A method for dynamic assessment of comprehensive risk of drought disasters

Abstract

The present invention relates to a method for dynamically assessing the comprehensive risk of drought disasters. Taking the comprehensive risk of drought disasters as the assessment object, comprehensive risk assessment factors are selected from four aspects: disaster-causing factors, disaster-forming environments, disaster-bearing bodies, and disaster prevention and mitigation capabilities of drought disasters, and a dynamic assessment mathematical model for the comprehensive risk of drought disasters is constructed to dynamically assess the comprehensive risk of regional drought disasters in terms of time and space. The method of the present invention takes into account the evolution process of each risk factor in time and space, can characterize the comprehensive risk characteristics of drought disasters in different regions at different times, and to a certain extent makes up for the deficiency of the traditional method that only relies on drought frequency to represent the risk of disaster-causing factors of drought. At the same time, the method of the present invention also considers the influence of factors such as disaster-forming environments, disaster-bearing bodies, and disaster prevention and mitigation capabilities on risks, realizing the leap from drought risk to drought disaster risk.

Description

Technical Field

[0001] The present invention relates to the fields of water conservancy projects, emergency management, environmental engineering and their interdisciplinary fields, and particularly relates to a method for dynamically evaluating the comprehensive risk of drought disasters. Background Art

[0002] The risk assessment of drought disasters is the key to the transformation of the drought disaster crisis management mode to the drought disaster risk management mode. It refers to measuring the degree and possibility of the impact and harm of drought disasters on the social economy and natural systems through various methods, covering the whole process from the drought phenomenon evolving into a drought disaster to the disappearance of the disaster. In recent years, with the rapid development and application of satellite remote sensing technology, the data available for drought research have been greatly expanded in terms of type and magnitude. The spatio-temporal characteristics of the data can timely reflect all aspects of the transformation from drought to drought disaster, providing data conditions for the transformation of risk research from focusing on drought to focusing on drought disasters. At the same time, the spatio-temporal characteristics of the data also lay a foundation for the dynamic assessment of drought disaster risks. Summary of the Invention

[0003] The problems to be solved by the present invention are: according to the spatio-temporal characteristics of the comprehensive risk of drought disasters, propose calculation methods for evaluation indicators such as the hazard of disaster-causing factors, the exposure of disaster-bearing environments, the vulnerability of disaster-affected bodies, and the disaster prevention and mitigation capabilities, and construct a dynamic assessment mathematical model for drought disaster risks to realize the dynamic analysis of the comprehensive risks of drought disasters in the evaluation area in terms of time and space.

[0004] The present invention adopts the following technical solutions: A method for dynamically evaluating the comprehensive risk of drought disasters, comprising the following steps:

[0005] Step S1, collect and sort out various types of data according to the characteristics of each evaluation unit in the evaluation area;

[0006] Step S2, construct a conceptual model for dynamically evaluating the comprehensive risk of drought disasters that reflects the change characteristics of each risk index in terms of time and space;

[0007] Step S3, calculate the hazard index of disaster-causing factors according to the data in Step S1 and the conceptual model for dynamically evaluating the comprehensive risk of drought disasters in Step S2;

[0008] Step S4, calculate the exposure index of disaster-bearing environments according to the data in Step S1 and the conceptual model for dynamically evaluating the comprehensive risk of drought disasters in Step S2;

[0009] Step S5, calculate the vulnerability index of disaster-affected bodies according to the data in Step S1 and the conceptual model for dynamically evaluating the comprehensive risk of drought disasters in Step S2;

[0010] Step S6: Calculate the disaster prevention and mitigation capacity indicators based on the data in Step S1 and the dynamic assessment conceptual model of drought disaster comprehensive risk in Step S2;

[0011] Step S7: Based on the dynamic assessment conceptual model of drought disaster comprehensive risk in Step S2, the hazard index of disaster-causing factors in Step S3, the exposure index of disaster-bearing environment in Step S4, the vulnerability index of disaster-affecting bodies in Step S5, and the disaster prevention and mitigation capacity indicators in Step S6, construct a dynamic assessment mathematical model of drought disaster comprehensive risk to evaluate the drought disaster comprehensive risk of each assessment unit;

[0012] Among them, for Step S7 to construct the dynamic assessment mathematical model of drought disaster comprehensive risk, see Formula (1);

[0013] (1);

