Method and device for determining asynchronous duration and type of flood peak and sand peak in flood process

Abstract

The present invention provides a method and device for determining the asynchronous duration and type of flood peaks and sand peaks during a flood process, which can quickly, accurately and conveniently determine the asynchronous duration and asynchronous type of flood peak and sand peak calculation during a flood process. The method includes: step 1, obtaining the annual flow process of the control hydrological station in the study area, and determining all flood processes in the year according to the flow process; step 2, calculating the deviation value of two time series based on the measured data of flow and sediment content during the flood process of the control hydrological station; step 3, judging the asynchronous type based on the total deviation: setting the characteristic time t according to the measurement accuracy cri ; If the absolute value of the total deviation is less than t cri , it is judged that during the flood, the flood peak and the sand peak are basically synchronized; the absolute value of the total deviation value is greater than t cri , and the sign is positive, it is judged that during the flood, the sand peak is ahead of the flood peak; the absolute value of the total deviation value is greater than t cri , and the sign is negative, it is judged that during the flood process, the sand peak lags behind the flood peak.

Description

Technical Field

[0001] The present invention belongs to the technical field of water conservancy river engineering, and particularly relates to a method and device for determining the asynchronous duration and type of flood peak and sediment peak in the process of a single flood event. Technical Background

[0002] For large natural rivers, the water and sediment transport has different time scales. Among them, the transport on a longer time scale is the inter-annual or seasonal changes in runoff and sediment transport, while the short time scale is represented by the flood peak and sediment peak process transport in a single flood event. Under the influence of one or a combination of factors such as rainfall intensity and distribution, geology and geomorphology, vegetation conditions, riverbed composition, and boundary conditions, the flood peak and sediment peak in the river usually move downstream asynchronously. The phenomenon of asynchronous movement of the flood peak and sediment peak is not only an important manifestation of the water and sediment production and transport in the basin and the characteristics of the river itself, but also has an important impact on the river itself. Due to the imbalance of water and sediment, the asynchronous flood peak and sediment peak will lead to problems such as "rising scouring and falling silting" and "flood disasters in small water flows".

[0003] Existing research has recognized this problem. For the judgment of the asynchronous type of flood peak and sediment peak in the process of a single flood event, the SSC-Q (sediment concentration - discharge) relationship curve proposed by Williams is often used. Based on the time variation of this relationship curve, the asynchronous situation of the flood peak and sediment peak is classified. The most common are the counterclockwise and clockwise curves. Sun proposed more complex asynchronous types such as the figure-eight curve and the single line plus loop. For the judgment of the asynchronous duration, in previous studies, the time difference between the appearance of the flood peak and sediment peak was directly used as the asynchronous duration.

[0004] Although the existing methods are relatively intuitive, the discrimination of different lag type curves is still based on manual judgment. The SSC-Q relationship curve in the process of natural single flood events generally will not be a strictly single-line type or single-loop type. The boundary between different curve types is relatively blurred, and there is a certain subjective factor in the judgment. Moreover, the asynchronous duration only considers the influence of the peak value and ignores the entire water and sediment process, and to a certain extent, it cannot correctly reflect the lag phenomenon of water and sediment transport in the process of a single flood event. Therefore, the above existing methods have the disadvantages of poor adaptability to the relationship curve of complex flood processes and lack of numerical definition criteria for asynchronous type judgment, and there are obvious limitations in the actual application process and the research on the mechanism of asynchronous propagation of flood peak and sediment peak. Summary of the Invention

[0005] The present invention is made to solve the above problems, and aims to provide a method and device for determining the asynchronous duration and type of flood peak and sediment peak in the process of a single flood event, which can quickly and conveniently judge the asynchronous duration and asynchronous type of flood peak and sediment peak in the process of a single flood event, and provide a basis for the research on sediment peak sediment discharge scheduling based on the asynchronous characteristics of flood peak and sediment peak.

