Drought disaster comprehensive risk dynamic assessment method

Abstract

The invention relates to a drought disaster comprehensive risk dynamic assessment method, which takes a drought disaster comprehensive risk as an assessment object, selects comprehensive risk assessment factors from four aspects of a disaster-inducing factor, a disaster-pregnant environment, a disaster-bearing body and disaster prevention and reduction capability of a drought disaster, and constructs a drought disaster comprehensive risk dynamic assessment mathematical model. And dynamically evaluating the comprehensive risk of the regional drought disaster in time and space. According to the method, the evolution process of each risk factor in time and space is considered, the comprehensive risk characteristics of drought disasters in different areas at different moments can be represented, the defect that the risk of the drought disaster-inducing factor is represented only by the drought frequency traditionally is made up to a certain extent, and meanwhile, the method has a good application prospect. According to the method, the influence of factors such as a disaster-pregnant environment, a disaster-bearing body and disaster prevention and reduction capability on the risk is also considered, and the spanning from the drought risk to the drought disaster risk is realized.

Description

Technical Field

[0001] The invention relates to water conservancy engineering, emergency management, environmental engineering and their interdisciplinary fields, and in particular to a method for dynamic assessment of comprehensive risk of drought disasters. Background Art

[0002] Drought disaster risk assessment is the key to the transformation from drought disaster crisis management mode to drought disaster risk management mode. It refers to the use of various methods to measure the degree and possibility of the impact and harm caused by drought disasters on social economy and natural systems, covering the entire process from the evolution of drought phenomena to drought disasters to the final disappearance of disasters. In recent years, with the rapid development and application of satellite remote sensing technology, the data available for drought research has been greatly expanded in both type and magnitude. The spatiotemporal characteristics of the data can timely reflect the various links of the transformation from drought to drought disasters, providing data conditions for the transformation of risk research from drought to drought disasters. At the same time, the spatiotemporal characteristics of the data also lay the foundation for the dynamic assessment of drought disaster risks. Summary of the invention

[0003] The problem to be solved by the present invention is: based on the spatiotemporal characteristics of the comprehensive risk of drought disasters, a calculation method for evaluation indicators such as the danger of disaster-causing factors, exposure to disaster-prone environments, vulnerability of disaster-bearing bodies, and disaster prevention and mitigation capabilities is proposed, and a mathematical model for dynamic assessment of drought disaster risks is constructed to achieve dynamic analysis of the comprehensive risk of drought disasters in the assessment area in time and space.

[0004] The present invention adopts the following technical solution: a method for dynamic assessment of comprehensive risk of drought disasters, comprising the following steps: 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 capability 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 It is obtained by normalizing the disaster prevention and mitigation capability index of the yth evaluation unit at time t in step S6.

[0005] Furthermore, 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 comprehensive risk of drought disaster includes four aspects: the hazard of disaster-causing factors, the vulnerability of disaster-bearing bodies, the exposure of disaster-prone environments, and the disaster prevention and mitigation capabilities. The conceptual model for dynamic assessment of the 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.

[0006] Furthermore, 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.

[0007] Furthermore, 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.

[0008] Furthermore, 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, It is the accumulated value of multi-year average surface rainfall in the yth assessment unit in the year.

[0009] Furthermore, 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.

[0010] Furthermore, 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 indicator value of evaluation unit y at time t.

[0011] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects: (1) Based on the theory of four disaster factors, this paper proposes a dynamic assessment model for the comprehensive risk of drought disasters that takes into account indicators such as the hazard of disaster-causing factors, exposure to disaster-prone environments, vulnerability of disaster-bearing bodies, and disaster prevention and mitigation capabilities. This model makes up for the deficiency of traditional risk assessment that only relies on the hazard of disaster-causing factors but does not involve the essence of drought disasters, and achieves a leap from drought risk to drought disaster risk.

[0012] (2) The indicators and calculation methods proposed in this invention for dynamic assessment of comprehensive risk of drought disasters can reflect the risk evolution process of different assessment units in the spatial area to be assessed before and after the drought disaster. The model results characterize the dynamic change characteristics of comprehensive risk of drought disasters in time and space, making up for the deficiency of static risk when traditional risk assessment relies on the hazard of disaster factors, and realizing the dynamic assessment of comprehensive risk of drought disasters. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The present invention is a flowchart of a method for dynamic assessment of comprehensive risk of drought disasters. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the application is further elaborated in detail below in conjunction with 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 on this embodiment belong to the protection scope of the present invention. At the same time, for the step numbering in the embodiment of the present invention, it is only set for the convenience of explanation, and the order between the steps is not limited in any way. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0015] like Figure 1 As shown, a method for dynamic assessment of comprehensive risk of drought disasters comprises the following steps: 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 capability 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 It is obtained by normalizing the disaster prevention and mitigation capability index of the yth evaluation unit at time t in step S6.

[0016] Furthermore, 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 comprehensive risk of drought disaster includes four aspects: the hazard of disaster-causing factors, the vulnerability of disaster-bearing bodies, the exposure of disaster-prone environments, and the disaster prevention and mitigation capabilities. The conceptual model for dynamic assessment of the 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.

[0017] Furthermore, 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.

[0018] In the embodiment of the present invention, it is assumed that the value of the standardized precipitation evapotranspiration index is -1, which is the drought threshold of the assessment area.

[0019] Furthermore, 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.

[0020] Furthermore, 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, It is the accumulated value of multi-year average surface rainfall in the yth assessment unit in the year.

[0021] Furthermore, 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.

[0022] Furthermore, 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.

[0023] In summary, the method for dynamic assessment of comprehensive risk of drought disasters in this embodiment, starting from the theory of four elements of natural disasters, proposes a dynamic assessment model of comprehensive risk of drought disasters that takes into account indicators such as the hazard of disaster-causing factors, exposure of disaster-prone environments, vulnerability of disaster-bearing bodies, and disaster prevention and mitigation capabilities, which 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, and realizes the transition 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 assessment units in the spatial area to be assessed before and after the drought disaster. The results characterize the dynamic change characteristics of the comprehensive risk of drought disasters in time and space, making up for the deficiency of static risk when traditional risk assessment relies on the hazard of disaster-causing factors, and realizing the dynamic assessment of the comprehensive risk of drought disasters.

[0024] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection 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 It is obtained by normalizing the disaster prevention and mitigation capability index of the yth evaluation unit at time t in step S6.

2. The method for dynamic assessment of comprehensive risk of drought disaster according to claim 1, characterized in that: 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.

3. The method for dynamic assessment of comprehensive risk of drought disaster according to claim 2, characterized in that: 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.

4. The method for dynamic assessment of comprehensive risk of drought disaster according to claim 3, characterized in that: 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.

5. The method for dynamic assessment of comprehensive risk of drought disaster according to claim 4, characterized in that: 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, It is the accumulated value of multi-year average surface rainfall in the yth assessment unit in the year.

6. A method for dynamic assessment of comprehensive risk of drought disaster according to claim 5, characterized in that: 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.

7. A method for dynamic assessment of comprehensive risk of drought disaster according to claim 6, 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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