Enteromorpha green tide disaster early warning area determination method based on traceability numerical simulation

Abstract

The invention discloses an enteromorpha green tide disaster early warning area determination method based on traceability numerical simulation, and belongs to the field of enteromorpha green tide disaster early warning. The method comprises the following steps: a, determining a disaster sensitive target; b, collecting enteromorpha green tide distribution, hydrological and meteorological factors in a sea area near the disaster sensitive target; c, constructing an enteromorpha green tide drift numerical traceability model; d, carrying out enteromorpha green tide drift value traceability simulation on a sea area near the disaster sensitive target, and backtracking drift positions of enteromorpha green tide particles at different moments; e, determining an early warning area; counting distribution positions of enteromorpha green tide particles at different moments; the outer envelope line is determined according to the distribution position of the enteromorpha green tide particles, and then the early warning area range is determined. According to the method, the traceability numerical simulation method is adopted, the drifting numerical traceability model and multidirectional scheme design are combined to determine the early warning area range of the enteromorpha green tide disaster, and the determined early warning area range is high in precision, so that the emergency response efficiency can be improved, and the disaster can be timely coped with.

Description

Technical Field

[0001] The present invention relates to the field of Enteromorpha prolifera green tide disaster warning, and more particularly to a method for determining a warning area of Enteromorpha prolifera green tide disaster based on traceability numerical simulation. Background Art

[0002] Enteromorpha prolifera green tide is characterized by high biomass, long-distance migration process and great influence. The Enteromorpha prolifera green tide has caused serious impacts on coastal tourism, aquaculture, ecological protection red line areas, nuclear power plants, etc.

[0003] How to determine the warning area for sensitive targets of Enteromorpha prolifera green tide disasters such as offshore and nearshore aquaculture areas, marine ranches, nuclear power plants, and coastal tourism areas is the key and difficult point of the current prevention and control work of Enteromorpha prolifera green tide. Currently, the methods for determining the warning area mainly include statistical and physical numerical model methods. The statistical method refers to identifying possible risk areas based on the historical occurrence of Enteromorpha prolifera green tide disasters and determining the warning area according to the experience of experts. The physical numerical model method refers to forecasting the risk area of the future distribution of Enteromorpha prolifera green tide based on the monitored distribution of Enteromorpha prolifera green tide, and then determining the warning area. Both of these methods start from the disaster itself and determine the possible risk areas based on the monitoring and prediction of the disasters that have occurred, which results in the determined warning area being highly dependent on the real-time monitoring and prediction results of Enteromorpha prolifera green tide disasters. Once the monitoring is not timely or the prediction is inaccurate, there will be a large uncertainty and prediction error in the range of the warning area.

[0004] Currently, there are also methods for determining the warning area starting from disaster-sensitive targets, but only determine the warning area range by simply calculating the length and width of the warning area. From practice, the accuracy of the warning area range determined by this method still needs to be further improved. Summary of the Invention

[0005] Based on the above technical problems, the present invention proposes a method for determining a warning area of Enteromorpha prolifera green tide disaster based on traceability numerical simulation.

[0006] The technical solution adopted by the present invention is as follows: A method for determining a warning area of Enteromorpha prolifera green tide disaster based on traceability numerical simulation, comprising the following steps: a. Determine disaster-sensitive targets; b. Collect the distribution of Enteromorpha prolifera green tide and meteorological elements in the sea area where the disaster-sensitive targets are located; c. Construct a numerical traceability model for the drift of Enteromorpha prolifera green tide; d. Carry out numerical traceability simulation of the drift of Enteromorpha prolifera green tide in the sea area where the disaster-sensitive targets are located, and trace back the drift positions of Enteromorpha prolifera green tide particles at different times; e. Determine the warning area; The distribution positions of the Enteromorpha green tide particles at different times are counted; the outer envelope line is determined according to the distribution positions of the Enteromorpha green tide particles, thereby determining the scope of the early warning area.

