CN110766327A - A risk assessment method for island reef desalination water bodies under tidal action - Google Patents

Abstract

The invention proposes a method for evaluating the risk of desalinated water bodies of islands and reefs under the action of tides. , and determine the grades of the effective wave height and period of the tidal scenario under evaluation according to the grade standard of the single risk index; establish the conversion function of a single index, convert the effective wave height and period, and obtain the effective wave height conversion function value and period conversion function value; set For the reference sequence, calculate the correlation coefficient between each single-item conversion function value sequence and the reference sequence, and calculate the correlation degree according to the correlation coefficient of each single-item index; determine the comprehensive index to judge the risk index level according to the correlation degree. The present invention fully considers the influence of effective wave height and period, which are two important indicators of tides, on the risk of desalinated water bodies of islands and reefs, and can be used to evaluate the risk level that tides may cause to desalinated water bodies of islands and reefs.

Description

A risk assessment method for island reef desalination water bodies under tidal action

technical field

The invention relates to the technical field of risk assessment, in particular to a risk assessment method for desalinated water bodies of islands and reefs under the action of tides.

Background technique

The desalinated water bodies of islands and reefs are formed under the combined action of abundant atmospheric precipitation, special coral geology, and differences in the proportion of fresh and salty water. Coral islands and reefs of a certain width may form desalinated water bodies. If the water quality can reach the standard of irrigation water, it can be used for residents' living, greening, livestock breeding, island forestation, etc., which can fundamentally improve the quality of life of island residents; even industrial and agricultural development provides important basic conditions. The main factors affecting the formation of desalinated water bodies are hydrogeological characteristics (the distribution of permeability, the development of fractures, pores and karst caves, and the depth of unconformity, etc.). Because of the reef's geographic location surrounded by water, tides can pose unknown risks to desalinated water bodies.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve at least one of the technical defects.

Therefore, the purpose of the present invention is to propose a risk assessment method for desalinated water bodies of islands and reefs under the action of tides.

In order to achieve the above purpose, an embodiment of the present invention provides a method for assessing the risk of desalination water bodies of islands and reefs under the action of tides, comprising the following steps:

Step S1, taking the effective wave height and period of the tide as a single risk index, and setting a single risk index level standard;

Step S2, obtaining the effective wave height and period of the evaluated tidal scenario, and respectively determining the grades of the effective wave height and period of the evaluated tidal scenario according to the single risk index level standard;

Step S3, establishing a single index conversion function, converting the effective wave height and period, to obtain the effective wave height conversion function value and the period conversion function value, so that the value range of the effective wave height conversion function value and the period conversion function value is located at (0,1) ;

Step S4, set the reference sequence, calculate the correlation coefficient between each single item conversion function value sequence and the reference sequence, and calculate the correlation degree according to each single item index correlation coefficient;

Step S5: Determine the comprehensive index to judge the risk index level according to the correlation degree.

Further, in the step S1, the setting of a single risk index level standard includes the following steps:

According to each single statistical index, the risk index is divided into 5 levels, including: extremely dangerous, highly dangerous, significant danger, general danger, rare danger, and different statistical indexes correspond to different disaster levels.

Further, in the step S3, the conversion function of the effective wave height is established, and the single-item index conversion function value of the effective wave height is calculated, according to the following formula:

Among them, U _p is the conversion function value of the absolute value of the significant wave height; X is the absolute value of the significant wave height; lg is the logarithm of X in the base 10.

Further, in the step S3, the conversion function of the cycle is established, and the single-item index conversion function value of the cycle is calculated, according to the following formula:

Among them, _UR is the conversion function value of the absolute value of the period; X is the absolute value of the period; lg is the logarithm of X in the base 10. Further, in the step S4, the correlation coefficients λ _p and λ _Z of the effective wave height and the period are calculated, according to the following formula:

Among them, Δ _p = |U _op -U _p |; Δ _R = |U _oR -U _R |; U _Op and U _OR are the reference values of the effective wave height and the absolute value of the period, respectively; U _p and U _R are the comparison values, That is, the conversion function value of the effective wave height and the absolute value of the period.

