Grid point surface air temperature calculations with a fast turnaround: Combining the results of IMAGE and a GCM     

Matthias Jonas  Katharina Fleischmann  Andrey V. Ganopolski  Jaroslav Krabec  Uta Sauer  Krzysztof Olendrzyński  Vladimir K. Petoukhov  Roderick W. Shaw 《Climatic change》1996,34(3-4):479-512

This paper describes a methodology that combines the outputs of (1) the Integrated Model to Assess the Greenhouse Effect (IMAGE Version 1.0) of the Netherlands National Institute of Public Health and Environmental Protection (RIVM) (given a greenhouse gas emission policy, this model can estimate the effects such as global mean surface air temperature change for a wide variety of policies) and (2) ECHAM-1/LSG, the Global Circulation Model (GCM) of the Max-Planck Institute for Meteorology in Hamburg, Germany. The combination enables one to calculate grid point surface air temperature changes for different scenarios with a turnaround time that is much quicker than that for a GCM. The methodology is based upon a geographical pattern of the ratio of grid point temperature change to global mean values during a certain period of the simulation, as calculated by ECHAM-1/LSG for the 1990 Scenarios A and D of the Intergovernmental Panel on Climate Change (IPCC). A procedure, based upon signal-to noise ratios in the outputs, enabled us to estimate where we have confidence in the methodology; this is at about 23% to 83% of the total of 2,048 grid points, depending upon the scenario and the decade in the simulation. It was found that the methodology enabled IMAGE to provide useful estimates of the GCM-predicted grid point temperature changes. These estimates were within 0.5K (0.25K) throughout the 100 years of a given simulation for at least 79% (74%) of the grid points where we are confident in applying the methodology. The temperature ratio pattern from Scenario A enabled IMAGE to provide useful estimates of temperature change within 0.5K (0.25K) in Scenario D for at least 88% (68%) of the grid points where we have confidence; indicating that the methodology is transferable to other scenarios. Tests with the Geophysical Fluid Dynamics Laboratory GCM indicated, however, that a temperature ratio pattern may have to be developed for each GCM. The methodology, using a temperature ratio pattern from the 1990 IPCC Scenario A and involving IMAGE, gave gridded surface air temperature patterns for the 1992 IPCC radiative-forcing Scenarios C and E and the RIVM emission Scenario B; none of these scenarios has been simulated by ECHAM-1/LSG. The simulations reflect the uncertainty range of a future warming.The work reported by the authors was carried out during their stay at the project Forestry and Climate Change of the International Institute for Applied Systems Analysis, Laxenburg, Austria.  相似文献   

Assessing the reliability of the modified three-component spatial autocorrelation technique   总被引：3，自引：0，他引：3  

Andreas Köhler  Matthias Ohrnberger  Frank Scherbaum  Marc Wathelet  Cecile Cornou 《Geophysical Journal International》2007,168(2):779-796

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Estimating the influence of increased nitrate loads from wastewater on phosphorus mobility in river sediments     

Oliver Gabriel  Dagmar Balla  Thomas Kalettka  Christian Schilling  Matthias Zessner 《洁净——土壤、空气、水》2006,34(4):333-345

Research on the sediment‐surface water transition zone in three study site regions, different in hydrological conditions, was conducted to estimate to which extent nitrate in surface water can contribute to riverbed sediment oxidation and thus prevent release of sediment phosphorus to surface water. Consequently, the Du tch Flow Model (DUFLOW) based water quality model “Spreewald” and results from the emission model “ Mo delling N utrient E missions in Ri ver S ystems” (MONERIS) were used to estimate to which extent wastewater treatment plants (WWTPs) could contribute to the NO₃^– concentration in surface waters if they were operated without denitrification. It is demonstrated that an effective phosphorus retention in sediments by means of surface water NO₃^– is possible only under specific conditions, i. e. (i) a sufficient supply of surface water to the sediment by advective fluxes, (ii) a sufficient amount of sediment iron to provide phosphorus binding sites in the case of sediment oxidation, (iii) a redox system not leading to a rapid NO₃^– and FeOOH depletion and to phosphorus release from organic pools by high microbial activities. Model results show that in‐stream denitrification processes counteract a significant increase of NO₃^– surface water concentrations from WWTPs operated without denitrification during summer, when eutrophication risk through phosphorus is highest. The increase of NO₃^– surface water concentrations in winter due to decreased denitrification in the surface water is of minor relevance for phosphorus release from sediments.  相似文献   

