Multigenetic gravity couple across a modern convergent margin: inheritance from Cretaceous asymmetric extension     

Peter J. J. Kamp  Kerry A. Hegarty 《Geophysical Journal International》1989,96(1):33-41

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关于正确处理对流－弥散方程和渗流方程中源汇项的若干问题     

郭东屏 《地球科学与环境学报》1995,(3)

对流─弥散方程和渗流基本微分方程中的源汇项，分别是决定含水层中任一内点上水质量和溶质质量时变率的重要因素之一。而关于源汇项不适当的乃至是错误的表述，在文献中却不乏其见，其影响之大是显而易见的．本文深入分析了某些表述的不当或错误之处，给出了正确的处理与表述方法。  相似文献   

A dislocation model for the earthquake cycle at convergent plate boundaries   总被引：1，自引：0，他引：1  

Mitsuhiro Matsu'ura  Toshinori Sato 《Geophysical Journal International》1989,96(1):23-32

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Performance of a flux splitting scheme when solving the single-phase pressure equation discretized by MPFA     

T.?AadlandEmail author  I.?Aavatsmark  H.?K.?Dahle 《Computational Geosciences》2004,8(4):325-340

In this article we present a series of tests to study how well suited the TPFA coefficient matrix is as a preconditioner for the MPFA discrete system of equations in an iterative solver, using a flux splitting method. These tests have been conducted for single-phase flow for a wide range of anisotropy, heterogeneity, and grid skewness (mainly parallelogram grids). We use the K-orthogonal part of the MPFA transmissibilities for a parallelogram grid to govern the TPFA transmissibilities. The convergence of the flux splitting method is for each test case measured by the spectral radius of the iteration matrix.  相似文献   

Helmert方差分量估计严密公式与简化公式等价性的证明   总被引：3，自引：0，他引：3  

刘长建  吴洪举  明锋 《测绘科学》2006,31(2):66-67

在分析了Helmert方差分量估计严密公式与简化公式迭代收敛结果一些统计性质的基础上,导出了关于收敛结果共同的求解方程,从理论上证明了两种结果的等价性,为使用简化公式提供了依据。  相似文献   

Moisture transport over the Arabian Sea associated with summer rainfall over Pakistan in 1994 and 2002   总被引：2，自引：0，他引：2  

高守亭 《大气科学进展》2012,29(3):501-508

In this study,we aimed to elucidate the critical role of moisture transport affecting monsoon activity in two contrasting summers over the Arabian Sea during the years 1994,a relatively wet year,and 2002,a relatively dry year.A comprehensive diagnostic evaluation and comparisons of the moisture fields were conducted;we focused on the precipitation and evaporation as well as the moisture transport and its divergence or convergence in the atmosphere.Monthly mean reanalysis data were obtained from the National Centers for Environmental Prediction(NCEP-I and-II).A detailed evaluation of the moisture budgets over Pakistan during these two years was made by calculating the latent energy flux at the surface(E P) from the divergence of the total moisture transport.Our results confirm the moisture supply over the Arabian Sea to be the major source of rainfall in Pakistan and neighboring regions.In 1994,Pakistan received more rainfall compared to 2002 during the summer monsoon.Moisture flow deepens and strengthens over Arabian Sea during the peak summer monsoon months of July and August.Our analysis shows that vertically integrated moisture transport flux have a significant role in supplying moisture to the convective centers over Pakistan and neighboring regions from the divergent regions of the Arabian Sea and the Bay of Bengal.Moreover,in 1994,a deeper vertically integrated moisture convergence progression occurred over Pakistan compared to that in 2002.Perhaps that deeper convergence resulted in a more intense moisture depression over Pakistan and also caused more rainfall in 1994 during the summer monsoon.Finally,from the water budget analysis,it has been surmised that the water budget was larger in 1994 than in 2002 during the summer monsoon.  相似文献   

Modulation of Western North Pacific Tropical Cyclone Genesis by Intraseasonal Oscillation of the ITCZ: A Statistical Analysis   总被引：1，自引：0，他引：1  

