A method for assessing water resources stress integrating socio-economic and climate change

Abstract

The application relates to a water resource pressure assessment method integrating social economy and climate change. It relates to the technical field of water resource pressure assessment in arid river basins. The method comprises the following steps: obtaining historical values and predicted values of social economic data, correcting the predicted values of the social economy to obtain corrected predicted values; calculating potential evapotranspiration in different scenarios based on historical scenario meteorological data and corrected future climate mode data; calculating future basin water resources based on the correlation between basin rainfall and water resources; extracting drought intensity characteristics according to the change trend of the historical scenario and the future scenario basin drought index; constructing a basin water resource pressure index calculation formula; and according to the calculated water resource pressure index of the water resource region, standardizing the index to obtain a standardized index, and evaluating the change trend of the water resource pressure of the region in different scenarios according to the standardized index. The method solves the problem of quantification and evaluation of basin water resource pressure under complex conditions.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of watershed water resource pressure assessment, and particularly relates to a water resource pressure assessment method integrating social economy and climate change. BACKGROUND

[0002] Under the influence of rapid social and economic development and climate change, global water resource usage and demand are rapidly increasing, leading to prominent contradictions between water resource supply and demand and continuous increase of water resource pressure. Water resource pressure assessment is a key link of watershed water management. By analyzing and predicting the correlation between watershed water supply and water resource development and utilization, it is not only helpful to grasp the balance between watershed water development and protection, but also to identify key areas of water resource protection and restoration and promote sustainable utilization of watershed water resources. It is very important to establish a water resource pressure assessment method considering the influence of social and economic development and climate change for the construction of a resource-saving and environment-friendly society.

[0003] At present, there are many methods for assessing watershed water resource pressure, such as single index evaluation methods based on water resource development and utilization rate, water resource vulnerability index and water resource pressure index, which are characterized by simple concept and easy understanding, but less influencing factors. Another commonly used method for water resource pressure assessment is to build a comprehensive watershed water resource pressure evaluation index system through analytic hierarchy process and water resource pressure model. The advantage of the comprehensive index system method is that it can cover social economy, ecological environment and other aspects, but a large amount of data is needed for calculation, and the selection of regional indicators and the weighting of indicators of different industrial structures have certain subjectivity and uncertainty. In addition, the current water resource pressure assessment technology rarely considers the influence of climate change. Studies have found that the frequency and intensity of future droughts will increase, which has a significant impact on watershed water resource pressure, but there is no quantitative assessment method at present. SUMMARY

[0004] The application provides a water resource pressure assessment method integrating social economy and climate change to establish the response relationship between social economy, permanent population, watershed precipitation and water resource quantity, water conservancy construction, drought characteristic change and watershed water resource pressure, and design a water resource pressure assessment scheme considering social economy and climate change.

[0005] To achieve the above purpose, the technical scheme adopted by the application is as follows:

[0006] A water resource pressure assessment method integrating social economy and climate change, comprising:

[0007] obtain historical values and predicted values of socioeconomic data, and correct the predicted values of the socioeconomic data to obtain corrected predicted values; wherein the historical values and predicted values of the socioeconomic data include historical values of gross domestic product, resident population, reservoir capacity, and basin water resources of each water resources region, and predicted values of gross domestic product and resident population;

[0008] calculate potential evapotranspiration of the basin under different scenarios based on meteorological data of historical scenarios and corrected future climate mode data;

[0009] calculate future basin water resources based on the correlation between basin rainfall and water resources;

[0010] calculate a basin drought index, and extract drought intensity features according to the change trend of the basin drought index under historical scenarios and future scenarios;

[0011] construct a calculation formula of a basin water resources pressure index considering the comprehensive influence of socioeconomic and climate change;

[0012] substitute the corrected predicted values, potential evapotranspiration of the basin under different scenarios, future basin water resources, and drought intensity features into the calculation formula of the basin water resources pressure index to obtain regional water resources pressure indexes of water resources regions under historical scenarios and future scenarios, standardize the regional water resources pressure indexes of water resources regions under historical scenarios and future scenarios to obtain standardized indexes, and evaluate the change trend of regional water resources pressure under different scenarios according to the standardized indexes.

[0013] In a possible design, the predicted values of the socioeconomic data are corrected by the following formula to obtain corrected predicted values:

[0014]

[0015] In the formula, N F is the corrected predicted value; A i is the area of each administrative region in the basin; A is the total area of the basin; N ih is the historical value of the resident population or gross domestic product of the basin; N i is the actual value of the resident population or gross domestic product of the basin in the statistical yearbook; and N if is the predicted value of the resident population or gross domestic product of the basin.

