was utilized to model the hygroscopic growth of these particles. Some parameters used in this model are unknown for sea-salt. These parameters are combined in an "ionic density" ρion. For each sea-salt sample an average ρion was determined by fitting the Köhler equation to the data from the hygroscopic growth measurements. LACIS was also used to measure the activation of the sea-salt particles at three different supersaturations: 0.11%, 0.17% and 0.32%. A CCN-closure was tested by calculating the critical diameters Dcrit for the sea-salt particles at these supersaturations, using the Köhler model and the corresponding ρion as derived from the hygroscopic growth data. These calculated critical diameters were compared to the measured ones. Measured and calculated values of Dcrit agree within the level of uncertainty. Based on this successful closure, a new parameterization to describe sea-salt-particle hygroscopic growth (at RH>95%) and activation has been developed.
Highlights
Most of the earth’s surface is covered by oceans
For this study the hygroscopic growth of the different seasalt particles was measured in a relative humidity (RH) range from 80.0% up to 99.1% (For the first time, measurements were performed at this high RH on sea-salt particles)
The hygroscopic growth of sea-salt particles generated from three different sea-water samples was investigated with Leipzig Aerosol Cloud Interaction Simulator (LACIS) at RHs from 80.0% up to 99.1%
Summary
Most of the earth’s surface is covered by oceans. For that reason marine aerosol particles largely affect the global climate. The optical properties of the particles depend Due to their hygroscopicity the marine aerosol particles act as cloud condensation nuclei (CCN). Measurements have shown that for small wind speeds the concentration of nss-sulfate particles in the accumulation mode, i.e., in the mode which provides most of the CCN, is larger than that of the sea-salt particles. To include the influences of sea-salt particles on scattering and cloud formation into numerical models, measurements of hygroscopic growth and activation are required. In this context it is relevant to know, whether or not possible differences in the chemical composition of the oceans influence the hygroscopic growth and activation behavior of the generated sea-salt particles. A new parameterization to consistently describe sea-salt-particle hygroscopic growth (at RH>95%) and activation was developed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