[0014] In the formula, is the dynamic assessment mathematical model of drought disaster comprehensive risk, is the hazard index of disaster-causing factors corresponding to the standardized precipitation evapotranspiration index x at the y-th assessment unit in the evaluation area at time t, 、 、 are respectively the coefficients of the exposure factor of disaster-bearing environment , the vulnerability factor of disaster-affecting bodies and the disaster prevention and mitigation capacity factor at the y-th assessment unit at time t;

[0015] The exposure factor of disaster-bearing environment is obtained by normalizing the exposure index of the disaster-bearing environment at the y-th assessment unit at time t in Step S4;

[0016] The vulnerability factor of disaster-affecting bodies is obtained by normalizing the vulnerability index of the disaster-affecting bodies at the y-th assessment unit at time t in Step S5;

[0017] The disaster prevention and mitigation capacity factor is obtained by normalizing the disaster prevention and mitigation capacity indicators at the y-th assessment unit at time t in Step S6.

[0018] Furthermore, in Step S1, various types of data include meteorological data, land cover type data, data on the types and areas of land cover affected by drought, population quantity data, data on the locations of water conservancy projects, and data on the beneficial storage capacities. The data are statistically calculated with the assessment units in the evaluation area as the statistical units;

[0019] In step S2, the comprehensive risk of drought disasters includes four aspects: the hazard of disaster-causing factors, the vulnerability of disaster-bearing bodies, the exposure of disaster-forming environments, and the ability of disaster prevention and mitigation. The conceptual model for dynamic assessment of the comprehensive risk of drought disasters is shown in formula (2);

[0020] (2);

[0021] In the formula, is the conceptual model for dynamic assessment of the comprehensive risk of drought disasters, is the hazard index of disaster-causing factors for drought disasters at time t, is the comprehensive impact index of drought disasters at time t. H is the element of the hazard of disaster-causing factors, E is the element of the exposure of disaster-forming environments, V is the element of the vulnerability of disaster-bearing bodies, and A is the element of the ability of disaster prevention and mitigation.

[0022] Furthermore, in step S3, the hazard index of disaster-causing factors is calculated as follows:

[0023] The hazard index of disaster-causing factors is shown in formula (3);

[0024] (3);

[0025] In the formula, is the element of the hazard of disaster-causing factors corresponding to the standardized precipitation evapotranspiration index x of the y-th evaluation unit, is the probability corresponding to the standardized precipitation evapotranspiration index x of the y-th evaluation unit at time t, is the probability that the standardized precipitation evapotranspiration index x is -1.

[0026] Furthermore, in step S4, the exposure index of disaster-forming environments is calculated as follows:

[0027] The exposure index of disaster-forming environments is shown in formula (4);

[0028] (4);

[0029] In the formula, is the exposure index of disaster-forming environments of the y-th evaluation unit at time t within the evaluation area, is the area of the type of ground object affected by drought of the y-th evaluation unit at time t within the evaluation area, is the total area of the evaluation area.

[0030] Furthermore, in step S5, the vulnerability index of disaster-bearing bodies is calculated as follows:

[0031] The vulnerability index of disaster-bearing bodies is shown in formula (5);

[0032] (5);

[0033] In the formula, is the vulnerability index of the disaster-bearing body of the y-th evaluation unit at time t in the evaluation area, is the scale of the disaster-bearing body, that is, the ratio of the population of the y-th evaluation unit at time t to the total population of the evaluation area, is the vulnerability coefficient of the disaster-bearing body, that is, the difference between the dimensionless water demand coefficient and the dimensionless precipitation coefficient of the y-th evaluation unit at time t;

[0034] Disaster-bearing body scale as shown in formula (6);

[0035] (6);

[0036] In the formula, is the population of the y-th evaluation unit at time t, is the total population of the evaluation area at time t;

[0037] Total population of the evaluation area at time t is the sum of the populations of each evaluation unit at time t, as shown in formula (7);

[0038] (7);

[0039] In the formula, n is the number of evaluation units in the evaluation area;

[0040] Vulnerability coefficient of the disaster-bearing body as shown in formula (8);

[0041] (8);

[0042] In the formula, is the dimensionless water demand coefficient of the y-th evaluation unit at time t, is the dimensionless precipitation coefficient of the y-th evaluation unit at time t;

[0043] The dimensionless water demand coefficient of the y-th evaluation unit at time t is shown in formula (9);

[0044] (9);

[0045] The dimensionless precipitation coefficient of the y-th evaluation unit at time t is shown in formula (10);

[0046] (10);

[0047] In the formula, is the multi-year average normalized difference vegetation index of the y-th evaluation unit at time t, is the cumulative value of the multi-year average normalized difference vegetation index for the y-th assessment unit within the year, is the multi-year average areal rainfall for the y-th assessment unit at time t, is the cumulative value of the multi-year average areal rainfall for the y-th assessment unit within the year.