[0016] In a possible design, the potential evapotranspiration of the basin under different scenarios is calculated based on meteorological data of historical scenarios and corrected future climate mode data, including:

[0017] The corrected future climate mode data are calculated by the following formula:

[0018]

[0019] wherein: 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 for different scenarios is calculated by the following formula:

[0021]

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

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

[0024] WR = α0 + α1P + α2P 2 + ε (4)

[0025] wherein: WR is the future basin water resources, P is the basin annual precipitation, α0, α1, α2 are coefficients of the basin annual precipitation P, 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 the drought intensity features are extracted according to the variation trend of the basin drought index in the historical scenario and the future scenario, including:

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

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

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

[0030] wherein: D tP = P - PET t P = P - PET t P = P - PET

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

[0032]

[0033] In the formula: 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, and α, β and γ are the scale parameter, shape parameter and location parameter respectively, which are calculated by the least squares method;

[0034] The SPEI is obtained by standardizing the cumulative water deficit sequence to the normal distribution by the following formula:

[0035]

[0036] In the formula: P cum is the cumulative probability, when P cum ≤0.5, P cum =F(x); when P cum >0.5, P cum =1-F(x); M is an intermediate parameter for SPEI calculation; c0, c1, c2, d1, d2 and d3 are all constants, wherein c0=2.515517, c1=0.802853, c2=0.010328, d1=1.432788, d2=0.189269, and d3=0.001308.

[0037] The intensity of the drought event with a drought duration of 2 months or more and a monthly SPEI≤-1 is calculated, and the change in the probability distribution of the drought intensity between the historical scenario and the future scenario is compared by using kernel density estimation to obtain the drought intensity characteristics.

[0038] In one possible design, the calculation formula of the watershed water resources pressure index under the comprehensive influence of social economy and climate change is as follows:

[0039]

[0040]

[0041] In the formula, C is a water resource pressure index; K is a precipitation coefficient; P is annual precipitation of a basin; R is population; Z is gross domestic product; W is total water resources; S is capacity of regional water conservancy projects; a is an upper limit value of regional water resource development and utilization rate; e λ is a correction coefficient of climate change on basin water resource pressure; λ is a comparison coefficient of drought intensity under climate change and historical scenarios; k is the number of climate change scenarios; D jf is drought intensity under the j scenario, and the drought intensity is a ratio of drought intensity to drought duration; D h is historical scenario drought intensity.

[0042] The application has the advantages that:

[0043] The application comprehensively considers the influences of social and economic development, population increase and decrease, water conservancy project construction, and future climate change on basin water resource pressure, solves the problems of quantification and evaluation of basin water resource pressure under complex conditions, has the advantages of easy-to-obtain parameters and efficient calculation, and can accurately and efficiently analyze the change law of basin water resource pressure under complex conditions. BRIEF DESCRIPTION OF DRAWINGS

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

[0045] Figure 1 is a flowchart of a water resource pressure evaluation method provided by an embodiment of the application, which comprehensively considers social economy and climate change;

[0046] Figure 2 is a result graph of prediction of changes in gross domestic product and population in a water resource area provided by an embodiment of the application;

[0047] Figure 3 is a graph of correlation between rainfall and water resources in a water resource area provided by an embodiment of the application;

[0048] Figure 4 is a graph of change in drought intensity probability distribution in a water resource area under different scenarios provided by an embodiment of the application.

[0049] Figure 5 is a result graph of evaluation of regional water resource pressure under comprehensive influences of social economy and climate change provided by an embodiment of the application.

[0050] Through the above drawings, specific embodiments of the application have been shown, and will be described in more detail hereinafter. The drawings and the written description are not intended to restrict the scope of the concept of the application by any means, but to illustrate the concept of the application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

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

[0052] The present application will be further described in conjunction with the accompanying drawings.

[0053] The embodiment of the present application provides a water resource pressure assessment method integrating social economy and climate change, Figure 1 The embodiment of the present application provides a flow chart of a water resource pressure assessment method integrating social economy and climate change. The water resource pressure assessment method can be implemented based on an electronic terminal. The water resource pressure assessment method constructs a simple and efficient water resource pressure assessment method by comprehensively considering the influence of social economy, population and climate change on the water resource pressure of a basin, and the specific process is shown in the accompanying drawings Figure 1 .

