A method, device and medium for determining the influence degree of drought on base flow change

Abstract

The application discloses a method and device for determining the influence degree of drought on base flow change and a medium. The method comprises the following steps: obtaining first historical hydrological data of a target basin in a non-drought period; determining a physical formula for base flow, wherein the effective water storage capacity parameter and the evaporation efficiency parameter in the physical formula are calibrated by using the first historical hydrological data; obtaining second historical hydrological data of the target basin in a drought period, wherein the second historical hydrological data comprises a second historical base flow, a second historical precipitation and a second historical potential evaporation; determining a predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation by using the physical formula, and then determining the influence degree of drought on the base flow change in the target basin. The application can accurately quantify the influence of drought on the base flow change, and provide effective data support for the reasonable planning and design of a water resource system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrological research, in particular to a method and device for determining the influence degree of drought on base flow change and a medium. BACKGROUND

[0002] The consistency assumption of water cycle in nature is the basis for planning and design of water resources system. The consistency assumption of water cycle refers to that the basin structure and statistical characteristics of hydrological data of a basin remain unchanged in the future.

[0003] However, with the long-term drought of a basin, drought may have an impact on the hydrological process of the basin, for example, drought may change the base flow of the basin, resulting in changes in the consistency assumption of water cycle, and the planning and design of the water resources system are not reasonable enough.

[0004] Therefore, how to accurately quantify the influence of drought on base flow change is of great significance for the reasonable planning and design of water resources system. SUMMARY

[0005] The embodiments of the present application provide a method and device for determining the influence degree of drought on base flow change and a medium, which aims to accurately quantify the influence of drought on base flow change and provide effective data support for the reasonable planning and design of water resources system.

[0006] In one aspect, the present application provides a method for determining the influence degree of drought on base flow change, which comprises:

[0007] obtaining first historical hydrological data of a target basin in a non-drought period, the first historical hydrological data including first historical base flow, first historical precipitation and first historical potential evaporation;

[0008] determining a physical formula for base flow, the physical formula including an effective storage capacity parameter and an evaporation efficiency parameter, the effective storage capacity parameter and the evaporation efficiency parameter being calibrated using the first historical hydrological data;

[0009] obtaining second historical hydrological data of the target basin in a drought period, the second historical hydrological data including second historical base flow, second historical precipitation and second historical potential evaporation;

[0010] using the physical formula, determining the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation;

[0011] based on the predicted base flow, the second historical base flow and the first historical base flow, determining the influence degree of drought on base flow change in the target basin.

[0012] In some embodiments, the influence degree of the drought on the base flow change in the target basin comprises: an actual change value of the base flow in the drought period compared with a non-drought period, an influence degree of base flow yield inconsistency caused by long-term drought on the base flow change in the target basin, and an influence degree of changes in meteorological elements during the long-term drought on the base flow change in the target basin.

[0013] In some embodiments, the actual change value of the base flow in the drought period compared with the non-drought period is determined based on a first difference value between the second historical base flow and the first historical base flow.

[0014] The influence degree of base flow yield inconsistency caused by long-term drought on the base flow change in the target basin is determined based on a second difference value between the predicted base flow and the second historical base flow.

[0015] The influence degree of changes in meteorological elements during the long-term drought on the base flow change in the target basin is determined based on a difference value between the first difference value and the second difference value.

[0016] In some embodiments, the influence degree of base flow yield inconsistency caused by long-term drought on the base flow change in the target basin is determined according to a ratio of the second difference value to the first difference value.

[0017] In some embodiments, before the obtaining the first historical hydrological data of the target basin in the non-drought period, the method further comprises:

[0018] In the preset basin, the target basin with a drought period longer than a preset length is determined.

[0019] In some embodiments, the determining the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation by using the physical formula comprises:

[0020] The second historical precipitation is taken as the precipitation in the physical formula, and the second historical potential evaporation is taken as the potential evaporation in the physical formula, to determine the value of the base flow in the physical formula.

[0021] The value of the base flow in the physical formula is taken as the value of the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation.

[0022] In some embodiments, the physical formula comprises a relationship among a drought index, a basin retention index, a base flow index, and an evaporation efficiency parameter, wherein the drought index comprises a ratio between the potential evaporation and the precipitation, the basin retention index comprises a ratio between an effective water storage capacity parameter and the precipitation, and the base flow index comprises a ratio between the base flow and the precipitation.

[0023] In some embodiments, the physical formula comprises the following formula:

[0024]

[0025] wherein Q b is the base flow, P is the precipitation, S p is the effective storage capacity parameter, E p is the potential evaporation, and a is the evaporation efficiency parameter.

