A method for calculating the impact area of ​​cloud catalysis operation in complex vertical wind fields

Abstract

The present invention discloses a method for calculating the influence zone of cloud catalytic operation in a complex vertical wind field, which obtains flight information, selects the sounding station data closest to the flight position of the aircraft, matches the wind field data of the sounding station at the same height according to the aircraft's sowing height; calculates the influence zone position parameters of the sowing layer height based on the aircraft's sowing operation time, sowing concentration and the obtained horizontal movement data of the sowing height, calculates the distance movement parameters caused by shear, and adds the influence zone position parameters to the distance movement parameters caused by shear to obtain the final sowing influence zone position. The present invention can more accurately simulate the influence of the wind field on the sowing layer, improves the accuracy of the calculation, and takes into account the influence of the complex wind field on the sowing operation by defining wind shear and calculating the distance movement caused by shear; and can more accurately predict the diffusion path and range of the sowing material.

Description

Technical Field

[0001] The invention relates to the calculation of an operation influence zone after an artificial rainfall enhancement operation, and in particular to a method for calculating a cloud catalysis operation influence zone in a complex vertical wind field. Background Art

[0002] Artificial weather modification refers to the activities of artificially intervening in the cloud physics process of the local atmosphere through scientific and technological means under appropriate weather conditions in order to avoid or mitigate meteorological disasters and rationally utilize climate resources, so that the weather develops in a direction that meets human expectations and achieves the goals of increasing rain (snow), preventing hail, reducing rain, and eliminating fog. In recent years, with the continuous development of the country's economy, society, and industrialization, while bringing convenience to people, it has also brought some negative effects. Meteorological disasters such as droughts, heavy rains, and strong winds have occurred frequently, making artificial weather modification more widely concerned. Therefore, the demand for artificial rainmaking to resist drought, artificial hail prevention, and artificial rain reduction is increasing. And with the increase of my country's social influence, it has undertaken more and more large-scale activities. The Shanghai Import Expo and others have put forward different meteorological guarantee requirements such as reducing rain, increasing rain and reducing pollution. This has also prompted the continuous development of my country's artificial weather modification business in recent years, and the increasing number of artificial catalytic operations such as aircraft across the country.

[0003] However, after the aircraft seeding operation, how to determine the effective diffusion range of the catalyst after it enters the cloud and how the catalytic influence area changes over time are very critical and difficult issues in artificial weather modification. The determination of the effective influence area of ​​catalyst diffusion transmission is also the basis for subsequent effect testing.

[0004] At present, there are some calculation methods. For example, Yu Xing et al. established a catalyst transport and diffusion simulation system composed of a three-dimensional time-varying smoke puff trajectory model and a three-dimensional fine grid non-hydrostatic model. The system was used to conduct subtle three-dimensional time-varying simulation studies on the catalytic diffusion area and diffusion rate. However, the model system is based on the combination of the cloud model and the diffusion transmission model. Its accuracy is closely related to the accuracy of the model forecast, and it has certain limitations in business applications. Zhou Yuquan and others transformed the aircraft seeding into a set of instantaneous point sources at different times and locations. On the basis of the analytical solution of point source advection diffusion, they developed a calculation model for the diffusion transmission and effective influence range of aircraft-seeded catalysts. This model has been applied in actual human shadow business. However, when the model is used to calculate the effective influence range of diffusion in actual business and research, it is mainly to first obtain the horizontal movement of the diffusion layer, and then put the horizontal movement into the model for calculation.

