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Two types of variability are discernible in the ocean: a response to the atmospheric forcing and the so-called internal/intrinsic ocean variability, which is associated with internal instabilities, nonlinearities and the interactions between processes at different scales. Producing an ensemble of 20 multi-year ocean simulations of the Mediterranean Sea, initialized with realistic initial conditions, but using the same atmospheric forcing, the study examines the intrinsic variability in terms of its spatial distribution and seasonality. In general, the importance of the external forcing decreases with depth but dominates in extended shelves such as the Adriatic Sea and the Gulf of Gabes. In the case of temperature, the atmospheric forcing plays a major role in the uppermost 50 m of the water column during summer and the uppermost 100 m during winter. Additionally, intrinsic variability displays a distinct seasonal cycle in the surface layers, with a prominent maximum at around 30 m depth during the summer probably connected to the summer thermocline formation processes. Concerning current velocity, the internal variability has a significant influence at all depths. [ABSTRACT FROM AUTHOR]

Since ages, the topic of climate – in the sense of "usual weather" – has in the western tradition attracted attention as a possible explanatory factor. Climate, and its purported impact on society, is an integrated element in western thinking and perception. In this lecture, the history of ideas about the climatic impact on humans and society, and the emergence of the ideology of climatic determinism are sketched. This ideology favored the perception of westerners being superior to the people in the rest of the world, giving legitimacy to colonialism. In modern time, when natural sciences instituted self-critical processes (repeatability, falsification) and norms (CUDOS @Merton), the traditional host for climate issues, namely geography, lost its grip, and physics took over. This led to a more systematic, critical, and rigorous approach of building and testing hypotheses and concepts. This gain in methodical rigor, however, went along with the loss of understanding that climate is hardly a key explanatory factor for societal differences and developments. Consequently, the large segments of the field tacitly and unknowingly began reviving the abandoned concept of climatic determinism. Climate science finds itself in a "post-normal" condition, which leads to a frequent dominance of political utility over methodical rigor. [ABSTRACT FROM AUTHOR]

Lead has become less ubiquitous in industrialized countries as a result of increasingly stringent policies to limit the use of this heavy metal as an anti-knock additive in gasoline after emission reached maximum rates in the 1960s and 1970s. An empirical model is constructed that estimates lead concentrations in human blood (PbB) given lead emissions in Europe (PbE) and it is found that the regulation instituted in Germany since the 1970s has reduced significant health hazards.

The statistics of tropical intraseasonal variability are studied using European Centre for Medium-Range Weather Forecasts analyses and several ECHAM General Circulation Model experiments made with different model versions (ECHAM2 and ECHAM3, which have different convection schemes) and different horizontal resolutions (T21, T42, and T106). The study applies the principal oscillation pattern technique to the 200-mb equatorial velocity potential. Associated patterns of tropical outgoing longwave radiation, equatorial zonal wind, and equatorial divergence are also presented. The intercomparison of ECHAM2 and ECHAM3 simulations at low (T21) resolution shows that the improved model physics has a beneficial impact on the simulated Madden-Julian oscillation (MJO). The MJO produced by the ECHAM2 model has an unrealistic spatial distribution of convection, whereas the MJO simulated by the ECHAM3 model appears to be related to convective activity over the Indian Ocean and the West Pacific, which is consistent with the observed MJO. An increase of the horizontal resolution of the ECHAM3 model seems to actually degrade the results. At T42 and T106, the ECHAM3 MJO exhibits too much convective activity over central and equatorial America, with only a marginal effect of the MJO on the West Pacific-Indonesian region.

The principal oscillation pattern (POP) analysis is a technique to empirically identify time-dependent spatial patterns in a multivariate time series of geophysical or other data. In order to investigate medium-scale and synoptic waves in the atmosphere it has been applied to tropospheric geopotential height fields of ECMWF analyses from 1984 to 1987. The data have been subjected to zonal Fourier decomposition and to time filtering so that variations with periods between 3 and 25 days were retained. Analyses have been performed separately for each zonal wavenumber 5-9 on the Northern Hemisphere in winter and on the Southern Hemisphere in summer (DJF). POPs can be seen as normal modes of a linear approximation to a more complex dynamical system. The system matrix is estimated from observations of nature. This concept is compared with conventional stability analysis where the system matrix of the linear system is derived from theoretical, in this case quasigeostrophic, reasoning. Only the mean basic flow depends on time- and space-averaged fields of observed wind and temperature from the ECMWF data. It turns out that the most significant POPs are very similar in time and spatial structure to the most unstable waves in the stability analysis. They describe the linear growth phase of baroclinic, unstable waves that propagate eastward with periods of 3-7 days. Since the POPs are purely derived from observations, the results indicate the appropriateness of the assumptions usually made in linear stability analysis of zonally symmetric flows to explain high-frequency atmospheric fluctuations. Moreover, the POP analysis reveals patterns that are not found in the linear stability analysis. These can possibly be attributed to the nonlinear decay phase of baroclinic waves. Eliassen-Palm cross sections help clarify the interpretation of the POPs in terms of the life cycle of nonlinear baroclinic waves.