Characterization of aerosol number size distributions and their effect on cloud properties at Syowa Station, Antarctica

Abstract

Abstract. We took aerosol measurements at Syowa Station, Antarctica, to characterize the aerosol number–size distribution and other aerosol physicochemical properties in 2004–2006. Four modal structures (i.e., mono-, bi-, tri-, and quad-modal) were identified in aerosol size distributions during measurements. Particularly, tri-modal and quad-modal structures were associated closely with new particle formation (NPF). To elucidate where NPF proceeds in the Antarctic, we compared the aerosol size distributions and modal structures to air mass origins computed using backward trajectory analysis. Results of this comparison imply that aerosol size distributions involved with fresh NPF (quad-modal distributions) were observed in coastal and continental free troposphere (FT; 12 % of days) areas and marine and coastal boundary layers (1 %) during September–October and March and in coastal and continental FT (3 %) areas and marine and coastal boundary layers (8 %) during December–February. Photochemical gaseous products, coupled with ultraviolet (UV) radiation, play an important role in NPF, even in the Antarctic troposphere. With the existence of the ozone hole in the Antarctic stratosphere, more UV radiation can enhance atmospheric chemistry, even near the surface in the Antarctic. However, linkage among tropospheric aerosols in the Antarctic, ozone hole, and UV enhancement is unknown. Results demonstrated that NPF started in the Antarctic FT already at the end of August–early September by UV enhancement resulting from the ozone hole. Then, aerosol particles supplied from NPF during periods when the ozone hole appeared to grow gradually by vapor condensation, suggesting modification of aerosol properties such as number concentrations and size distributions in the Antarctic troposphere during summer. Here, we assess the hypothesis that UV enhancement in the upper troposphere by the Antarctic ozone hole modifies the aerosol population, aerosol size distribution, cloud condensation nuclei capabilities, and cloud properties in Antarctic regions during summer.

Physical Properties, Chemical Components, and Transport Mechanisms of Atmospheric Aerosols Over a Remote Area on the South Slope of the Tibetan Plateau

“…The number size distribution showed a fine mode with a peak at 63.8 nm and the volume size distribution showed a bimodal pattern with peaks at 201.7 nm and 2.3 μm (Figure S3 in Supporting Information ). The aerosol modes were defined based on the particle size range as follows: nucleation mode (Dp < 25 nm), Aitken mode (25 nm ≤ Dp < 100 nm), accumulation mode (100 nm ≤ Dp < 1 μm), and coarse mode (Dp ≥ 1 μm) (Brock et al., 2021; Hara et al., 2021). The average number concentration of atmospheric aerosols at Yadong was 365 cm −3 , with the Aitken mode accounting for the majority (66%) of the distribution during observations.…”

Size‐Dependent Nighttime Formation of Particulate Secondary Organic Nitrates in Urban Air

“…In particular, the size distributions of NO 3,org_Sec at 600–900 nm showed a rapid decrease during the non‐fog‐rain days, while it showed a little peak during the fog‐rain days. To further investigate the difference of NO 3,org_Sec in large particle sizes, the modal structures of NO 3,org_Sec size distribution were fit to the multi‐modal lognormal distribution function with the nonlinear least‐squares method (Hara et al., 2021; Wu & Boor, 2021). As shown in Figure 3 (right), the average mass size distributions (circles) of NO 3,org_Sec were accurately reproduced by the bimodal structure (dash line).…”

Particle Number Size Distribution of Wintertime Alpine Aerosols and Their Activation as Cloud Condensation Nuclei in the Guanzhong Plain, Northwest China

“…Particle growth also depended significantly on the concentration of gaseous precursors in the atmosphere. For instance, the higher concentration of O 3 was favorable for the photochemical reaction to form new smaller particles and increase the concentration of particles (Baalbaki et al, 2021;Hara et al, 2021;Huang et al, 2021;Qi et al, 2015;Ueda et al, 2016). D. Wang et al (2016) pointed out that enhanced formation of sulfate and SOA driven by photochemical oxidation could promote the formation and growth of new particles.…”