Water resource pressure assessment method integrating social economy and climate change

Abstract

The invention relates to a water resource pressure assessment method integrating social economy and climate change. Relates to the technical field of drought basin water resource pressure assessment. The method comprises the following steps: acquiring a historical value and a predicted value of social economic data, and correcting the predicted value of the social economic data to obtain a corrected predicted value; calculating the potential evapotranspiration of the drainage basin in different scenes based on the meteorological data of the historical scenes and the corrected future climate mode data; calculating a future drainage basin water resource quantity based on a correlation between drainage basin rainfall and the water resource quantity; according to the variation trend of the drainage basin drought index in the historical scene and the future scene, drought intensity characteristics are extracted; constructing a drainage basin water resource pressure index calculation formula; and according to the calculated water resource pressure index of the water resource area, standardization is carried out to obtain a standardization index, and according to the standardization index, the water resource pressure change trend of different scene areas is evaluated. According to the method, the quantization and evaluation problem of the drainage basin water resource pressure under the complex condition is solved.

Description

Technical Field

[0001] The present application relates to the technical field of water resources pressure assessment in river basins, and in particular to a water resources pressure assessment method that integrates social economy and climate change. Background Art

[0002] Under the dual influence of rapid socio-economic development and climate change, global water use and demand have increased rapidly, resulting in prominent contradictions between water supply and demand in river basins and increasing water resource pressure. Water resource pressure assessment is a key link in river basin water management. By analyzing and predicting the correlation between water resource supply and water resource development and utilization in a river basin, it is not only helpful to grasp the balance between water resource development and protection in a river basin, but also to identify key areas for water resource protection and restoration, and promote the sustainable use of water resources in a river basin. Establishing a water resource pressure assessment method that comprehensively considers the impact of socio-economic development and climate change is very important for building a resource-saving and environmentally friendly society.

[0003] At present, there are many methods for assessing water resources stress in river basins, such as single index evaluation methods based on water resources development and utilization rate, water resources vulnerability index, and water resources stress index. The characteristics are simple concepts and easy to understand, but fewer influencing factors are considered. Another commonly used water resources stress assessment method is to build a comprehensive water resources stress assessment index system through hierarchical analysis method and water resources stress model. The advantage of the comprehensive indicator system method is that it can cover multiple aspects such as social economy and ecological environment, but a large amount of data support is required for calculation, and the selection and weighting of regional indicators for different industrial structures are subjective and uncertain. In addition, current water resources stress assessment technology rarely considers the impact of climate change. Studies have found that the frequency and intensity of droughts will increase in the future, which will have a significant impact on water resources stress in the river basin, but there is currently no quantitative assessment method. Summary of the invention

[0004] This application proposes a water resource stress assessment method that integrates social economy and climate change to establish the response relationship between social economy, permanent population, basin precipitation and water resources, water conservancy project construction, changes in drought characteristics and basin water resource stress, and designs a water resource stress assessment scheme that comprehensively considers social economy and climate change.

[0005] In order to achieve the above purpose, the technical solution adopted in this application is:

[0006] A water resources stress assessment method that integrates socio-economic and climate change considerations, including:

[0007] Obtaining historical values ​​and predicted values ​​of social and economic data, and correcting the predicted values ​​of the social and economic data to obtain corrected predicted values; wherein the historical values ​​and predicted values ​​of the social and economic data include historical values ​​of gross domestic product, permanent population, reservoir capacity, and water resources in the river basin of each water resource area, as well as predicted values ​​of gross domestic product and permanent population;

[0008] Based on the meteorological data of historical scenarios and the calibrated future climate model data, the potential evapotranspiration of the basin under different scenarios is calculated;

[0009] Based on the correlation between basin rainfall and water resources, calculate the future water resources in the basin;

[0010] Calculate the basin drought index and extract drought intensity characteristics based on the changing trends of the basin drought index in historical and future scenarios;

[0011] Construct a calculation formula for the basin water resources stress index considering the combined impact of social economy and climate change;

[0012] The corrected predicted values, the potential evapotranspiration of the basin under different scenarios, the future water resources in the basin and the drought intensity characteristics are substituted into the calculation formula of the basin water resources stress index to obtain the water resources stress index of the regional water resources area under the historical scenarios and the future scenarios, and the water resources stress index of the regional water resources area under the historical scenarios and the future scenarios is standardized to obtain a standardized index, and the changing trend of regional water resources stress under different scenarios is evaluated based on the standardized index.

