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M. N. Saquib M. L. Kavvas P. S. Puri 《Stochastic Environmental Research and Risk Assessment (SERRA)》1988,2(4):281-294
The time-space evolution of an extratropical cyclonic precipitation field over U S A is simulated in a stochastic setting as outlined in Kavvas et al. (1988). The birth of a cyclonic storm is characterized by the simultaneous birth of a cyclone center and births of subsynoptic precipitation areas (SPA) at preferred locations around the cyclone center. The precipitation cores and cells which are used as the fundamental building blocks of the SPAs are approximated by circular precipitation areas (CPA) of different sizes. The time space evolution of the precipitation field after the birth is governed by (1) the movement of the synoptic cyclone described by the cyclone center trajectory, (2) independent nonidentically distributed random velocities of the individual CPAs relative to the cyclone center, (3) the births of new CPAs in time and space relative to the cyclone center, (4) the independent evolution in time of the individual spatially uniform intensities of the existing CPAs, (5) the expansion and shrinkage of the existing CPAs in the course of movement and (6) the dissipation (death) of a random number of existing CPAs within the cyclonic system. The computer simulation, the results of which are presented in this paper, successfully reproduced the general mesoscale and synoptic scale features of the radar detected cyclonic rain fields as observed by Austin and Houze (1972), Houze et al. (1976), Hobbs (1978), Hobbs and Locatelli (1978), Houze (1981), Houze and Hobbs (1982) and others. 相似文献
714.
Several physically based stochastic dynamic models (SDM) are described including year-to-year variations of water volume in terminal and non-terminal lakes, streamflow of lake-fed rivers, and salinity of an inland sea (the Sea of Azov). All of these models are based upon the SDM of water volume of terminal lakes developed by Kritzky and Menkel in 1946 in co-operation with Kolomogorov. Explicit formulae are derived for second order statistical moments of the output processes, including variance, correlation function, spectra, etc., under the assumption that the forcing functions from stationary random sequences. The least-squares prediction problem is solved for both stationary and non-stationary cases. Some of the processes are shown to possess high statistical predictability. Actual predictions are compared with independent observations. Problems for further study are stated. 相似文献
715.
谢剑飞 《水文地质工程地质》1993,20(2):42-43,57
本文论述了R-C电网络模型的基本原理及模拟装置,分析了不同类型的层状含水系统。根据榴似性原理,建立了不同类型的电网络模型。在此基础上,预测了内蒙古某露天煤矿的矿坑疏干涌水量,取得了比较满意的结果。 相似文献
716.
陈葆仁 《水文地质工程地质》1993,20(4):40-43
文章以漯河市为例说明了城市地下水最大可采资源的确定和开发管理中遵循不断变化着的实际情况,走科研与生产相结合道路的必要性。全文分3个方面介绍了开采条件下的人工串层补给,随机边界条件及地下水管理模拟中常见的几个核心问题的处理。文章最后强调,地下水数值模拟中辅以同位素年龄研究的重要性。 相似文献
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The Fourier Integral Method: An efficient spectral method for simulation of random fields 总被引:4,自引:0,他引:4
The Fourier Integral Method (FIM) of spectral simulation, adapted to generate realizations of a random function in one, two, or three dimensions, is shown to be an efficient technique of non-conditional geostatistical simulation. The main contribution is the use of the fast Fourier transform for both numerical calculus of the density spectral function and as generator of random finite multidimensional sequences with imposed covariance. Results obtained with the FIM are compared with those obtained by other classic methods: Shinozuka and Jan Method in 1D and Turning Bands Method in 2D and 3D, the points for and against different methodologies are discussed. Moreover, with the FIM the simulation of nested structures, one of which can be a nugget effect and the simulation of both zonal and geometric anisotropy is straightforward. All steps taken to implement the FIM methodology are discussed. 相似文献
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