[0007] The beneficial technical effects of the present invention are: The present invention adopts a traceability numerical simulation method, combined with a drift numerical traceability model and a multi-faceted scheme design, to determine the scope of the early warning zone for the Ulva green tide disaster. The determined early warning zone has high accuracy, thereby improving the efficiency of emergency response, ensuring timely response to disasters, and avoiding as much as possible the waste of manpower and material resources caused by the excessive size of the early warning zone.

[0008] The present invention considers that the drift of Enteromorpha green tide particles is affected by the atmosphere and ocean environment, and constructs a refined tracing model of Enteromorpha green tide numerical drift for sensitive targets and distribution of Enteromorpha green tide disasters, and designs a scheme to carry out tracing simulation, thereby determining early warning areas in different time periods such as 24h, 48h and 72h. The present invention can provide disposal (salvage or interception, etc.) auxiliary decision-making technical support for sensitive targets of Enteromorpha green tide disasters, improve the scientificity and effectiveness of decision-making, and play an important role in the field of Enteromorpha green tide disaster prevention and control. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a flow chart of a method for determining an early warning area for a green tide disaster of Enteromorpha based on source tracing numerical simulation of the present invention; Figure 2 It is a schematic diagram of throwing green tide particles of Enteromorpha at a certain location and the determined outer envelope line in a specific application example of the present invention. DETAILED DESCRIPTION

[0010] The present invention will be further described below in conjunction with the accompanying drawings and specific implementations.

[0011] like Figure 1 As shown, a method for determining an early warning area for a green tide disaster of Enteromorpha enteromorpha based on source tracing numerical simulation comprises the following steps: a. Identify disaster-sensitive targets.

[0012] Based on the impact of the Ulva green tide disaster on marine-related industries and the needs of the government or enterprises and institutions, disaster-sensitive targets are identified, such as: nuclear power plant water intakes, sailing racing areas, seawater aquaculture areas, bathing beaches, etc.

[0013] b. Collect and organize the distribution, hydrological and meteorological elements of green tides in the sea areas near disaster-sensitive targets.

[0014] The time and distribution range of the Ulva green tide disaster affecting disaster-sensitive targets in the past five years, as well as the distribution characteristics of ocean currents and sea surface winds in the sea areas near disaster-sensitive targets, were collected and analyzed, and the average wind speed in the sea areas near the sensitive targets was calculated.

[0015] c. Build a refined numerical traceability model for the short-term drift of Enteromorpha prolifera green tides.

[0016] Based on the Lagrangian particle tracking method, without considering ecological processes such as the growth and decay of Enteromorpha prolifera, the floating Enteromorpha prolifera green tide patches are discretized into a certain number of Enteromorpha prolifera green tide particles. Mainly considering the drag effects of wind and current on the Enteromorpha prolifera green tide patches, the calculation of the drift position of a certain Enteromorpha prolifera green tide particle is shown in formula (1).

[0017] (1) In formula (1), x t is the position of the Enteromorpha prolifera green tide particle at time t; x t0 is the position of the Enteromorpha prolifera green tide particle at the initial time t0. v a is the surface current velocity, v d is the wind speed at 10 m above the sea surface; R1 is the current action coefficient; R2 is the wind action coefficient, representing the direct drag effect of the wind on the Enteromorpha prolifera green tide particle; represents the change in the movement direction of the Enteromorpha prolifera green tide particle by the wind; the x-axis direction is and the y-axis direction is where is the angle between the wind and the x-axis coordinate, in degrees, is the wind drag deflection angle, in degrees.

[0018] The grid resolution of the refined numerical traceability model for the short-term drift of Enteromorpha prolifera green tides can depict the distribution characteristics of sensitive targets and shorelines.

[0019] d. Design a traceability scheme and conduct numerical traceability simulations of the drift of Enteromorpha prolifera green tides.

[0020] d1. Set the initial release position and the duration of the traceability simulation of the model; According to the distribution of Enteromorpha prolifera green tides and the geographical distribution of disaster-sensitive targets, release Enteromorpha prolifera green tide particles (the number of released Enteromorpha prolifera green tide particles is generally more than 50). The release range of Enteromorpha prolifera green tide particles is the area included by the main shoreline parallel to the sea area near the disaster-sensitive target and m kilometers offshore (the distance parallel to the main shoreline and the offshore distance are generally less than the drift distance of Enteromorpha prolifera green tides caused by the average sea surface wind speed).