[0013] In a possible design, the predicted value of the socio-economic factors is corrected by the following formula to obtain a corrected predicted value:

[0014]

[0015] Where: N F is the predicted value after correction; A m is the area of ​​each administrative district in the basin; A is the total area of ​​the basin; N ih is the historical value of the basin's permanent population or gross domestic product; N i is the actual value of the basin's permanent population or gross domestic product in the statistical yearbook; N if It is the predicted value of the basin’s permanent population or gross domestic product.

[0016] 3. The method according to claim 1 is characterized in that the potential evapotranspiration of the basin under different scenarios is calculated based on the meteorological data of historical scenarios and the corrected future climate model data, including:

[0017] The corrected future climate model data is calculated using the following formula:

[0018]

[0019] Where: x mc is the corrected climate model data; x m,v (t) is the uncorrected climate model data; F m,c is the cumulative distribution function of the uncorrected climate model data for the historical period; is the cumulative distribution function of the data;

[0020] The potential evapotranspiration of the basin under different scenarios is calculated by the following formula:

[0021]

[0022] Where: PET is the reference crop evaporation, Δ is the gradient of the saturated water vapor pressure-temperature curve de / dT, R n is the net radiation of the crop surface, G is the heat flux into the soil, γ is the air humidity constant, T is the average temperature at a height of 2m, U2 is the average wind speed at a height of 2m, and e s and e a are the saturated water vapor pressure of air and the actual water vapor pressure of air respectively.

[0023] In a possible design, the future water resources in the basin are calculated based on the correlation between basin rainfall and water resources:

[0024] WR=α0+α1P+α2P 2 +ε(4)

[0025] Where: WR is the future water resources in the basin, P is the annual precipitation in the basin, α0, α1, α2 are the coefficients of the annual precipitation P in the basin respectively; ε is the error term, ε~N(0,σ 2 ), N(0,σ 2 ) represents a normal distribution with a mathematical expectation of 0 and a standard deviation of σ.

[0026] In one possible design, the basin drought index is calculated, and drought intensity characteristics are extracted based on the changing trends of the basin drought index under historical and future scenarios, including:

[0027] The standardized precipitation evapotranspiration index (SPEI) is used as the basin drought index and is calculated by the following method:

[0028] The difference between monthly precipitation and potential evapotranspiration is calculated using the following formula:

[0029] D i =P i -PET i (5)

[0030] Where: D iis the difference between monthly precipitation and potential evapotranspiration; P i is monthly precipitation; PET i is the monthly potential evapotranspiration;

[0031] The probability distribution of the cumulative water deficit sequence is calculated by the three-parameter log-logistic probability distribution function. The probability density function and probability distribution function of the cumulative water deficit sequence are shown in equations (6) and (7):

[0032]

[0033] Where: f(x) is the probability density function of the cumulative water deficit sequence, F(x) is the probability distribution function of the cumulative water deficit sequence, x is the cumulative water deficit, α, β and γ are the scale parameter, shape parameter and location parameter respectively, and the least squares method is used for calculation;

[0034] The SPEI is obtained by normalizing the cumulative water deficit series using the following formula:

[0035]

[0036] Where: P cum is the cumulative probability, when P cum When ≤0.5, P cum =F(x); when P cum When >0.5, P cum =1-F(x); M is the intermediate parameter calculated by SPEI; c0, c1, c2, d1, d2 and d3 are constants, among which c0=2.515517, c1=0.802853, c2=0.010328, d1=1.432788, d2=0.189269, d3=0.001308.