[0054] In the embodiment, the Minjiang and Tuojiang water resource region, the Jialingjiang water resource region and the Hanjiang water resource region are taken as the research objects, and the future climate change scenario is taken as an example to elaborate the water resource pressure assessment method provided by the present application, including the following steps S100 to S600.

[0055] In step S100, the historical value and the predicted value of the social economic data are obtained, and the predicted value of the social economic data is corrected to obtain the corrected predicted value. The historical value and the predicted value of the social economic data include the historical value of the gross domestic product, the permanent population, the reservoir capacity and the water resource quantity of each water resource region, and the predicted value of the gross domestic product and the permanent population.

[0056] In the embodiment, the historical value of the gross domestic product and the permanent population of the Minjiang and Tuojiang water resource region, the Jialingjiang water resource region and the Hanjiang water resource region is obtained by counting the statistical yearbooks of the provinces in the Yangtze River Economic Belt, and the historical value of the reservoir capacity and the water resource quantity can be obtained from the annual Water Resources Bulletin of the Yangtze River Basin and the Southwest Rivers. The reservoir capacity is counted according to the geographical position of the reservoir to the water resource region to be evaluated.

[0057] Based on the historical value of the gross domestic product and the permanent population of each water resource region, the area weight and the population density distribution are considered, the existing predicted results of the gross domestic product and the permanent population are corrected, and the correction method is as formula (1). The corrected predicted value of the future change trend of the gross domestic product and the population of the Minjiang and Tuojiang water resource region, the Jialingjiang water resource region and the Hanjiang water resource region is shown in the accompanying drawings Figure 2 .

[0058]

[0059] In the formula: N F is the corrected prediction value, in this case, the gross domestic product or the resident population; A i is the area of each administrative region in the basin (km 2 ); A is the total area of the basin (km 2 ); N ih is the historical value of the resident population or the gross domestic product of the basin; N i is the actual value of the resident population or the gross domestic product of the basin in the statistical yearbook; N if is the predicted value of the resident population or the gross domestic product of the basin.

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

[0061] In this embodiment, the historical meteorological observation data required for calculation is collected and downloaded from the National Meteorological Science Data Center, the Resource and Environment 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 standardize the data with inconsistent time scales or spatial scales. Global climate model (GCM) data is selected as the basis for future meteorological data calculation. First, by comparing the standard deviation and correlation coefficient of historical meteorological observation values and future climate model simulation values, the applicability of the climate model data is evaluated, and climate model data with small standard deviation and high correlation coefficient are obtained. Then, using the quantile mapping method, the error of the future climate model data is further corrected to obtain the corrected climate model data. The calculation principle of the quantile mapping method is as formula (2):

[0062]

[0063] In the formula: 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 in the historical period; is the cumulative distribution function of the data.

[0064] Based on the historical observation data and the corrected future climate model data, the potential evapotranspiration of each water resources region in different scenarios is calculated using the potential evapotranspiration calculation formula (such as the Penman-Montieth method, as shown in formula (3)).

[0065]

[0066] where PET is the reference crop evapotranspiration (mm d -1 ), Δ is the slope of the saturation vapor pressure-temperature curve de / dT (kPa °C -1 ), R n is the net radiation at the crop surface (MJ m -2 d -1 ), G is the heat flux into the soil (MJ m -2 d -1 ), γ is the psychrometric constant (kPa °C -1 ), T is the mean air temperature at 2 m height (°C), U2 is the mean wind speed at 2 m height (m s -1 ), e s and e a are the saturation and actual vapor pressures in the air (kPa), respectively.

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

[0068] In this embodiment, in order to evaluate the water resource pressure change trend of Minjiang and Tuojiang water resource area, Jialing River water resource area and Hanjiang water resource area, it is necessary to calculate the water resources of each water resource area. Based on the data of "Yangtze River Basin and Southwest Rivers Water Resources Bulletin" from 2010 to 2022, this example uses a polynomial function to fit the "rainfall-water resources" correlation of Minjiang and Tuojiang water resource area, Jialing River water resource area and Hanjiang water resource area, and the results are shown in the attached Figure 3 Figure. Input the corrected rainfall data in step S200 into formula (4), and the water resources of the future water resource area can be obtained.

[0069] WR = a0 + a1P + a2P 2 + ε (4)

[0070] where a0, a1, a2 are the coefficients of precipitation P respectively; ε is the error term, and is usually assumed that ε ~ N(0, σ 2 ).

