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  • 11
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract.  This study evaluates simulations of the East Asian winter monsoon in eight GCMs that participated in the Atmospheric Model Intercomparison Project (AMIP). In addition to validating the mean state of the winter monsoon, the cold surge and its transient properties, which includes the frequency, intensity, preferred propagation tracks, and the evolution patterns of the surges, are examined. GCM simulated temporal distribution of the Siberian high and cold surges is also discussed. Finally, the forcing of the cold surges on the tropical surface wind and convection, along with their interannual variation is analyzed. The mean state of the winter monsoon is generally portrayed well in most of the models. These include the climatological position of the Siberian high, the 200 hPa divergent center, and the large-scale wind patterns at the surface and the 200 hPa. Models display a wide range of skill in simulating the cold surge and its transient properties. In some of the models, the simulated cold surge trajectory, intensity, frequency, propagation patterns and source regions are in general agreement with those from the observed. While in others, the models cannot adequately capture these observed characteristics. The temporal distribution of the Siberian high and cold surges were realistically reproduced in most GCMs. Most models were able to simulate the effect of the cold surges on the tropical surface wind, although a few models unrealistically generated subtropical southerly wind in the mid-winter. The relationship between cold surges and the tropical convection was not satisfactorily simulated in most models. The common discrepancies in the winter monsoon simulation can be attributed to many factors. In some models, the reason is directly related to the improper location of the large-scale convective center near the western Pacific. The satisfactory simulations of the monsoon circulation and the cold surges are partly due to the topographical characteristics of the East Asian continent, i.e., the Tibetan Plateau to the west and the oceans to the east. The correct simulation of the interannual variation of the surface wind near the South China Sea (SCS) and the maritime continent is a demanding task for most of the models. This will require adequate simulations of many aspects, including tropical convection, the Siberian cold dome, the extratropical-tropical linkage, and the air-sea interaction. The discrepancies noted here furnish a guide for the continuing improvement of the winter monsoon simulations. Improved simulations will lead to an adequate delineation of the surface wind and convection near the maritime continent, which is essential for portraying the winter monsoon forcing in a coupled model.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1432-041X
    Keywords: Neural induction ; Lectins ; Cell architecture ; Cell surface ; SEM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Scanning electron microscopic studies revealed that Concanavalin A (ConA) induces characteristic changes of the cell surface and the cell architecture of the presumptive ectoderm associated with differentiation into neural tissues. In Con A-treated cells, the filopodia with which cells were connected to each other disappeared from the interior (blastocoelic) surface and the cellular adhesivity decreased significantly. Thereafter, the cells underwent from those of the control explants. After cultivation for 60 h, a certain pattern of cell arrangement, which resembled the architecture of neural tissues, was observed among randomly arranged cells in the explants treated with Con A. The morphological changes specifically observed in Con A-treated explants were different from those found in explants treated with succinyl Con A (S-Con A) orDolichos biflorus agglutinin (DBA), which is unable to induce formation of the neural tissues. The molecular organization of the plasma membrane appears to be important in the mechanism of neural induction.
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  • 13
    ISSN: 0014-5793
    Keywords: Arabinofuranosylcytosine transport ; Cell cycle ; Differentiation
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1349-9432
    Keywords: stereo CCD endoscope ; topographic measurement ; image sequency ; stereo matching ; disparity ; inclined view ; gastrointestinal surface
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In endoscopic diagnosis, there has been a strong requirement to measure the internal surface topography of the rectum or esophagus. Accurate measurement, however, is very difficult, because the object is usually observed from an inclined view. In this paper, we propose a method to overcome this difficulty utilizing sequential stereo-pair images; the relative shape is roughly measured from sequential images taken by one of the change coupled device (CCD) cameras, and the size is determined by stereo-pair matching using the measured shape. A coarse-to-fine approach is also used to improve the resolution of topographic measurement. Through a basic experiment using a monocular CCD endoscope and a polyp phantom, the proposed method is confirmed to improve measurement accuracy in comparison with conventional methods.
    Type of Medium: Electronic Resource
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  • 15
    Publication Date: 2004
    Keywords: CC 1/1 ; Coordinating Committee ; Himalayas
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  • 16
    Publication Date: 2016-11-07
    Description: Climate model simulations available from the PMIP1, PMIP2 and CMIP (IPCC-AR4) intercomparison projects for past and future climate change simulations are examined in terms of polar temperature changes in comparison to global temperature changes and with respect to pre-industrial reference simulations. For the mid-Holocene (MH, 6,000 years ago), the models are forced by changes in the Earth’s orbital parameters. The MH PMIP1 atmosphere-only simulations conducted with sea surface temperatures fixed to modern conditions show no MH consistent response for the poles, whereas the new PMIP2 coupled atmosphere–ocean climate models systematically simulate a significant MH warming both for Greenland (but smaller than ice-core based estimates) and Antarctica (consistent with the range of ice-core based range). In both PMIP1 and PMIP2, the MH annual mean changes in global temperature are negligible, consistent with the MH orbital forcing. The simulated last glacial maximum (LGM, 21,000 years ago) to pre-industrial change in global mean temperature ranges between 3 and 7°C in PMIP1 and PMIP2 model runs, similar to the range of temperature change expected from a quadrupling of atmospheric CO2 concentrations in the CMIP simulations. Both LGM and future climate simulations are associated with a polar amplification of climate change. The range of glacial polar amplification in Greenland is strongly dependent on the ice sheet elevation changes prescribed to the climate models. All PMIP2 simulations systematically underestimate the reconstructed glacial–interglacial Greenland temperature change, while some of the simulations do capture the reconstructed glacial–interglacial Antarctic temperature change. Uncertainties in the prescribed central ice cap elevation cannot account for the temperature change underestimation by climate models. The variety of climate model sensitivities enables the exploration of the relative changes in polar temperature with respect to changes in global temperatures. Simulated changes of polar temperatures are strongly related to changes in simulated global temperatures for both future and LGM climates, confirming that ice-core-based reconstructions provide quantitative insights on global climate changes.
