Untersuchung der CO2-Konzentration im Tropopausenniveau     

Dieter Jost 《Pure and Applied Geophysics》1971,86(1):209-218

Zusammenfassung Zwischen 50° bis 85°N Breite wurde die atmosphärische CO₂-Konzentration während mehrerer Messflüge registriert. Diese war oberhalb der Tropopause bis zu 7 ppm (im Mittel etwa 2 ppm) niedriger als in der oberen Troposphäre. Im Jahresmittel entspricht diese CO₂-Konzentrationsdifferenz einem Fluss von etwa 10^–2 g CO₂/cm² Jahr aus der nördlichen Troposphäre in die Stratosphäre. Die Bedeutung dieser CO₂-Konzentrationsunterschiede für den atmosphärischen CO₂-Haushalt sowie für die Strahlungsbilanz im Tropopausenniveau kann erst nach Vorlage weiterer, über das ganze Jahr verteilter Messdaten erfolgen.

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Summary CO₂-concentration was measured during several flights in northern latitudes (50°–85°). Above Tropopause CO₂-concentration was up to 7 ppm (as a mean some 2 ppm) smaller than in upper troposphere. As a mean this difference in CO₂-concentration cm² year conforms to a CO₂-flux of some 10^–2 g CO₂/cm² year from northern troposphere into stratosphere. The importance of these CO₂-differences for atmospheric CO₂-system and for radiation balance in tropopause-height may be considered as soon as more CO₂-concentration data for the whole year are available.

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Phase partitioning of aerosol particles in clouds at Kleiner Feldberg     

A. Hallberg  K. J. Noone  J. A. Ogren  I. B. Svenningsson  A. Flossmann  A. Wiedensohler  H. -C. Hansson  J. Heintzenberg  T. L. Anderson  B. G. Arends  R. Maser 《Journal of Atmospheric Chemistry》1994,19(1-2):107-127

The partitioning of aerosol particles between cloud droplets and interstitial air by number and volume was determined both in terms of an integral value and as a function of size for clouds on Mt. Kleiner Feldberg (825 m asl), in the Taunus Mountains north-west of Frankfurt am Main, Germany. Differences in the integral values and the size dependent partitioning between two periods during the campaign were observed. Higher number and volume concentrations of aerosol particles in the accumulation mode were observed during Period II compared to Period I. In Period I on average 87±11% (±one standard deviation) and 73±7% of the accumulation mode volume and number were incorporated into cloud droplets. For Period II the corresponding fractions were 42±6% and 12±2% in one cloud event and 64±4% and 18±2% in another cloud event. The size dependent partitioning as a function of time was studied in Period II and found to have little variation. The major processes influencing the partitioning were found to be nucleation scavenging and entrainment.  相似文献   

Über den Zusammenhang zwischen luftchemischen und meteorologischen Parametern im Hochtal von St. Moritz     

Prof. Dr. H. W. Georgii  Dr. D. Jost  Dr. R. S. Kaller  Dr. J. Müller 《Theoretical and Applied Climatology》1974,22(4):363-373

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Assessment of Cyto‐ and Genotoxic Effects of a Variety of Chemicals Using Saccharomyces cerevisiae     

Marcel Schmitt  Georg Gellert  Jost Ludwig  Hella Lichtenberg‐Frat 《洁净——土壤、空气、水》2005,33(1):56-63

Saccharomyces cerevisiae as the most simple eukaryotic organism is broadly accepted as a laboratory model organism. For the detection of potential toxic effects of pure compounds and complex composed samples like wastewater a miniaturised short‐term in vitro cyto‐ and genotoxicity screening assay was developed. The assay based on genetically modified S. cerevisiae cells deleted in the prominent drug efflux transporters Pdr5, Snq2, and Yor1 that facilitate pleiotropic drug resistance. The yeast strain devoid of these proteins that mediate the efflux of structurally diverse hydrophobic compounds exhibited an increased sensitivity to a variety of organic compounds. The DNA damage inducible RAD54 promoter fused to a yeast optimized derivative of the GFP (green fluorescent protein) gene from the jelly fish Aequorea victoria served as an indicator of DNA damage in this strain. Various pure compounds including the direct‐acting genotoxins methyl‐N‐nitro‐N‐nitrosoguanidine (MNNG), 4‐nitroquinoline‐N‐oxide (4‐NQO), methyl methanesulfonate (MMS) and hydroxyurea as well as the heavy metals cadmium and chromium(VI), the insecticide lindane and the central nervous system stimulant caffeine were tested exhibiting dose dependent induction of green fluorescence. All compounds were in parallel examined for chronic toxicity. A bioassay detecting simultaneously geno‐ and cytotoxic effects of potential toxicants in a single assay can be an important tool with a variety of applications in environmental monitoring and aquatic ecotoxicology. By partial automation and miniaturisation to microtitration scale this bioassay enables sensitive and fast biomonitoring for a multitude of samples.  相似文献   

