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.
Evaluation of WRF SCM Simulations of Stratocumulus-Topped Marine and Coastal Boundary Layers and Improvements to Turbulence and Entrainment Parameterizations
