A method for establishing a two-parameter monthly-scale hydrological model based on the hydrothermal complementary equation

Abstract

The invention discloses a method for establishing a two-parameter monthly-scale hydrological model based on a hydrothermal complementary equation, belonging to the field of hydrology. The method includes the following steps: collecting hydrological data of the research area; dividing the calibration period and the verification period according to the time series; constructing a two-parameter monthly-scale hydrological model based on the hydrothermal complementary equation; using the SCE-UA algorithm for parameter calibration; and model testing and accuracy evaluation. The monthly-scale hydrological model established by the method provided by the invention has the characteristics of a solid theoretical basis, a simple structure, fewer parameters, and high simulation accuracy, and is suitable for popularization and use in humid and semi-humid regions, providing technical support for water resource planning and rational allocation.

Description

Technical Field

[0001] The present invention belongs to the field of hydrology, and more specifically, relates to a method for establishing a two-parameter monthly-scale hydrological model based on a water-heat complementary equation. Background Technique

[0002] In recent years, the increasing imbalance between water supply and water demand has attracted great attention from relevant departments and the public to water resource planning schemes. The monthly-scale hydrological model plays an important role in simulating and predicting hydrological processes, integrated water resource management, and runoff simulation in data-deficient areas. Its simulation accuracy and efficiency directly affect regional water resource management and decision-making. Therefore, how to accurately and efficiently simulate runoff has always been a hot and difficult issue.

[0003] The monthly-scale hydrological model is based on the water balance equation, and generalizes the relationship between various hydrological elements into empirical formulas to simulate the basin hydrological process. Currently, the mainstream monthly-scale hydrological models at home and abroad mainly include the abcd model, the Xin'anjiang monthly model, the Australian water balance model, etc. Their complexities are different, and the number of parameters is also different. For the monthly-scale hydrological model, on the one hand, the model should have a certain theoretical basis or a reasonable model structure to facilitate popularization and application in other regions; on the other hand, the model parameters should be as few as possible to reduce the model uncertainty caused by the correlation between parameters. Therefore, on the premise of ensuring the theoretical nature of the monthly-scale hydrological model, how to improve the simulation accuracy with as few model parameters as possible is an urgent problem to be solved in the current hydrological field. Summary of the Invention

[0004] In view of the above defects or improvement requirements of the prior art, the present invention provides a method for establishing a two-parameter monthly-scale hydrological model based on a water-heat complementary equation to solve the problems of weak theoretical basis, insufficient accuracy, more required parameters, and complex calculation of the existing monthly-scale hydrological model.

[0005] To achieve the above object, according to the first aspect of the present invention, there is provided a method for establishing a two-parameter monthly-scale hydrological model based on a water-heat complementary equation, including:

[0006] 1) Collect and preprocess the historical hydrometeorological data of the research basin to obtain the monthly potential evapotranspiration E p , monthly precipitation P t and observed monthly runoff Q obs,t ;

[0007] 2) Construct a two-parameter monthly-scale hydrological model based on the water-heat complementary equation:

[0008]

[0009] where E tis the actual monthly evaporation in the basin, S t-1 , S t are the water storage capacity of the basin at the beginning and end of the period, n and S p are two parameters of the model, n is a parameter reflecting the characteristics of the underlying surface of the watershed, S p is the potential water storage capacity of the basin;

[0010] 3) Solve the above equations using the bisection method and get E t and S t , according to the formula Q t =S t-1 +P t -E t -S t The simulated monthly runoff Q is calculated sim,t ;

[0011] 4) Parameter calibration is performed using the Nash efficiency coefficient NSE as the objective function, and n and S are determined by maximizing the objective function. p ;

[0012] in, Q sim,i and Q obs,i are the simulated monthly runoff and observed monthly runoff at time i, m is the number of simulated months, is the observed monthly mean runoff.

[0013] According to a second aspect of the present invention, there is provided a two-parameter monthly-scale hydrological model establishment device based on a water-heat complementarity equation, comprising:

[0014] The preprocessing module is used to collect and preprocess the historical hydrological and meteorological data of the study basin to obtain the monthly potential evapotranspiration E of the basin. p , monthly precipitation P t and observed monthly runoff Q obs,t ;

[0015] Model building module, used to construct a two-parameter monthly-scale hydrological model based on the water-heat complementarity equation:

[0016]

[0017] Among them, E t is the actual monthly evaporation in the basin, S t-1 , S t are the water storage capacity of the basin at the beginning and end of the period, n and S p are two parameters of the model, n is a parameter reflecting the characteristics of the underlying surface of the watershed, S p is the potential water storage capacity of the basin;

[0018] The first processing module is used to solve the above equations by the bisection method to obtain E t and S t , and calculate the simulated monthly runoff Q t according to the formula Q t-1 = S t + P t - E t - S sim,t ;

[0019] The second processing module is used to calibrate parameters with the Nash efficiency coefficient NSE as the objective function, and determine n and S p by maximizing the objective function;

[0020] wherein, Q sim,i and Q obs,i are the simulated monthly runoff and the observed monthly runoff at time i respectively, m is the number of simulated months, is the mean value of the observed monthly runoff.