[0005] In the existing calculation scheme, the aircraft seeding is regarded as a point source, which ignores the fact that the aircraft seeding actually has a certain initial width and length. Although the model simulates this width and length by giving an initial time, this simplification may not fully and accurately reflect the actual situation. In the calculation, the turbulence coefficient (horizontal and vertical directions) is a key parameter, but the determination of these coefficients often depends on experience and region-specific data, which may lead to uncertainty in the calculation results. This calculation method is mainly suitable for the situation where the upper and lower wind fields are consistent and there is no vertical shear. If there is a complex wind field on the day, the wind field in the lower layer of the seeding layer changes significantly (that is, when there is shear in the lower layer), the current calculation method alone cannot correctly obtain the calculation of the diffusion influence range. Therefore, it is necessary to improve the calculation method to obtain a more accurate calculation method for the catalytic diffusion influence range. Summary of the invention

[0006] In view of the above defects of the prior art, the technical problem to be solved by the present invention is how to accurately calculate the diffusion influence area under complex wind fields. Based on the currently disclosed aircraft catalytic diffusion transmission operation influence area calculation scheme, a method for calculating the operation influence area under complex wind field seeding is proposed.

[0007] To achieve the above object, the present invention provides a method for calculating the influence area of ​​cloud catalysis operation in a complex vertical wind field, which specifically includes the following steps:

[0008] A obtains flight information, wherein the flight information includes the flight position of the aircraft, the spreading time period, the spreading concentration and the spreading height;

[0009] B selects the sounding station data closest to the aircraft's flight position, and matches the wind field data at the same height of the sounding station according to the aircraft's sowing height;

[0010] C calculates the influence zone position parameters of the spreading layer height based on the aircraft spreading operation time, spreading concentration and the acquired spreading height horizontal movement data;

[0011] D determines the height at which shear occurs based on the change in wind direction in the sounding data. The wind field shear is defined as the height within 1 km and the wind direction change exceeds 90°. The distance movement parameter caused by shear is calculated using the following formula:

[0012]

[0013] in It is the horizontal movement direction and speed of the high-level, that is, the wind field information above the shear height of 1 km. is the horizontal movement direction and speed of the low layer, that is, the wind field information below the shear height of 1 km, ΔH is and Height difference, V t is the final falling velocity, and Vt Take the final falling speed of a small raindrop as about 2m / s;

[0014] E adds the influence zone position parameter to the distance movement parameter caused by shear to obtain the final sowing influence zone position.

[0015] Furthermore, in step C, the aircraft seeding can be regarded as a point source in the diffusion calculation of the aircraft seeding, and the point source is (x n ,y n ,z n ,t n ), the catalyst concentration caused by mobile diffusion to all points (x, y, z, t) is q n (x,y,z,t), the calculation formula is:

[0016]

[0017] Where x n ,y n 、z n , for aircraft t n The spatial position, diffusion coefficient and horizontal movement in the model, Q n is the point source intensity, Q n =RΔt, R is the spreading rate;

[0018] Adding together the contributions from all point sources gives the total concentration spread by aircraft:

[0019]

[0020] Aircraft spreading point (x n ,y n ,z n ,t n ) Take the interval once per second, the distance is V a *1s, V a is the aircraft speed in m / s.

[0021] Furthermore, in layered clouds, the diffusion coefficient k is H =140m 2 / s,k v =70m 2 / s, with 10s of diffusion representing the initial width and length.

[0022] Using the above scheme, the method for calculating the influence area of ​​cloud catalysis operation in a complex vertical wind field disclosed in the present invention has the following advantages:

[0023] (1) The present invention can more accurately simulate the impact of wind fields on the spreading layer, improve the accuracy of calculation, and take into account the impact of complex wind fields on the spreading operation by defining wind shear and calculating the distance movement caused by shear;

[0024] (2) The present invention combines the distance movement caused by shear with the position of the impact zone at the height of the spreading layer, which can more accurately predict the diffusion path and range of the spread material. By combining the sounding station data and the aircraft spreading data, this method can provide a prediction of the spreading impact zone that is closer to reality, which is of great significance for operation design and implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an overall flow chart of a method for calculating the influence area of ​​cloud catalytic operation in a complex vertical wind field according to the present invention;

[0026] Figure 2 An aircraft flight trajectory for an implementation example of the complex vertical wind field cloud catalytic seeding operation impact area of ​​the present invention;

[0027] Figure 3 This is a radiosonde image of the A zone at 08:00 on March 19, 2017 of the impact area of ​​a complex vertical wind field cloud catalytic seeding operation of the present invention;