[0021] Set the duration of the traceability numerical simulation according to the protection requirements of disaster-sensitive targets, generally 72 h.

[0022] d2. Design a scheme and conduct traceability numerical simulations.

[0023] Drive the ocean current model using the climatological atmospheric fields (wind field, heat flux, etc.) in the sea area near the disaster-sensitive target. After the ocean current model stabilizes, carry out 8 or 16 design schemes. The schemes are as follows: Drive the ocean current model using the 10m wind field at the mean sea surface in eight directions (wind speed obtained from step b) and the climatological heat flux field to obtain the surface ocean currents under 8 schemes. Each scheme is the mean sea surface wind field in one direction (v d ), and the corresponding surface ocean current (v a ). Based on the model constructed in step c, carry out backward numerical simulation to trace back the drift positions of the Enteromorpha prolifera green tide particles at different times. Based on 8 or 16 design schemes, obtain the drift positions of the Enteromorpha prolifera green tide particles at different times under 8 or 16 design schemes.

[0024] Generally speaking, taking 8 design schemes as an example, according to the average wind speed obtained in step b and combined with the 8 designed wind directions, the wind field can be obtained; according to the obtained wind field, drive the ocean current model to further obtain the surface ocean current; combine the obtained wind field and surface ocean current with the constructed backward tracing model to inversely deduce the particle drift trajectory. If there are 8 wind directions, it corresponds to releasing particles to obtain 8 drift trajectories. If the output points are taken every hour, 24×8 particle points are obtained after 24 hours, and correspondingly 72×8 particle points are obtained after 72 hours. Use the envelope line of all these particle points to further obtain the range of the early warning area.

[0025] In the above steps, the simulation duration of the ocean current model needs to be greater than the simulation duration of the backward numerical tracing model for the Enteromorpha prolifera green tide drift; in the model constructed based on step c, the spatial range of the 10m wind field at the sea surface and the surface ocean current data is greater than the range where the disaster-sensitive target is located and the sea area where all Enteromorpha prolifera green tide particles may drift during the numerical simulation.

[0026] e. Determine the early warning area.

[0027] Statistically analyze the distribution positions of the Enteromorpha prolifera green tide particles at different times; determine the envelope line according to the distribution positions of the Enteromorpha prolifera green tide particles, thereby determining the range of the early warning area.

[0028] Specifically, according to the backward tracing results of 8 or 16 design schemes, statistically analyze the distribution positions of the Enteromorpha prolifera green tide particles at 0 - 24h, 0 - 48h, and 0 - 72h; determine the envelope line according to the distribution positions of the Enteromorpha prolifera green tide particles. The area within the envelope line at 0 - 24h is the 24h Enteromorpha prolifera green tide early warning area; the area within the envelope line at 0 - 48h is the 48h Enteromorpha prolifera green tide early warning area; the area within the envelope line at 0 - 72h is the 72h Enteromorpha prolifera green tide early warning area.

[0029] The following further illustrates the present invention with specific application examples.

[0030] 1. Determine the disaster-sensitive target.

[0031] Enteromorpha prolifera is extremely easy to entangle on the cooling water intake filters of nuclear power plants, blocking the water inlet channels of the units and posing a threat to the safe and stable power generation of nuclear power plants. This can cause the nuclear power plant to reduce power or shut down due to insufficient cooling water flow. Since the current nuclear power in China generally adopts the design of multiple units sharing a water intake, it will also cause multiple units to reduce power or shut down continuously in a short period of time, impacting the power grid. When the blockage is particularly severe, it may lead to insufficient cooling water flow for the reactor main pump and the spent fuel pool cooling water, directly threatening nuclear safety. In this application example, the nuclear power water intake is selected as the disaster-sensitive target.

[0032] 2. Collect the distribution of Enteromorpha prolifera and hydro-meteorological elements in the waters near the disaster-sensitive target.