[0006] To achieve the above object, the present invention adopts the following solutions:

[0007] <Method>

[0008] The present invention provides a method for determining the asynchronous duration and type of flood peak and sediment peak in the process of a flood event, which is characterized by including the following steps:

[0009] Step 1: Obtain the annual flow process of the control hydrological station in the study area, and determine all flood events in the year according to the flow process;

[0010] Step 2: Calculate the deviation values of two time series based on the measured data of flow and sediment concentration in the flood event process of the control hydrological station, including the following sub-steps:

[0011] Step 2-1: Based on the flood event process, perform normalization preprocessing on the flow and sediment concentration processes as new sequences s1 and s2. Then, based on the DTW algorithm, calculate the Euclidean distance matrix D between the two time series, and find a warping path w corresponding to sequence s2 to sequence s1 according to the distance matrix;

[0012] Step 2-2: Based on the fitted warping path w and the reference line y = kx, where the value of k is determined by the lengths of the two sequences x and y, draw the deviation image between the two sequences, and gradually calculate the control area S corresponding to each time according to the sequence length i (It can be stipulated that the area of the graph below the reference line is positive, and vice versa). To consider the influence strength of the flood peak flow process and the non-flood peak flow process on the asynchronous type, set different weights for the control areas corresponding to different times. The weight is determined by the relative magnitude q0 of the flow in the flood event process, and the weight satisfies W i = 1 / (1 + e -q0i ); Calculate the total deviation value T i and variance Var of the two sequences according to the weight W i and S q-s ; The total deviation value T q-s characterizes the overall asynchronous duration in time between the two sequences, corresponding to the horizontal time difference; the variance Var characterizes the similarity of the two sequences; i is the i-th time unit;

[0013] Step 3: Determine the asynchronous type based on the total deviation:

[0014] Set the characteristic time t cri according to the measurement accuracy;

[0015] If the absolute value of the total deviation value is less than t cri , it is determined that the flood peak and sediment peak are basically synchronous in the flood event process; if the absolute value of the total deviation value is greater than t criIf it is positive, it is determined that during the flood process of a flood event, the sediment peak leads the flood peak; the absolute value of the total deviation value is greater than t cri If it is negative, it is determined that during the flood process of a flood event, the sediment peak lags behind the flood peak.

[0016] Preferably, the method for determining the asynchronous duration and type of the flood peak and sediment peak during the flood process of a flood event provided by the present invention may further have the following characteristics: in step 2, the weight is determined by the sigmoid function.

[0017] Preferably, the method for determining the asynchronous duration and type of the flood peak and sediment peak during the flood process of a flood event provided by the present invention may further have the following characteristics: in step 3, half of the observation time accuracy of the hydrological data is set as the characteristic time t cri For example, if the observation time accuracy of the hydrological data is 1 day, then the characteristic time t cri is set to 0.5 days.

[0018] Preferably, the method for determining the asynchronous duration and type of the flood peak and sediment peak during the flood process of a flood event provided by the present invention may further have the following characteristics: in step 3, first, based on the calculation situation of the flood event, the critical absolute value of the variance is determined; when the absolute value of the variance Var exceeds the critical value of the variance, it is determined that the variance value is large, the similarity of the two sequences is low, and there is no obvious relationship between the flood peak and the sediment peak during the flood process of the flood event, and the asynchronous type judgment is no longer performed; when the absolute value of the variance Var is less than or equal to the critical absolute value of the variance, the asynchronous type is further judged.

[0019] Preferably, the method for determining the asynchronous duration and type of the flood peak and sediment peak during the flood process of a flood event provided by the present invention may further have the following characteristics: in step 3, the variances calculated for each flood event are arranged in ascending order of absolute value. Let the absolute value of the last variance among the variances arranged in the first 75% - 90% be A, and the absolute value of the variance arranged after it be B. The critical absolute value of the variance is taken as an integer value within the range greater than or equal to A and less than B.