Further, in the step S4, the calculated correlation degree is based on the following formula:

Among them, α is the correlation degree, and λ _p and λ _Z are the correlation coefficients of effective wave height and period, respectively.

Further, in the step S5, determining the comprehensive index to judge the risk index level according to the correlation degree includes: comparing the calculated correlation degree with a preset comprehensive index to judge the risk index level table, so as to match and determine the correlation The comprehensive index corresponding to the degree is used to judge the risk index level.

The present invention is a method for assessing the risk of desalinated water bodies of islands and reefs under the action of tides, which fully considers the influence of effective wave height and period, which are two important indicators of tides, on the risks of desalination water bodies of islands and reefs, and proposes the risk assessment of water bodies of islands and reefs under the action of tides. new method. The invention theoretically makes up for the blank of the risk assessment of the desalinated water bodies of islands and reefs under the action of tides, can be used to assess the risk level that tides may cause to the desalinated water bodies of islands and reefs, and has important scientific value and practical significance.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a flowchart of a method for assessing the risk of desalinated water bodies of islands and reefs under the action of tides according to an embodiment of the present invention.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

The invention provides a risk assessment method for desalinated water bodies of islands and reefs under the action of tides, which can be used to assess the risk level that tides may cause to the desalinated water bodies of islands and reefs.

As shown in FIG. 1 , the method for assessing the risk of desalination water bodies of islands and reefs under the action of tides according to an embodiment of the present invention includes the following steps:

Step S1, taking the effective wave height and period of the tide as a single risk index, and setting a single risk index level standard.

Specifically, setting a single risk index level standard includes the following steps:

According to each single statistical index, the risk index is divided into 5 levels, including: extremely dangerous, highly dangerous, significant danger, general danger, rare danger, and different statistical indexes correspond to different disaster levels.

In this step, different statistical indicators correspond to different disaster levels, as shown in Table 1.

Table 1 Standard of individual index grades

In step S2, the effective wave height and period of the evaluated tidal scenario are obtained, and the grades of the effective wave height and period of the evaluated tidal scenario are respectively determined according to the grade standard of a single risk index.

Step S3, establishing a single index conversion function, converting the effective wave height and period, to obtain the effective wave height conversion function value and the period conversion function value, so that the value range of the effective wave height conversion function value and the period conversion function value is located at (0,1) . Among them, the corresponding relationship between the single-item index level and the single-item conversion function value is shown in Table 2.

Specifically, the single index conversion function value of the significant wave height is calculated according to the following formula:

Among them, U _p is the conversion function value of the absolute value of the significant wave height; X is the absolute value of the significant wave height, in meters; lg is the logarithm of X in the base 10.

Calculate the conversion function value of the single indicator for the period according to the following formula:

Among them, U _R is the conversion function value of the absolute value of the period; X is the absolute value of the period, in seconds; lg is the logarithm of X in the base 10.

Table 2 Corresponding relationship between single-item index level and single-item conversion function value

According to the calculation, the effective wave height transfer function value and the period transfer function value are obtained, and the index level is determined by matching with the level relationship in Table 2.

Step S4, referring to the grey relational analysis method, set a reference sequence, calculate the correlation coefficient between each single item conversion function value sequence and the reference sequence, and calculate the correlation degree according to each single item index correlation coefficient.

In this step, the correlation coefficients λ _p and λ _Z of the effective wave height and period are calculated according to the following formula:

Among them, Δ _p = |U _op -U _p |; Δ _R = |U _oR -U _R |; U _Op and U _OR are the reference values of the effective wave height and the absolute value of the period in the South China Sea (effective wave height 10 meters, period 4 seconds); U _p and _UR are comparison values, that is, the conversion function values of the effective wave height and the absolute value of the period.

Then calculate the correlation according to the following formula:

Among them, α is the correlation degree, and λ _p and λ _R are the correlation coefficients of effective wave height and period, respectively.

In step S5, the comprehensive index is determined according to the correlation degree to judge the risk index level.

