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The large-scale convergence of homotopy parametric inversion method on the water quality model parameters calculated was used, with application in parametric inversion calculation of total phosphorus of Beijing Miyun Reservoir. Through calculated and compared the error of sedimentation rate by homotopy parametric inversion method and genetic inversion calculation method, the results indicate that homotopy parametric inversion method has good stability, calculating speed, and even if the initial selection away from the objective function, the solution still has a good convergence. 相似文献
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Hydrological model parameter estimation is an important aspect in hydrologic modelling. Usually, parameters are estimated through an objective function minimization, quantifying the mismatch between the model results and the observations. The objective function choice has a large impact on the sensitivity analysis and calibration outcomes. In this study, it is assessed whether spectral objective functions can compete with an objective function in the time domain for optimization of the Soil and Water Assessment Tool (SWAT). Three empirical spectral objective functions were applied, based on matching (i) Fourier amplitude spectra, (ii) periodograms and (iii) Fourier series of simulated and observed discharge time series. It is shown that most sensitive parameters and their optimal values are distinct for different objective functions. The best results were found through calibration with an objective function based on the square difference between the simulated and observed discharge Fourier series coefficients. The potential strengths and weaknesses of using a spectral objective function as compared to utilising a time domain objective function are discussed. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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对T106分析/预报场可预报性的初步分析 总被引:3,自引:3,他引:3
本文围绕日常天气预报的需求和为区域数值天气预报模式定义天气背景场和初值场的需要,针对9210工程MICAPS系统中T106谱模式的客观分析场和预报场的可预报性进行了初步诊断,定量分析比较了T106、欧洲中心ECMWT、华盛顿KEBC和日本JAPAN数值模式对天气环流形势和预报的统计误差,并初步探讨了模式误差的自身预报问题。文中指出了T106模式的误差源主要来自于其客观分析场的固定误差,提出了以集成客观分析场作为客观分析,提供预报员预报参考或作为数值预报的背景初值场。 相似文献
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The paper treats the problem of interpolating annual runoff from regular streamflow measurements in a regional scale applying objective methods. These methods are adapted to point processes like temperature and precipitation. Modifications are needed to account for the fact that streamflow is an integrated process following the hierarchical structure of river systems. The most straightforward method is therefore to relate the interpolation to the existing river network. For theoretical reasons it is preferable to interpolate the lateral inflow rather than the flow in the river itself. Procedures for the interpolation with the different approaches are developed and discussed. Special attention is put on the question how the equation of continuity can be satisfied. The Laagen drainage basin in southern Norway is used as a test area. The data consist of annual observations of streamflow and digital map information on river networks and drainage basin boundaries. 相似文献
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A simple method of the objective frontal analysis (OFA) based on a thermal definition of atmospheric fronts is proposed for the area of Central Europe with the aid of gridded numerical weather prediction model (NWP model) outputs. The OFA includes both mathematical and graphical techniques that enable a computer to draw fronts entirely automatically in atmospheric cross-sections by means of one locating equation and four masking criteria. The OFA also enables to analyse the frontal wave position and the type, activity, and future development of fronts.The OFA is applied to two synoptically analogous cold-frontal situations, which occurred over the Czech Republic in summer season and were characterised by quite different precipitation amounts. The outputs (12h, 18h, and 24h forecasts) of the NWP model Europa Modell/Deutschland Modell are used in computations. The equivalent potential temperature is considered as an input thermal parameter of the OFA. The impact of applying and changing the OFA masking criteria is various and among others also depends on synoptic situation. The comparison between the objective and subjective analysed fronts subserves to evaluate the values of masking threshold constants. Some obtained results of the analysis of the extreme precipitation situation support the possibility of enhanced precipitation amounts. The analysis of the second non-extreme precipitation situation revealed a few different features that do not support the forecast of enhanced precipitation amounts. The results show the OFA could contribute to the improvement of the general short-range weather forecast. 相似文献
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预报员在未来天气预报中的作用探讨 总被引:2,自引:0,他引:2
在没有数值天气预报的年代 ,天气预报是由预报员作出的 ,随着数值天气预报业务水平的不断提高 ,它首先取代了预报员的天气形势预报 ,目前正进入取代部分天气要素预报的时代。未来 1 0~ 2 0年中尺度数值天气预报和集合预报以及后处理技术将获得重大进展 ,客观预报有可能取代目前预报员的一些预报项目 ,但是预报员的作用仍然是不可缺少的 ,但需要按与时俱进的观点 ,认真分析客观预报与主观预报的最佳结合点 ,以不断提高天气预报水平 相似文献
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