[0026] In another aspect, the embodiments of the present application provide a device for determining the influence degree of drought on base flow change, comprising:

[0027] a first obtaining module, configured to obtain first historical hydrological data of a target basin in a non-drought period, the first historical hydrological data comprising a first historical base flow, a first historical precipitation, and a first historical potential evaporation;

[0028] a first determining module, configured to determine a physical formula for base flow, the physical formula comprising an effective storage capacity parameter and an evaporation efficiency parameter, the effective storage capacity parameter and the evaporation efficiency parameter being calibrated by using the first historical hydrological data;

[0029] a second obtaining module, configured to obtain second historical hydrological data of the target basin in a drought period, the second historical hydrological data comprising a second historical base flow, a second historical precipitation, and a second historical potential evaporation;

[0030] a second determining module, configured to determine a predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation by using the physical formula;

[0031] a third determining module, configured to determine the influence degree of drought on base flow change in the target basin based on the predicted base flow, the second historical base flow, and the first historical base flow.

[0032] In another aspect, the embodiments of the present application further provide a computer device, comprising:

[0033] one or more processors;

[0034] a memory; and

[0035] one or more application programs, wherein the one or more application programs are stored in the memory and configured to be executed by the processor to implement the steps in any of the methods for determining the influence degree of drought on base flow change.

[0036] In another aspect, the present application also provides a computer readable storage medium, which stores a computer program, and the computer program is loaded by a processor to execute the steps of the method for determining the influence degree of drought on base flow change.

[0037] In another aspect, the present application also provides a computer program product, which comprises a computer program or instructions, and the computer program or instructions are executed by a processor to implement the method for determining the influence degree of drought on base flow change according to any one of the above.

[0038] The embodiment of the present application provides a method, device and medium for determining the influence degree of drought on base flow change. According to first historical hydrological data of a target basin in a non-drought period, effective water storage capacity parameters and evaporation efficiency parameters in a physical formula for base flow are calibrated. Then, the physical formula is used to determine a predicted base flow rate corresponding to second historical precipitation and second historical potential evaporation of the target basin in a drought period. Based on the predicted base flow rate, the second historical base flow rate and the first historical base flow rate, the influence degree of drought on base flow change in the target basin is determined. In this embodiment, the physical formula for base flow is determined, the physical formula includes effective water storage capacity parameters and evaporation efficiency parameters, the physical formula for base flow is used to accurately quantify the influence of drought on base flow change, and effective data support is provided for reasonable planning and design of a water resource system. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0040] Figure 1 is an embodiment flow schematic diagram of the method for determining the influence degree of drought on base flow change provided in the embodiments of the present application;

[0041] Figure 2 is a schematic diagram of the attribution decomposition of base flow change in a target basin provided in the embodiments of the present application;

[0042] Figure 3 is a schematic diagram of the influence degree of base flow yield inconsistency caused by long-term drought on base flow change in a target basin and the influence degree of changes of meteorological elements during long-term drought on base flow change in a target basin provided in the embodiments of the present application;

[0043] Figure 4 is a frequency cumulative distribution schematic diagram of simulation effects of different simulation methods of predicted base flow rate on multiple target basins;

[0044] Figure 5 is an embodiment of a terminal structure schematic diagram of a computer device provided in an embodiment of the present application.

[0045] wherein, Figure 2 , Figure 3 and Figure 4 color pictures are used to distinguish different objects in the picture using different colors. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. In the description of the present application, the terms “first” and “second” are only used for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with “first” and “second” can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of “a plurality of” is two or more, unless otherwise specifically limited. In the present application, the term “in some embodiments” is used to indicate “as an example, illustration or description”. Any embodiment described as “in some embodiments” in the present application is not necessarily interpreted as more preferred or more advantageous than other embodiments.

[0047] It should be noted that the system in the embodiments of the present application is executed in a computer device, and the processing objects of each computer device exist in the form of data or information, such as time, which is essentially time information. It can be understood that in subsequent embodiments, if the size, quantity, position, etc. are mentioned, they all exist in the corresponding data for the computer device to process, and specific details are not described here.

[0048] In the related art, the hydrological data statistical characteristics and the basin structure of a basin change with climate change. The consistency of the basin structure means that the predicted climate change will have a similar impact on the basin runoff mechanism as the observed impact in the past. The impact of human activities on the basin structure is usually fully considered, but the impact of natural changes and variability is not fully considered. The multi-year drought in some areas has been proven to change the response of the basin hydrology to changes in climate conditions, such as changes in the relationship between precipitation and runoff, and the failure of the precipitation-runoff model when using parameters from non-drought periods to simulate precipitation during the drought period.

