ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Due to complex hydrodynamic and biological inhomogeneities, the phytoplankton species succession cannot be satisfactorily observed, apart from the seasonal blooms which occur in temperate waters. Large flexible plastic tanks have proved to be useful for such observations. In 1972, for 28 days, a phytoplankton succession in nutrient-poor water in the outer harbor of Helgoland was observed in a flexible plastic tank (3 m3). During this period, 3 phytoplankton biomass maxima were formed with many significant correlations. In the first 7 days the ammonia concentration decreased from over 6 to 2 μ mol 1-1 for 14 days. The nitrate concentration remained in the range of 3–6 μ mol 1-1 and then fell abruptly to 0–2 μ mol 1-1. The phosphate concentration was about 0.1 μ mol 1-1. Lauderia borealis dominated the first period, and its increase was significantly correlated with the decrease in ammonia. The diatom was succeeded by two dinoflagellates, Dinophysis acuminata and Prorocentrum micans. The last period of the experiment was characterized by a stronger development of Rhizosolenia species. The rapid recovery of the crop in the nutrient-poor water points to intensive remineralization processes. The irregular occurrence of ammonia near the surface was correlated with the appearance of Noctiluca miliaris at this depth. It is expected that repetitions of this type of experiment will permit further explanations of statistical correlations which are not yet clear. As a first step, in order to test hypotheses, a correlation analysis was employed to eliminate the statistically non-significant correlations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International journal of biometeorology 28 (1984), S. 326-326 
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Four time-dependent greenhouse warming experiments were performed with the same global coupled atmosphere-ocean model, but with each simulation using initial conditions from different “snapshots” of the control run climate. The radiative forcing — the increase in equivalent CO2 concentrations from 1985–2035 specified in the Intergovernmental Panel on Climate Change (IPCC) scenario A — was identical in all four 50-year integrations. This approach to climate change experiments is called the Monte Carlo technique and is analogous to a similar experimental set-up used in the field of extended range weather forecasting. Despite the limitation of a very small sample size, this approach enables the estimation of both a mean response and the “between-experiment” variability, information which is not available from a single integration. The use of multiple realizations provides insights into the stability of the response, both spatially, seasonally and in terms of different climate variables. The results indicate that the time evolution of the global mean warming signal is strongly dependent on the initial state of the climate system. While the individual members of the ensemble show considerable variation in the pattern and amplitude of near-surface temperature change after 50 years, the ensemble mean climate change pattern closely resembles that obtained in a 100-year integration performed with the same model. In global mean terms, the climate change signals for near surface temperature, the hydrological cycle and sea level significantly exceed the variability among the members of the ensemble. Due to the high internal variability of the modelled climate system, the estimated detection time of the global mean temperature change signal is uncertain by at least one decade. While the ensemble mean surface temperature and sea level fields show regionally significant responses to greenhouse-gas forcing, it is not possible to identify a significant response in the precipitation and soil moisture fields, variables which are spatially noisy and characterized by large variability between the individual integrations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Climate dynamics 2 (1987), S. 63-90 
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Inorganic carbon in the ocean is modelled as a passive tracer advected by a three-dimensional current field computed from a dynamical global ocean circulation model. The carbon exchange between the ocean and atmosphere is determined directly from the (temperature-dependent) chemical interaction rates in the mixed layer, using a standard CO2 flux relation at the air-sea interface. The carbon cycle is closed by coupling the ocean to a one-layer, horizontally diffusive atmosphere. Biological sources and sinks are not included. In this form the ocean carbon model contains essentially no free tuning parameters. The model may be regarded as a reference for interpreting numerical experiments with extended versions of the model including biological processes in the ocean (Bacastow R and Maier-Reimer E in prep.) and on land (Esser G et al in prep.). Qualitatively, the model reproduces the principal features of the observed CO2 distribution bution in the surface ocean. However, the amplitudes of surface pCO2 are underestimated in upwelling regions by a factor of the order of 1.5 due to the missing biological pump. The model without biota may, nevertheless, be applied to compute the storage capacity of the ocean to first order for anthropogenic CO2 emissions. In the linear regime, the response of the model may be represented by an impulse response function which can be approximated by a superposition of exponentials with different amplitudes and time constants. This provides a simple reference for comparison with box models. The largest-amplitude (∼0.35) exponential has a time constant of 300 years. The effective storage capacity of the oceans is strongly dependent on the time history of the anthropogenic input, as found also in earlier box model studies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract. Four time-dependent greenhouse warming experiments were performed with the same global coupled atmosphere-ocean model, but with each simulation using initial conditions from different ”snapshots" of the control run climate. The radiative forcing – the increase in equivalent CO2 concentrations from 1985–2035 specified in the Intergovernmental Panel on Climate Change (IPCC) scenario A – was identical in all four 50-year integrations. This approach to climate change experiments is called the Monte Carlo technique and is analogous to a similar experimental set-up used in the field of extended range weather forecasting. Despite the limitation of a very small sample size, this approach enables the estimation of both a mean response and the ”between-experiment" variability, information which is not available from a single integration. The use of multiple realizations provides insights into the stability of the response, both spatially, seasonally and in terms of different climate variables. The results indicate that the time evolution of the global mean warming signal is strongly dependent on the initial state of the climate system. While the individual members of the ensemble show considerable variation in the pattern and amplitude of near-surface temperature change after 50 years, the ensemble mean climate change pattern closely resembles that obtained in a 100-year integration performed with the same model. In global mean terms, the climate change signals for near surface temperature, the hydrological cycle and sea level significantly exceed the variability among the members of the ensemble. Due to the high internal variability of the modelled climate system, the estimated detection time of the global mean temperature change signal is uncertain by at least one decade. While the ensemble mean surface temperature and sea level fields show regionally significant responses to greenhouse-gas forcing, it is not possible to identify a significant response in the precipitation and soil moisture fields, variables which are spatially noisy and characterized by large variability between the individual integrations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Climate dynamics 4 (1990), S. 95-125 