Kamafugitic diatremes: facies characterisation and genesis—examples from the Goiás Alkaline Province, Brazil     

Tereza Cristina Junqueira-Brod  Jos Affonso Brod  Jos Carlos Gaspar  Hardy Jost 《Lithos》2004,76(1-4):261-282

This paper describes the internal organisation of two diatremes (Águas Emendadas and Neuzinha) and one small breccia-filled conduit (Tigre) in the central portion of the Late Cretaceous Goiás Alkaline Province (GAP), central Brazil, and explores the criteria for facies recognition. The GAP kamafugitic diatremes are emplaced into Carboniferous sandstones of the Aquidauana Formation, at the northern margin of the Paraná Basin. They are usually elliptical structures, not longer than 900 m, filled with breccia and partially covered by thin kamafugitic to basanitic lava flows. The breccias are dominated by juvenile pyroclasts, with subordinate amounts of cognate fragments and xenoliths. In addition to variations in ash and lapilli proportions, juvenile fragment types may be used to discriminate genetic processes and the corresponding pyroclastic deposits.

An extensive field, textural and compositional dataset was analysed by multivariate statistical techniques. Combined with field observations, this allowed us to define a set of facies for kamafugitic diatremes, and, more importantly, to understand the internal structure of the studied bodies and to cross-correlate them. Seven distinct facies were recognised. The Fluidised Conduit Facies (FCF) represents high-energy, strongly fluidised but only moderately fragmented systems. It occurs in a confined environment, and is typical of deeper parts of the conduit, before the actual diatreme level is reached by the ascending fluidised magma. Large amounts of spinning droplets are formed within this region. The Fluidised Conduit–Diatreme Facies (FCDF) is characteristic of intermediate depths in the conduit, where highly fluidised and highly fragmented systems produce large amounts of ash. Spinning droplets decrease in abundance, ordinary juvenile fragments become very common, and xenoliths from the country rock in the immediate vicinity of the diatreme are present. The Fluidised Fragmented Facies (FFF) and the Magmatic Fluidised Facies (MFF) produce very heterogeneous deposits that dominate the shallower part of the system, making up most of the diatreme-filling materials. The Fluidised Fragmented Facies can be distinguished by much higher degrees of fluidisation, fragmentation and system energy. It occupies the internal part of the diatreme and is characterised by the common presence of tuff pockets, tuff fragments, and accretionary and armoured lapilli. The Magmatic Fluidised Facies typically occupies the outer portion of the diatreme and can be distinguished from the Fluidised Fragmented Facies by the dominance of lapilli over ash and by the presence of abundant wrapped fragments. The Magmatic Facies (MF) and the Coherent Magmatic Facies (CMF) are volumetrically subordinate and represent late stages, when less fluidised and less fragmented material, or even coherent magma erupts relatively passively, in the aftermath of the main explosive stage that generated the diatreme. The Border Facies is defined by the increased abundance of material from the immediate country rock. At Águas Emendadas and Neuzinha this facies is marked by the presence of fragments of peperite-like rock, formed by the interaction of the fluidised magma with friable sandstone.  相似文献   

An overview of the ACE‐2 clear sky column closure experiment (CLEARCOLUMN)     

Philip B. Russell  Jost Heintzenberg 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):463-483

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Climate change impacts on wildfires in a Mediterranean environment     

Marco Turco  Maria-Carmen Llasat  Jost von Hardenberg  Antonello Provenzale 《Climatic change》2014,125(3-4):369-380

We analyse the observed climate-driven changes in summer wildfires and their future evolution in a typical Mediterranean environment (NE Spain). By analysing observed climate and fire data from 1970 to 2007, we estimate the response of fire number (NF) and burned area (BA) to climate trends, disentangling the drivers responsible for long-term and interannual changes by means of a parsimonious Multi Linear Regression model (MLR). In the last forty years, the observed NF trend was negative. Here we show that, if improvements in fire management were not taken into account, the warming climate forcing alone would have led to a positive trend in NF. On the other hand, for BA, higher fuel flammability is counterbalanced by the indirect climate effects on fuel structure (i.e. less favourable conditions for fine-fuel availability and fuel connectivity), leading to a slightly negative trend. Driving the fire model with A1B climate change scenarios based on a set of Regional Climate Models from the ENSEMBLES project indicates that increasing temperatures promote a positive trend in NF if no further improvements in fire management are introduced.  相似文献   