[0048] Furthermore, in step S6, the disaster prevention and mitigation capacity index is calculated, specifically as follows:

[0049] The disaster prevention and mitigation capacity index is shown in formula (11);

[0050] (11);

[0051] In the formula, is the disaster prevention and mitigation capacity index for the y-th assessment unit at time t within the assessment area, is the beneficial storage capacity of the j-th reservoir within the y-th assessment unit at time t in the assessment area.

[0052] Furthermore, the normalization method is shown in formula (12);

[0053] (12);

[0054] is the normalized index value of the assessment index in the assessment unit at time t, is the minimum value of the assessment index among several assessment units at time t, is the maximum value of the assessment index among several assessment units at time t; is the index value of the assessment unit y at time t.

[0055] Compared with the prior art, the present invention adopts the above technical solutions and has the following technical effects:

[0056] (1) Through the four elements of disaster theory, the present invention proposes a dynamic assessment model for the comprehensive risk of drought disasters, considering indicators such as the hazard of disaster-causing factors, the exposure of disaster-bearing environments, the vulnerability of disaster-affected bodies, and the disaster prevention and mitigation capacity. This model makes up for the deficiency of traditional risk assessment that only relies on the hazard of disaster-causing factors and does not involve the essence of drought disasters, achieving a leap from drought risk to drought disaster risk.

[0057] (2) The indicators and calculation methods proposed by the present invention for the dynamic assessment of the comprehensive risk of drought disasters can reflect the risk evolution process of different assessment units in the spatial area to be evaluated before and after drought disasters. The model results characterize the dynamic change characteristics of the comprehensive risk of drought disasters in time and space, making up for the deficiency of traditional static risk assessment relying on the hazard of disaster-causing factors and achieving the dynamic assessment of the comprehensive risk of drought disasters. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a flowchart of a method for dynamically evaluating the comprehensive risk of drought disasters in the present invention. Detailed implementation manners

[0059] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the application will be further elaborated in detail below with reference to the accompanying drawings. The described embodiments are only a part of the embodiments involved in the present invention. All non-innovative embodiments of other researchers in the field based on this embodiment belong to the protection scope of the present invention. At the same time, for the step numbers in the embodiments of the present invention, they are only set for the convenience of elaboration and explanation, and no limitation is imposed on the order between the steps. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0060] As Figure 1 shown, a method for dynamically evaluating the comprehensive risk of drought disasters includes the following steps:

[0061] Step S1: Collect and sort out various types of data according to the characteristics of each evaluation unit in the evaluation area;

[0062] Step S2: Construct a conceptual model for dynamically evaluating the comprehensive risk of drought disasters that reflects the change characteristics of each risk index in time and space;

[0063] Step S3: Calculate the hazard index of the disaster-causing factor according to the data in Step S1 and the conceptual model for dynamically evaluating the comprehensive risk of drought disasters in Step S2;

[0064] Step S4: Calculate the exposure index of the disaster-bearing environment according to the data in Step S1 and the conceptual model for dynamically evaluating the comprehensive risk of drought disasters in Step S2;

[0065] Step S5: Calculate the vulnerability index of the disaster-affected body according to the data in Step S1 and the conceptual model for dynamically evaluating the comprehensive risk of drought disasters in Step S2;

[0066] Step S6: Calculate the disaster prevention and mitigation capacity index according to the data in Step S1 and the conceptual model for dynamically evaluating the comprehensive risk of drought disasters in Step S2;

[0067] Step S7: Based on the conceptual model for dynamically evaluating the comprehensive risk of drought disasters in Step S2, the hazard index of the disaster-causing factor in Step S3, the exposure index of the disaster-bearing environment in Step S4, the vulnerability index of the disaster-affected body in Step S5, and the disaster prevention and mitigation capacity index in Step S6, construct a mathematical model for dynamically evaluating the comprehensive risk of drought disasters to evaluate the comprehensive risk of drought disasters of each evaluation unit;