Specifically, determining the comprehensive index to judge the risk index level according to the correlation degree includes: comparing the calculated correlation degree with a preset comprehensive index judgment risk index level table (as shown in Table 3) to match and determine the correlation degree The corresponding comprehensive index is used to judge the risk index level.

Table 3 Comprehensive index levels

According to the method for assessing the risk of desalinated water bodies of islands and reefs under the action of tides in the embodiment of the present invention, the effect of effective wave height and period, two important indicators that characterize tides, on the risks of desalinated water bodies of islands and reefs is put forward. A new approach to risk assessment. The invention theoretically makes up for the blank of the risk assessment of the desalinated water bodies of islands and reefs under the action of tides, can be used to assess the risk level that tides may cause to the desalinated water bodies of islands and reefs, and has important scientific value and practical significance.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and those of ordinary skill in the art will not depart from the principles and spirit of the present invention Variations, modifications, substitutions, and alterations to the above-described embodiments are possible within the scope of the present invention without departing from the scope of the present invention. The scope of the invention is defined by the appended claims and their equivalents.

Claims (7)

1. An island desalination water body risk assessment method under the action of tides is characterized by comprising the following steps:

step S1, taking the effective wave height and period of tide as a single risk index, and setting a single risk index grade standard;

step S2, obtaining the effective wave height and the period of the evaluated tidal scene, and respectively determining the grade of the effective wave height and the period of the evaluated tidal scene according to the grade standard of the single risk index;

step S3, establishing a single index conversion function, and converting the effective wave height and the period to obtain an effective wave height conversion function value and a period conversion function value, so that the value ranges of the effective wave height conversion function value and the period conversion function value are positioned in the (0,1) interval;

step S4, setting a reference sequence, calculating the correlation coefficient of each single conversion function value sequence and the reference sequence, and calculating the correlation degree according to each single index correlation coefficient;

and step S5, determining the comprehensive index evaluation risk index grade according to the relevance.

2. The tidal island desalination water risk assessment method according to claim 1, wherein the step S1 of setting a single risk index rating standard comprises the steps of:

the risk indicators are divided into 5 grades according to each single statistical indicator, including: extremely dangerous, highly dangerous, obvious dangerous, general dangerous, rare danger, different statistical indexes correspond different calamity grades.

3. The tidal island desalination water risk assessment method according to claim 1, wherein in step S3, a transfer function of the absolute value of the effective wave height is established, and a one-index transfer function value of the absolute value of the effective wave height is calculated according to the following formula:

wherein, U_pIs the conversion function value of the absolute value of the effective wave height; x is the absolute value of the effective wave height; lg is the logarithm of base 10X.

4. The tidal island desalination water risk assessment method of claim 1, wherein in step S3, a periodic transfer function is established, and a periodic monomial index transfer function value is calculated according to the following formula:

wherein, U_RIs a conversion function value of the cycle absolute value; x is the absolute value of the period; lg is the logarithm of base 10X.

5. The tidal island desalination water risk assessment method according to claim 1, wherein in step S4, the correlation coefficient λ of the significant wave height and period is calculated_pAnd λ_ZAccording to the following formula:

wherein, Delta_p＝|U_op-U_p|；Δ_R＝|U_oR-U_R|；U_OpAnd U_ORReference values for the effective wave height and the cycle absolute value respectively; u shape_pAnd U_RThe comparison value is the conversion function value of the effective wave height and the absolute value of the period.

6. The tidal island desalination water risk assessment method according to claim 5, wherein in step S4, the calculating of the correlation degree is according to the following formula:

wherein α is the degree of association, λ_pAnd λ_RRespectively, the correlation coefficient of the effective wave height and the period.

7. The tidal island desalination water risk assessment method according to claim 1, wherein the determining a composite index evaluation risk index grade according to the correlation degree in step S5 comprises: and comparing the calculated association degree with a preset comprehensive index judgment risk index grade table to match and determine the comprehensive index judgment risk index grade corresponding to the association degree.

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