[0021] According to the third aspect of the present invention, a two-parameter monthly-scale hydrological model establishment system based on the water-heat complementary equation is provided, including: a computer-readable storage medium and a processor;

[0022] The computer-readable storage medium is used to store executable instructions;

[0023] The processor is used to read the executable instructions stored in the computer-readable storage medium and execute the method described in the first aspect.

[0024] Generally speaking, compared with the prior art by the above technical solution conceived by the present invention, the following beneficial effects can be achieved:

[0025] (1) The two-parameter monthly-scale hydrological model establishment method based on the water-heat complementary equation provided by the present invention constructs a monthly-scale hydrological model based on the water-heat coupling balance equation and the water balance equation of the basin, and has a strong theoretical basis.

[0026] (2) The two-parameter monthly-scale hydrological model established by using the method provided by the present invention has a simple structure, only two parameters, and the physical meanings of the parameters are clear, reducing the uncertainty of the model.

[0027] (3) After actual verification, the two-parameter monthly-scale hydrological model established by using the method provided by the present invention has high simulation accuracy, stronger applicability in humid and semi-humid regions, and is convenient for popularization and application. Description of the Drawings

[0028] Figure 1Schematic flowchart of the method for establishing a two-parameter monthly-scale hydrological model based on the water-heat complementary equation provided by an embodiment of the present invention.

[0029] Figure 2 Schematic diagram of the measured-simulated flow process line provided by an embodiment of the present invention. Detailed implementation manners

[0030] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] An embodiment of the present invention provides a method for establishing a two-parameter monthly-scale hydrological model based on the water-heat complementary equation, including:

[0032] 1) Collect and preprocess the historical hydrological and meteorological data of the research basin to obtain the monthly potential evapotranspiration E p of the basin, the monthly precipitation P t and the observed monthly runoff Q obs,t ;

[0033] 2) Construct a two-parameter monthly-scale hydrological model based on the water-heat complementary equation:

[0034]

[0035] where E t is the monthly actual evaporation of the basin, S t-1 , S t are the water storages of the basin at the beginning and end of the period respectively, n and S p are the two parameters of the model, n is the parameter reflecting the underlying surface characteristics of the basin, and S p is the potential water storage of the basin;

[0036] 3) Use the bisection method to solve the above equations to obtain E t and S t , and calculate the simulated monthly runoff Q t according to the formula Q t-1 =S t +P t -E t -S sim,t ;

[0037] 4) Use the Nash efficiency coefficient NSE as the objective function for parameter calibration, and determine n and S p by maximizing the objective function;

[0038] where Q sim,i and Q obs,i are the simulated monthly runoff and the observed monthly runoff at time i, respectively, m is the number of simulated months, is the mean value of the observed monthly runoff.

[0039] Furthermore, in step 4), the SCE-UA optimization algorithm is used for parameter calibration.

[0040] Furthermore, in step 4), the value range of n is set to 0.1 - 3, and S P has a value range of 0 - 1000.

[0041] Furthermore, step 1) further includes: according to the monthly potential evapotranspiration E p , monthly precipitation P t and the observed monthly runoff Q obs,t of the time series length, divide the data into calibration period data and validation period data;

[0042] In step 4), the calibration period data is used for parameter calibration, and after step 4), it further includes: using the validation period data for model verification and conducting model accuracy evaluation.

[0043] Next, in combination with Figure 1 the method provided by the present invention will be further described.

[0044] As Figure 1 shown, the method for constructing a two-parameter monthly-scale hydrological model based on the water-heat complementary equation provided by the present invention includes the following steps:

[0045] S1: Collect and preprocess the historical hydrometeorological data of the study area to obtain the monthly potential evapotranspiration, monthly precipitation, and observed monthly runoff of the basin.

[0046] S2: Divide the calibration period and the validation period according to the time series length of the above hydrometeorological data.

[0047] S3: Construct a two-parameter monthly-scale hydrological model based on the water-heat complementary equation, and the model structure is as follows:

[0048]

[0049] In the formula, E t is the monthly actual evaporation of the basin, E p is the monthly potential evaporation, P t is the monthly precipitation, S t-1 , S t are the water storage volumes of the basin at the beginning and end of the time period, respectively. n and S p are the two unknown parameters of the model, where n is the parameter reflecting the underlying surface characteristics of the basin, and Sp is the potential water storage capacity of the basin.