[0020] <Device>

[0021] Furthermore, the present invention also provides a device for determining the asynchronous duration and type of the flood peak and sediment peak during the flood process of a flood event that automatically implements the above <method>, which is characterized in that it includes:

[0022] A data acquisition unit that acquires the annual flow process of the control hydrological station in the study area and determines the annual flood event process according to the flow process;

[0023] A deviation value calculation unit that calculates the deviation value of two time series based on the measured data of the flow rate and sediment concentration during the flood event process of the control hydrological station to determine the asynchronous duration, including the following sub - steps:

[0024] Step 2-1: Based on the flood process of each event, normalize the flow rate and sediment concentration processes to obtain new sequences s1 and s2. Then, based on the DTW algorithm, calculate the Euclidean distance matrix D between the two time series. According to the distance matrix, find the warping path w that maps sequence s2 to sequence s1.

[0025] Step 2-2: Based on the fitted warping path w and the baseline y = kx, where the value of k is determined by the lengths of the two sequences x and y, draw the deviation image between the two sequences. Gradually calculate the control area S corresponding to each time according to the sequence lengths. i To consider the influence strengths of the flood peak flow process and non-flood peak flow process on the asynchronous type, set different weights for the control areas corresponding to different times. The weights are determined by the relative magnitude q0 of the flow rate in the flood process of each event, and the weights satisfy According to the weight W i and S i calculate the total deviation value T of the two sequences. q-s and the variance Var; the total deviation value T q-s characterizes the overall asynchronous duration in time between the two sequences, and the variance Var characterizes the similarity between the two sequences; i is the i-th time unit.

[0026] Asynchronous type judgment unit: Based on the total deviation, judge the asynchronous type: Set the characteristic time t according to the measurement accuracy. cri ; If the absolute value of the total deviation value is less than t cri , it is judged that during the flood process of each event, the flood peak and sediment peak are basically synchronous; if the absolute value of the total deviation value is greater than t cri , and the sign is positive, it is judged that during the flood process of each event, the sediment peak is ahead of the flood peak; if the absolute value of the total deviation value is greater than t cri , and the sign is negative, it is judged that during the flood process of each event, the sediment peak lags behind the flood peak.

[0027] Control unit: Communicatively connected to the data acquisition unit, deviation value calculation unit, and asynchronous type judgment unit, and controls their operations.

[0028] Preferably, the device for determining the asynchronous duration and type of flood peak and sediment peak in the flood process of each event provided by the present invention may further have the following characteristics: Input display unit, which allows the user to input operation instructions and displays the data and files of the corresponding units in the form of text, table, or graph according to the operation instructions.

[0029] Preferably, the device for determining the asynchronous duration and type of flood peak and sediment peak in the flood process of each event provided by the present invention may further have the following characteristics: In the asynchronous type judgment unit, half of the observation time accuracy of the hydrological data is set as the characteristic time t. cri .

[0030] Preferably, the device for determining the asynchronous duration and type of flood peak and sediment peak in the process of a single flood event provided by the present invention may further have the following features: In the asynchronous type determination unit, first, based on the calculation situation of a single flood event, the critical absolute value of variance is determined; when the absolute value of the variance Var exceeds the critical value of variance, it is determined that the variance value is too large, the similarity of the two sequences is low, and there is no obvious relationship between the flood peak and the sediment peak in the process of a single flood event, and the asynchronous type determination is no longer performed; when the absolute value of the variance Var is less than or equal to the critical absolute value of variance, the asynchronous type is further determined.

[0031] Preferably, the device for determining the asynchronous duration and type of flood peak and sediment peak in the process of a single flood event provided by the present invention may further have the following features: In the asynchronous type determination unit, the variances calculated for each single flood event are arranged in ascending order of absolute value. Let the absolute value of the last variance among the variances arranged in the first 75% - 90% be A, and the absolute value of the variance arranged after it be B. The critical absolute value of variance is taken as an integer value within the range greater than or equal to A and less than B.