[0028] Figure 4 It is a superposition diagram of the catalyst influence area at different typical moments and the CAPPI at an altitude of 2000m obtained by calculating the diffusion plus shear distance ΔL of the diffusion layer horizontal movement of the influence area of ​​the cloud catalytic spreading operation in a complex vertical wind field of the present invention;

[0029] Among them, a1 is 11:10 and diffuses for 29 minutes; a2 is 11:44 and diffuses for 63 minutes; a3 is 12:12 and diffuses for 91 minutes; a4 is 12:41 and diffuses for 120 minutes. DETAILED DESCRIPTION

[0030] The following describes the embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, which are exemplary descriptions, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0031] The specific flow chart is as follows Figure 1 As shown in the figure, if there is a complex wind field on that day and there is shear in the wind field below the seeding layer, the following steps need to be performed based on the existing calculation scheme for the impact area of ​​aircraft catalytic diffusion transmission operations:

[0032] Step 1: First, obtain the aircraft flight information of the day, including the aircraft flight position, aircraft seeding time period, aircraft seeding concentration and the seeding height of the day.

[0033] Step 2: Obtain the data of the sounding stations near the flight location on that day, and select the data of the nearest sounding station.

[0034] Step 3: According to the dispersion height of the aircraft, match the horizontal movement (wind field data) of the selected sounding station at the same height.

[0035] Step 4: Based on the known aircraft seeding operation time, aircraft seeding concentration and the acquired horizontal movement of seeding height, the influence zone position of the seeding layer height is calculated by bringing it into the existing aircraft catalytic diffusion transmission operation influence zone calculation scheme.

[0036] Step 5: Determine the height at which shear occurs based on the change in wind direction in the sounding data. This patent defines shear as a change in wind direction of more than 90° within a height of 1 km. For example, the wind direction at 3000 m is 220°, and the wind direction at 2000 m is 110°. This means that wind shear exists at a location of 1 km, which facilitates the subsequent calculation of the distance moved due to the shear.

[0037] Step 6: When complex wind shear occurs, calculate the distance traveled due to the shear. The calculation formula is:

[0038]

[0039] Take a set of data from the sounding data to calculate ΔL, where is the horizontal movement direction and speed of the high-level, that is, the wind field information above the shear height, is the horizontal movement direction and speed of the lower layer, that is, the wind field information below the shear height, ΔH is and Height difference, V t is the final falling velocity, and V t The final speed of a small raindrop falling is about 2m / s. Substituting the above data into the calculation formula, we can get the distance movement ΔL caused by shear, and the direction of the moving distance, i.e. the direction of ΔL, is direction.

[0040] Step 7: Add the influence zone position calculated in step 4 and the distance movement caused by shear calculated in step 6 to obtain the final sowing influence zone position.

[0041] In the implementation case, take an aircraft catalytic operation at location A on March 19, 2017 as an example. The flight trajectory of the aircraft is as follows: Figure 2As shown, the black line is the aircraft operation time, and the aircraft passed through areas B and C. The Yun-12 aircraft took off from the airport in area A at 10:25, flew 33km north and turned west after takeoff, and began to spread the catalyst at 10:41 after turning west. Due to airspace restrictions, it turned east at 11:06, stopped spreading at 11:14, and then the flight altitude continued to drop to 3191m, and landed at 11:43, with a spreading duration of 34min. Therefore, the aircraft took off at 10:25; the landing time was 11:43; the catalytic operation time was 10:41-11:14; the catalytic operation altitude was about 3700 meters; the catalytic operation concentration was: the total length of the spreading line was 125km, 6 silver iodide smoke strips were spread, and a total of 750g of silver iodide was spread. Existing studies have shown that after this individual dispersal operation, large particles formed after catalysis were observed on the radar, resulting in enhanced echoes. Based on this observation fact, the location of the impact area of ​​the aircraft catalytic diffusion transmission operation under complex wind fields can be determined.

