On the submicron aerosol distributions and CCN number concentrations in and around the Korean Peninsula

Abstract

Abstract. Total number concentrations of particles having a diameter larger than 10 nm (N CN ), cloud condensation nuclei at several supersaturation (S) values (N CCN ) and number size distributions of particles with 10-414 nm diameter were measured in Seoul between 2004 and 2010. Overall average values of N CN and geometric mean diameter were 17 811 ± 5581 cm −3 and 48 ± 6 nm. Average N CCN at 0.4, 0.6 and 0.8 % S were 4145 ± 2016, 5323 ± 2453 and 6067 ± 2780 cm −3 and corresponding N CCN / N CN were 0.26 ± 0.11, 0.33 ± 0.11 and 0.37 ± 0.12. There is a clear seasonal variation in aerosol concentration, which seems to be due to the monsoon. N CN and N CCN are also found to depend on the volume of traffic and the height of the planetary boundary layer, respectively.During aircraft campaigns in 2009 and 2011, N CN and N CCN at 0.6 % S (N 0.6 % ) were measured in and around the Korean Peninsula. During the 2011 campaign, the aerosol scattering coefficient was also measured. N CN and N 0.6 % in the lower altitudes were generally higher than at higher altitudes, except for cases when particle formation and growth events were thought to occur at higher altitudes. N CN and N 0.6 % generally show a positive correlation with aerosol scattering coefficients but this correspondence tends to vary with altitude. Occasional instances of low (< 0.3) N 0.6 % / N CN in the boundary layer are demonstrated to be associated with particle formation and growth events. With the support of ground measurements, it is confirmed that a particle formation and growth event did indeed occur over the Yellow Sea on a flight day, and the areal extent of this event is estimated to be greater than 100 km × 450 km.With the combination of the current and several relevant previous studies, a composite map of N CN and N CCN in and around the Korean Peninsula is produced. Overall, the exhibited concentrations are typical of values measured over polluted regions elsewhere on the globe. Moreover, there is a generally decreasing trend from west to east over the region, implying that the region is constantly under the dominant influence of continental outflow.

Aerosol and monsoon climate interactions over Asia

“…H . Kim et al . [2014] found that aerosol hygroscopicity varied to a large extent along the western coast of Korea, depending on whether air masses come from China (higher hygroscopicity) or Korea/Japan (lower hygroscopicity).…”

Effects of model resolution and parameterizations on the simulations of clouds, precipitation, and their interactions with aerosols

“…This factor is based on observations showing that reduction in aerosol loading between polluted days and clean days is generally tenfold over Seoul and Houston (Lance et al, 2009;Kim et al, 2014). This simulation is referred to as the low-aerosol-Seoul run for the Seoul case and the low-aerosol-Houston run for the Houston case.…”

What do we learn from long-term cloud condensation nuclei number concentration, particle number size distribution, and chemical composition measurements at regionally representative observatories?

“…For that reason, emphasis was given to the quality check of the CCN number 20 concentrations that had not previously been published in most cases. Exceptions are the data from Seoul (Kim et al, 2014) and ATTO , whereby the latter station is not included in Schmale et at. (2017).…”