Perchlorate in Year-Round Antarctic Precipitation

Year-round precipitation in coastal East Antarctica and Antarctic Peninsula was used to investigate the seasonal patterns in sources of atmospheric perchlorate ((Figure presented.)). Although featuring distinct climates, the two locations exhibit similar annual mean and seasonal cycles of (Figure presented.) concentration, with higher values in autumn and lower concentrations in winter and spring. Tropospheric formation dominates atmospheric (Figure presented.) in spring and summer, which is influenced by both oxidants levels and environmental conditions (e.g., air humidity). Tropospheric (Figure presented.) production may also be promoted by elevated levels of oxidants brought by air mass from the interior Antarctic ice sheet in spring and summer. The autumn concentration maximum may originate from (Figure presented.) produced in the stratosphere through reactions between reactive chlorine and ozone during spring and summer. In winter, the stratospheric input may contribute to (Figure presented.) via polar stratospheric clouds sedimentation.