[0050] The two equations of the model are derived from the water-heat coupling balance equation of the basin and have a strong theoretical basis.

[0051] The above equations are solved by the bisection method to obtain E t and S t , and the initial value of S t-1 is set artificially according to the characteristics of the basin.

[0052] According to the water balance equation, the simulated monthly runoff Q t at time t is obtained as follows:

[0053] Q t = S t-1 + P t - E t - S t

[0054] S4: Calibrate the model parameters using the hydrometeorological data during the calibration period of the basin. Taking the Nash efficiency coefficient NSE as the objective function and adopting the SCE-UA optimization algorithm, maximize the objective function to perform parameter calibration. Among them,

[0055]

[0056] In the formula, Q sim,i and Q obs,i are the simulated flow and the observed flow at time i, respectively. m is the number of simulated months, is the mean of the observed flow.

[0057] Thus, the parameters n and S p can be determined.

[0058] It can be understood that the values of the parameters n and S p vary according to different research areas.

[0059] S5: Use the hydrometeorological data during the verification period of the basin to conduct model testing and perform model accuracy evaluation.

[0060] Furthermore, the main inputs of the model are the monthly precipitation P t and the monthly potential evapotranspiration E p , and the output is the monthly runoff.

[0061] Furthermore, the model parameters include the parameter n reflecting the characteristics of the basin's underlying surface and the parameter S p reflecting the potential water storage capacity of the basin. During the parameter calibration process, the value range needs to be set first, and the value range of the model parameters is shown in Table 1.

[0062] Table 1 Model parameter range

[0063] parameter range of values n 0.1-3 <![CDATA[S p > 0-1000

[0064] Furthermore, the SCE-UA algorithm is a global optimization algorithm used to optimize model parameters.

[0065] The following is a further detailed description of the method provided by the present invention in conjunction with examples. At the same time, in order to highlight the advantages of the present invention, a model established by the method provided by the present invention will be compared and analyzed with the widely used four-parameter abcd model.

[0066] For the Tiesuoguan Basin of the Hanjiang River, a two-parameter monthly-scale hydrological model based on the water-heat complementarity equation is constructed. The construction method includes the following steps:

[0067] S1: Data collection: Collect the hydrometeorological data of the basin from 1966 to 1989, including monthly precipitation data, monthly evaporation pan observations, and monthly runoff data (observed monthly runoff), and use the monthly evaporation pan observations as monthly potential evapotranspiration data.

[0068] S2: Data segmentation: Divide the calibration period and the verification period according to a ratio of 7:3. In this example, the period from 1966 to 1983 is used as the model calibration period, and the period from 1984 to 1989 is used as the model verification period.

[0069] S3: Model construction: Construct a two-parameter monthly-scale hydrological model based on the water-heat complementarity equation.

[0070] S4: Parameter calibration: Use the hydrometeorological data of the basin calibration period to calibrate the model parameters. Take the Nash efficiency coefficient NSE as the objective function and use the SCE-UA optimization algorithm for parameter calibration. The model calibration results are shown in Table 2:

[0071] Table 2 Model parameter calibration results

[0072] parameter parameter value n 2.55 <![CDATA[S p > 73.59

[0073] S5: Model test and accuracy evaluation: Use the verification period data to test the model, calculate using the calibrated model parameters, compare the simulated and measured flow hydrographs, and conduct accuracy evaluation. The simulation result diagram is shown in Figure 1 . The comparison results (NSE values) with the abcd model are shown in Table 3:

[0074] Table 3 NSE comparison results of model simulation

[0075] model calibration period validation period the model of the present invention 0.96 0.94 abcd model 0.94 0.93

[0076] It can be seen that the Nash efficiency coefficients of the model established by the method provided by the present invention are 0.96 and 0.94 during the calibration period and the verification period respectively, both greater than 0.9 and higher than that of the abcd model. The simulation accuracy is quite high. Referring to the "Hydrological Information and Forecasting Specification" of our country, a deterministic coefficient greater than 0.9 is of Class A accuracy, indicating that the model established by the method provided by the present invention has strong applicability to this basin.

[0077] An embodiment of the present invention provides a runoff simulation method, including:

[0078] Input the monthly precipitation and monthly potential evapotranspiration into a two-parameter monthly-scale hydrological model established by the method described in the first aspect to obtain the simulated monthly runoff.

