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951.
Charles A. Lin 《Meteorology and Atmospheric Physics》1984,34(4):309-317
Summary The zonally averaged meridional energy transport is parameterized in terms of the zonally averaged temperature gradient and its radiative equilibrium value. Two climate regimes are identified: radiative equilibrium and isothermal climates. The transport and temperature gradient are intermediate between corresponding quantities of these two climates. The parameterization assumes a linear increase of transport as temperature gradient departs from its radiative equilibrium value. The parameterization is formulated using a one-dimensional climate model. Ice-albedo feedback provides the mechanism for climate changes. The parameterization works well for climates associated with seasonal changes.
With 4 Figures 相似文献
Parameterisierung des meridionalen Energiestromes in einem eindimensionalen Klimamodell
Zusammenfassung Der zonal gemittelte, meridionale Energietransport wird in Abhängigkeit vom zonal gemittelten Temperaturgradienten und seinem Strahlungsgleichgewicht parameterisiert. Zwei Klimaregime können identifiziert werden: Strahlungsgleichgewicht und isothermes Klima. Der Transport und der Temperaturgradient befinden sich zwischen den korrespondierenden Werten dieser zwei Klimate. Die Parameterisierung nimmt eine lineare Zunahme des Transportes mit der Abweichung des Temperaturgradienten vom seinem Strahlungsgleichgewichtswert an. Die Parameterisierung wird unter Verwendung eines eindimensionalen Klimamodelles formuliert. Die Eis-Albedo-Rückkopplung liefert den Mechanismus für Klimadnderungen. Die Parameterisierung funktioniert gut fur Klimate, welche jahreszeitliche Anderungen beinhalten.
With 4 Figures 相似文献
952.
On the basis of its geological characteristics, the Gushan iron deposit should be assigned to volcano-hydrothermal type with hematite-quartz as its principal mineral assemblage. Iron concentration of the ore solution has been estimated from the ratio of hematite to quartz in the ore. By using experimental and thermodynamic data, the solubility of ferro-minerals at elevated temperatures and pressures have been calculated in the system FeO?Fe2O3?NaCl?HCl?H2O. The effects ofT, P, pH,f O 2 and total Cl concentration on the solubility of ferrominerals are discussed. Thermodynamic calculations based on presumed physico-chemical conditions for the ore solution are in good agreement with geological observations. The calculation shows that ferro-minerals were deposited at logf O 2=?21~?25, log(mHCl+mH+)=?2.5~?3,P=1?0.75 (or 0.5) kb, andT=400°?350°C. It is believed that the original solution was an acid NaCl-bearing solution of magmatic derivation. However, iron in the solution was enriched with falling temperatures by dissolving pre-existing ferro-minerals in consolidated rocks rather than extracting directly from the magma. Either temperature (below 400°C) or pressure decrease may result in the precipitation of ferro-minerals from the solution, but the Fe/Si ratio in the ore is dependent mainly upon pH. The widespread siliceous veins of later stages are a reflection of decreasing acidity of the solution. An increase inf O 2 will also favor the deposition of ferro-minerals. The hypabyssal occurrence and the existence of the Huangmaqing sandy shale have contributed greatly to the formation of hematite. 相似文献
953.
河西沿祁连山冷凉灌区春小麦气候生态的研究 总被引:7,自引:0,他引:7
河西冷凉灌区春小麦增产潜力大,具有光能丰富、温度适中、光温配合好、降水相对集中、有效风速大等气候优势,它可成为我国又一个小麦高产地区。限制该区春小麦生产潜力发挥的气候因素是分蘖—拔节期的干旱和开花—灌浆期的光照不足。本文还提出了相应的提高气候生产潜力的途径。 相似文献
954.
955.
我国钻探用金刚石聚晶材料的工艺研究 总被引:8,自引:0,他引:8
系统地阐述了我国钻探用金刚石聚晶材料(PCL)的工艺研究方面的独到之处,特别是在确定影响PCD耐磨性的主要工艺因素,以及如何提高、调整和控制耐磨性的工艺方法方面的研究成果。 相似文献
956.
Time-delay causes unsynchronized application of the control forces which may not only degrade the performance of the control system but also even induce instability to the dynamic system. Time-delay control algorithm is developed in this paper to solve this practical problem. The control system is first formulated in discrete-time form. In the presence of time-delay, the motion equation of the discrete-time control system remains a difference equation which can be transformed into first-order difference equation by augmenting the state variables. Optimal time-delay control algorithm is derived based on the augmented system. The time-delay control forces are simply generated from the time-delay states multiplied by the constant feedback gain. Numerical simulation is illustrated to verify the feasibility of the proposed control algorithm. Since time-delay effect is incorporated in the mathematical model for the structural control system throughout the derivation of the proposed algorithm, system performance and dynamic stability are guaranteed. 相似文献
957.
Study on electric variations of media in epicentral area by geomagnetic transfer functions 总被引:1,自引:0,他引:1
StudyonelectricvariationsofmediainepicentralareabygeomagneticransferfunctionsXiao-PingZENG;(曾小苹)Yun-FangLINI;(林云芳)Zhong-JieZH... 相似文献
958.
In this paper,a tropical atmospheric model of relevance to shorts-term climate variations(Wang and Li 1993)is util-ized for study of the development of Madden-Julian oscillation.The model contains an interactive process ofboundary-layer Ekman convergence and precipitation heating.The model is solved by expanding dependent variables interms of parabolic cylindrical functions in the meridional direction and truncating three meridional modes n=0,2,4 forequatorial symmetric solutions.The free wave solutions obtained under long-wave approximation are induced as aKelvin wave and two Rossby waves.After considering the effect of boundary-layer dynamic process,the modifiedKelvin wave becomes unstable in long-wave bands with a typical growth rate on an order of 10~(-6) s~(-1)and an eastwardphase speed of 10 m s~(-1);the most unstable mode is wavenumber one.These theoretical results are consistent with the ob-served Madden-Julian oscillation in equatorial area.For the two modified Rossby waves,one with a smaller meridionalscale(n=4)decays except for extra long-waves;the other with a larger meridional scale(n=2)grows in short-wavebands.This may be relevant to explaining the westward propagation of super cloud clusters in the Madden-Julianoscillation.The theory suggests that the boundary-layer dynamic process is an important mechanism in the develop-ment of the Madden-Julian oscillation. 相似文献
959.
Jiahao Lin Guizhen Song Yong Sun F. W. Williams 《Soil Dynamics and Earthquake Engineering》1995,14(4)
In this paper, a direct Ritz method is presented for analysing the responses of non-uniform shear beams subjected to the action of an evolutionary random seismic excitation. Because of the use of a pseudo ground acceleration, time-dependent random responses can conveniently be calculated by solving a set of deterministic equations of motion. These responses include power spectral densities, variances and higher spectral moments of any required responses of the beam. A non-uniform beam example was solved and the time-dependent variances and second spectral moments of both the beam-top displacement and the beam-base shear force are given to show the simplicity and effectiveness of the method, which can also easily be applied to other continuous elastic structures. 相似文献
960.
The results of a parametric study on the dynamic interaction between adjacent foundations are presented. Addressed in this study are the effects of distance, direction of alignment, embedment and structural inertia. Several conclusions are drawn regarding the significance of each of these factors. 相似文献