[0032] Functions and effects of the invention

[0033] The method and device for determining the asynchronous duration and type of flood peak and sediment peak in the process of a single flood event provided by the present invention are directed at the asynchronous phenomenon of flood peak and sediment peak occurring in the process of a single flood event in a natural river channel. It fully considers the asynchronous influence of the entire flow process in the process of a single flood event, and converts the image features of the asynchronous flood peak and sediment peak into numerical features: calculates the Euclidean distance matrix D between two time series, and finds a regular path w corresponding to sequence s2 to sequence s1 according to the distance matrix; based on the fitted regular path w and the reference line y = kx, draws the deviation image between the two sequences, and gradually calculates the control area S corresponding to each time according to the sequence length i , in order to consider the strength of the influence of the flood peak flow process and the non - flood peak flow process on the asynchronous type, different weights are set for the control areas corresponding to different times According to the weight W i and S i calculate the total deviation value T of the two sequences q-s and the variance Var; through the total deviation value T q-sCharacterize the overall asynchronous duration between two sequences over time; then determine the asynchronous type based on the total deviation; thus quickly, conveniently, and accurately determine the asynchronous type of the flood peak and sediment peak during a flood event and calculate the asynchronous duration, with the advantages of high precision, strong versatility, and easy judgment, providing a scientific basis for the research on sediment peak sediment discharge scheduling based on the asynchronous characteristics of the flood peak and sediment peak, making the research on related fields such as sediment peak transport and refined reservoir sediment discharge scheduling more targeted. Based on the asynchronous characteristics of the flood peak and sediment peak, research on sediment peak sediment discharge scheduling of reservoirs during the flood season can be carried out to reduce reservoir siltation, extend the service life of the reservoir, and facilitate the beneficial exploration of the new "clear water storage and muddy water discharge" mode of the reservoir. At the same time, to explain the asynchronous propagation law of the flood peak and sediment peak, explore the influence mechanism of changes in hydrodynamic and sediment characteristics on the asynchronous propagation of the flood peak and sediment peak, and provide data and theoretical basis for the refined sediment discharge scheduling mode of the sediment peak process of reservoirs (groups). Description of the Drawings

[0034] Figure 1 It is a flowchart of the method for determining the asynchronous duration and type of the flood peak and sediment peak in the flood event process involved in the embodiment of the present invention;

[0035] Figure 2 It is a graph of the normalized flow rate and sediment concentration processes in a certain flood event process involved in the embodiment of the present invention;

[0036] Figure 3 It is a schematic diagram of the alignment path of two sequences based on the DTW algorithm in a certain flood event process involved in the embodiment of the present invention;

[0037] Figure 4 It is a schematic diagram of setting asynchronous weights at different flow levels based on the Sigmoid function in a certain flood event process involved in the embodiment of the present invention;

[0038] Figure 5 It is a graph of the judgment results of the asynchronous type and asynchronous duration of the flood peak and sediment peak in a certain flood event process involved in the embodiment of the present invention;

[0039] Figure 6 It is a graph of the judgment results of the asynchronous type of the flood peak and sediment peak by the SSC-Q method in two typical flood event processes involved in the comparative example, where (a) is the first flood event process and (b) is the second flood event process;

[0040] Figure 7 It is a graph of the judgment results of the asynchronous type of the flood peak and sediment peak by the method of the present invention in two flood event processes involved in the comparative example, where (a) is the first flood event process and (b) is the second flood event process. Detailed Embodiment

[0041] The following will describe in detail the method and device for determining the asynchronous duration and type of the flood peak and sediment peak in the flood event process involved in the present invention with reference to the accompanying drawings.

[0042] <Example>

[0043] As Figure 1 shown, the method for determining the asynchronous duration and type of flood peak and sediment peak in the flood process provided in this embodiment includes the following steps:

[0044] Step 1: Obtain the annual flow process of the control hydrological station in the study area, and determine the annual flood processes according to the flow process.