[0049] Baseflow plays a key role in maintaining river flow in a catchment during drought periods. As a component of total runoff, baseflow and quick runoff have different responses to climate change and land cover change. Clarifying the variation characteristics of total runoff and its components during drought periods is of great significance for a comprehensive understanding of the adaptive strategies of hydrological systems to drought. During the long drought period, the response of the catchment hydrology to changes in climatic conditions is changed due to changes in the structure of the catchment (including vegetation, soil and groundwater, etc.), and further changes the generation mechanism of the catchment runoff (including total runoff and its components) during the drought period. For example, tree death caused by drought may lead to a decreasing trend in total runoff of the catchment. The low runoff coefficient (ratio of runoff to precipitation) of most catchments is due to changes in the water storage capacity of the catchment during long-term drought. The depletion of groundwater during long-term drought will also affect the non-uniformity of runoff and its components.

[0050] The actual way to evaluate the impact of drought on the non-uniformity of total runoff of the catchment can be achieved by using a regression model, a hydrological model, a precipitation-runoff model and a Budyko framework. Compared with the hydrological model, the model structure of the Budyko framework, the precipitation-runoff model and the regression model is more concise, and can more intuitively reveal the non-uniformity. However, when the regression model is used to conduct attribution analysis on the changes in the hydrology of the catchment, the impact of drought on the changes in baseflow is more uncertain than the impact of drought on the total runoff and quick runoff of the catchment, that is, the accuracy of the quantified results is lower when quantifying the degree of impact of drought on the changes in baseflow.

[0051] To this end, the embodiments of the present application provide a method, device and medium for determining the degree of impact of drought on the changes in baseflow. By determining a physical formula for baseflow, the physical formula including an effective water storage capacity parameter and an evaporation efficiency parameter, the degree of impact of drought on the changes in baseflow is accurately quantified, and effective data support is provided for the rational planning and design of the water resource system.

[0052] Reference Figure 1 In an embodiment, the method for determining the degree of impact of drought on the changes in baseflow comprises:

[0053] 101, obtaining first historical hydrological data of a target catchment during a non-drought period, the first historical hydrological data including first historical baseflow, first historical precipitation and first historical potential evaporation.

[0054] In the embodiments of the present application, the plurality of target flow regions can be a plurality of flow regions of a certain regional large data sample (CAMELS) record. The first historical hydrological data of each target flow region in the non-drought period is the actual hydrological data of the target flow region in the non-drought period, which can be extracted from the historical data recorded by the Global Runoff Data Center, for example. The first historical base flow, the first historical precipitation and the first historical potential evaporation of the target flow region are the actual base flow, the actual precipitation and the actual potential evaporation of the target flow region in the non-drought period, respectively. The first historical base flow of the target flow region is segmented from the total flow of the target flow region by using a preset digital filtering algorithm (for example, Lyne-Hollick (LH) method).

[0055] In some embodiments of the present application, the screening process of the target flow region is described. Specifically, before obtaining the first historical hydrological data of the target flow region in the non-drought period, it can further include: determining the target flow region with a drought period longer than a preset length in the preset flow region. The preset flow region can be a flow region recorded by a certain regional large data sample (CAMELS). When the drought period of the preset flow region is longer than the preset length, it indicates that the preset flow region is a long-term drought (for example, multi-year drought), that is, a drought climate. In this way, for each target flow region, the influence degree of the base flow yield inconsistency caused by the long-term drought on the change of the base flow of the target flow region will be more accurate.

[0056] 102. Determine a physical formula for the base flow, the physical formula including an effective storage capacity parameter and an evaporation efficiency parameter, the effective storage capacity parameter and the evaporation efficiency parameter being calibrated using the first historical hydrological data.

[0057] In the embodiments of the present application, the physical formula for the base flow includes an effective storage capacity parameter and an evaporation efficiency parameter, and the effective storage capacity parameter and the evaporation efficiency parameter are calibrated using the first historical base flow, the first historical precipitation and the first historical potential evaporation of the target flow region. Specifically, the physical formula records the physical relationship between the base flow, the precipitation, the potential evaporation, the evaporation efficiency parameter and the effective storage capacity parameter. Therefore, by substituting the first historical base flow (as the base flow), the first historical precipitation (as the precipitation) and the first historical potential evaporation (as the potential evaporation) of the target flow region into the physical formula, the values of the effective storage capacity parameter and the evaporation efficiency parameter in the physical formula can be determined by using a genetic algorithm, thereby calibrating the effective storage capacity parameter and the evaporation efficiency parameter in the physical formula and obtaining the physical formula for the base flow. The specific details of the physical formula are described below.

