Volatile organic compounds (VOCs) were measured at the South Pole (SP) from late Austral spring to mid-summer 2000 as part of the Investigation of Sulfur Chemistry in the Antarctic Troposphere Program (ISCAT-2000). This paper focuses on VOCs that are directly emitted from the ocean, specifically dimethyl sulfide (DMS), methyl nitrate (CH3ONO2), methyl iodide (CH 3I) and bromoform (CHBr3). A partial seasonal cycle of these gases was also recorded during the year following ISCAT-2000. During the summer, the SP periodically receives relatively fresh marine air containing short-lived oceanic trace gases, such as DMS (τ≈1 day). However, DMS was not detected at the SP until January even though DMS emissions from the Southern Ocean typically start peaking in November and elevated levels of other ocean-derived VOCs, including CH3ONO2 and CHBr 3, were observed in mid-November. We speculate that in November and December most of the DMS is oxidized before it reaches the SP: a strong correlation between CH3ONO2 and methane sulfonate (MSA), an oxidation product of DMS, supports this hypothesis. Based on a limited number of samples taken over the course of one year, CH3ONO2 apparently accumulates to a quasi-steady-state level over the SP in winter, most likely due to continuing emissions of the compound coupled with a lower rate of photochemical destruction. Oceanic emissions were concluded to be the dominant source of alkyl nitrates at the SP; this is in sharp contrast to northern high latitudes where total alkyl nitrate mixing ratios are dominated by urban sources. © 2004 Elsevier Ltd. All rights reserved.

The Antarctic Tropospheric Chemistry Investigation (ANTCI) was carried out from late November to December 2003 with both extended ground-based and tethered balloon studies at Amundsen Scott Station, South Pole. ANTCI 2003 was the first of two Antarctic field studies with the primary goal of further exploring the active photochemistry of the South Pole region that was first identified in the previous Investigation of Sulfur Chemistry in the Antarctic Troposphere (ISCAT) program. Since ISCAT was fully ground-based, ANTCI 2003 goals included expanding chemical studies both vertically upward to investigate mixing and horizontally to better understand large-scale plateau NOx production and transport. Thus, in addition to ground-based experiments at South Pole, Twin Otter aircraft sampling took place out to hundreds of kilometers in several directions from the South Pole. These were designed to specifically address the issue of how representative past South Pole chemical measurements are of the surrounding high plateau region. The Twin Otter was also used to make transects along the coast both north and south of McMurdo Station. The present paper summarizes the overall setting and results of this investigation and highlights the many new findings that were obtained. © 2007 Elsevier Ltd. All rights reserved.