[0033] Collect and collate the Enteromorpha prolifera green tide disaster situation, sea current, and wind field. The time when the Enteromorpha prolifera green tide affects the waters near the target is from mid-June to mid-July. The Enteromorpha prolifera green tide near the target waters is mainly affected by the south wind and the northeastward current, and the average wind speed of the wind field is about 5 m / s.

[0034] 3. Set the release positions of Enteromorpha prolifera green tide particles.

[0035] According to the distribution of Enteromorpha prolifera green tide and the geographical distribution of nuclear power, set the release range. Due to the average sea surface wind speed near this sensitive target, the drifting distance of the Enteromorpha prolifera green tide is about 5 km. The release range is set as the area included by the line parallel to the main shoreline near the waters of the disaster-sensitive target (with the disaster-sensitive target as the center point, extending 5 kilometers from both ends to the coastal shoreline) and 5 kilometers offshore. Release Enteromorpha prolifera green tide particles at equal intervals within the release range. In this application example, 67 Enteromorpha prolifera green tide particles are released in the waters near the nuclear power water intake, as Figure 2 shown.

[0036] 4. Construct a refined numerical tracing model for the short-term drift of Enteromorpha prolifera green tide.

[0037] Based on the Lagrangian particle tracking method, without considering ecological processes such as the growth and extinction of Enteromorpha prolifera, discretize the floating Enteromorpha prolifera green tide patches into a certain number of Enteromorpha prolifera green tide particles, mainly considering the dragging effects of wind and current on the Enteromorpha prolifera green tide patches. The calculation of the drifting position of a certain particle is shown in formula (1).

[0038] (1) In formula (1), x t is the position of the Enteromorpha prolifera green tide patch at time t; x t0 is the position of the Enteromorpha prolifera green tide patch at the initial time t0. v a is the surface flow velocity, v d is the sea surface wind speed at 10 m; R1 is the sea current action coefficient; R2 is the wind action coefficient, representing the direct dragging effect of the wind on the Enteromorpha prolifera green tide patch; Indicates the effect of wind on the movement direction of the Enteromorpha prolifera green tide patches; the x-axis direction is , and the y-axis direction is , where is the angle between the wind and the x-axis coordinate, in degrees, is the wind drag deflection angle, in degrees.

[0039] The grid resolution of the refined numerical tracing model for the short-term drift of the Enteromorpha prolifera green tide is set to 1 km, and it can depict the distribution characteristics of nuclear power sensitive targets and shorelines.

[0040] 5. Design scheme: Carry out tracing numerical simulation based on the refined numerical tracing model for the short-term drift of the Enteromorpha prolifera green tide.

[0041] Use the climatological ERA5 atmospheric field and heat flux field affecting the waters near sensitive targets to drive the ocean current model ROMS. After the ocean current model is stabilized, 8 schemes are designed.

[0042] Scheme design: Adopt a uniform mean wind field (5 m / s) in the waters near the target, and divide 360° into 8 azimuths as the wind field directions.

[0043] Scheme 1: Use the northward sea surface wind (UV = 5 m / s, DIR = 0°), north wind and heat flux field to drive the ocean current model to obtain the surface ocean current in the waters near the disaster sensitive target. Use the sea surface wind (v d ) and surface ocean current (v a ) data. Based on the refined numerical tracing model for the short-term drift of the Enteromorpha prolifera green tide, trace back the drift positions of Enteromorpha prolifera green tide particles every hour within 72 h; the ocean current action coefficient R1 in the refined numerical tracing model for the short-term drift of the Enteromorpha prolifera green tide is set to 1, the wind action coefficient R2 is set to 0.01, and the wind drag deflection angle is set to 20°. The duration of the ocean current and sea surface wind data is not shorter than the duration of the drift numerical simulation; the data spatial range is larger than the range where the target is located and the waters where all Enteromorpha prolifera green tide particles may drift during the numerical simulation.

