From 1993 to 1995, chloroacetic acids have been determined in rainwater collected near the center of Zu ¨rich and in a rural area of Switzerland (Alpthal). The chloroacetic acids have been enriched either by evaporation or by anion exchanger, derivatized to their respective propyl esters, and determined by gas chromatography (GC) with electron capture detection (ECD), by coupled-column GC-ECD (GC-GC-ECD), or by GC/mass spectrometry (MS). Monochloroacetic acid is most abundant, followed by dichloro-and trichloroacetic acid. Concentrations range from 0.01 up to 9 µg/L; the dependence on meteorological conditions and sampling site is discussed.

We investigate behavior of the continuous stochastic signals above some threshold, bursts, when the exponent of multiplicativity is higher than one. Earlier we have proposed a general nonlinear stochastic model applicable for the modeling of absolute return and trading activity in financial markets which can be transformed into Bessel process with known first hitting (first passage) time statistics. Using these results we derive PDF of burst duration for the proposed model. We confirm derived analytical expressions by numerical evaluation and discuss bursty behavior of return in financial markets in the framework of modeling by nonlinear SDE.

We present a model for the α-beauty contest that explains common patterns in experimental data of oneshot and iterative games. The approach is based on two basic assumptions. First, players iteratively update their recent guesses. Second, players estimate intervals rather than exact numbers to cope with incomplete knowledge of other players' rationality. Under these assumptions we extend the cognitive hierarchy model of Camerer et al. [Camerer, C., Ho, T., Chong, J., 2003b. A cognitive hierarchy model of one-shot games. Quart. J. Econ. 119, 861-898]. The extended model is estimated on experimental data from a newspaper experiment.

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Synthetic halocarbons are used for a wide range of applications such as air conditioning or foam blowing. The first generation of these compounds, the CFCs and halons, were harmful for the stratospheric ozone layer and were subsequently replaced by compounds degradable in the troposphere and by "ozone-friendly" compounds free of chlorine and bromine. CFCs and many of the new compounds are, however, strong greenhouse gases. At the High Altitude Research Station Jungfraujoch, measurements of halocarbons began in the year 2000 and are contributing today to the global network of the Advanced Global Atmospheric Gases Experiment. In this contribution we review previous source attribution studies applied to observations at Jungfraujoch using Lagrangian trajectory and particle dispersion models. Based on a trajectory statistical method we qualitatively identify prominent source regions of five selected halocarbons over central Europe and describe their evolution with time over the years 2003-2011. For quantitative source estimation we have developed and applied different inverse modeling techniques in combination with the particle dispersion model FLEXPART. Emissions estimates need to be complemented with a realistic estimate of their uncertainties, and a particularly critical issue in this context for a high-Alpine site like Jungfraujoch is the choice of the initial trajectory height in the transport simulation. Using meteorological data at a resolution of 0.2°× 0.2°, the optimal release height is estimated to be around 3000 m above sea level, which is more than 500 m below the true station altitude but still 900 m above the smooth model surface.