A HIGH RESOLUTION MODEL FOR CHEMICAL SPECIES EXCHANGE IN TROPOSPHERE   总被引：3，自引：0，他引：3       下载免费PDF全文

Lei Xiao''en  Julius S. Chang 《Acta Meteorologica Sinica》1992,6(4):479-490

Based on the regional acid deposition model(RADM),a high resolution model for species exchange in thetroposphere(EM3)is designed.EM3 differs considerably in the following 5 aspects from RADM.First,the vertical gridlevels in the planetary boundary layer(PBL)are increased.Second,layered vertical eddy diffusivity patterns in thetroposphere(TL)are considered.Third,layered horizontal eddy diffusivity patterns within TL is used.Fourth,new drydeposition velocity pattern including the effect of plant canopy layer(CL)vertical structure is adopted.Fifth,advectivescheme of second-order moment conservation with less numerical diffusion is used.OSCAR 4 case is comparativelysimulated with both EM3 and RADM.The results show that 3-D distribution laws of chemical species in whole TL areforecasted by EM3 better than by RADM.Under the same conditions,all ratios of the central concentrations simulatedwith both models in lower PBL are more than 1.8,the maximum can be more than 3.  相似文献   

Das Glazialdiluvium Dänemarks,Hollands und Norddeutschlands vom geschiebekundlichen Standpunkt aus     

Julius Hesemann 《International Journal of Earth Sciences》1931,22(3-4):145-155

Zusammenfassung Die Geschiebeführung des Diluviums in Dänemark, Holland und Norddeutschland bezüglich der kristallinen Geschiebe und des Flintgehaltes wird besprochen und daraus die Hauptbewegungsrichtung des Eises während der einzelnen Vereisungen abgeleitet. Da die Ablagerungen jeder Vereisung durch ihren Geschiebeinhalt identifiziert werden können, ergeben sich interessante Anwendungsmöglichkeiten für das Diluvium Dänemarks und des Hohen Flämings, für den Odergletscher usw.Zwei große Gletscher, aus der Verschmelzung der skandinavischen Einzelgletscher hervorgegangen, überziehen von Norwegen und von der Ostsee her Norddeutschland. Der Ostseegletscher drängt den norwegischen Gletscher zunächst allmählich, von der Pommerschen Phase ab endgültig von Dänemark und Deutschland ab.Für den Geschiebebestand Norddeutschlands und Hollands gelten folgende Verhältnisse: In den Ablagerungen der Elster-Vereisung dominieren die ostfennoskandischen, in denen der Saale-Vereisung die westlichen Geschiebegruppen. Das jüngere Diluvium enthält alle nordischen Geschiebe zu etwa gleichen Anteilen, demgegenüber die Geschiebeverhältnisse des Odergletschers und Dänemarks durchweg abweichende, aber erklärbare Züge aufweisen.  相似文献   

Zur Berechnung der Abgaskonzentration am Boden im Lee isolierter Industrieschornsteine     

Julius Drimmel 《Pure and Applied Geophysics》1963,56(1):203-215

Zusammenfassung Im Falle homogener Turbulenz läßt sich bei höhenkonstantem Wind die Konzentration im Lee einer punktförmigen Gasquelle über dem Boden in einfacher Weise berechnen. Die Formel ist bei geeigneter Parameterwahl auch auf die natürlichen Verhältnisse anwendbar. — In der vorliegenden Arbeit werden die effektiven Mittelwerte der in die Konzentrationsformel eingehenden Turbulenzparameter so ermittelt, daß eine weitgehende Übereinstimmung mit der Natur gewährleistet ist. Es zeigt sich, daß dieSuttonsche Diffusionsformel die maximale Gaskonzentration mit den geringsten Fehlern (ca.+10%) bei lebhaften Winden und kräftiger Einstrahlung wiedergeben kann, diese aber bei extrem stabiler Schichtung und turbulenter Strömung von geringer Geschwindigkeit um mehr als 100% überschätzt. — Die Theorie liefert eine gute Übereinstimmung mitPasquills Kurven für die Rauchwolkenhöhe, sofern man Fälle extremer Abweichungen vom adiabatischen Zustand ausschließt.

