Condensation particle concentrations (daily means, measured by a condensation nuclei counter) and the mean seasonality at Neumayer. Note the stepwise increase of particle concentrations from polar winter (below 100 cm-3) to the maximum in late austral summer (around 1000 cm-3) and the delayed appearence of the particle concentration maximum compared to the methanesulfonate (MSA) and nss-sulfate maxima. Like MSA condensation particle are formed in the marine troposphere by photooxidation of DMS emitted by algae. Due to the relatively short atmospheric lifetime of condensation particle, regional sources (Atka bay) dominate the signal. For further information contact Rolf Weller.
Surface ozone mixing ratios (daily means in parts per 109 by volume) at Neumayer (a). Maximum ozone values of about 32 ppbv can be observed in August while during polar summer (December) they decrease to a minimum of 13 ppbv. From August to September characteristic ozone depletion events can frequently be detected (b). Comparable to stratopheric ozone depletion, reactive halogen compounds are responsible for this pecularity. However, in contrast to processes in the stratosphere, tropospheric ozone depletion is a natural phenomenon caused by release of reactive bromine compounds from sea-salt aerosol over the sea-ice covered ocean.
Wessel, S., S. Aoki, P. Winkler, R. Weller, A. Herber, H. Gernandt, and O. Schrems, Tropospheric ozone depletion events in polar regions: A comparison of observations in the Arctic and Antarctic, Tellus, 50B, 34-50, 1998.
Vogt, R., P.J. Crutzen, R. Sander, A mechanism for halogen release from sea-salt aerosol in the remote marine boundary layer, Nature, 383, 327-330, 1996.
For further information contact Rolf Weller.
222Rn activity, measured by on-line alpha spectroscopy of 222Rn decay products (dots: 3-hour averages, line: 32 points running mean) at Neumayer. The radioactive 222Rn is a decay product of 238U. 222Rn activity can be used as a tracer for long range transport of continental air masses (identifiable as distinct peaks in the signal, the so called radon storms). The oceans and the nearly totally ice covered Antarctic are negligible sources. For further information contact Ingeborg Levin (Institut für Umweltphysik).