[0044] Scheme 2: The same as Scheme 1, the difference is that: use the northeast wind (UV = 5 m / s, DIR = 45°) and the northeast wind to drive the ocean current model; Scheme 3: The same as Scheme 1, the difference is that: use the east wind (UV = 5 m / s, DIR = 90°) and the east wind to drive the ocean current model; Scheme 4: The same as Scheme 1, the difference is that: use the southeast wind (UV = 5 m / s, DIR = 135°) and the southeast wind to drive the ocean current model; Scheme 5: The same as Scheme 1, the difference is that: use the south wind (UV = 5 m / s, DIR = 180°) and the south wind to drive the ocean current model; Scenario 6: Same as Scenario 1, the difference is that a southwest wind (UV = 5 m / s, DIR = 225°) and a southwest wind-driven ocean current model are adopted; Scenario 7: Same as Scenario 1, the difference is that a west wind (UV = 5 m / s, DIR = 270°) and a west wind-driven ocean current model are adopted; Scenario 8: Same as Scenario 1, the difference is that a northwest wind (UV = 5 m / s, DIR = 315°) and a northwest wind-driven ocean current model are adopted; Among them, UV is the wind speed and DIR is the wind direction.

[0045] Based on the 8 scenarios, the drift positions of Enteromorpha prolifera particles within 72 hours under the 8 scenarios are obtained.

[0046] 5. Warning area demarcation.

[0047] According to the tracing results of the 8 design scenarios, the distribution positions of Enteromorpha prolifera particles at 0 - 24h, 0 - 48h, and 0 - 72h are statistically analyzed. Calculate its outer envelope line based on the particle distribution positions, as Figure 2 shown. The area within the 0 - 24h outer envelope line is the 24h Enteromorpha prolifera green tide warning area; the area within the 0 - 48h outer envelope line is the 48h Enteromorpha prolifera green tide warning area; the area within the 0 - 72h outer envelope line is the 72h Enteromorpha prolifera green tide warning area.

Claims

1. A method for determining a warning area of Enteromorpha prolifera green tide disaster based on traceability numerical simulation, characterized in that It includes the following steps: a. Determine disaster-sensitive targets; b. Collect the distribution of Enteromorpha prolifera green tides and meteorological elements in the sea area where the disaster-sensitive targets are located; c. Construct a numerical tracing model for the drift of Enteromorpha prolifera green tides; d. Conduct a numerical tracing simulation of the drift of Enteromorpha prolifera green tides in the sea area where the disaster-sensitive targets are located, and trace back the drift positions of Enteromorpha prolifera green tide particles at different times; e. Determine the early warning area; Statistically analyze the distribution positions of Enteromorpha prolifera green tide particles at different times; determine their outer envelope lines according to the distribution positions of Enteromorpha prolifera green tide particles, so as to determine the scope of the early warning area.

2. The method for determining a warning area for Enteromorpha prolifera green tide disasters based on traceability numerical simulation according to claim 1, wherein In step a: The disaster-sensitive targets include nuclear power plant water intakes, sailing competition areas, mariculture areas and seawater bathing beaches.

3. The method for determining a warning area of Enteromorpha prolifera green tide disaster based on traceability numerical simulation according to claim 1, characterized in that In step b: Collect and analyze the time, distribution of Enteromorpha prolifera green tide disasters affecting disaster-sensitive targets in the past 5 years or more, as well as the distribution characteristics of ocean currents and sea surface winds in the sea area where the disaster-sensitive targets are located, and calculate the average wind speed in the sea area where the disaster-sensitive targets are located.

4. A method for determining a warning area of the Enteromorpha prolifera green tide disaster based on traceability numerical simulation according to claim 1, characterized in that, In step c: Based on the Lagrangian particle tracking method, considering the drag effects of wind and current on Enteromorpha prolifera green tide particles, the drift position of a certain Enteromorpha prolifera green tide particle can be calculated by formula (1); The numerical tracing model for the drift of Enteromorpha prolifera green tides is shown in formula (1): （1） In Equation (1), x t is the position of the Enteromorpha prolifera green tide particle at time t; x t0 is the position of the Enteromorpha prolifera green tide particle at the initial time t0; v a is the surface flow velocity, and v d is the wind speed at 10 m above the sea surface; R1 is the coefficient of the ocean current effect; R2 is the coefficient of the wind effect, representing the direct dragging effect of the wind on the Enteromorpha prolifera green tide particle; represents the effect of the wind on changing the movement direction of the Enteromorpha prolifera green tide particle; the x-axis direction is , and the y-axis direction is , where is the angle between the wind and the x-axis coordinate axis, in degrees, is the wind drag deflection angle, in degrees.