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Summary It is not difficult to calculate the gas concentration at ground level in the lee of a point source, if the turbulence is homogeneous and the windspeed is assumed to be constant with height. With a suitable choice of the parameters, however, the derived formula can be applied to real conditions, too. — In the present paper the necessary parameters are chosen as mean values in such a manner, that best agreement with nature is guaranted. It is found, thatSuttons diffusion formula overestimates the maximum gas concentration about 10 per cent in case of strong winds and strong insolation, but more than 100 per cent in case of light turbulent winds and extreme stability. Our theory is in good accordance withPasquills different curves for the vertical spread of smoke as a function of distance, if cases of extreme diabatic conditions are excluded.

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Weakly nonlinear shallow water magnetohydrodynamic waves     

Steven D. London 《地球物理与天体物理流体动力学》2014,108(3):323-332

We consider an electrically conducting rotating fluid governed by the shallow water magnetohydrodynamic equations with no diffusion. We use an a priori asymptotic technique (the method of geometric optics or ray method) to study weakly nonlinear hydromagnetic waves. These waves are intermediate in length in the following sense: they are much longer than the fluid depth but much shorter than the radius of the earth. The time scale for the waves is much longer than that of the free surface oscillations and the approximation varies on an even longer timescale. The waves we are considering are studied in the beta plane approximation for an ambient magnetic field parallel to the equator which varies in the direction perpendicular to the equator. The leading order approximation gives a dispersion relation for the waves, which are generally found to be confined to bands about the equator as well as in bands at higher and lower latitudes. At the next order of approximation, a conservation law is found for the wave amplitude. We also obtain an equation governing the behavior of the leading order mean azimuthal velocity which is forced to grow linearly with time.  相似文献   

Solubility of excess alumina in hydrous granitic melts in equilibrium with peraluminous minerals at 700–800 °C and 200 MPa,and applications of the aluminum saturation index     

Antonio?Acosta-VigilEmail author  David?London  George?B.?MorganVI  Thomas?A.?Dewers 《Contributions to Mineralogy and Petrology》2003,146(1):100-119

We have studied the controls on the Aluminum Saturation Index (ASI = molec. Al₂O₃/[(CaO)+(Na₂O)+(K₂O)]) and the concentration of normative corundum of granitic liquids saturated in alumina by equilibrating peraluminous minerals with initially metaluminous haplogranitic minimum composition liquids at 700–800 °C and 200 MPa, at, and below H₂O saturation. The ASI and normative corundum increase with increasing H₂O concentration in the melt (0.04 to 0.10 moles excess Al₂O₃ per mole of H₂O), temperature, and with addition of the non-haplogranitic components Fe, Mg, and B. The ASI parameter and concentration of normative corundum cannot be used to monitor aAl₂O₃ between different mineral assemblages and melt because other components that affect the solubility of alumina, including H₂O, Fe, Mg, and B, do not appear in their formulations. ASI and normative corundum, however, provide petrogenetic information about magmas generated by partial melting of strongly peraluminous protoliths by virtue of their regular and predictable variation with melt composition (e.g., H₂O concentration) and temperature. For the application of these data to natural rocks it is necessary to choose as an analogue system the ASI-solubility or normative corundum-solubility relations of the most chemically complex peraluminous mineral present in the rock. Comparison of ASI values of anatectic leucosomes and allochthonous leucogranites with experimentally predicted values suggests low H₂O concentrations in melt during crustal partial melting. Rapid melt segregation before equilibration with restitic peraluminous phases is also suggested in some cases.Editorial responsibility: I. Carmichael  相似文献   

Phosphorus distribution between potassic alkali feldspar and metaluminous haplogranitic liquid at 200 MPa (H<Subscript>2</Subscript>O): the effect of undercooling on crystal–liquid systematics     

