Description: During three summer campaigns in January/February 2000, 2001, and 2002 the ionic composition of the aerosol at the European Project for Ice Coring in Antarctica (EPICA) deep-drilling site at Kohnen Station was measured in daily resolution. In 2000 and 2002 we observed mean (±std) non-sea-salt sulfate (nss-[SO4]2-) concentrations of 353 ± 100 ng/m**3 and 320 ± 250 ng/m**3, as well as methane sulfonate (MS) concentrations of 59 ± 36 ng/m**3 and 74 ± 80 ng/m**3, respectively. For the summer campaign in 2001, significantly lower nss-[SO4]2- and MS levels of 164 ± 150 ng/m**3 and 19 ± 12 ng/m**3, respectively, were typical. The mean MS/nss-[SO4]2- ratio ranged from about 0.1 to 0.2. MS and nss-[SO4]2- concentrations and their variability were roughly comparable to coastal stations at summer. Supported by air mass back trajectory analyses, this finding documented an efficient long-range transport to Kohnen via the free troposphere. MS/nss-[SO4]2- ratios exhibited a strong dependence on the MS concentration with systematically higher ratios at higher MS concentrations, a peculiarity which is also evident in a firn core drilled at this site.

Description: Atmospheric trace element concentrations were measured from March 1999 through December 2003 at the Air Chemistry Observatory of the German Antarctic station Neumayer by inductively coupled plasma - quadrupol mass spectrometry (ICP-QMS) and ion chromatogra-phy (IC). This continuous five year long record derived from weekly aerosol sampling re-vealed a distinct seasonal summer maximum for elements linked with mineral dust entry (Al, La, Ce, Nd) and a winter maximum for the mostly sea salt derived elements Li, Na, K, Mg, Ca, and Sr. The relative seasonal amplitude was around 1.7 and 1.4 for mineral dust (La) and sea salt aerosol (Na), respectively. On average a significant deviation regarding mean ocean water composition was apparent for Li, Mg, and Sr which could hardly be explained by mir-abilite precipitation on freshly formed sea ice. In addition we observed all over the year a not clarified high variability of element ratios Li/Na, K/Na, Mg/Na, Ca/Na, and Sr/Na. We found an intriguing co-variation of Se concentrations with biogenic sulfur aerosols (methane sul-fonate and non-sea salt sulfate), indicating a dominant marine biogenic source for this element linked with the marine biogenic sulfur source.

Description: We measured optical properties and ionic composition of the aerosol at Neumayer Station from 2004 through 2006 by an integrating nephelometer and chemical analysis of daily aerosol samples, respectively. From this unique data set we discuss the seasonality of aerosol optical parameters along with their chemical composition. Austral summer (November through March) was characterized by mean particle number concentrations of 472±260 cm**-3 compared to 168±160 cm**-3 during winter (April through October), mean scattering Ångström exponents of 1.7±0.6 compared to 1.3±0.6 during winter, and mean backscattering ratios at 700 nm of 0.21±0.13 compared to 0.17±0.08 during winter. In contrast, light scattering coefficients (ssp) showed a broad maximum during winter (4.8±5.3 1/µm for ssp(550)). The mean single scattering albedo was 0.99± at 550 nm. We further derived mass scattering and mass backscattering efficiencies for biogenic sulfate aerosol (BSA) at 450 nm, 550 nm, and 700 nm for relative humidities between 5% and 11%. At 550 nm the scattering efficiency for biogenic sulfate aerosol sigma bsBSA(550) was 8.9±0.7 m**2/g with a corresponding backscattering efficiency sigma bsBSA(550) of 1.0±0.08 m**2/g. From the seasonality of the aerosol composition we inferred a dominant contribution of sulfate aerosol regarding radiative forcing in the lower troposphere from December through January at Neumayer, while the impact of sea salt aerosol prevailed for the rest of the year.

Description: The first Air Chemistry Observatory at the German Antarctic station Georg von Neumayer (GvN) was operated for 10 years from 1982 to 1991. The focus of the established observational programme was on characterizing the physical properties and chemical composition of the aerosol, as well as on monitoring the changing trace gas composition of the background atmosphere, especially concerning greenhouse gases. The observatory was designed by the Institut für Umweltphysik, University of Heidelberg (UHEIIUP). The experiments were installed inside the bivouac lodge, mounted on a sledge and put upon a snow hill to prevent snow accumulation during blizzards. All experiments were under daily control and daily performance protocols were documented. A ventilated stainless steel inlet stack (total height about 3-4 m above the snow surface) with a 50% aerodynamic cut-off diameter around 7-10 µm at wind velocities between 4-10 m/s supplied all experiments with ambient air. Contamination free sampling was realized by several means: (i) The Air Chemistry Observatory was situated in a clean air area about 1500 m south of GvN. Due to the fact that northern wind directions are very rare, contamination from the base can be excluded for most of the time. (ii) The power supply (20 kW) is provided by a cable from the main station, thus no fuel-driven generator is operated in the very vicinity. (iii) Contamination-free sampling is controlled by the permanently recorded wind velocity, wind direction and by condensation particle concentration. Contamination was indicated if one of the following criteria were given: Wind direction within a 330°-30° sector, wind velocity 〈2.2 m/s or 〉17.5 m/s, or condensation particle concentrations 〉2500/cm**3 during summer, 〉800/cm**3 during spring/autumn and 〉400/cm**3 during winter. If one or a definable combination of these criteria were given, high volume aerosol sampling and part of the trace gas sampling were interrupted. Starting at 1982 through 1991-01-14 surface ozone was measured with an electrochemical concentration cell (ECC). Surface ozone mixing ratio are given in ppbv = parts per 10**9 by volume. The averaging time corresponds to the given time intervals in the data sheet. The accuracy of the values are better than ±1 ppbv and the detection limit is around 1.0 ppbv. Aerosols were sampled on two Whatman 541 cellulose filters in series and analyzed by ion chromatography at the UHEI-IUP. Generally, the sampling period was seven days but could be up to two weeks on occasion. The air flow was around 100 m**3/h and typically 10000-20000 m**3 of ambient air was forced through the filters for one sample. Concentration values are given in nanogram (ng) per 1 m**3 air at standard pressure and temperature (1013 mbar, 273.16 K). Uncertainties of the values were approximately ±10% to ±15% for the main components MSA, chloride, nitrate, sulfate and sodium, and between ±20% and ±30% for the minor species bromide, ammonium, potassium, magnesium and calcium.