[0045] Step 2: Calculate the deviation values of two time series based on the measured data of flow and sediment concentration in the flood processes of the control hydrological station, including the following sub-steps:

[0046] Step 2-1: Based on the flood process, perform normalization preprocessing on the flood flow and sediment concentration processes to obtain new time series s1 and s2, which are used as the basic data for judging the asynchrony of flood peak and sediment peak. Then, based on the DTW algorithm, calculate the Euclidean distance matrix D between the two time series, and find a warping path w from one sequence s2 corresponding to the sequence s1 according to the distance matrix to reflect the similarity between the two sequences. The warping path is a path from the lower left corner (starting point of the time series) to the upper right corner (ending point of the time series) of the distance matrix, satisfying that the sum of the corresponding Euclidean distances between points on the path is the smallest along the way. The corresponding relationship of each point on the warping path indicates the new corresponding relationship obtained by "distorting" the original time series under the condition of the smallest sum of Euclidean distances.

[0047] Step 2-2: Based on the fitted warping path w and the baseline y = kx, where the value of k is determined by the lengths of the two sequences x and y, draw the deviation image between the two sequences, and gradually calculate the control area S corresponding to each time according to the sequence length i , to consider the influence strength of flood peak flow process and non-flood peak flow process on the asynchronous type, set different weights for the control areas corresponding to different times. The weight is determined by the relative magnitude q0 of the flow in the flood process, and the weight satisfies W i = 1 / (1 + e -q0i ); Calculate the total deviation value T i and variance Var of the two sequences according to the weight W i and S q-s ; The total deviation value T q-s characterizes the overall asynchronous duration in time between the two sequences, and the variance Var characterizes the similarity between the two sequences; i is the i-th time unit.

[0048] The deviation between the regular path and the reference selection can represent the deviation between two time series. Calculate the deviation area corresponding to each time node in sequence according to the sequence length. It is stipulated that the area below the reference line is positive and the area above the reference line is negative. Consider the strength of the asynchronous influence of the peak flow level and non-peak flow level during the flood flow process of each flood event, and different asynchronous weights corresponding to the flow values at different time nodes. Calculate the total deviation value of the two time series and the variance of the deviation area according to the asynchronous weights and deviation areas at different time nodes according to the principle of weighted average. Calculate the asynchronous weight values corresponding to different flow levels through the Sigmoid function.

[0049] Step 3. Judge the asynchronous type based on the total deviation:

[0050] Set the characteristic time t according to the measurement accuracy cri ; Set half of the observation interval of the measured hydrological data as the characteristic time according to the observation interval of the measured hydrological data.

[0051] Judge the similarity of the two time series based on the variance value. If the variance value is too large, it indicates that the similarity of the two time series is low, and the correlation between the peak flow and sediment peak during the flood event is poor. It can be considered that there is no obvious corresponding relationship between the two time series.

[0052] During the flood event, if the variance value of the deviation area is small, it means that the similarity between the peak flow and sediment peak during this flood event is high and the corresponding relationship is good, and the asynchronous type can be judged.

[0053] Specifically, calculate the variances of each flood event, arrange them in ascending order of absolute value. Let the absolute value of the last variance in the variances arranged in the first 75% - 90% be A, and the absolute value of the variance after that be B. The critical absolute value of the variance is taken as an integer value within the range greater than or equal to A and less than B. When the absolute value of the variance Var exceeds the critical value of the variance, it indicates that there is no obvious relationship between the peak flow and sediment peak during the flood event, and the asynchronous type is no longer judged; when the absolute value of the variance Var is less than or equal to the critical absolute value of the variance, then further judge the asynchronous type.

[0054] If the absolute value of the total deviation value is less than t cri , it is judged that during the flood event, the peak flow and sediment peak are basically synchronous; if the absolute value of the total deviation value is greater than t cri , and the sign is positive, it is judged that during the flood event, the sediment peak is ahead of the peak flow; if the absolute value of the total deviation value is greater than t cri , and the sign is negative, it is judged that during the flood event, the sediment peak lags behind the peak flow.

[0055] In this embodiment, taking the Baihetan cascade reservoir in the upper reaches of the Yangtze River as an example, the selected control station is the Baihetan Station, the outfall control station of the Baihetan Reservoir. The flood process of the Baihetan Station in 2018 is selected, and the peak flood and peak sediment asynchronous duration and asynchronous type during this flood process are judged according to the following discrimination steps in combination with the measured daily average flow and sediment concentration data.