[0071] Step S400, calculate the basin drought index, and extract the drought intensity characteristics according to the change trend of the basin drought index of the historical scenario and the future scenario.

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

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

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

[0075] where D t is the difference between monthly precipitation and potential evapotranspiration; P t is the monthly precipitation; and PET t is the monthly potential evapotranspiration.

[0076] The probability distribution of the cumulative water deficit sequence was calculated by the three-parameter log-logistic probability distribution function, and its probability density function and probability distribution function are shown in equations (6) and (7):

[0077]

[0078] where a, b, and g are the scale parameter, shape parameter, and location parameter, respectively, which can be calculated by the least squares method. The sequence was standardized and normalized to obtain the corresponding SPEI.

[0079]

[0080]

[0081] where P cum is the cumulative probability, P cum = F(x) when P cum ≤ 0.5, and P cum = 1-F(x) when P cum > 0.5; M is the intermediate parameter for SPEI calculation; c0, c1, c2, d1, d2, and d3 are constants, where c0 = 2.515517, c1 = 0.802853, c2 = 0.010328, d1 = 1.432788, d2 = 0.189269, and d3 = 0.001308.

[0082] To avoid the interference of single-month drought events on the evaluation results, the intensity of drought events with a drought duration of 2 months or more and an SPEI of ≤-1 each month was calculated using the run theory, and the change in the probability distribution of drought intensity in the historical and future scenarios was compared using kernel density estimation, which was one of the bases for analyzing regional water resource pressure under climate change. The calculation results are shown in FIG. 2. Figure 4

[0083] Step S500, constructing a calculation formula of a watershed water resource pressure index considering the comprehensive influence of social economy and climate change.

[0084] ​The watershed water resource pressure index calculation formula proposed in this embodiment, considering the combined effects of socio-economic factors and climate change, not only takes into account the correlation between watershed precipitation, water resources, GDP, and resident population, but also newly introduces the impact of water conservancy project construction and future climate change on regional water resource pressure. Among these, precipitation and watershed water resources primarily represent the available water resources in the region, while GDP and resident population represent the consumption of regional water resources from the perspectives of industrial, agricultural, and domestic water use. Based on considering the upper limit of the region's exploitable water resources, the formula also considers the regulatory capacity of water conservancy projects, represented by reservoirs, through measures such as water storage and discharge to regulate regional water resources. Additionally, [the following is a separate section / appendix]. Figure 4 This indicates that the drought characteristics of the Minjiang and Tuojiang water resource areas, the Jialingjiang water resource area, and the Hanjiang water resource area have changed significantly in the future. The greater the drought intensity and the longer the duration, the more obvious the regional water resource deficit, and the more severe the impact of drought on the economy and people's lives. The degree of impact can be considered to be exponentially related to the drought intensity. Therefore, it is necessary to revise the regional water resource pressure assessment results by comparing the changes in drought intensity under the same probability conditions in historical and future scenarios. In summary, the calculation method of the basin water resource pressure index considering the comprehensive impact of socio-economic and climate change is as shown in equation (10):

[0085]

[0086] In the formula: C is the water resource load index; K is the precipitation coefficient; P is the annual precipitation of the basin, mm; R is the population, ten thousand people; Z is the GDP, 100 million yuan; W is the total water resources, 100 million m³. 3 S represents the reservoir capacity of the regional water conservancy project, in 100 million m³. 3 ;a represents the upper limit of regional water resource development and utilization rate, which can generally be taken as 0.4 to 0.5 according to literature;e λ The correction coefficient for considering the impact of climate change on watershed water resource pressure; λ is the coefficient comparing drought intensity under climate change and historical scenarios. If λ > 0, it indicates that drought intensity will increase under future climate change, and vice versa; k is the number of climate change scenarios to be considered; D jf Let D be the drought intensity under scenario j, where drought intensity is the ratio of drought severity to drought duration; h This represents the intensity of drought under historical scenarios.

[0087] Step S600: Substitute the corrected predicted values, the potential evapotranspiration of the basin under different scenarios, the future water resources volume of the basin, and the drought intensity characteristics into the water resources pressure index calculation formula to obtain the water resources pressure index of the regional water resources area under historical and future scenarios. Then, standardize the water resources pressure index of the regional water resources area under historical and future scenarios to obtain the standardized index. Based on the standardized index, assess the trend of water resources pressure change in different scenarios.