Routine analysis of sediment pore water of high ionic strength     

Peter Herzsprung  Elke Bozau  Olaf Büttner  Anja Duffek  Kurt Friese  Matthias Koschorreck  Martin Schultze  Wolf v. Tümpling  Katrin Wendt‐Potthoff 《洁净——土壤、空气、水》2006,34(6):593-607

Pore water of sediments plays an important role in aquatic systems as mediator and as the reactive zone between the sediment and surface water. Sediment pore waters with high ionic strength from acidified pit lakes were investigated to obtain information about the influence on the lake water quality. The analysis of soluble reactive phosphorus, nitrate, ammonium, silica, dissolved organic carbon, ferrous iron, sulfate, chloride, sodium, potassium, calcium, magnesium, manganese, and total dissolved iron was predetermined as the dataset required for evaluation of water quality. The data collection procedure was optimised by designing a methodology for stabilisation, dilution of pore water samples and adaptation of analytical methods. The developed methodology was evaluated with respect to the effort required in the laboratory under routine conditions. In the first round of analyses, 72% of 638 individual analyses from a random selection of pore water profiles were found to be within the calibration ranges. Remedial actions to handle the remaining 28% of invalid analytical results are exemplified. Differences between comparative analyses of some ions by continuous flow analysis, ion chromatography, and atomic emission spectroscopy were evaluated. The majority of results measured by ion chromatography differed on a highly significant level from results measured by atomic emission spectroscopy. Possible reasons, originating from the extreme sample matrix, are discussed. Finally, the designed methodology and the results of the method comparison are used to recommend the selection of analytical methods under specific conditions.  相似文献   

Natural vs. human-induced facies changes in recent,shallow fjord sediments of the Store Lungegårdsvannet in Bergen (western Norway)     

Matthias Paetzel  Hans Schrader 《Environmental Geology》2003,43(4):484-492

A basin-wide change from an older homogeneous bioturbated to a younger laminated facies occurs in sediments from the 26-m-deep, permanently anoxic Store Lungegårdsvannet fjord. The younger facies consists of alternating packages of light and dark layers, each containing millimetre-scale laminae. The composition of the dark layers differs from that of the light layers in the occurrence of predominantly marine benthic diatoms, larger grain size, lower loss-on-ignition (LOI) and lower trace metal (Cu, Pb, Zn) concentrations. Total trace metal concentrations correlate with the redox-sensitive trace elements Mo and V (r>0.8) and with LOI (r=0.6). The correlation of the minerogenic matter and the grain-size related elements Al and Li is poor (r=0.2). The shoaling of the sill depth and reduction of the fjord area resulting in the reduction of bottom water exchange accounted for the shift from bioturbated to laminated sediments during the end of the last century. The alternating changes within the laminated facies are the result of alternating wind forces. During years of calm wind conditions (1908-1919 and 1945-1961), undisturbed sedimentation of organic matter from primary production and an associated accumulation of trace metals prevail. Years of high wind force (1919-1945 and 1961-1991) trigger shore erosion and an increased influx of minerogenic matter.  相似文献   

Gravitational lensing of type Ia supernovae by galaxy clusters     

Tsafrir S. Kolatt  & Matthias Bartelmann 《Monthly notices of the Royal Astronomical Society》1998,296(3):763-772

We propose a method to remove the mass-sheet degeneracy that arises when the mass of galaxy clusters is inferred from gravitational shear. The method utilizes high-redshift standard candles that undergo weak lensing. Natural candidates for such standard candles are type Ia supernovae (SNe Ia).
When corrected with the light-curve shape (LCS), the peak magnitude of SNe Ia provides a standard candle with an uncertainty in apparent magnitude of Δ m ≃0.1–0.2. Gravitational magnification of a background SN Ia by an intervening cluster would cause a mismatch between the observed SN Ia peak magnitude compared with that expected from its LCS and redshift. The average detection rate for SNe Ia with a significant mismatch of ≥2Δ m behind a cluster at z ≃0.05–0.15 is about 1–2 supernovae per cluster per year at J , I , R ≲25–26.
Since SNe are point-like sources for a limited period, they can experience significant microlensing by massive compact halo objects (MACHOs) in the intracluster medium. Microlensing events caused by MACHOs of ∼10⁻⁴ M⊙ are expected to have time-scales similar to that of the SN light curve. Both the magnification curve by a MACHO and the light curve of a SN Ia have characteristic shapes that allow us to separate them. Microlensing events caused by MACHOs of smaller mass can unambiguously be identified in the SN light curve if the latter is continuously monitored. The average number of identifiable microlensing events per nearby cluster ( z ≲0.05) per year is ∼0.02 ( f /0.01), where f is the fraction of the cluster mass in MACHOs of masses 10⁻⁷< M _macho/M⊙<10⁻⁴.  相似文献   