CAO Xi  HUANG Ping  CHEN Guanghu  CHEN Wen 《大气科学进展》2012,29(4):744-754

The present study investigates modulation of western North Pacific(WNP) tropical cyclone(TC) genesis in relation to different phases of the intraseasonal oscillation(ISO) of ITCZ convection during May to October in the period 1979-2008.The phases of the ITCZ ISO were determined based on 30-80-day filtered OLR anomalies averaged over the region(5-20 N,120-150 E).The number of TCs during the active phases was nearly three times more than during the inactive phases.The active(inactive) phases of ISO were characterized by low-level cyclonic(anticyclonic) circulation anomalies,higher(lower) midlevel relative humidity anomalies,and larger(smaller) vertical gradient anomalies of relative vorticity associated with enhanced(weakened) ITCZ convection anomalies.During the active phases,TCs tended to form in the center of the ITCZ region.Barotropic conversion from the low-level mean flow is suggested to be the major energy source for TC formation.The energy conversion mainly depended on the zonal and meridional gradients of the zonal flow during the active phases.However,barotropic conversion weakened greatly during the inactive phases.The relationship between the meridional gradient of absolute vorticity and low-level zonal flow indicates that the sign of the absolute vorticity gradient tends to be reversed during the two phases,whereas the same sign between zonal flow and the absolute vorticity gradient is more easily satisfied in the active phases.Thus,the barotropic instability of low-level zonal flow might be an important mechanism for TC formation over the WNP during the active phases of ISO.  相似文献   

盛夏渤海湾大气边界层辐合线触发对流风暴对比分析   总被引：2，自引：2，他引：0  

赵金霞  徐灵芝  卢焕珍  范苏丹 《气象》2012,38(3):336-343

本文对渤海湾2008—2009年,由大气边界层辐合线引起的对流风暴进行了分析。结果表明,在高温、高湿不稳定大气层结环境条件下：（1）单一的海风锋在其端点可产生对流性降水。（2）海风锋与弱冷锋相遇,或者两条海风锋相交,或者雷暴单体的出流边界与海风锋相遇均会产生强对流风暴。（3）渤海湾边界层辐合线触发对流风暴大多发生在每年7 8月,且在副热带高压控制渤海湾后东退的过程中,此时大气层结处在高温、高湿不稳定状态。辐合线触发的对流风暴是沿辐合线移动,移动方向取决于辐合线两侧的主导风向。（4）边界层辐合线触发对流风暴,具有突发性强,持续时间短等特点,分析渤海湾边界层辐合线的移动与演变能提高强对流风暴的临近预报、预警,减少突发性天气引起的灾害。  相似文献   

梅雨锋上两类中尺度对流系统形成的边界层特征   总被引：3，自引：0，他引：3  

许长义  林永辉  管兆勇 《南京气象学院学报》2012,35(1):51-63

采用具有较高时空分辨率的地面观测资料以及WRF（Weather reasearch and forecasting）模式输出资料,分析了2009年6月29一-30日梅雨锋暴雨过程中两类不同的中尺度对流系统（rnesoscale convective system,MCS）边界层特征及边界层对两类MCS的触发维持机理,重点分析了海平面气压场特征、边界层冷池、干线及其在MCS中的影响。结果表明：两类中尺度对流系统的海平面气压特征存在着明显的差异,对流爆发阶段地面风场存在辐合线,再次激发阶段气压场呈“跷跷板”型的中尺度扰动,即由前置中低压和后置中高压组成,最强的对流带位于中低压和中高压之间的过渡区内;边界层辐合线是第一类中尺度对流系统（MCSl）维持的重要因素;MCSl爆发后边界层冷池生成,冷池前的冷出流与低层环境风产生的强辐合触发了第二类中尺度对流系统（MCS2）;存在于中低压和中高压之间的中尺度干线是MCS2的重要特点之一。  相似文献   

非线性Schrödinger方程的一个线性化紧致差分格式     

王廷春 《南京气象学院学报》2012,4(6):569-572

对非线性Schrödinger方程给出了一个线性化紧致差分格式,运用不动点定理和能量方法证明了格式的唯一可解性,还运用能量方法和数学归纳法,避开困难的先验估计,证明格式在空间方向和时间方向分别具有四阶和二阶精度,数值算例验证了格式的精度和数值稳定性.  相似文献