5. The method for determining the warning area of Enteromorpha prolifera green tide disaster based on traceability numerical simulation according to claim 1, characterized in that Step d includes the following steps: d1. Set the initial release position and tracing simulation duration of the numerical tracing model for the drift of Enteromorpha prolifera green tides; d2. Design a plan and conduct a tracing numerical simulation; Adopt the numerical tracing model for the drift of Enteromorpha prolifera green tides and the released Enteromorpha prolifera green tide particles, and based on the environmental field results of the designed plan, conduct a numerical tracing simulation of the drift of Enteromorpha prolifera green tides to trace back the drift positions of Enteromorpha prolifera green tide particles at different times.

6. The method for determining a warning area for Enteromorpha prolifera green tide disasters based on traceability numerical simulation according to claim 5, wherein, In step d1: According to the distribution of Enteromorpha prolifera green tides and the geographical distribution of disaster-sensitive targets, release Enteromorpha prolifera green tide particles; the release range of Enteromorpha prolifera green tide particles is the area included by the line parallel to the shoreline of the sea area where the disaster-sensitive targets are located and m kilometers away from the shore; set the tracing numerical simulation duration according to the protection requirements of disaster-sensitive targets.

7. A method for determining a warning area for Enteromorpha prolifera green tide disasters based on traceability numerical simulation according to claim 6, characterized in that: The number of released Enteromorpha prolifera green tide particles is greater than 50, and the tracing numerical simulation duration is greater than or equal to 72h.

8. The method for determining a warning area for Enteromorpha prolifera green tide disasters based on traceability numerical simulation according to claim 5, wherein, In step d2: Use the climatological atmospheric field in the sea area where the disaster-sensitive targets are located to drive the ocean current model; after the ocean current model is stable, design 8 or 16 plans, that is, drive the ocean current model with the sea surface 10 m wind speed in 8 or 16 directions; the simulation duration of the ocean current model is greater than the simulation duration of the numerical tracing model for the drift of Enteromorpha prolifera green tides; the spatial range of the sea surface 10m wind field and surface ocean current data is greater than the range where the disaster-sensitive targets are located and the sea area where all Enteromorpha prolifera green tide particles can drift during the numerical simulation.

9. The method for determining the warning area of Enteromorpha prolifera green tide disaster based on traceability numerical simulation according to claim 8, wherein: The sea current model is driven by the sea surface 10 m wind speed and the climatological heat flux field in 8 directions or 16 directions to obtain the surface sea currents under 8 or 16 scenarios; the sea surface 10 m wind speed is obtained through step b; each design scenario is the sea surface 10 m wind speed v in one direction d and the corresponding surface sea current v a ; then, based on the model constructed in step c, a backward numerical simulation is carried out to trace back the drift positions of the Enteromorpha prolifera green tide particles at different times; the drift positions of the Enteromorpha prolifera green tide particles at different times are obtained under 8 or 16 design scenarios.

10. A method for determining a warning area of Enteromorpha prolifera green tide disaster based on traceability numerical simulation according to claim 5, characterized in that In step e: According to the tracing results in step d, statistically analyze the distribution positions of Enteromorpha prolifera green tide particles at 0-24h, 0-48h, and 0-72h; the range within the outer envelope line corresponding to 0-24h is the 24h Enteromorpha prolifera green tide early warning area; the range within the outer envelope line corresponding to 0-48h is the 48h Enteromorpha prolifera green tide early warning area; the area within the 0-72h outer envelope line is the 72h Enteromorpha prolifera green tide early warning area.

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