[0037] The intensity of drought events lasting 2 months or more with monthly SPEI ≤ -1 was calculated, and the changes in the probability distribution of drought intensity between historical scenarios and future scenarios were compared using kernel density estimation to obtain the drought intensity characteristics.

[0038] In a possible design, the calculation formula of the basin water resources stress index considering the combined impact of socio-economic and climate change is as follows;

[0039]

[0040]

[0041] In the formula: C is the water resources pressure index; K is the precipitation coefficient; P is the annual precipitation in the basin; R is the population; Z is the gross domestic product; W is the total water resources; S is the reservoir capacity of the regional water conservancy project; a is the upper limit of the regional water resources development and utilization rate; e α is the correction coefficient for the impact of climate change on water resources pressure in the basin; α is the drought intensity comparison coefficient between climate change and historical scenarios; n is the number of climate change scenarios; D if is the drought intensity under scenario i, which is the ratio of drought severity to drought duration; D h is the drought intensity in historical scenarios.

[0042] The benefits of this application are:

[0043] This application comprehensively considers the impact of social and economic development, population growth and decline, water conservancy project construction and future climate change on basin water resources pressure, solves the problem of quantification and evaluation of basin water resources pressure under complex conditions, has the advantages of easy parameter acquisition and efficient calculation, and can accurately and efficiently analyze the changing laws of basin water resources pressure under complex conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0045] Figure 1 A flow chart of a method for assessing water resource stress that integrates socio-economic and climate change provided in an embodiment of the present application;

[0046] Figure 2 A graph showing the forecast results of the GDP and population change trends in the water resource area provided in the embodiment of the present application;

[0047] Figure 3 A correlation diagram between rainfall and water resources in a water resource area provided in an embodiment of the present application;

[0048] Figure 4 A graph showing the probability distribution changes of drought intensity in water resource areas under different scenarios provided in the embodiments of the present application.

[0049] Figure 5 This is a graph of regional water resources pressure assessment results under the combined influence of socio-economic and climate change provided in an embodiment of the present application.

[0050] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0051] The following examples are only for better explanation of the present invention, but the content of the present invention is not limited to the application in the examples. Therefore, those skilled in the art can make non-essential improvements and adjustments to the implementation scheme according to the above content of the invention and apply them to other examples, which are still within the protection scope of the present invention.

[0052] The present invention will now be further described with reference to the accompanying drawings.

[0053] This application embodiment provides a water resources pressure assessment method that integrates social economy and climate change. Figure 1 This is a flow chart of a method for assessing water resource stress that integrates social economy and climate change provided in an embodiment of the present application. This method for assessing water resource stress can be implemented based on an electronic terminal. This method for assessing water resource stress comprehensively considers the impact of social economy, population and climate change on water resource stress in a river basin, and constructs a simple and efficient method for assessing water resource stress in a river basin. For details of the specific process, please see the attached Figure 1 .

[0054] In the embodiment, the water resource areas of the Minjiang River and Tuojiang River, the Jialing River and the Hanjiang River are taken as research objects, and the future climate change scenario is taken as an example to elaborate on the water resource pressure assessment method proposed in the present invention, including the following steps S100 to S600.

[0055] Step S100, obtaining historical values ​​and predicted values ​​of socio-economic data, and correcting the predicted values ​​of socio-economics to obtain corrected predicted values; wherein the historical values ​​and predicted values ​​of socio-economic data include the historical values ​​of GDP, permanent population, reservoir capacity, and water resources in the river basin of each water resource area, as well as the predicted values ​​of GDP and permanent population.

