ALBERT

Beschreibung: Im heutigen visuell dominierten Zeitalter prägen und formen visuelle (Re-)Präsentationen die Wahrnehmung und Aneignung von Regionen massgeblich. Bilder vermitteln Vorstellungen davon, welche Beziehungen zu einem bestimmten Raum eingenommen werden können und sollen. Sie zeigen, was sich in den Regionen tun lässt, welche Raumnutzungen vorhanden, möglich und erwünscht sind. In diesem Artikel wird eine Methode vorgestellt, durch die die potenzielle Raumwirksamkeit visueller Bilder erfasst werden kann. Sie ermöglicht, bildreiche Präsentationen von «Räumen» in ein übersichtliches Gesamtbild zu übersetzen und so unterschiedliche, unter Umständen in Konflikt zueinander stehende Raumaneignungsweisen herauszuarbeiten. Demonstriert wird die Methode anhand unterschiedlicher Publikationen über die UNESCO Biosphäre Entlebuch. Die Analyse offenbart die Differenz zwischen alltagsnaher Innensicht und romantisierender Aussensicht und dokumentiert einen im Ansatz unkonventionellen, Klischees aufbrechenden touristischen Auftritt.

Beschreibung: The NERC UK SOLAS-funded Reactive Halogens in the Marine Boundary Layer (RHaMBLe) programme comprised three field experiments. This manuscript presents an overview of the measurements made within the two simultaneous remote experiments conducted in the tropical North Atlantic in May and June 2007. Measurements were made from two mobile and one ground-based platforms. The heavily instrumented cruise D319 on the RRS Discovery from Lisbon, Portugal to São Vicente, Cape Verde and back to Falmouth, UK was used to characterise the spatial distribution of boundary layer components likely to play a role in reactive halogen chemistry. Measurements onboard the ARSF Dornier aircraft were used to allow the observations to be interpreted in the context of their vertical distribution and to confirm the interpretation of atmospheric structure in the vicinity of the Cape Verde islands. Long-term ground-based measurements at the Cape Verde Atmospheric Observatory (CVAO) on São Vicente were supplemented by long-term measurements of reactive halogen species and characterisation of additional trace gas and aerosol species during the intensive experimental period. This paper presents a summary of the measurements made within the RHaMBLe remote experiments and discusses them in their meteorological and chemical context as determined from these three platforms and from additional meteorological analyses. Air always arrived at the CVAO from the North East with a range of air mass origins (European, Atlantic and North American continental). Trace gases were present at stable and fairly low concentrations with the exception of a slight increase in some anthropogenic components in air of North American origin, though NOx mixing ratios during this period remained below 20 pptv. Consistency with these air mass classifications is observed in the time series of soluble gas and aerosol composition measurements, with additional identification of periods of slightly elevated dust concentrations consistent with the trajectories passing over the African continent. The CVAO is shown to be broadly representative of the wider North Atlantic marine boundary layer; measurements of NO, O3 and black carbon from the ship are consistent with a clean Northern Hemisphere marine background. Aerosol composition measurements do not indicate elevated organic material associated with clean marine air. Closer to the African coast, black carbon and NO levels start to increase, indicating greater anthropogenic influence. Lower ozone in this region is possibly associated with the increased levels of measured halocarbons, associated with the nutrient rich waters of the Mauritanian upwelling. Bromide and chloride deficits in coarse mode aerosol at both the CVAO and on D319 and the continuous abundance of inorganic gaseous halogen species at CVAO indicate significant reactive cycling of halogens. Aircraft measurements of O3 and CO show that surface measurements are representative of the entire boundary layer in the vicinity both in diurnal variability and absolute levels. Above the inversion layer similar diurnal behaviour in O3 and CO is observed at lower mixing ratios in the air that had originated from south of Cape Verde, possibly from within the ITCZ. ECMWF calculations on two days indicate very different boundary layer depths and aircraft flights over the ship replicate this, giving confidence in the calculated boundary layer depth.

Beschreibung: Strontium isotopic ratios of gypsums recovered from upper Miocene (Messinian) evaporites at ODP Leg 107 Holes 652A, 653B, and 654A (Tyrrhenian Sea) are lower than expected. The values for the Messinian balatino-like gypsum, single gypsum crystals, and anhydrites range from 0.70861 to 0.70886 and are approximately 25 * 10**-5 less than would be expected for evaporites precipitated from Messinian seawater (0.70891-0.70902). Pre-evaporitic planktonic foraminifers from Hole 654A show variable degrees of dolomitization and 87Sr/86Sr values that irregularly decrease upward from normal marine values approximately 81m below the lowest evaporite occurrence. This suggests diagenetic alteration by advecting interstitial water with a low 87Sr/86Sr ratio or that the lower Sr isotopic ratios for the Messinian evaporites could have resulted from a greater influence of fresh water on the Sr isotopic composition of the desiccating Tyrrhenian Sea. Fluctuations of the 87Sr/86Sr-ratio for evaporites in the sedimentary cycles recognized for Holes 653B and 654A, the generally low Sr isotopic ratio of river water entering the Mediterranean Sea, and the presence of dwarf marine microfossils suggest that the 87Sr/86Sr ratio of the evaporites responded to hydrologic variations in a very restricted basin with variable rates of marine and fresh water input. The strontium isotopic ratios of the Messinian anhydrites from the proposed lacustrine sequence at Hole 652A fall in the same range as the marine evaporites from Holes 654A and 653B. This suggests a common or similar origin of the brines at the three locations. The complex depositional and hydrologic conditions in the Mediterranean during the Messinian salinity crisis preclude the use of Sr isotopic values from the evaporites for stratigraphic correlation and dating. They are, however, very useful in the interpretation of the depositional history of the basin. General calculations assuming a closed system suggest that the 87Sr/86Sr ratio of Messinian seawater (-0.7090) could be reduced to that of the evaporites (-0.7087) by mixing with fresh water (e.g., Nile River) in times of 10**4 to 10**5 yr.

Beschreibung: We investigate the extent to which commonly considered quantities, based on total column ozone observations and simulations, are applicable as measures of ozone loss in the polar vortices. Such quantities have been used frequently in ozone assessments by the World Meteorological Organization (WMO) and to assess the performance of chemistry-climate models. The most commonly considered quantity is monthly mean column ozone poleward of a latitude of 63° in spring. For the Arctic, these monthly means were found to be insensitive to the exact choice of the latitude threshold, unlike the Antarctic where greater sensitivity was found. Choosing a threshold based on the location of the transport barrier at the vortex boundary instead of geometric latitude led to a roughly similar year-to-year variability of the monthly means, but in particular years deviations of several tens of Dobson units occurred. Moreover, the minimum of daily total ozone minima poleward of a particular latitude, another popular measure, is debatable, insofar as it relies on one single measurement or model grid point. For Arctic conditions, this minimum value occurred often in air outside polar vortex, both in the observations and in a chemistry-climate model. As a result, we recommend that the minimum of daily minima no longer be used when comparing polar ozone loss in observations and models. As a possible alternative, we suggest considering the minimum of daily average total ozone poleward of a particular equivalent latitude (or in the vortex) in spring. This definition both obviates relying on one single data point and reduces the impact of year-to-year variability in the Arctic vortex breakup on ozone loss measures. However, compact relations of such simple measures with meteorological quantities that describe the potential for polar heterogeneous chlorine activation and thus ozone loss were not found. Therefore, we argue that where possible, more sophisticated measures of chemical polar ozone loss that include additional information to disentangle the impact of transport and chemistry on ozone, should be employed.