[0058] 103. obtaining second historical hydrological data of the target basin in the dry period, the second historical hydrological data comprising second historical base flow, second historical precipitation and second historical potential evaporation.

[0059] In embodiments of the present application, the specific connotation of the second historical hydrological data of the target basin in the dry period can refer to the first historical hydrological data of the target basin in the non-dry period, which is not repeated here.

[0060] 104. determining the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation by using a physical formula.

[0061] In embodiments of the present application, the predicted base flow refers to the predicted value of the base flow, that is, the base flow is predicted based on the second historical precipitation and the second historical potential evaporation of the target basin in the dry period.

[0062] In some embodiments of the present application, the prediction of the base flow is realized based on the above-mentioned physical formula. Specifically, determining the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation by using a physical formula can include: taking the second historical precipitation as the precipitation in the physical formula, and taking the second historical potential evaporation as the potential evaporation in the physical formula, combining the effective water storage capacity parameter and the evaporation efficiency parameter in the physical formula to calculate the base flow, to determine the value of the base flow in the physical formula; taking the value of the base flow in the physical formula as the value of the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation, thereby realizing the prediction of the base flow of the target basin in the dry period.

[0063] In some embodiments of the present application, the physical formula includes the relationship among the drought index, the basin retention index, the base flow index and the evaporation efficiency parameter, wherein the drought index includes the ratio between the potential evaporation and the precipitation, the basin retention index includes the ratio between the effective water storage capacity parameter and the precipitation, and the base flow index includes the ratio between the base flow and the precipitation.

[0064] In some embodiments of the present application, the physical formula may, for example, include:

[0065]

[0066] wherein Q b is the base flow, P is the precipitation, E p is the potential evaporation, a is the evaporation efficiency parameter, and S p is the effective water storage capacity parameter. It can be seen that the physical formula for the base flow realizes the physical relationship description of the base flow, the precipitation, the potential evaporation, the evaporation efficiency parameter and the effective water storage capacity parameter.

[0067] In some embodiments of the present application, the physical formula can be implemented based on the Budyko framework. Specifically, the "limit concept" in the Budyko framework is first described:

[0068] In the aspect of catchment hydrology, the Budyko framework can simulate the long-term catchment total runoff Q and actual evaporation E by considering the water supply (usually the precipitation P) and energy demand (usually the potential evaporation E a p a The "limit" concept as the basic theory of the Budyko framework sets two theoretical limits for the actual evaporation E a Mathematically, the "limit" concept can be expressed as:

[0069] In the extreme dry condition, E a / P→1, when E p / P→∞;

[0070] In the extreme wet condition, E a →E p , when E p / P→0.

[0071] That is, in the extreme dry condition, when evaporation is limited by the precipitation P, the actual evaporation E a will asymptote to the precipitation P. And in the extreme wet condition, when evaporation is limited by the energy demand, the actual evaporation E a will asymptote to the potential evaporation E p . The "limit" concept of evaporation can be extended to the catchment precipitation retention CR. The precipitation P of the target catchment can be divided into the surface runoff Q s and the catchment precipitation retention CR (i.e. P = Q s + CR). CR also satisfies the "limit" concept, which can be defined as:

[0072] In the extreme dry condition, CR / P→1, when CR0 / P→∞;

[0073] In the extreme wet condition, CR→CR0, when CR0 / P→0.

[0074] In the formula, the demand limit CR0 of CR is the sum of the effective water storage capacity parameter S p and the potential evaporation E p of the target catchment. The water supply limit of CR is P. The control effect of CR0 / P on CR is similar to the control effect of the aridity index (E p / P) on the actual evaporation E a in the Budyko framework. ​​

[0075] Next, the physical formula for the base flow is derived based on the "limit" concept. The physical formula can be called the BFC (Budyko-Fu constraint) curve. The BFC curve is used to describe the spatial variation of the multi-year average base flow.

[0076] Based on the "limit" concept, the calculation of the total runoff coefficient (Q / P) and the surface runoff coefficient (Q s / P) of a basin are both based on the Budyko framework. The base flow index (Q b / P) can be calculated as Q / P-Q s / P.

[0077] E a / P satisfies the Budyko curve, and the calculation of E a / P satisfies the Fu formula, and the parameter a1 to be calibrated in the Fu formula is a1, which can be expressed as:

[0078]

[0079] When the change in the water storage of the basin can be ignored, Q / P can be calculated as 1-E a / P, which gives:

[0080]

[0081] where a1 is a parameter to be calibrated, representing the control effect of the basin attribute data on evaporation. The parameter a1 ranges from 1 to ∞. The higher a1 is, the greater the evaporation efficiency is, that is, under the given precipitation and potential evaporation conditions, the greater the actual evaporation is, and the smaller the total runoff coefficient of the basin is.