[0056] In this embodiment, the historical values ​​of GDP and permanent population of the Minjiang and Tuojiang water resource areas, Jialingjiang water resource areas and Hanjiang water resource areas are obtained by statistically analyzing the statistical yearbooks of various provinces in the Yangtze River Economic Belt over the years. The historical values ​​of reservoir capacity and water resources in the river basin can be obtained from the data of the "Yangtze River Basin and Southwest River Water Resources Bulletin" over the years. Among them, the reservoir capacity is counted according to the geographical location of the reservoir to the water resource area that needs to be evaluated.

[0057] Based on the historical values ​​of GDP and permanent population in each water resource area, the existing GDP and permanent population forecast results are corrected by considering the area weight and population density distribution. The correction method is shown in formula (1). The corrected future GDP and population change trend forecast values ​​of the Minjiang and Tuojiang water resource areas, Jialingjiang water resource area and Hanjiang water resource area are shown in the attached figure. Figure 2 shown.

[0058]

[0059] Where: N F is the corrected forecast value, in this case, it is the gross domestic product or permanent population; A m is the area of ​​each administrative district in the basin (km 2 ); A is the total area of ​​the basin (km 2 );N ih is the historical value of the basin's permanent population or gross domestic product; N i is the actual value of the basin's permanent population or gross domestic product in the statistical yearbook; N if It is the predicted value of the basin’s permanent population or gross domestic product.

[0060] Step S200, based on the meteorological data of historical scenarios and the corrected future climate model data, the potential evapotranspiration of the watershed in different scenarios is calculated.

[0061] In this embodiment, historical meteorological observation data required for calculation are collected and downloaded from the National Meteorological Science Data Center, the Resource and Environmental Science and Data Center of the Chinese Academy of Sciences and other units, including precipitation, average temperature, wind speed, relative humidity, air pressure and net radiation. Resampling, interpolation and other methods are used to regularize data with inconsistent time scales or spatial scales. The global climate model data (globalclimatemodel, GCM) is selected as the basis for calculating future meteorological data. First, by comparing the standard deviation and correlation coefficient of historical meteorological observations and future climate model simulation values, the applicability of climate model data is evaluated, and climate model data with small standard deviation and high correlation coefficient are initially obtained. The quantile mapping method is then used to further correct the errors in future climate model data to obtain corrected climate model data. The calculation principle of the quantile mapping method is as shown in formula (2):

[0062]

[0063] Where: x mc is the corrected climate model data; x m,v (t) is the uncorrected climate model data; F m,c is the cumulative distribution function of the uncorrected climate model data for the historical period; is the cumulative distribution function of the data.

[0064] Based on historical observation data and corrected future climate model data, the potential evapotranspiration calculation formula (such as the Penman-Montieth method, as shown in formula (3)) is used to calculate the potential evapotranspiration of each water resource area under different scenarios.

[0065]

[0066] Where: PET is the reference crop evapotranspiration (mmd -1 ), Δ is the gradient of the saturated water vapor pressure-temperature curve de / dT (kPa℃ -1 ), R n is the net radiation on the crop surface (MJm -2 d -1 ), G is the heat flux into the soil (MJm -2 d -1 ), γ is the air humidity constant (kPa℃ -1 ), T is the average temperature at 2m height (℃), U2 is the average wind speed at 2m height (ms -1 ), e s and e a are the saturated water vapor pressure of air and the actual water vapor pressure of air (kPa) respectively.

[0067] Step S300, based on the correlation between the rainfall in the basin and the amount of water resources, calculate the future amount of water resources in the basin.

[0068] In this example, in order to evaluate the future trend of water resource pressure changes in the Minjiang and Tuojiang water resource areas, the Jialingjiang water resource area, and the Hanjiang water resource area, it is necessary to calculate the water resource volume of each water resource area. This example is based on the data of the "Yangtze River Basin and Southwest River Water Resources Bulletin" from 2010 to 2022, and uses a polynomial function to fit the "rainfall-water resource volume" correlation of the Minjiang and Tuojiang water resource areas, the Jialingjiang water resource area, and the Hanjiang water resource area. The results are shown in the attached figure. Figure 3 As shown. Input the corrected rainfall data in step 2 into equation (4) to obtain the water resources in the future water resource area.