Computing the elastic scattering from inclusions using the multiple multipoles method in three dimensions     

Matthias G. Imhof 《Geophysical Journal International》2004,156(2):287-296

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Buchbesprechungen     

Hans M. Keller  Peter Perret  H. R. Preisig  Peter Perret 《Aquatic Sciences - Research Across Boundaries》1979,41(1):161-163

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Anabaena bergii var.limnetica,nov. var., Cyanophyceae,Nostocaceae     

Alain Couté  Hans Rudolf Preisig 《Aquatic Sciences - Research Across Boundaries》1978,40(2):374-383

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Über den Einfluß fluktuierender Windfelder auf ein stetig geschichtetes Meer     

Matthias Tomczak Jr. 《Ocean Dynamics》1967,20(3):101-129

Zusammenfassung Am geschichteten Meer werden die erzwungenen Schwingungen theoretisch untersucht, die ein an der Oberfl?che angreifender Wind hervorruft. Grunds?tzlich entsteht an der Oberfl?che eine Grenzschicht mit gro?er Horizontalgeschwindigkeit. Für den Fall, da? ihre Ausdehnung klein gegenüber der inneren Region ist, werden die erzwungenen Schwingungen (Abschnitt 2) analytisch berechnet. Interne Wellen oberhalb der Tr?gheitsperiode sind klein und auf sehr kleine Wellenzahlen beschr?nkt. Die physikalische Erl?uterung sowie die Tatsache, da? einige spezielle Windfelder keine internen Wellen anregen k?nnen, bringt Abschnitt 3, die numerische L?sung für beliebige Frequenzen und Wellenzahlen Abschnitt 4. Interne Wellen unterhalb der Tr?gheitsperiode werden haupts?chlich durch die Divergenz des Windfeldes hervorgerufen, solche oberhalb der Tr?gheitsperiode durch die Rotation des Windfeldes, und es ergeben sich unterschiedliche funktionale Zusammenh?nge zwischen Wind und internen Wellen. Die hier vorgelegten Ergebnisse k?nnen nur mit Hilfe einer tangential an der Oberfl?che angreifenden Kraft erhalten werden und weisen wesentliche Unterschiede gegenüber ?hnlichen Ergebnissen auf, die für den Windeinflu? eine Volumenkraft annehmen.

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On the influence of fluctuating winds on a continuously stratified ocean

Summary The model of a stratified ocean is used for a theoretical study of the forced oscillations caused by the wind acting upon the surface. A boundary layer with high horizontal velocity is principally generated at the surface. If it is narrow as compared with the inner region, the forced oscillations (section 2) are computed analytically. Internal waves above the inertia period are small and confined to very small wave numbers. The physical explanation and the fact that special wind fields cannot generate internal waves, are given in section 3; the numerical solution for arbitrary frequences and wave numbers is treated in section 4. Internal waves below the inertia period are mainly caused by the divergence of the wind field; those above the inertia period by the rotation of the wind field; and different functional connections between the wind and the internal waves are the results. The results presented here can be obtained only by means of a force acting tangentially upon the surface. They differ essentially from similar results based upon the assumption of a volume force for the wind effect.

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Influence de champs de vent fluctuants sur une mer contin?ment stratifiée

Résumé On étudie et on calcule analytiquement (paragraphe 2) pour une mer stratifiée, les oscillations provoquées par un vent s'attaquant à la surface. En principe, il se forme à la surface une couche-limite à grande vitesse horizontale. Les ondes internes au-dessus de la période d'inertie sont petites et se limitent à de très petits nombres d'ondes. Le paragraphe 3 donne l'explication physique et signale le fait que quelques champs de vent spéciaux ne peuvent pas provoquer d'ondes internes; le paragraphe 4 apporte une solution numérique pour des fréquences et des caractéristiques numériques d'ondes quelconques. Les ondes internes au-dessous de la période d'inertie sont dues principalement à la divergence du champ de vent, celles au-dessus de la période d'inertie, à la rotation de ce champ; et on trouve des rapports fonctionnels distincts entre le vent et les ondes internes. Les résultats exposés ici ne peuvent être obtenus qu'à l'aide d'une force attaquant tangentiellement la surface, ils diffèrent notablement des résultats correspondants obtenus en admettant que l'influence du vent s'exerce sous forme d'une force non tangentielle.

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Mit der — hier gekürzt — vorliegenden Arbeit promovierte der Verfasser bei der Mathematisch-Naturwissenschaftlichen Fakult?t der Christian-Albrechts-Universit?t Kiel.  相似文献