[0056] I. Preprocess the measured flow and sediment concentration data during the flood process.

[0057] Normalize the flow process and sediment concentration process during the flood process of the Baihetan Station in 2018, and draw the flow and sediment concentration sequence curves. See Figure 2 . Calculate the Euclidean distance matrix between each point of the normalized flow and sediment concentration sequences through the DTW algorithm. Follow the principle that the sum of the distances along the path is the smallest, solve a regular path from the data start point to the data end point, draw the distance matrix and the regular path, and then draw the reference line according to the lengths of the two time series. In the embodiment, the lengths of the sediment concentration and flow sequences are the same, and the reference line is y = x. At this time, calculate the deviation area corresponding to different times in sequence according to the sequence length. See Figure 3 . Then, set the asynchronous weights at different flow levels and normalize the flow process. Considering the characteristics of the Sigmoid function, the weights need to satisfy that the weight corresponding to the peak flow value is large, the weight corresponding to the non-peak flow value is small, and the intermediate flow values change continuously. Therefore, the normalization interval is set to [-6, 6], and the weight setting is shown in Figure 4 . Calculate the total deviation value T q-s and the variance Var by weighted average according to the weights corresponding to different flow levels and the deviation area. The results are shown in Figure 5 .

[0058] II. Judge the asynchronous duration and asynchronous type.

[0059] Since the measured daily average data of water and sediment are used and the observation interval is 1 day, the characteristic time is set to 0.5 day and the critical value is 10. Judge the asynchronous type and asynchronous duration based on the calculated total deviation value and variance of the two time series. As shown in Figure 5 , the total deviation value between the flow and sediment concentration sequences during the flood process of the Baihetan Station in 2018 is 2.7522 day, and the variance of the deviation area is 0.7026. The variance value is small (generally less than 20), indicating that the similarity of the two time series is high. The absolute value of the total deviation value exceeds the characteristic time of 0.5 day, and the sign is positive, indicating that during this flood process, the peak sediment is ahead of the peak flood.

[0060] Further, this embodiment also provides a device for determining the asynchronous duration and type of the flood peak and sediment peak in the process of a single flood event that can automatically implement the above method. The device includes a data acquisition unit, a deviation value calculation unit, an asynchronous type judgment unit, an input and display unit, and a control unit.

[0061] The data acquisition unit can acquire the annual flow process of the control hydrological station in the study area and determine the annual single flood events based on the flow process.

[0062] The deviation value calculation unit can calculate the deviation value of two time series based on the measured data of flow and sediment concentration in the process of a single flood event of the control hydrological station to determine the asynchronous duration.

[0063] The asynchronous type judgment unit judges the asynchronous type based on the total deviation: set the characteristic time t according to the measurement accuracy cri ; if the absolute value of the total deviation value is less than t cri , it is judged that in the process of a single flood event, the flood peak and sediment peak are basically synchronous; if the absolute value of the total deviation value is greater than t cri , and the sign is positive, it is judged that in the process of a single flood event, the sediment peak is ahead of the flood peak; if the absolute value of the total deviation value is greater than t cri , and the sign is negative, it is judged that in the process of a single flood event, the sediment peak lags behind the flood peak.

[0064] The control unit is communicatively connected to the data acquisition unit, the deviation value calculation unit, the asynchronous type judgment unit, and the input and display unit to control their operations.

[0065] <Comparative Example>

[0066] This comparative example takes two single flood event processes of the Panzhihua Hydrological Station in the upper reaches of the Yangtze River as examples, and compares the results of the SSC-Q method and the method of the present invention in judging the asynchronous type of the flood peak and sediment peak and calculating the asynchronous duration.

[0067] For two single flood event processes in the study area, Figure 6 The SSC-Q method gives the judgment of the asynchronous type of the flood peak and sediment peak in the above two single flood event processes. The judgment basis of the method proposed by Williams for judging the asynchronous type based on the SSC-Q curve is the clockwise and counterclockwise characteristics of the curve. However, this method has no clear division for complex flood processes and the boundaries between different curve types, and still requires manual judgment. See Figure 6 , for the SSC-Q curve corresponding to the first single flood event process, there is no obvious classification type, and there is almost no strictly linear curve in the natural single flood event process. For the second single flood event process, the SSC-Q curve shows counterclockwise, but the boundary with the linear curve (the flood peak and sediment peak are basically synchronous) is difficult to define.