[0069] WR=α0+α1P+α2P 2 +ε(4)

[0070] Where: α0, α1, α2 are the coefficients of precipitation P respectively; ε is the error term, and it is usually assumed that ε~N(0,σ 2 ).

[0071] Step S400, calculating the watershed drought index, and extracting drought intensity characteristics according to the changing trend of the watershed drought index in historical scenarios and future scenarios.

[0072] In this embodiment, the Standardized Precipitation Evapotranspiration Index (SPEI) is used to calculate the drought index of different water resource areas in the Yangtze River Basin in historical and future scenarios. The calculation method is as follows:

[0073] First, calculate the difference between monthly precipitation and potential evapotranspiration:

[0074] D i =P i -PET i (5)

[0075] Where: D i is the difference between monthly precipitation and potential evapotranspiration; P i is monthly precipitation (mm); PET i is the monthly potential evapotranspiration (mm).

[0076] The probability distribution of the cumulative water deficit series is calculated using the three-parameter log-logistic probability distribution function. Its probability density function and probability distribution function are shown in equations (6) and (7):

[0077]

[0078] Where: α, β and γ are scale parameter, shape parameter and location parameter respectively, which can be calculated by least square method. The sequence is normalized and the corresponding SPEI is obtained:

[0079]

[0080] Where: P cum is the cumulative probability, when P cum When ≤0.5, P cum =F(x); when P cum When >0.5, P cum =1-F(x); M is the intermediate parameter calculated by SPEI; c0, c1, c2, d1, d2 and d3 are constants, among which c0=2.515517, c1=0.802853, c2=0.010328, d1=1.432788, d2=0.189269, d3=0.001308.

[0081] In order to avoid the interference of single-month drought events on the assessment results, the run theory is used to calculate the intensity of drought events with a drought duration of 2 months or more and a monthly SPEI ≤ -1. The kernel density estimation is used to compare the changes in the probability distribution of drought intensity in historical scenarios and future scenarios. This is used as one of the foundations for analyzing regional water resource stress under the influence of climate change. The calculation results are shown in the attached figure. Figure 4 shown.

[0082] Step S500, constructing a calculation formula for the basin water resources pressure index considering the comprehensive impact of social economy and climate change.

[0083] The calculation formula for the water resources pressure index of a river basin under the combined influence of social economy and climate change proposed in this embodiment not only considers the correlation between precipitation, water resources, gross domestic product, and permanent population in the river basin, but also newly introduces the impact of water conservancy project construction and future climate change on regional water resources pressure. Among them, precipitation and water resources in the river basin mainly characterize the available amount of regional water resources, while gross domestic product and permanent population characterize the consumption of regional water resources in terms of industrial, agricultural and domestic water use. On the basis of considering the upper limit of the exploitable amount of regional water resources, the water conservancy projects represented by reservoirs are considered to regulate regional water resources through scheduling measures such as interception and discharge. At the same time, the attached Figure 4 It shows that the drought characteristics of the Minjiang and Tuojiang water resource areas, Jialingjiang water resource areas and Hanjiang water resource areas will change significantly in the future. The greater the intensity of the drought and the longer the duration, the more obvious the regional water resource deficit, the more serious the impact of drought on the economy and residents' lives, and the degree of impact can be considered to be exponentially related to the intensity of the drought. Therefore, it is necessary to revise the regional water resource stress assessment results by comparing the changes in drought intensity under the same probability conditions in historical scenarios and future scenarios. In summary, the calculation method of the basin water resource stress index considering the comprehensive impact of social economy and climate change is as shown in formula (10):

[0084]