[0042] Figure 3 The sounding data at 08:00 on the same day. Figure 3 This is the L-band radiosonde image of Jinghe in Xi'an, Shaanxi Province at 08:00 on March 19, 2017. The green color in the image is the cloud range. There was a single layer of cloud on that day, with a cloud top height of about 4200m and a cloud base height of about 1800m. Figure 3 The Jinghe sounding map shows that the wind speed and direction (horizontal movement) at 3700m (diffusion layer) on that day was about 10m / s, 233°; the wind speed and direction at 2000m was about 6m / s, 110°. Figure 3 ) It can be found that there is a small shear between 3000m and 2000m.

[0043] The diffusion layer obtained by the sounding is moved horizontally, and combined with the sowing of 750g of silver iodide (AgI) and the diffusion coefficient k H =140m 2 / s,k v =70m 2 / s and the operation time period 10:41-11:14 are brought into the existing aircraft catalytic diffusion transmission operation influence zone calculation scheme to calculate the influence zone position of the spreading layer height, which is the content of the above step 4.

[0044] From the sounding data ( Figure 3 ) It can be found that there is a small shear between 3000m and 2000m. Calculate according to step 6 and take a set of data from the sounding data to estimate ΔL. Take 3000m as about 6m / s and 220°; Take 2200m as about 4m / s, 121°; V t Take the final speed of a small raindrop as about 2m / s and substitute it into the distance movement formula ΔL is about 0.8 km, and the direction is The direction is about 258°.

[0045] The position of the diffusion influence area is calculated by using the horizontal movement of the seeding layer and the shear distance is the final diffusion influence area position. The result is superimposed with the position of the impact echo in the 2000m CAPPI as shown in the figure. Figure 4 It can be seen that the position of the diffusion influence area calculated by the horizontal movement of the seeding layer plus the shear distance ΔL is basically consistent with the position of the impact echo in the 2000m CAPPI. This confirms the accuracy of the calculation scheme of the operation influence area under complex wind field seeding.

[0046] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for calculating the influence area of ​​cloud catalysis operation in a complex vertical wind field, characterized in that: The following steps are involved: A obtains flight information, wherein the flight information includes the flight position of the aircraft, the spreading time period, the spreading concentration and the spreading height; B selects the sounding station data closest to the aircraft's flight position, and matches the wind field data at the same height of the sounding station according to the aircraft's sowing height; C calculates the influence zone position parameters of the spreading layer height based on the aircraft spreading operation time, spreading concentration and the acquired spreading height horizontal movement data; D. Determine the height at which wind shear occurs based on the change in wind direction in the sounding data. Shear is defined as the change in wind direction exceeding 90° within 1 km of the height. Calculate the distance movement parameter caused by shear. The calculation formula is: ， in It is the horizontal movement direction and speed of the high-level, that is, the wind field information above the shear height of 1 km. It is the horizontal movement direction and speed of the low layer, that is, the wind field information below the shear height of 1 km. for and Height difference, is the final falling velocity, assuming that Take the final falling speed of the small raindrop as 2m / s; E adds the influence zone position parameter to the distance movement parameter caused by shear to obtain the final sowing influence zone position.

2. According to claim 1, a method for calculating the influence area of ​​cloud catalytic operation in a complex vertical wind field is characterized in that: In step C, the aircraft seeding can be regarded as a point source in the diffusion calculation of the aircraft seeding, and the point source is ( , , , ), after moving and spreading, to all points in the field The catalyst concentration is , the calculation formula is: In the formula , , For aircraft The spatial position at the time of the diffusion coefficient and horizontal movement in the model, is the point source intensity, , R is the spreading rate; Adding together the contributions from all point sources gives the total concentration spread by aircraft: Aircraft seeding point ( , , , ) with an interval of once per second, the distance is , is the aircraft speed in m / s.

3. According to claim 1, a method for calculating the influence area of ​​cloud catalysis operation in a complex vertical wind field is characterized in that: In layered clouds, the diffusion coefficient is , , using 10s of diffusion to represent the initial width and length.

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