[0068] Figure 7The calculation result of the asynchronous type judged by the method of the present invention is given. The asynchronous type of this method provides a numerical judgment basis, and the judgment result is scientific, reasonable, intuitive and accurate.

[0069] The above embodiments are only illustrative examples of the technical solution of the present invention. The method and device for determining the asynchronous duration and type of the peak flood and peak sediment during the flood process involved in the present invention are not limited to the content described in the above embodiments, but are subject to the scope defined by the claims. Any modification, supplement or equivalent replacement made by those skilled in the art to which the present invention pertains on the basis of this embodiment is within the scope protected by the claims of the present invention.

Claims

1. Method for determining the asynchronous duration and type of flood peak and sediment peak in a single flood event process, characterized in that, Including the following steps: Step 1: Obtain the annual flow process of the control hydrological station in the study area, and determine the flood processes within the year based on the flow process; Step 2: Calculate the deviation values of two time series using the measured data of flow and sediment concentration in the flood processes of the control hydrological station, including the following sub-steps: Step 2-1: Based on the flood processes, perform normalization preprocessing on the flow and sediment concentration processes to obtain new time series s1 and s2. Then, based on the DTW algorithm, calculate the Euclidean distance matrix D between the two time series, and find a warping path w that maps sequence s2 to sequence s1 according to the distance matrix; Step 2-2: Based on the fitted regular path w and the baseline y = kx, where the value of k is determined by the lengths of the two sequences x and y, draw the deviation image between the two sequences, and gradually calculate the control area S corresponding to each time according to the sequence length. i , to consider the influence strength of the flood peak flow process and the non-flood peak flow process on the asynchronous type, different weights are set for the control areas corresponding to different times. The weight is determined by the relative magnitude q0 of the flow rate in the flood event process, and the weight satisfies According to the weight W i and S i to calculate the total deviation value T of the two sequences. q-s and the variance Var; the total deviation value T q-s characterizes the overall asynchronous duration in time between the two sequences, and the variance Var characterizes the similarity of the two sequences; i is the i-th time unit. Step 3: Determine the asynchronous type based on the total deviation; Set the characteristic time t according to the measurement accuracy cri ; If the absolute value of the total deviation value is less than t cri , it is judged that during the flood process of the flood event, the flood peak and the sediment peak are basically synchronous; if the absolute value of the total deviation value is greater than t cri , and the sign is positive, it is judged that during the flood process of the flood event, the sediment peak is ahead of the flood peak; if the absolute value of the total deviation value is greater than t cri , and the sign is negative, it is judged that during the flood process of the flood event, the sediment peak lags behind the flood peak.

2. The method for determining the asynchronous duration and type of flood peak and sediment peak in a single flood event process according to claim 1, characterized in that: Wherein, In Step 2, the weight is determined by the sigmoid function.

3. The method for determining the asynchronous duration and type of flood peak and sediment peak in a single flood event process according to claim 1, characterized in that: Wherein, In step 3, half of the observation time accuracy of the hydrological data is set as the characteristic time t cri .

4. The method for determining the asynchronous duration and type of flood peak and sediment peak in a single flood event process according to claim 1, characterized in that: Wherein, In Step 3, first determine the critical absolute value of variance based on the flood calculation situation. When the absolute value of variance Var exceeds the critical value of variance, it is judged that the variance value is large, the similarity between the two sequences is low, and there is no obvious relationship between the flood peak and sediment peak in the flood process, and no further asynchronous type judgment is performed. When the absolute value of variance Var is less than or equal to the critical absolute value of variance, the asynchronous type is further judged.