[0088] In this embodiment, the data of gross domestic product, resident population, annual precipitation, reservoir capacity and the like calculated in steps S100 to S400 are substituted into formula (10) to calculate the water resources pressure index C of the historical and future scenarios of the water resources region. The water resources pressure index results of each water resources subregion are normalized by using the normalization method. The closer the index is to 10, the higher the water resources pressure of the region, and the closer the index is to 0, the lower the water resources pressure. Because the water resources pressure index is obviously different in different periods, in this example, in order to more accurately grasp the water resources pressure change characteristics of the Minjiang and Tuojiang River water resources region, the Jialing River water resources region and the Hanjiang River water resources region in different periods, the results are output according to 2025-2050, 2051-2075 and 2076-2100. The water resources pressure evaluation results of the Minjiang and Tuojiang River water resources region, the Jialing River water resources region and the Hanjiang River water resources region under the comprehensive influence of social economy and climate change are shown in Table 1. Figure 5

[0089] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the above embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application.​

Claims

1. A method for assessing water resource pressure by integrating socio-economic and climate change factors, characterized in that, include: Historical and predicted values ​​of socioeconomic data are obtained, and the predicted values ​​of the socioeconomic data are corrected to obtain corrected predicted values; wherein, the historical and predicted values ​​of the socioeconomic data include historical values ​​of GDP, resident population, reservoir capacity, and watershed water resources for each water resource area, as well as predicted values ​​of GDP and resident population; Based on historical meteorological data and corrected future climate model data, the potential evapotranspiration of the watershed under different scenarios is calculated. Based on the correlation between watershed rainfall and water resources, the future watershed water resources are calculated; Calculate the watershed drought index and extract drought intensity characteristics based on the changing trends of the watershed drought index under historical and future scenarios; Construct a formula for calculating the watershed water resource pressure index that takes into account the combined effects of socio-economic factors and climate change; The corrected predicted values, the potential evapotranspiration of the basin under different scenarios, the future water resources volume of the basin, and the drought intensity characteristics are substituted into the water resources pressure index calculation formula of the basin to obtain the water resources pressure index of the regional water resources area under historical and future scenarios. The water resources pressure index of the regional water resources area under historical and future scenarios is then standardized to obtain the standardized index. The trend of water resources pressure change in different scenarios is evaluated based on the standardized index. The predicted values ​​of the socioeconomic data are corrected using the following formula to obtain the corrected predicted values: Where: N F The corrected predicted value; A i N represents the area of ​​each administrative region within the basin; A represents the total area of ​​the basin; N represents the total area of ​​the basin. ih N represents the historical value of the basin's permanent resident population or GDP. i The actual value of the resident population or GDP of the river basin in the statistical yearbook; N if The projected value is the permanent resident population or GDP of the basin. The formula for calculating the watershed water resource pressure index considering the combined effects of socio-economic factors and climate change is shown below. Where: C is the water resource pressure index; K is the precipitation coefficient; P is the annual precipitation of the basin; R is the population; Z is the gross domestic product; W is the total water resources; S is the reservoir capacity of regional water conservancy projects; a is the upper limit of regional water resource development and utilization rate; e λ The correction factor for the impact of climate change on watershed water resource pressure; λ is the coefficient comparing drought intensity under climate change and historical scenarios; k is the number of climate change scenarios; D jf Let D be the drought intensity under scenario j, where drought intensity is the ratio of drought severity to drought duration; h This represents the intensity of drought under historical scenarios.

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

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

4. The method according to claim 1, characterized in that, Calculate the watershed drought index, and extract drought intensity characteristics based on the changing trends of the watershed drought index under historical and future scenarios, including: Using the Standardized Precipitation Evapotranspiration Index (SPEI) as the watershed drought index, the SPEI is calculated using the following method: The difference between monthly precipitation and potential evapotranspiration is calculated using the following formula: D t =P t -PET t (5) In the formula: D t P represents the difference between monthly precipitation and potential evapotranspiration. t Monthly precipitation; PET t This represents the potential monthly evapotranspiration. The probability distribution of the cumulative water deficit sequence is calculated using 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): In the formula: 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 standardizing the cumulative water deficit series to a normal distribution using the following formula: In the formula: P cum For cumulative probability, when P cum When P is ≤0.5 cum =F(x); when P cum When P > 0.5, cum =1-F(x); M is an intermediate parameter calculated by SPEI; c0, c1, c2, d1, d2 and d3 are all constants, where 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 a monthly SPEI ≤ -1 is calculated. Kernel density estimation is used to compare the changes in the probability distribution of drought intensity under historical and future scenarios to obtain drought intensity characteristics.

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