[0082] Q s / P is determined based on the precipitation storage coefficient (CR / P) of the target basin, that is, Q s / P=1-CR / P. The calculation of CR / P also adopts the Fu formula form. Assuming that CR satisfies the Budyko curve, the parameter a2 to be calibrated in the corresponding formula is a2, and the mathematical equation for estimating CR / P is:

[0083]

[0084] Q s / P can be calculated as 1-CR / P:

[0085]

[0086] where a2 is a parameter to be calibrated, representing the control effect of the basin attribute data (except the effective water storage capacity parameter S pthe impact on the water retention of the basin. The larger the value of a2, the more precipitation will be retained and less surface runoff will occur. As mentioned before, S p is the effective water storage capacity parameter of the target basin, defined as the maximum amount of water that the target basin can hold after a precipitation event.

[0087] Q b / P is calculated as Q / P - Q s / P:

[0088]

[0089] In the case of very limited effective water storage capacity parameter (e.g. impermeable basin), the water available to generate the baseflow is close to 0 and the baseflow discharge is also close to 0, i.e.:

[0090] Q b / P→0, when S p / P→0.

[0091] Therefore, when (E p +S p ) / P approaches E p / P (i.e. S p / P→0), Q s / P should be close to Q / P so that Q b / P→0. To satisfy this boundary condition, the parameter a1 must be equal to the parameter a2. Therefore, the formula of Q b / P can be written as:

[0092]

[0093] where a is a new parameter, i.e. the evaporation efficiency parameter, reflecting the secondary control of the basin attribute data on the baseflow discharge. The value of a ranges from [1, ∞]. It can be seen that the formula of Q b / P is simplified. In addition, since both a1 and a2 reflect the secondary control of the basin attribute on the baseflow discharge, the simplification a1 = a2 has little effect on the shape of the BFC curve. As can be seen from the BFC curve, the baseflow index (Q b / P) is a function of the drought index (E p / P) and the basin retention index (S p / P). The sum of E p / P and S p / P represents the ability of the target basin to store precipitation for baseflow and evaporation. P, E p , S p are the dominant factors that determine how much precipitation will become the baseflow discharge Q b .

[0094] Based on the above BFC curve (i.e. Q b / P formula), which can achieve accurate prediction of baseflow flow in the target basin during drought period.

[0095] 105. Determine the impact of drought on baseflow changes in the target watershed based on the predicted baseflow, the second historical baseflow, and the first historical baseflow.

[0096] In this embodiment, the impact of drought on baseflow changes in the target watershed can include: the actual change in baseflow during drought periods compared to non-drought periods; the impact of baseflow inconsistency caused by long-term drought on baseflow changes in the target watershed; and the impact of changes in meteorological factors (drought index) during long-term drought on baseflow changes in the target watershed. Using this impact, we can accurately determine the impact of drought on baseflow changes in the target watershed.

[0097] In some embodiments of the present application, the actual change value of the base flow during the drought period compared to the non-drought period can be determined based on the first difference between the second historical base flow and the first historical base flow. For example, the first difference can be directly used as the actual change value of the base flow during the drought period compared to the non-drought period.

[0098] In some embodiments of the present application, the degree of impact of baseflow inconsistency caused by a long-term drought on baseflow variation in the target watershed can be determined based on a second difference between the predicted baseflow and the second historical baseflow. It can be seen that the second difference represents the difference between the actual baseflow value of the target watershed under the long-term drought climate and the predicted value, and thus the degree of impact of baseflow inconsistency caused by a long-term drought on baseflow variation in the target watershed.

[0099] In some embodiments of the present application, the degree of influence of baseflow inconsistency caused by long-term drought on baseflow changes in the target watershed can be determined based on the ratio of the second difference to the first difference. For example, the ratio of the second difference to the first difference can be directly used as the degree of influence of baseflow inconsistency caused by long-term drought on baseflow changes in the target watershed (that is, the contribution of baseflow inconsistency caused by long-term drought to baseflow changes in the target watershed).

[0100] Similarly, the degree of influence of changes in meteorological factors during a long-term drought on baseflow changes in the target watershed can be determined based on the difference between the first difference and the second difference. Specifically, the degree of influence of changes in meteorological factors during a long-term drought on baseflow changes in the target watershed can be determined based on the ratio of the difference between the first difference and the second difference relative to the first difference. For example, this ratio can be directly used as the degree of influence of changes in meteorological factors during a long-term drought on baseflow changes in the target watershed (i.e., the contribution of changes in meteorological factors during a long-term drought to baseflow changes in the target watershed).