[0079] An embodiment of the present invention provides a device for establishing a two-parameter monthly-scale hydrological model based on the water-heat complementary equation, including:

[0080] A preprocessing module for collecting and preprocessing the historical hydrometeorological data of the research basin to obtain the monthly potential evapotranspiration E p , monthly precipitation P t and observed monthly runoff Q obs,t ;

[0081] A model establishment module for constructing a two-parameter monthly-scale hydrological model based on the water-heat complementary equation:

[0082]

[0083] where E t is the monthly actual evaporation of the basin, S t-1 , S t are the water storages of the basin at the beginning and end of the time period respectively, n and S p are the two parameters of the model, n is the parameter reflecting the characteristics of the basin underlying surface, and S p is the potential water storage of the basin;

[0084] A first processing module for solving the above equations by the bisection method to obtain E t and S t , and calculating the simulated monthly runoff Q t according to the formula Q t-1 =S t +P t -E t -S t ; sim,t ;

[0085] A second processing module for parameter calibration with the Nash efficiency coefficient NSE as the objective function, and determining n and S p by maximizing the objective function;

[0086] Among them, Q sim,i and Q obs,i are the simulated monthly runoff and the observed monthly runoff at time i, respectively, m is the number of simulated months, is the mean value of the observed monthly runoff.

[0087] An embodiment of the present invention provides a two-parameter monthly-scale hydrological model establishment system based on a water-heat complementary equation, including: a computer-readable storage medium and a processor;

[0088] The computer-readable storage medium is used to store executable instructions;

[0089] The processor is used to read the executable instructions stored in the computer-readable storage medium and execute the model establishment method described in any of the above embodiments, or the runoff simulation method described in the above embodiments.

[0090] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for establishing a two-parameter monthly-scale hydrological model based on a hydrothermal complementary equation, characterized in that Including: 1) Collect and preprocess historical hydrometeorological data of the study basin to obtain the monthly potential evapotranspiration E p of the basin, monthly precipitation P t and observed monthly runoff Q obs,t ; 2) Construct a two-parameter monthly-scale hydrological model based on the water-heat complementary equation: Among them, E t is the monthly actual evaporation of the basin, S t-1 , S t are the water storage volumes of the basin at the beginning and end of the time period respectively, n and S p are two parameters of the model, n is the parameter reflecting the underlying surface characteristics of the basin, S p is the potential water storage volume of the basin; 3) Use the bisection method to solve the above equations to obtain E t and S t , and calculate the simulated monthly runoff Q t according to the formula Q t-1 = S t + P t - E t - S sim,t ; 4) The Nash efficiency coefficient NSE is used as the objective function for parameter calibration, and n and S are determined by maximizing the objective function p ; Among them, Q sim,i and Q obs,i are the simulated monthly runoff and the observed monthly runoff at time i, respectively, m is the number of simulated months, is the mean value of the observed monthly runoff.

2. The method according to claim 1, characterized in that In step 4), the SCE-UA optimization algorithm is used for parameter calibration.

3. The method according to claim 1 or 2, characterized in that, In step 4), the value range of n is set to 0.1 - 3, and the value range of S P is set to 0 - 1000.

4. The method according to claim 1, characterized in that, Step 1) also includes: according to the monthly potential evapotranspiration E of the basin p , monthly precipitation P t and the observed monthly runoff Q obs,t Divide the time series length into calibration period data and validation period data; In step 4), the calibration period data is used for parameter calibration, and after step 4), it further includes: using the verification period data for model verification and conducting model accuracy evaluation.

5. A runoff simulation method, characterized in that, Including: Input the monthly precipitation and monthly potential evapotranspiration into the two-parameter monthly-scale hydrological model established by the method described in any one of claims 1-4 to obtain the simulated monthly runoff.

6. A two-parameter monthly-scale hydrological model establishment device based on a hydrothermal complementary equation, characterized in that Including: A preprocessing module for collecting and preprocessing historical hydrometeorological data of the study basin to obtain the monthly potential evapotranspiration E p , monthly precipitation P t and observed monthly runoff Q obs,t ; A model establishment module for constructing a two-parameter monthly-scale hydrological model based on the water-heat complementary equation: Among them, E t is the monthly actual evaporation of the basin, S t-1 , S t are the water storages of the basin at the beginning and end of the time period respectively, n and S p are two parameters of the model, n is the parameter reflecting the characteristics of the underlying surface of the basin, S p is the potential water storage of the basin; The first processing module is used to solve the above equations by the bisection method to obtain E t and S t , and calculate the simulated monthly runoff Q t according to the formula Q t-1 = S t + P t - E t - S sim,t ; A second processing module, configured to perform parameter calibration with the Nash efficiency coefficient NSE as the objective function, and determine n and S by maximizing the objective function p ; wherein, Q sim,i and Q obs,i are the simulated monthly runoff and the observed monthly runoff at time i, respectively, m is the number of simulated months, is the mean value of the observed monthly runoff.

7. A two-parameter monthly-scale hydrological model establishment system based on the hydrothermal complementary equation, characterized in that, Including: A computer-readable storage medium and a processor; The computer-readable storage medium is used for storing executable instructions; The processor is used for reading the executable instructions stored in the computer-readable storage medium and executing the method described in any one of claims 1-4.

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