Adaptive Multiscale Permeability Estimation

With multiscale permeability estimation one does not select parameterization prior to the estimation. Instead, one performs a hierarchical search for the right parameterization while solving a sequence of estimation problems with an increasing parameterization dimension. In some previous works on the subject, the same refinement is applied all over the porous medium. This may lead to over-parameterization, and subsequently, to unrealistic permeability estimates and excessive computational work. With adaptive multiscale permeability estimation, the new parameterization at an arbitrary stage in the estimation sequence is such that new degrees of freedom are not necessarily introduced all over the porous medium. The aim is to introduce new degrees of freedom only where it is warranted by the data. In this paper, we introduce a novel adaptive multiscale estimation. The approach is used to estimate absolute permeability from two-phase pressure data in several numerical examples.     

ENSO事件中纬向异常流反向与东西侧边界反射的联系

建立一个中等复杂程度的海-气耦合模式研究东、西边界反射,纬向平流项-u′(δ)(T+T′)/(δ)x在ENSO循环位相转换中的作用及东、西边界反射与纬向异常流(u′) 符号改变的关系.结果得到:u′超前Nio3区SSTA位相转变的原因是东、西边界反射造成的.Sverdrup 平衡时所产生的地转流(ur)与东、西边界反射所产生的地转流(ur)的方向在大部分时间里是相反的,同时ur与风应力强迫之间大约有9个月的滞后时间(Kelvin波从180°E出发经东边界反射产生的Rossby波到达180°E时间).在模式ENSO事件消亡过程中的某一时刻以后,边界反射产生的调整过程变为主要过程,u′主要由ur来决定,这样就造成了u′的反向先于Nio区SSTA的反向.它实际上是海洋的调整过程与风应力强迫之间滞后关系的一种反映.敏感性数值试验表明,取消东边界反射,耦合模式能够模拟ENSO循环,但其周期比控制试验的周期短一年(3年).取消-u′(δ)(T+T′)/(δ)x,耦合模式能够模拟ENSO循环,但其周期比控制试验的周期长2年(6年).     

卫星测高问题的球谐级数解法

研究了球界面下卫星测高问题的解法，利用有限逼近方法得到了下列结论：若陆地部分是球冠，则卫星测高问题的解可以转换成关于球谐级数位系统的线性方程组。同时证明了常用的Stokes问题、Dirichlet问题、Neumann问题可以看成卫星测高问题的特殊情况。     

实验速度场测量技术及对流边界层特征研究

在对流槽中对对流边界层(CBL)温度场实验研究的基础上,进一步尝试通过实验技术测量速度场并分析研究CBL中的速度场特征。在应用PIV测量技术时选用铝粉作示踪粒子。实验证明了在混合层中速度分布明显具有对流边界层热泡特性;混合层顶部的速度分布很好地反应出夹卷层的结构特征;湍流速度特征量的垂直分布合理,与野外实测结果和类似的对流槽实验结果接近;误差分析表明示踪粒子的跟随性良好,粒子速度的测量结果能真实地反应流体的运动特征,从而得证了分析结果的可靠性。     

对下扬子与华南边界结合带东延问题的地球物理探讨

以江山-绍兴、铅山-宜春等断裂带作为华南与扬子块体之间的边界结合带，这种认识目前已基本为大家所接受．但是，这条边界结合带向东延伸入海之后的位置与去向一直是多年来研究的热点．本文基于黄、东海研究区的地球物理数据(空间重力数据、布格重力数据和地震层析成像结果)，利用方向导数等处理方法，对研究区的地球物理数据进行处理，并对研究区的地球物理场进行了分析，划分出不同的区块．结合研究区的磁力与地质资料，利用各种成图、成像技术，形成一系列分析图件．在此基础上对华南与扬子块体之间的边界结合带进行了追踪．研究结果认为：该结合带的位置有可能比传统认识中自长江口至大黑山群岛的位置更向南一些，在杭州湾-长崎、对马海峡一线，并呈现向北略微凸出的弓形．边界结合带在深度上属于深大断裂带，一直可以追索到上地幔的顶部．与中朝与扬子块体之间的边界结合带相比较，本条结合带的踪迹不是十分清晰．表明加里东运动之后，该结合带的运动明显减弱．     

A Case Study Of An On-Ice Air Flow Over The Arctic Marginal Sea-Ice Zone

A case study of warm air advection over the Arctic marginalsea-ice zone is presented, based on aircraft observations with direct flux measurements carriedout in early spring, 1998. A shallow atmospheric boundary layer (ABL) was observed, which wasgradually cooling with distance downwind of the ice edge. This process was mainly connected with astrong stable stratification and downward turbulent heat fluxes of about 10–20 W m^-2, but wasalso due to radiative cooling. Two mesoscale models, one hydrostatic and the other non-hydrostatic,having different turbulence closures, were applied. Despite these fundamental differences betweenthe models, the results of both agreed well with the observed data. Various closure assumptions had amore crucial influence on the results than the differences between the models.Such an assumption was, for example,the parameterization of the surface roughness for momentum (z₀) and heat (z_T). This stronglyaffected the wind and temperature fields not only close to the surface but also within and abovethe temperature inversion layer. The best results were achieved using a formulation for z₀ that took intoaccount the form drag effect of sea-ice ridges together withz_T = 0.1z₀. The stability within theelevated inversion strongly depended on the minimum eddy diffusivity K_min. A simple ad hocparameterization seems applicable, where K_min is calculated as 0.005 timesthe neutral eddy diffusivity. Although the longwave radiative cooling was largest within the ABL, theapplication of a radiation scheme was less important there than above the ABL. This was related to theinteraction of the turbulent and radiative fluxes. To reproduce the strong inversion, it wasnecessary to use vertical and horizontal resolutions higher than those applied in most regional andlarge-scale atmospheric models.     

Comparison of the Langrangian Footprint

We compare flux and concentration footprint estimates of athree-dimensional Lagrangian stochastic dispersion modelapplying backward trajectories with the results of ananalytical footprint model by Kormann and Meixner.The comparison is performed for varying stability regimesof the surface layer as well as for different measurementheights. In general, excellent correspondence is found.     

GRP文件格式到MIF格式的实现

为将ＧＲＰ文件格式转换成ＭＩＦ文件格式，提供一种数据不变，而文件存储方式改变的数据转换方法和实例。     

Construction of Green's function to the external Dirichlet boundary-value problem for the Laplace equation on an ellipsoid of revolution

Green's function to the external Dirichlet boundary-value problem for the Laplace equation with data distributed on an ellipsoid of revolution has been constructed in a closed form. The ellipsoidal Poisson kernel describing the effect of the ellipticity of the boundary on the solution of the investigated boundary-value problem has been expressed as a finite sum of elementary functions which describe analytically the behaviour of the ellipsoidal Poisson kernel at the singular point ψ = 0. We have shown that the degree of singularity of the ellipsoidal Poisson kernel in the vicinity of its singular point is of the same degree as that of the original spherical Poisson kernel. Received: 4 June 1996 / Accepted: 7 April 1997     

非均匀层结下的对称不稳定

研究了非均匀层结下的对称不稳定，给出了不稳定发生的判据，并将该微分方程的特征值问题化为一个实对称矩阵的特征值问题，还取不同的层结廓线进行了数值计算。