[0068] Among them, for Step S7 to construct the mathematical model for dynamically evaluating the comprehensive risk of drought disasters, see Formula (1) as shown;

[0069] (1);

[0070] Wherein, is the dynamic assessment mathematical model of the comprehensive risk of drought disasters, is the hazard index of the disaster-causing factor corresponding to the standardized precipitation evapotranspiration index x of the y-th assessment unit at time t in the assessment area, , , are respectively the coefficients of the disaster-bearing environment exposure factor , the vulnerability factor of the disaster-affected body and the disaster prevention and mitigation capacity factor at time t for the y-th assessment unit;

[0071] The disaster-bearing environment exposure factor is obtained by normalizing the disaster-bearing environment exposure index of the y-th assessment unit at time t in step S4;

[0072] The vulnerability factor of the disaster-affected body is obtained by normalizing the vulnerability index of the disaster-affected body of the y-th assessment unit at time t in step S5;

[0073] The disaster prevention and mitigation capacity factor is obtained by normalizing the disaster prevention and mitigation capacity index of the y-th assessment unit at time t in step S6.

[0074] Furthermore, in step S1, various types of data include meteorological data, land cover type data, land cover types and area data affected by drought, population quantity data, water conservancy project location data and beneficial storage capacity data, and the data are statistically calculated with the assessment units in the assessment area as the units;

[0075] In step S2, the comprehensive risk of drought disasters includes four aspects: the hazard of the disaster-causing factor, the vulnerability of the disaster-affected body, the exposure of the disaster-bearing environment, and the disaster prevention and mitigation capacity. The constructed conceptual model for the dynamic assessment of the comprehensive risk of drought disasters is shown in formula (2);

[0076] (2);

[0077] Wherein, is the conceptual model for the dynamic assessment of the comprehensive risk of drought disasters, is the hazard index of the drought disaster-causing factor at time t, is the comprehensive impact index of the drought disaster at time t, H is the element of the hazard of the disaster-causing factor, E is the element of the exposure of the disaster-bearing environment, V is the element of the vulnerability of the disaster-affected body, and A is the element of the disaster prevention and mitigation capacity.

[0078] Further, in step S3, the hazard index of the disaster-causing factor is calculated as follows:

[0079] The hazard index of the disaster-causing factor is shown in formula (3);

[0080] (3);

[0081] In the formula, is the hazard element of the disaster-causing factor corresponding to the standardized precipitation evapotranspiration index x of the y-th evaluation unit, is the probability corresponding to the standardized precipitation evapotranspiration index x of the y-th evaluation unit at time t, is the probability that the standardized precipitation evapotranspiration index x is -1.

[0082] In the embodiment of the present invention, it is assumed that when the value of the standardized precipitation evapotranspiration index is -1, it is the drought threshold of the evaluation area.

[0083] Further, in step S4, the exposure index of the disaster-bearing environment is calculated as follows:

[0084] The exposure index of the disaster-bearing environment is shown in formula (4);

[0085] (4);

[0086] In the formula, is the exposure index of the disaster-bearing environment of the y-th evaluation unit at time t in the evaluation area, is the area of the land cover type affected by drought of the y-th evaluation unit at time t in the evaluation area, is the total area of the evaluation area.

[0087] Further, in step S5, the vulnerability index of the disaster-affected body is calculated as follows:

[0088] The vulnerability index of the disaster-affected body is shown in formula (5);

[0089] (5);

[0090] In the formula, is the vulnerability index of the disaster-affected body of the y-th evaluation unit at time t in the evaluation area, is the scale of the disaster-affected body, that is, the proportion of the population of the y-th evaluation unit at time t in the total population of the evaluation area, is the vulnerability coefficient of the disaster-affected body, that is, the difference between the dimensionless water demand coefficient and the dimensionless precipitation coefficient of the y-th evaluation unit at time t;

[0091] The scale of the disaster-affected body is shown in formula (6);

[0092] (6);

[0093] Wherein, is the population of the y-th evaluation unit at time t, is the total population of the evaluation area at time t;

[0094] The total population of the evaluation area at time t is the sum of the populations of each evaluation unit at time t, as shown in formula (7);

[0095] (7);

[0096] Wherein, n is the number of evaluation units in the evaluation area;

[0097] Vulnerability coefficient of disaster-bearing body is shown in formula (8);

[0098] (8);

