An Improved Nash Efficiency Coefficient Calculation Method
A technology of efficiency coefficient and calculation method, which is applied in calculation, electrical digital data processing, special data processing applications, etc., and can solve problems such as poor simulation effect and high Nash efficiency coefficient
Active Publication Date: 2017-05-10
CHINA INST OF WATER RESOURCES & HYDROPOWER RES
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[0005] However, the practical application shows that the Nash efficiency coefficient is very sensitive to the peak value. As long as the peak value is simulated well, even if the simulation effect of low value is very poor, the Nash efficiency coefficient of the whole simulation process is also very high.
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[0020] The present invention will be further described below in conjunction with the accompanying drawings.
[0021] Such as figure 1 Shown, a kind of improved Nash efficiency coefficient calculation method of the present invention, it adopts following method step:
[0022] (1) Divide the observed flow into several groups according to certain requirements, and the requirement is that the flow span of each group can be the same or different;
[0023] (2) Use the variance sum of the observed flow rate and the mean value of the group where the flow rate is located as a benchmark to verify the variance;
[0024] (3) Use the variance of the simulated value and the observed value and multiply the grouping coefficient as the simulation verification variance;
[0025] (4) The grouping coefficient of each simulated data point is equal to the number of data points in the group divided by the nth power of the ratio of the number of total data points, wherein n can be artificially desig...
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The invention relates to the technical field of hydrological model efficiency calculation, in particular to an improved Nash efficiency coefficient calculation method. The method includes the following steps that firstly the observed flow is divided into several groups according to a certain requirement, and the requirement is that the flow span of all groups can be either the same or different; secondly the variance of the average value of the observed flow and the corresponding group wherein the flow is located serves as the benchmark validation variance; thirdly the variance sum of a simulation value and the observed value is multiplied by grouping coefficients to serve as the simulation validation variance; fourthly the grouping coefficients of all simulated data points is equal to n-th power of the proportion generated by dividing the number of data points in the corresponding group by the total number of data points, and n can be manually designated; fifthly the improved Nash efficiency coefficient equals to the specific value between the value obtained by subtracting the simulation validation variance from one and the benchmark validation variance. By means of the method, the error of an average model can be reduced, and thus Nash efficiency calculation accuracy is improved.
Description
technical field [0001] The invention relates to the technical field of model efficiency calculation of hydrological models, in particular to an improved Nash efficiency coefficient calculation method. Background technique [0002] Hydrological models are currently the main tools for studying the evolution of the water cycle in a watershed. Therefore, the efficiency of model simulation has become the main content of model application. The longest used model validation method is Nash efficiency. This method mainly expresses the relative effect of the simulated value of the model and only the average value as the simulation (average model). This method considers that the smaller the variance between the simulated value and the observed value, the better. Calculated as follows: [0003] [0004] Among them, NSE represents the Nash-Sutcliffe efficiency coefficient; Q sim Indicates the analog value (m 3 / s); Q obs Indicates the observed value (m 3 / s); N represents the ...
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IPC IPC(8): G06F17/50
Inventor 刘佳嘉周祖昊贾仰文王浩贾金生刘扬
Owner CHINA INST OF WATER RESOURCES & HYDROPOWER RES