[0085] Where: C is the water resource load index; K is the precipitation coefficient; P is the annual precipitation in the basin, mm; R is the population, ten thousand people; Z is the gross domestic product, billion yuan; W is the total water resources, billion m 3 S is the reservoir capacity of the regional water conservancy project, billion m 3 ; a is the upper limit of regional water resources development and utilization rate, which can be generally taken as 0.4 to 0.5 according to the literature; e α is the correction coefficient for the impact of climate change on water resources pressure in the basin; α is the comparison coefficient of drought intensity under climate change and historical scenarios. If α>0, it indicates that drought intensity will increase under future climate change, and vice versa; n is the number of climate change scenarios that need to be considered; D if is the drought intensity under scenario i, which is the ratio of drought severity to drought duration; D h is the drought intensity in historical scenarios.

[0086] Step S600, substitute the corrected predicted value, the potential evapotranspiration of the basin under different scenarios, the future water resources in the basin, and the drought intensity characteristics into the calculation formula of the basin water resources pressure index to obtain the water resources pressure index of the regional water resources area under the historical scenario and the future scenario, and standardize the water resources pressure index of the regional water resources area under the historical scenario and the future scenario to obtain the standardized index, and evaluate the changing trend of water resources pressure in different scenarios according to the standardized index.

[0087] In this embodiment, the data such as the GDP, permanent population, annual precipitation, reservoir capacity, etc. of each water resource area calculated in step S100 to step S400 are substituted into formula (10) to calculate the water resource pressure index C of the regional water resource area in the historical scenario and the future scenario. The water resource pressure index results of each water resource zone are standardized by the normalization method. The closer the index is to 10, the higher the regional water resource pressure is, and the closer the index is to 0, the lower the water resource pressure is. Because there are obvious differences in the water resource pressure index in different periods, in this example, in order to more accurately grasp the water resource pressure change characteristics of the Minjiang and Tuojiang water resource areas, the Jialingjiang water resource area and the Hanjiang water resource area in different periods, the results are divided into three analysis periods according to 2025-2050, 2051-2075, and 2076-2100 for output. The results of the water resource stress assessment for the Minjiang and Tuojiang water resource areas, Jialingjiang water resource area and Hanjiang water resource area under the combined impact of socio-economic and climate change are shown in the attached figure. Figure 5 shown.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and should all be included in the scope of the claims and specification of the present invention.

Claims

1. A water resources stress assessment method integrating socio-economic and climate change, characterized in that: include: Obtaining historical values ​​and predicted values ​​of social and economic data, and correcting the predicted values ​​of the social and economic data to obtain corrected predicted values; wherein the historical values ​​and predicted values ​​of the social and economic data include historical values ​​of gross domestic product, permanent population, reservoir capacity, and water resources in the river basin of each water resource area, as well as predicted values ​​of gross domestic product and permanent population; Based on the meteorological data of historical scenarios and the calibrated future climate model data, the potential evapotranspiration of the basin under different scenarios is calculated; Based on the correlation between basin rainfall and water resources, calculate the future water resources in the basin; Calculate the basin drought index and extract drought intensity characteristics based on the changing trends of the basin drought index in historical and future scenarios; Construct a calculation formula for the basin water resources stress index considering the combined impact of social economy and climate change; The corrected predicted values, the potential evapotranspiration of the basin under different scenarios, the future water resources in the basin and the drought intensity characteristics are substituted into the calculation formula of the basin water resources stress index to obtain the water resources stress index of the regional water resources area under the historical scenarios and the future scenarios, and the water resources stress index of the regional water resources area under the historical scenarios and the future scenarios is standardized to obtain a standardized index, and the changing trend of regional water resources stress under different scenarios is evaluated based on the standardized index.

2. The method according to claim 1, characterized in that The predicted value of the social economy is corrected by the following formula to obtain the corrected predicted value: Where: N F is the predicted value after correction; A m is the area of ​​each administrative district in the basin; A is the total area of ​​the basin; N ih is the historical value of the basin's permanent population or gross domestic product; N i is the actual value of the basin's permanent population or gross domestic product in the statistical yearbook; N if It is the predicted value of the basin’s permanent population or gross domestic product.