[0099] Wherein, is the dimensionless water demand coefficient of the y-th evaluation unit at time t, is the dimensionless precipitation coefficient of the y-th evaluation unit at time t;

[0100] The dimensionless water demand coefficient of the y-th evaluation unit at time t is shown in formula (9);

[0101] (9);

[0102] The dimensionless precipitation coefficient of the y-th evaluation unit at time t is shown in formula (10);

[0103] (10);

[0104] Wherein, is the multi-year average normalized vegetation index of the y-th evaluation unit at time t, is the cumulative value of the multi-year average normalized vegetation index of the y-th evaluation unit within a year, is the multi-year average surface rainfall of the y-th evaluation unit at time t, is the cumulative value of the multi-year average surface rainfall of the y-th evaluation unit within a year.

[0105] Furthermore, in step S6, calculate the disaster prevention and mitigation capacity index, specifically:

[0106] The disaster prevention and mitigation capacity index is shown in formula (11);

[0107] (11);

[0108] Wherein, is the disaster prevention and mitigation ability index of the y-th evaluation unit at time t in the evaluation area, is the beneficial storage capacity of the j-th reservoir in the y-th evaluation unit at time t in the evaluation area.

[0109] Furthermore, the normalization method is shown in formula (12);

[0110] (12);

[0111] is the normalized index value of the evaluation index in the evaluation unit at time t, is the minimum value of the evaluation index in several evaluation units at time t, is the maximum value of the evaluation index in several evaluation units at time t; is the index value of the evaluation unit y at time t.

[0112] In summary, a method for dynamically evaluating the comprehensive risk of drought disasters in this embodiment starts from the theory of the four elements of natural disasters, and proposes a dynamic evaluation model for the comprehensive risk of drought disasters considering indicators such as the hazard of disaster-causing factors, the exposure of disaster-forming environments, the vulnerability of disaster-bearing bodies, and the disaster prevention and mitigation ability, making up for the deficiency that the traditional risk assessment only relying on the hazard of disaster-causing factors does not involve the essence of drought disasters, and realizing the leap from drought risk to drought disaster risk. At the same time, the indicators and calculation methods proposed in the invention can reflect the risk evolution process of different evaluation units in the spatial area to be evaluated before and after drought disasters, and the results characterize the dynamic change characteristics of the comprehensive risk of drought disasters in time and space, making up for the deficiency of the traditional static risk assessment relying on the hazard of disaster-causing factors, and realizing the dynamic evaluation of the comprehensive risk of drought disasters.