George?B.?Morgan VIEmail author  David?London 《Contributions to Mineralogy and Petrology》2005,150(4):456-471

To evaluate the applicability of P₂O₅ concentration in potassic alkali feldspar as a monitor of P₂O₅ in melt for undercooled systems, crystal–melt partitioning for P was evaluated via feldspar growth experiments in P-bearing ((3 wt% P₂O₅), water-saturated haplogranitic liquids at 200 MPa, with liquidus undercoolings (ΔT) of 25, 50, 100, 200, and 300°C. Increasing undercooling in the range ΔT=25–200°C shows an evolution of crystal morphologies, from euhedral and well-filled individuals at ΔT=25–50°C to radial clusters with increasingly skeletal habit at greater undercooling. Experiments at ΔT=100–200°C also document the development of P- (up to (9 wt% P₂O₅) and Si-enriched, more alkaline boundary layers adjacent to crystals. Experiments at ΔT=300°C show an additional change in crystallization fabric in which spherulites of skeletal crystals form in open (vapor) space created by the dissolution of bulk silicate, and compositional boundary layers are not observed. We interpret the changes in reaction products at ΔT=300°C to indicate conditions below a glass transition; hence, partition coefficients were not determined for this undercooling. Values of K _d(P)^Kfs/melt from experiments at ΔT=25–200°C, calculated from pairs of crystal and immediately adjacent liquid compositions (including boundary layers at higher undercooling), are mostly in the range of 0.25–0.55 and show no effective change with increased undercooling. Essentially no change in K _d(P)^Kfs/melt with undercooling apparently stems from an interplay between boundary layer composition and a change in the substitution mechanism for P in feldspar from AlPSi₋₂, common in peraluminous to metaluminous liquids near equilibrium, to increasing proportions of ([ ],P)(M⁺,Si)₋₁ with increased undercooling. Bulk glass and liquid beyond boundary layers in experiments with significant percentages of crystallization are homogeneous, and show pronounced fractionation primarily due to the removal of an orthoclase component. Because crystallization was still in progress in experiments with ΔT≤200°C, compositional homogeneity in the bulk liquid requires extremely rapid diffusion of most haplogranite components (Na, K, and Al), apparently resulting from chemical potential gradients stemming from the removal of components from the liquid by crystal growth. Similar homogeneity and bulk fractionation in experiments with ΔT=300°C requires rapid diffusive equilibration for the alkalis even at temperatures below an apparent glass transition. Unlike the haplogranite components, P is only concentrated in liquid boundary layers (ΔT≤200°C) or low-density aqueous vapor (ΔT=300°C) adjacent to crystals. Hence, the P₂O₅ contents of melt inclusions likely are not representative of bulk melt concentrations in significantly undercooled systems (ΔT≤50–100°C).  相似文献   

Drought prediction     

Julius S. Oguntoyinbo 《Climatic change》1986,9(1-2):79-90

Drought prediction has been an age-old problem, but in more recent times the magnitude of the Sahelian drought has brought into focus the need to improve the techniques for predicting such droughts with some measure of accuracy. Prom the present state of knowledge, drought prediction is difficult, if not impossible. Two major approaches appear to be prominent in the search for appropriate techniques. These include the use of teleconnections and the development of numerical models.Essentially, time-lagged teleconnections rely on the assumption that changes induced in any one area of the world may produce changes elsewhere on a world-wide scale, though time-lagged. The 1972-73 El Nino off the west coast of South America is a good case in point. The development of numerical models which allow the incorporation of not only climatic factors but also man's impact on the natural environment, offers some ray of hope that the general circulation models (GCMs) may help to improve the techniques of drought prediction.  相似文献   

Ein Versuch zur numerischen Bestimmung des vertikalen Austauschkoeffizienten für Wasserdampf in der wassernächsten Luftschicht     

Dr. Julius Werner 《Meteorology and Atmospheric Physics》1971,20(2):159-174

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