3. The method according to claim 1, characterized in that Based on the meteorological data of historical scenarios and the calibrated future climate model data, the potential evapotranspiration of the basin under different scenarios is calculated, including: The corrected future climate model data is calculated using the following formula: Where: x mc is the corrected climate model data; x m,v (t) is the uncorrected climate model data; F m,c is the cumulative distribution function of the uncorrected climate model data for the historical period; is the cumulative distribution function of the data; The potential evapotranspiration of the basin under different scenarios is calculated by the following formula: Where: PET is the reference crop evaporation, Δ is the gradient of the saturated water vapor pressure-temperature curve de / dT, R n is the net radiation of the crop surface, G is the heat flux into the soil, γ is the air humidity constant, T is the average temperature at a height of 2m, U2 is the average wind speed at a height of 2m, and e s and e a are the saturated water vapor pressure of air and the actual water vapor pressure of air respectively.

4. The method according to claim 1, characterized in that Based on the correlation between basin rainfall and water resources, the future basin water resources are calculated: WR=α0+α1P+α2P 2 +e (4) Where: WR is the future water resources in the basin, P is the annual precipitation in the basin, α0, α1, α2 are the coefficients of the annual precipitation P in the basin respectively; ε is the error term, ε~N(0,σ 2 ), N(0,σ 2 ) represents a normal distribution with a mathematical expectation of 0 and a standard deviation of σ.

5. The method according to claim 1, characterized in that Calculate the basin drought index and extract drought intensity characteristics based on the changing trends of the basin drought index in historical and future scenarios, including: The standardized precipitation evapotranspiration index (SPEI) is used as the basin drought index and is calculated by the following method: The difference between monthly precipitation and potential evapotranspiration is calculated using the following formula: D i =P i -PET i (5) Where: D i is the difference between monthly precipitation and potential evapotranspiration; P i is monthly precipitation; PET i is the monthly potential evapotranspiration; The probability distribution of the cumulative water deficit sequence is calculated by the three-parameter log-logistic probability distribution function. The probability density function and probability distribution function of the cumulative water deficit sequence are shown in equations (6) and (7): Where: f(x) is the probability density function of the cumulative water deficit sequence, F(x) is the probability distribution function of the cumulative water deficit sequence, x is the cumulative water deficit, α, β and γ are the scale parameter, shape parameter and location parameter respectively, and the least squares method is used for calculation; The SPEI is obtained by normalizing the cumulative water deficit series using the following formula: Where: P cum is the cumulative probability, when P cum When ≤0.5, P cum =F(x); when P cum When >0.5, P cum =1-F(x); M is the intermediate parameter calculated by SPEI; c0, c1, c2, d1, d2 and d3 are constants, among which c0=2.515517, c1=0.802853, c2=0.010328, d1=1.432788, d2=0.189269, d3=0.001308. The intensity of drought events lasting 2 months or more with monthly SPEI ≤ -1 was calculated, and the changes in the probability distribution of drought intensity between historical scenarios and future scenarios were compared using kernel density estimation to obtain the drought intensity characteristics.

6. The method according to claim 1, characterized in that The calculation formula of the basin water resources stress index considering the combined impact of social economy and climate change is as follows; In the formula: C is the water resources pressure index; K is the precipitation coefficient; P is the annual precipitation in the basin; R is the population; Z is the gross domestic product; W is the total water resources; S is the reservoir capacity of the regional water conservancy project; a is the upper limit of the regional water resources development and utilization rate; e α is the correction coefficient for the impact of climate change on water resources pressure in the basin; α is the drought intensity comparison coefficient between climate change and historical scenarios; n is the number of climate change scenarios; D if is the drought intensity under scenario i, which is the ratio of drought severity to drought duration; D h is the drought intensity in historical scenarios.

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