[0101] It can be seen that the actual change in baseflow during the drought period compared with the non-drought period is affected by the inconsistency of baseflow abortion caused by long-term drought and the changes in meteorological elements during the long-term drought.

[0102] In some embodiments of the present application, a time trend method may be used to attribute the factors affecting the difference in baseflow flow in the target basin during the drought period relative to the non-drought period, so as to quantify the contribution of baseflow abortion inconsistency caused by long-term drought to baseflow changes in the target basin, and the contribution of changes in meteorological elements during long-term drought to baseflow changes in the target basin. During long-term droughts, changes in baseflow are caused by both meteorological changes (such as changes in meteorological elements during long-term droughts) and basin inconsistency (such as baseflow abortion inconsistency caused by long-term droughts). If multi-year droughts have no effect on the consistency of the target basin, the attribution method may assume that the baseflow index (BFC=Q b / P) will still follow the same BFC curve as in normal times. Therefore, the inconsistency in basin characteristics only comes from the long-term drought.

[0103] like Figure 2 As shown, the BFC curve is shown, and the horizontal axis is the drought index (E p / P), the vertical axis is the base flow index (Q b / P). Q1 is the first historical base flow of the target basin in the normal period, and P1 is the first historical precipitation of the target basin in the normal period. Q2 is the second historical base flow of the target basin in the drought period, and P2 is the second historical precipitation of the target basin in the drought period. Figure 2 As shown in the figure, the contribution of baseflow inconsistency caused by long-term drought to baseflow changes in the target basin can be calculated as:

[0104]

[0105] Where ΔQ ns It refers to the magnitude of baseflow change caused by baseflow inconsistency due to long-term drought (i.e., the second difference between the predicted baseflow and the second historical baseflow). The impact of changes in meteorological factors during long-term drought on baseflow changes in the target basin can be calculated by subtracting the baseflow change caused by long-term drought from the observed actual baseflow change:

[0106]

[0107] Where ΔQ cis the amplitude of the base flow change caused by the change of meteorological elements during long-term drought (i.e., the difference between the first difference and the second difference). AQ ns and / or AQ c may be positive or negative. AQ is the observed actual change in base flow (i.e., the actual change in base flow during the drought period compared to the non-drought period), which is calculated as follows:

[0108]

[0109] The BFC curve is combined with the time trend method to quantify the contribution of the base flow yield inconsistency caused by long-term drought and the contribution of the change of meteorological elements during long-term drought to the base flow change in the target basin. The quantification results are shown in Figure 3 . Figure 3 The contribution of the base flow yield inconsistency caused by long-term drought (i.e., inconsistency caused by multi-year drought) to the base flow change in the target basin is shown for 136 target basins. Figure 3 The contribution of the change of meteorological elements (i.e., drought index) during long-term drought to the base flow change in the target basin is also shown for 136 target basins. In addition, from Figure 3 it can be seen that, on the 136 target basins, the mean contribution of the inconsistency caused by multi-year drought to the base flow change in the target basin reaches 36%. The mean contribution of the change of meteorological elements (drought index) to the base flow change in the target basin reaches 64%. It can be seen that the combined effects of the two cause the change in the actual observed value of the base flow.

[0110] The simulation effect of the BFC curve and other methods on the base flow is compared, and the comparison results are shown in Figure 4 . Figure 4 The frequency cumulative distribution diagram of the simulation effect of different simulation methods for predicting the base flow on multiple target basins is shown, and the simulation effect can be embodied by the Nash-Sutcliffe efficiency coefficient (NSE). From Figure 4 it can be seen that the simulation effect of the BFC curve on the base flow is better than that of other methods, and the number of target basins with NSE>0 is the largest, indicating that the BFC curve has superiority in the simulation of the base flow.

[0111] In the embodiments of the present application, after determining the influence degree of drought on the base flow change in the target basin, the design parameters of the water resource system of the target basin can be corrected based on the influence degree of drought on the base flow change in the target basin, so that the design of the water resource system is more reasonable. The design parameters of the water resource system can be set based on actual needs, and the correction strategy of the design parameters can also be set based on actual needs, which are not limited herein.

[0112] In the technical solution disclosed in this embodiment, by determining a physical formula for base flow, which includes an effective water storage capacity parameter and an evaporation efficiency parameter, the physical formula for base flow is used to accurately quantify the impact of drought on base flow changes, providing effective data support for the rational planning and design of water resource systems.