5. The method for determining the asynchronous duration and type of flood peak and sediment peak in a single flood event process according to claim 4, characterized in that: Wherein, In Step 3, calculate the variances of each flood process and arrange them in ascending order of absolute value. Let the absolute value of the last variance among the variances ranked in the first 75% - 90% be A, and the absolute value of the variance ranked after it be B. The critical absolute value of variance is taken as an integer value within the range greater than or equal to A and less than B.

6. Device for determining the asynchronous duration and type of flood peak and sediment peak in a single flood event process, characterized in that, Including: Data acquisition unit, which obtains the annual flow process of the control hydrological station in the study area and determines the floods within the year based on the flow process; Deviation value calculation unit, which calculates the deviation values of two time series using the measured data of flow and sediment concentration in the flood processes of the control hydrological station to determine the asynchronous duration, including the following steps: Step 2-1: Based on the selected flood processes, perform normalization preprocessing on the flow and sediment concentration processes to obtain new sequences s1 and s2. Then, based on the DTW algorithm, calculate the Euclidean distance matrix D between the two time series, and find a warping path w that maps sequence s2 to sequence s1 according to the distance matrix; Step 2-2: Based on the fitted regular path w and the reference line y = kx, where the value of k is determined by the lengths of the two sequences x and y, draw the deviation image between the two sequences, and gradually calculate the control area S corresponding to each time according to the sequence length. i , To consider the influence strengths of the flood peak flow process and the non-flood peak flow process on the asynchronous type, different weights are set for the control areas corresponding to different times. The weights are determined by the relative magnitude q0 of the flow rate in the flood event process, and the weights satisfy According to the weight W i and S i calculate the total deviation value T of the two sequences. q-s and the variance Var; The total deviation value T q-s characterizes the overall asynchronous duration in time between the two sequences, and the variance Var characterizes the similarity of the two sequences; i is the i-th time unit. The asynchronous type judgment unit determines the asynchronous type based on the total deviation: set the characteristic time t according to the measurement accuracy cri ; if the absolute value of the total deviation value is less than t cri , it is judged that during the flood process of a flood event, the peak flood and the peak sediment are basically synchronous; if the absolute value of the total deviation value is greater than t cri , and the sign is positive, it is judged that during the flood process of a flood event, the peak sediment is ahead of the peak flood; if the absolute value of the total deviation value is greater than t cri , and the sign is negative, it is judged that during the flood process of a flood event, the peak sediment lags behind the peak flood; Control unit, which is communicatively connected to the data acquisition unit, the deviation value calculation unit, and the asynchronous type judgment unit, and controls their operations.

7. The device for determining the asynchronous duration and type of flood peak and sediment peak in a single flood event process according to claim 6, characterized in that, Also including: Input display unit, which allows the user to input operation instructions and displays the data and files of the corresponding unit in text, table, or graphical form according to the operation instructions.

8. The device for determining the asynchronous duration and type of flood peak and sediment peak in a single flood event process according to claim 6, characterized in that: Wherein, In the asynchronous type determination unit, half of the accuracy of the hydrological data observation time is set as the characteristic time t cri .

9. The device for determining the asynchronous duration and type of flood peak and sediment peak in a single flood event process according to claim 6, characterized in that: in, In the asynchronous type judgment unit, first determine the critical absolute value of variance based on the flood calculation situation. When the absolute value of variance Var exceeds the critical value of variance, it is judged that the variance value is large, the similarity between the two sequences is low, and there is no obvious relationship between the flood peak and sediment peak in the flood process, and no further asynchronous type judgment is performed. When the absolute value of variance Var is less than or equal to the critical absolute value of variance, the asynchronous type is further judged.

10. The device for determining asynchronous duration and type of flood peaks and sand peaks during a flood process according to claim 6, characterized in that: in, In the asynchronous type judgment unit, the variances of flood calculations for each flood event are arranged in ascending order of absolute values. Let the absolute value of the last variance among the variances ranked from the 75% to 90% in the arranged order be A, and the absolute value of the variance ranked after that be B. The critical absolute value of the variance is taken as an integer value within the range greater than or equal to A and less than B.

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