    Type: Article , PeerReviewed
    Format: text
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  • 17
    Publication Date: 2016-09-13
    Description: We describe the behaviour of 23 dynamical ocean-atmosphere models, in the context of comparison with observations in a common framework. Fields of tropical sea surface temperature (SST), surface wind stress and upper ocean vertically averaged temperature (VAT) are assessed with regard to annual mean, seasonal cycle, and interannual variability characteristics. Of the participating models, 21 are coupled GCMs, of which 13 use no form of flux adjustment in the tropics. The models vary widely in design, components and purpose: nevertheless several common features are apparent. In most models without flux adjustment, the annual mean equatorial SST in the central Pacific is too cool and the Atlantic zonal SST gradient has the wrong sign. Annual mean wind stress is often too weak in the central Pacific and in the Atlantic, but too strong in the west Pacific. Few models have an upper ocean VAT seasonal cycle like that observed in the equatorial Pacific. Interannual variability is commonly too weak in the models: in particular, wind stress variability is low in the equatorial Pacific. Most models have difficulty in reproducing the observed Pacific 'horseshoe' pattern of negative SST correlations with interannual Niño3 SST anomalies, or the observed Indian-Pacific lag correlations. The results for the fields examined indicate that several substantial model improvements are needed, particularly with regard to surface wind stress.
    Type: Article , PeerReviewed
    Format: text
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  • 18
    Publication Date: 2016-09-08
    Description:  An ensemble of twenty four coupled ocean-atmosphere models has been compared with respect to their performance in the tropical Pacific. The coupled models span a large portion of the parameter space and differ in many respects. The intercomparison includes TOGA (Tropical Ocean Global Atmosphere)-type models consisting of high-resolution tropical ocean models and coarse-resolution global atmosphere models, coarse-resolution global coupled models, and a few global coupled models with high resolution in the equatorial region in their ocean components. The performance of the annual mean state, the seasonal cycle and the interannual variability are investigated. The primary quantity analysed is sea surface temperature (SST). Additionally, the evolution of interannual heat content variations in the tropical Pacific and the relationship between the interannual SST variations in the equatorial Pacific to fluctuations in the strength of the Indian summer monsoon are investigated. The results can be summarised as follows: almost all models (even those employing flux corrections) still have problems in simulating the SST climatology, although some improvements are found relative to earlier intercomparison studies. Only a few of the coupled models simulate the El Niño/Southern Oscillation (ENSO) in terms of gross equatorial SST anomalies realistically. In particular, many models overestimate the variability in the western equatorial Pacific and underestimate the SST variability in the east. The evolution of interannual heat content variations is similar to that observed in almost all models. Finally, the majority of the models show a strong connection between ENSO and the strength of the Indian summer monsoon.
    Type: Article , PeerReviewed
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  • 19
    Electronic Resource
    Electronic Resource
    Melbourne, Australia : Blackwell Science Asia Pty. Ltd.
    Lakes & reservoirs 7 (2002), S. 0 
    ISSN: 1440-1770
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography
    Notes: Sixty-seven strains of seven species of Azolla were screened for tolerance to ammonium ion on the basis of their growth on the medium with or without 20 mmol/L ammonium. Azolla nilotica was the most sensitive species followed by Azolla rubra. Azolla pinnata var. pinnata was the most tolerant species. Twelve tolerant strains in Azolla mexicana, Azolla caroliniana, Azolla microphylla and A. pinnata var. pinnata were selected. No tolerant strain was found in Azolla filiculoides containing native strains in Japan.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Lakes & reservoirs 2 (1996), S. 0 
    ISSN: 1440-1770
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography
    Notes: The growth and nitrogen fixation of Azolla filiculoides cultured in polluted pond water and two types of secondary effluent were investigated. The gradual decreases in the growth and acetylene reduction activity (ARA) of the plants in pond water were due mainly to a phosphorus deficiency. In the secondary effluent, ammonium was an important factor limiting growth and ARA. Azolla plants were screened for tolerance to ammonium ion on the basis of their growth on the medium with or without ammonium. Azolla nilotica was the most sensitive species of all, followed by A. rubra. Azolla pinnata van pinnata was the most tolerant one. Nutrient removal capacities by 10 Azolla strains in batch culture were examined. The highest capacities and the growth were found in May for all Azolla strains. In August and December, Azolla strains showed poor growth and low nutrient removal capacities.
    Type of Medium: Electronic Resource
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