Analysis of the water column oxic/anoxic interface in the Black and Baltic seas with a numerical model     

E.V. Yakushev  F. Pollehne  G. Jost  I. Kuznetsov  B. Schneider  L. Umlauf 《Marine Chemistry》2007

A 1D hydrophysical-biogeochemical model was developed to study the cycling of the main elements in the pelagic redox layer in seas with anoxic conditions. The formation and decay of organic matter; the reduction and oxidation of nitrogen, sulfur, manganese, and iron species; and the transformation of phosphorus species were parameterized. Temporal and spatial developments of the model's variables were described by a system of horizontally integrated vertical diffusion equations for non-conservative substances. The calculated spatial and temporal distributions of the above-mentioned parameters were in good agreement with observed vertical distribution patterns of these processes.  相似文献   

U–Pb SHRIMP and Sm–Nd geochronology of granite–gneiss complexes and implications for the evolution of the Central Brazil Archean Terrain     

Cludia Lima Queiroz  Hardy Jost  Luiz Carlos da Silva  Neal J. McNaughton 《Journal of South American Earth Sciences》2008,26(1):100-124

The paper is a first attempt to unravel the Archean multi-stage metaplutonic assemblage of the Meso/Neoarchean terrane of the State of Goiás, Central Brazil, by means of the U–Pb SHRIMP zircon and Sm–Nd techniques. Two stages of granitic plutonism, spanning ca. 140 m.y., were precisely established for the accretion of the gneiss protoliths. The earliest stage embraces tonalitic to granodioritic and minor granitic orthogneisses with Nd juvenile signature, emplaced from ca. 2845 to ca. 2785 Ma, interpreted as the roots of an early arc. Inherited zircon xenocrysts and Nd isotopic data indicate that the juvenile magmas underwent contamination from a sialic crust as old as 3.3 Ga, from which there are, so far, no recognizable exposures. The second stage comprises granodioritic to granitic gneisses and lasted from ca. 2711 to 2707 Ma. Based on their Nd isotopic signatures and on inherited zircon crystals, their protoliths are interpreted as dominantly crustal-derived. The SHRIMP data from zircon crystals did not depict a Paleoproterozoic overprinting on the Archean gneisses, which is due to geological processes with prevailing temperatures below the isotopic stability of the U/Pb/Th system in the mineral. These processes comprise crustal extension and intrusion of a mafic dike swarm at ca. 2.3 Ga, followed by low grade events mostly related to shear zones between ca. 2.15 and 2.0 Ga. The study also revealed the extent of the Pan- African tectono-thermal overprinting on the Archean orthogneisses. Most of the zircon populations show morphological evidence of metamorphic peripheral recrystallization dated between ca. 750 and 550 Ma. One of the banded gneisses with a crystallization age of ca. 2700 Ma (2σ) has a more complex zircon population including magmatic new grains, which yielded a precise 206Pb/238U crystallization age of 590 ± 10 Ma (2σ). These new grains are interpreted to have grown in anatectic veins injected within strongly sheared gneiss.The data characterize a widespread Pan-African-aged metamorphic overprinting, culminating with localized anatexis of the Archean orthogneisses.  相似文献   

Photometry and bulk physical properties of Solar System surfaces icy analogs: The Planetary Ice Laboratory at University of Bern     

A. Pommerol  N. Thomas  M. Affolter  G. Portyankina  B. Jost  K. Seiferlin  K.-M. Aye 《Planetary and Space Science》2011,59(13):1601-1612

We have designed and constructed an original facility to characterize the VIS–NIR Bidirectional Reflectance Distribution Function (BRDF) and some complementary bulk physical properties of planetary analog samples containing water ice. The central part of the facility is a highly accurate gonio-radiometer (PHIRE-2) operating in the VIS–NIR spectral range (400–1100 nm) installed in a large laboratory freezer. Its development was based on the experience gained on the gonio-radiometer PHIRE-1 (Gunderson et al., 2006). The PHIRE-1 design was modified to permit operations at sub-zero temperatures and to optimize the performance of the instrument. The photometric measurements are complemented by a detailed simultaneous characterization of the physical state and possible temporal evolution of the samples using a combination of macro- and micro-imaging, thermal, electrical and sample mass measurements. The modified design will support the interpretation of current and future remote sensing and in-situ datasets on icy planetary objects with a special emphasis on cometary nuclei, Martian polar regions and Jovian satellites.  相似文献