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A three-dimensional model of the natural carbon cycle in the oceans is described. The model is an extension of the inorganic ocean-circulation carbon cycle model of Maier-Reimer and Hasselmann (1987) to include the effect of the ocean biota. It is based on a dynamic, general circulation model of the world oceans. Chemical species important to the carbon cycle are advected by the current field of the general circulation model. Mixing occurs through numerical diffusivity (related to finite box size), a small explicit horizontal diffusivity, and a convective adjustment. An atmospheric box exchanges CO2 with the surface ocean. There is no land biota provided in the present version of the model. The effect of the ocean biota on ocean chemistry is represented in a simple way and model distributions of chemical species are compared with distributions observed during the GEOSECS and other expeditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 77 (1990), S. 185-186 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1573-0662
    Keywords: Ozone laminae ; mid-latitudes ; ozone depletion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract In this paper, we show that the rate of ozone loss in both polar and mid-latitudes, derived from ozonesonde and satellite data, has almost the same vertical distribution (although opposite sense) to that of ozone laminae abundance. Ozone laminae appear in the lower stratosphere soon after the polar vortex is established in autumn, increase in number throughout the winter and reach a maximum abundance in late winter or spring. We indicate a possible coupling between mid-winter, sudden stratospheric warmings (when the vortex is weakened or disrupted) and the abundance of ozone laminae using a 23-year record of ozonesonde data from the World Ozone Data Center in Canada combined with monthly-mean January polar temperatures at 30 hPa. Results are presented from an experiment conducted during the winter of 1994/95, in phase II of the Second European Stratospheric And Mid-latitude Experiment (SESAME), in which 93 ozone-enhanced laminae of polar origin observed by ozonesondes at different time and locations are linked by diabatic trajectories, enabling them to be probed twice or more. It is shown that, in general, ozone concentrations inside laminae fall progressively with time, mixing irreversibly with mid-latitude air on time-scales of a few weeks. A particular set of laminae which advected across Europe during mid February 1995 are examined in detail. These laminae were observed almost simultaneously at seven ozonesonde stations, providing information on their spatial scales. The development of these laminae has been modelled using the Contour Advection algorithm of Norton (1994), adding support to the concept that many laminae are extrusions of vortex air. Finally, a photochemical trajectory model is used to show that, if the air in the laminae is chemically activated, it will impact on mid-latitude ozone concentrations. An estimate is made of the potential number of ozone molecules lost each winter via this mechanism.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1573-0662
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The chemically induced ozone loss inside the Arctic vortex during the winter 1994/95 has been quantified by coordinated launches of over 1000 ozonesondes from 35 stations within the Match 94/95 campaign. Trajectory calculations, which allow diabatic heating or cooling, were used to trigger the balloon launches so that the ozone concentrations in a large number of air parcels are each measured twice a few days apart. The difference in ozone concentration is calculated for each pair and is interpreted as a change caused by chemistry. The data analysis has been carried out for January to March between 370 K and 600 K potential temperature. Ozone loss along these trajectories occurred exclusively during sunlit periods, and the periods of ozone loss coincided with, but slightly lagged, periods where stratospheric temperatures were low enough for polar stratospheric clouds to exist. Two clearly separated periods of ozone loss show up. Ozone loss rates first peaked in late January with a maximum value of 53 ppbv per day (1.6 % per day) at 475 K and faster losses higher up. Then, in mid-March ozone loss rates at 475 K reached 34 ppbv per day (1.3 % per day), faster losses were observed lower down and no ozone loss was found above 480 K during that period. The ozone loss in hypothetical air parcels with average diabetic descent rates has been integrated to give an accumulated loss through the winter. The most severe depletion of 2.0 ppmv (60 %) took place in air that was at 515 K on 1 January and at 450 K on 20 March. Vertical integration over the levels from 370 K to 600 K gives a column loss rate, which reached a maximum value of 2.7 Dobson Units per day in mid-March. The accumulated column loss between 1 January and 31 March was found to be 127 DU (∼36 %).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1573-5060
    Keywords: marker-assisted selection ; genetics ; barley ; Hordeum vulgare ; scald ; Rhynchosporium secalis ; Canada
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The genetic basis of resistance to scald (Rhynchosporium secalis) within barley breeding populations is poorly understood. The design of effective genetically based resistance strategies is predicated on knowledge of the identity of the resistance genes carried by potential parents. The resistance exhibited by a broad selection of western Canadian barley lines was investigated by evaluating their reactions to five R. secalis isolates. Results were compared to the resistance exhibited by previously characterized lines. This comparison, combined with pedigree analysis indicated that there are two different resistance genes present inwwestern Canadian cultivars. These genes were shown to be independent through analysis of a segregating population derived from a cross between Falcon and CDC Silky. This evidence, along with observed linkage of the gene in CDC Silky with an allele specific amplicon developed for a Rhynchosporium secalis resistance locus on chromosome 3, provides evidence that the gene in Falcon is the Rh2 gene derived from Atlas, and the gene (s) in CDC Silky is located within the Rh/Rh3/Rh4 cluster and is similar to the Rh gene in Hudson.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...