[0113] In order to better implement the method for determining the degree of influence of drought on baseflow changes in the embodiment of the present application, based on the method for determining the degree of influence of drought on baseflow changes, the embodiment of the present application further provides a device for determining the degree of influence of drought on baseflow changes. The device for determining the degree of influence of drought on baseflow changes may include:

[0114] A first acquisition module is used to acquire first historical hydrological data of the target watershed during a non-drought period, wherein the first historical hydrological data includes a first historical base flow, a first historical precipitation, and a first historical potential evaporation;

[0115] a first determination module, configured to determine a physical formula for base flow, wherein the physical formula includes an effective water storage capacity parameter and an evaporation efficiency parameter, wherein the effective water storage capacity parameter and the evaporation efficiency parameter are calibrated using first historical hydrological data;

[0116] A second acquisition module is used to obtain second historical hydrological data of the target watershed during the drought period, wherein the second historical hydrological data includes a second historical base flow, a second historical precipitation, and a second historical potential evaporation;

[0117] A second determination module is used to determine the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation using a physical formula;

[0118] The third determination module is used to determine the impact of drought on the base flow change in the target watershed based on the predicted base flow, the second historical base flow and the first historical base flow.

[0119] The present application also provides a computer device that integrates any one of the devices for determining the degree of influence of drought on base flow change provided in the present application. Figure 5 , which shows a schematic diagram of the structure of the computer device involved in the embodiment of the present application, specifically:

[0120] The computer device may include one or more processing core processors 501, one or more computer readable storage media memories 502, a power supply 503, an input unit 504 and other components. Those skilled in the art will understand that Figure 5 The computer device structure shown in the figure is not intended to limit the computer device, and may include more or fewer components than shown in the figure, or combine certain components, or arrange components differently.

[0121] The processor 501 is a control center of the computer device, connects various parts of the computer device through various interfaces and lines, performs various functions of the computer device and processes data by running or executing software programs and / or modules stored in the memory 502 and calling data stored in the memory 502, thereby monitoring the computer device as a whole. Optionally, the processor 501 can include one or more processing cores; preferably, the processor 501 can integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface and application programs, etc., and the modem processor mainly processes wireless communication. It can be understood that the above-mentioned modem processor can also not be integrated into the processor 501.

[0122] The memory 502 can be used to store software programs and modules, and the processor 501 executes various functions and data processing by running the software programs and modules stored in the memory 502. The memory 502 can mainly include a program storage area and a data storage area, wherein the program storage area can store the operating system, at least one application program required by the function (such as sound playing function, image playing function, etc.) and the like; the data storage area can store data created according to the use of the computer device and the like. In addition, the memory 502 can include a high-speed random access memory, and can also include a non-volatile memory, for example, at least one magnetic disk storage device, flash memory device, or other volatile solid-state memory device. Accordingly, the memory 502 can also include a memory controller to provide the processor 501 with access to the memory 502.

[0123] The computer device further includes a power supply 503 for supplying power to various components, and preferably, the power supply 503 can be logically connected to the processor 501 through a power management system, so as to realize the functions of managing charging, discharging and power consumption management through the power management system. The power supply 503 can also include one or more than one direct current or alternating current power supply, a recharging system, a power failure detection circuit, a power converter or inverter, a power state indicator and any other components.

[0124] The computer device can also include an input unit 504, which can be used to receive input digital or character information, and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function control.

[0125] Although not shown, the computer device can also include a display unit and the like, which are not described here in detail. Specifically in the present embodiment, the processor 501 in the computer device will load the executable file corresponding to the process of one or more application programs into the memory 502 according to the following instructions, and run the application program stored in the memory 502 by the processor 501, thereby realizing various functions, for example:

[0126] obtain first historical hydrological data of the target basin in a non-drought period, the first historical hydrological data including first historical base flow, first historical precipitation and first historical potential evaporation; determine a physical formula for base flow, the physical formula including an effective storage capacity parameter and an evaporation efficiency parameter, the effective storage capacity parameter and the evaporation efficiency parameter being calibrated using the first historical hydrological data; obtain second historical hydrological data of the target basin in a drought period, the second historical hydrological data including second historical base flow, second historical precipitation and second historical potential evaporation; determine a predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation using the physical formula; and determine an influence degree of drought on base flow change in the target basin based on the predicted base flow, the second historical base flow and the first historical base flow.

[0127] Those skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructions, or by instructions controlling related hardware, which can be stored in a computer readable storage medium and loaded and executed by a processor.