[0113] The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for dynamic assessment of comprehensive risk of drought disaster, characterized by: The steps include: Step S1, collecting and collating various types of data according to the characteristics of each assessment unit in the assessment area; Step S2, constructing a conceptual model for dynamic assessment of comprehensive risk of drought disasters that reflects the changing characteristics of various risk indicators in time and space; Step S3, calculating the hazard index of the disaster-causing factor according to the data in step S1 and the conceptual model for dynamic assessment of drought disaster comprehensive risk in step S2; Step S4, calculating the exposure index of the disaster-prone environment according to the data in step S1 and the conceptual model for dynamic assessment of comprehensive risk of drought disaster in step S2; Step S5, calculating the vulnerability index of the disaster-bearing body according to the data in step S1 and the conceptual model for dynamic assessment of comprehensive risk of drought disaster in step S2; Step S6, calculating the disaster prevention and mitigation capability index according to the data in step S1 and the conceptual model for dynamic assessment of drought disaster comprehensive risk in step S2; Step S7, based on the conceptual model of dynamic assessment of comprehensive risk of drought disaster in step S2, the hazard index of disaster-causing factors in step S3, the exposure index of disaster-prone environment in step S4, the vulnerability index of disaster-bearing body in step S5, and the disaster prevention and mitigation capacity index in step S6, a mathematical model of dynamic assessment of comprehensive risk of drought disaster is constructed to assess the comprehensive risk of drought disaster in each assessment unit; Among them, step S7 constructs a mathematical model for dynamic assessment of comprehensive risk of drought disasters, as shown in formula (1); （1）； In the formula, It is a mathematical model for dynamic assessment of comprehensive risk of drought disasters. is the hazard index of the hazard factor corresponding to the standardized precipitation evapotranspiration index x of the y-th assessment unit at time t in the assessment area, , , are the disaster-prone environmental exposure factors of the yth assessment unit at time t. , Disaster-bearing body vulnerability factors and disaster prevention and mitigation capacity factors The coefficient of Disaster-prone environmental exposure factor The result obtained by normalizing the disaster-prone environment exposure index of the yth assessment unit at time t in step S4; Disaster-prone body vulnerability factor The result obtained by normalizing the vulnerability index of the disaster-bearing body of the yth assessment unit at time t in step S5; Disaster prevention and mitigation capability factor The result obtained by normalizing the disaster prevention and mitigation capability index of the yth evaluation unit at time t in step S6; In step S1, various types of data include meteorological data, land feature type data, land feature type and area data affected by drought, population data, water conservancy project location data and beneficial reservoir capacity data, and the data are statistically calculated using the assessment unit in the assessment area; In step S2, the conceptual model of dynamic assessment of comprehensive risk of drought disaster is constructed as shown in formula (2); （2）； In the formula, It is a conceptual model for dynamic assessment of comprehensive risk of drought disasters. is the risk index of drought disaster hazard factors at time t, is the comprehensive impact index of drought disaster at time t, H is the risk factor of disaster-causing factors, E is the exposure factor of disaster-prone environment, V is the vulnerability factor of disaster-bearing body, and A is the disaster prevention and mitigation capacity factor; In step S3, the hazard index of the disaster-causing factor is calculated, specifically: The hazard index of the disaster-causing factor is shown in formula (3); （3）； In the formula, is the hazard factor corresponding to the standardized precipitation evapotranspiration index x of the y-th assessment unit, is the probability corresponding to the standardized precipitation evapotranspiration index x of the y-th evaluation unit at time t, is the probability that the standardized precipitation evapotranspiration index x is -1; In step S4, the disaster-prone environment exposure index is calculated, specifically: The index of exposure to disaster-prone environment is shown in formula (4); （4）； In the formula, is the disaster-prone environmental exposure index of the yth assessment unit at time t in the assessment area, is the area of ​​the land feature type affected by drought in the yth assessment unit at time t within the assessment area, is the total area of ​​the assessment region; In step S5, the vulnerability index of the disaster-prone body is calculated, specifically: The vulnerability index of the disaster-bearing body is shown in formula (5); （5）； In the formula, is the vulnerability index of the hazard-bearing body of the yth assessment unit at time t in the assessment area, is the scale of the disaster-prone body, that is, the proportion of the population of the yth assessment unit at time t to the total population of the assessment area, is the vulnerability coefficient of the disaster-bearing body, that is, the difference between the dimensionless water demand coefficient and the dimensionless precipitation coefficient of the yth assessment unit at time t; Disaster-prone area See formula (6); （6）； In the formula, is the population of the yth evaluation unit at time t, is the total population of the evaluation area at time t; The total population of the evaluation area at time t is the sum of the population of each evaluation unit at time t, as shown in formula (7); （7）； Where n is the number of assessment units in the assessment area; Disaster-bearing body vulnerability coefficient See formula (8); （8）； In the formula, is the dimensionless water demand coefficient of the yth evaluation unit at time t, is the dimensionless precipitation coefficient of the yth evaluation unit at time t; The dimensionless water demand coefficient of the yth evaluation unit at time t is shown in formula (9); （9）； The dimensionless precipitation coefficient of the yth evaluation unit at time t is shown in formula (10); （10）； In the formula, is the multi-year average normalized difference vegetation index of the y-th assessment unit at time t, is the cumulative value of the multi-year average normalized difference vegetation index of the yth assessment unit in the year, is the multi-year average surface rainfall of the yth assessment unit at time t, is the accumulated value of multi-year average surface rainfall in the yth assessment unit in the year; In step S6, the disaster prevention and mitigation capability index is calculated, specifically: The disaster prevention and mitigation capability index is shown in formula (11); （11）； In the formula, is the disaster prevention and mitigation capability index of the yth assessment unit at time t in the assessment area, It is the beneficial storage capacity of the jth reservoir in the yth assessment unit at time t in the assessment area.

2. The method for dynamic assessment of comprehensive risk of drought disaster according to claim 1, characterized in that: The normalization method is shown in formula (12); （12）； is the normalized index value of the evaluation index in the evaluation unit at time t, is the minimum value of the evaluation index among several evaluation units at time t, It is the maximum value of the evaluation index among several evaluation units at time t; is the index value of evaluation unit y at time t.

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