[0128] To this end, an embodiment of the present application provides a computer readable storage medium, which can include a read only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc. A computer program is stored on the storage medium, and the computer program is loaded by a processor to execute steps in any of the methods for determining the influence degree of drought on base flow change provided by the embodiments of the present application. For example, the computer program loaded by the processor can execute the following steps:

[0129] The first historical hydrological data of the target basin in a non-drought period is acquired, the first historical hydrological data including first historical base flow, first historical precipitation and first historical potential evaporation; a physical formula for base flow is determined, the physical formula including an effective storage capacity parameter and an evaporation efficiency parameter, the effective storage capacity parameter and the evaporation efficiency parameter being calibrated by using the first historical hydrological data; the second historical hydrological data of the target basin in a drought period is acquired, the second historical hydrological data including second historical base flow, second historical precipitation and second historical potential evaporation; the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation is determined by using the physical formula; and the influence degree of drought on the change of base flow in the target basin is determined based on the predicted base flow, the second historical base flow and the first historical base flow.

[0130] In addition, the embodiment of the present application provides a computer program product or computer program, which comprises computer instructions stored in a computer readable storage medium. The processor of the electronic device reads the computer instructions from the computer readable storage medium and executes the computer instructions, so that the electronic device performs to realize the determination method of the influence degree of drought on the change of base flow according to any one of the above.

[0131] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the detailed description of other embodiments above, which will not be repeated here.

[0132] The specific implementation of each operation can refer to the previous embodiments, which will not be repeated here.

[0133] The above describes in detail the determination method of the influence degree of drought on the change of base flow, the device and the medium provided by the embodiment of the present application. The principle and implementation manner of the present application are described by applying specific examples in this paper. The above embodiment is only used to help understand the method and its core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manner and application range will be changed; and according to the above, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A method for determining the degree of influence of drought on changes in base flow, characterized by, The method comprises the following steps: obtaining first historical hydrological data of the target basin in a non-drought period, wherein the first historical hydrological data comprises first historical base flow, first historical precipitation and first historical potential evaporation; determining a physical formula for base flow, wherein the physical formula comprises an effective water storage capacity parameter and an evaporation efficiency parameter, and the effective water storage capacity parameter and the evaporation efficiency parameter are calibrated by using the first historical hydrological data; the physical formula comprises a relationship between a drought index, a basin retention index, a base flow index and the evaporation efficiency parameter, wherein the drought index comprises a ratio between the potential evaporation and the precipitation, the basin retention index comprises a ratio between the effective water storage capacity parameter and the precipitation, and the base flow index comprises a ratio between the base flow and the precipitation; obtaining second historical hydrological data of the target basin in a drought period, wherein the second historical hydrological data comprises second historical base flow, second historical precipitation and second historical potential evaporation; determining a predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation by using the physical formula; determining an influence degree of drought on the change of base flow in the target basin based on the predicted base flow, the second historical base flow and the first historical base flow; the physical formula comprises the following formula: where Q b is the base flow, P is the precipitation, S p is the effective storage capacity parameter, E p is the potential evaporation, and a is the evaporation efficiency parameter.

2. The method of claim 1, wherein the influence degree of drought on the change of base flow in the target basin comprises an actual change value of base flow in the drought period compared with the non-drought period, an influence degree of base flow discharge inconsistency caused by long-term drought on the change of base flow in the target basin, and an influence degree of change of meteorological elements during long-term drought on the change of base flow in the target basin.

3. The method of claim 2, wherein: the actual change value of base flow in the drought period compared with the non-drought period is determined based on a first difference between the second historical base flow and the first historical base flow; the influence degree of base flow discharge inconsistency caused by long-term drought on the change of base flow in the target basin is determined based on a second difference between the predicted base flow and the second historical base flow; the influence degree of change of meteorological elements during long-term drought on the change of base flow in the target basin is determined based on a difference between the first difference and the second difference.

4. The method of claim 3, wherein: the influence degree of base flow discharge inconsistency caused by long-term drought on the change of base flow in the target basin is determined according to a ratio of the second difference to the first difference.

5. The method for determining the impact of drought on base flow change according to claim 1, wherein: Before the step of obtaining the first historical hydrological data of the target basin in a non-drought period, the method further comprises: determining the target basin with a drought period longer than a preset length in a preset basin.

6. The method of claim 1, wherein the degree of influence of drought on base flow is determined by: the step of determining the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation by using the physical formula comprises: determining a value of the base flow in the physical formula by taking the second historical precipitation as the precipitation in the physical formula and taking the second historical potential evaporation as the potential evaporation in the physical formula; taking the value of the base flow in the physical formula as a value of the predicted base flow corresponding to the second historical precipitation and the second historical potential evaporation.

7. A computer device, comprising: The computer device comprises: one or more processors; a memory; and one or more application programs, wherein the one or more application programs are stored in the memory and configured to be executed by the processor to implement the steps in the determination method of the degree of influence of drought on base flow change according to any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that, A computer program is stored thereon, and the computer program is loaded by a processor to execute the steps in the determination method of the degree of influence of drought on base flow change according to any one of claims 1 to 6.

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