A tropical cyclone dynamic initialization method considering 1-wave vortex asymmetry

Abstract

The application discloses a tropical cyclone dynamic initialization method considering 1 wave vortex asymmetry, and belongs to the field of numerical weather prediction. Global background field, cyclone live data, satellite brightness temperature data and WRF model parameters are input first. The environment field and the vortex field are separated through 6-hour cycle integral, and the 1 wave component is extracted through Fourier decomposition. The 1 wave amplitude is corrected by constructing a correction coefficient based on the satellite observation statistics of the 1 wave / axial symmetric climatic average ratio of cyclones of different intensities. The 1 wave phase is adjusted according to the live four-quadrant wind circle radius. The axial symmetric and the corrected 1 wave component are superposed and are simultaneously scaled to match the live intensity. According to the intensity deviation, the cycle iterative integral or the direct output of the initial field is determined to carry out 72h prediction. The application quantitatively restricts the amplitude and phase of the 1 wave asymmetric structure, is suitable for all-grade open-ocean tropical cyclones, effectively improves the overestimation problem of the intensity prediction of weak tropical cyclones, and can be directly applied to the operational prediction of tropical cyclones in the northwest Pacific.

Description

Technical Field

[0001] This invention relates to the field of numerical weather prediction technology, and in particular to a method for initializing the dynamics of a tropical cyclone considering the asymmetry of wave vortex. Background Technology

[0002] Numerical forecasting of tropical cyclones relies on the initial vortex structure of the model, and the quality of the initial field directly determines the accuracy of cyclone path and intensity forecasts. Current mainstream tropical cyclone dynamic initialization schemes only optimize axisymmetric vortex components, lacking quantitative constraints on the asymmetric structure of the vortex, resulting in the following core technical deficiencies:

[0003] The amplitude of the asymmetric component is not standardized: if the asymmetric amplitude is too large, it will disrupt the main circulation of the cyclone, and if the amplitude is too small, it will easily cause a systematic overestimation of the intensity of weak tropical cyclones.

[0004] There is no objective correction method for the phase of asymmetric components: phase misalignment will amplify the prediction error caused by the interaction between vortices and large-scale environmental fields.

[0005] The asymmetric structural differences of cyclones of different intensities are not distinguished: strong cyclones tend to be axially symmetric, while weak cyclones have significant asymmetric characteristics. The existing uniform treatment method cannot be adapted to tropical cyclones of all levels.

[0006] Lacking quantitative statistical constraints based on satellite observations, the asymmetric vortices generated by pure model integration have a low degree of matching with the actual cyclone cloud system and wind circle distribution.

[0007] Existing research confirms that the first wave component is the dominant component of the asymmetric structure of tropical cyclones, but there is no complete, operational, and quantitatively constraining dynamic initialization process for the amplitude and phase of the first wave vortex. This results in high errors in 72-hour track and intensity forecasts, and the problem of overestimating the intensity of weak cyclones is difficult to eradicate. Summary of the Invention

[0008] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a tropical cyclone dynamic initialization method that takes into account the asymmetry of wave vortex.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] This invention provides a method for initializing the dynamics of a tropical cyclone considering the asymmetry of a single-wave vortex, comprising the following steps:

[0011] S1. Complete the standardized import of all input data sources and model parameters to build a unified calculation benchmark: input basic data and numerical model configuration parameters; the basic data includes global background field, tropical cyclone observation data, and satellite brightness temperature observation data; the numerical model is a multi-layer bidirectional nested grid WRF numerical model.

[0012] S2. Complete vortex field separation and harmonic decomposition to decouple axisymmetric and 1-wave asymmetric structures: Perform multiple rounds of 6-hour cyclic integration based on the WRF numerical model to obtain the integral full field; separate the integral full field into a large-scale environmental field and a total vortex field within a limited radius; perform cylindrical coordinate Fourier decomposition on the total vortex field to obtain the 0-wave axisymmetric component field and the multi-order Fourier harmonic asymmetric component field, and extract the 1-wave component field as the dominant component of the asymmetric structure;

[0013] S3. Quantitatively constrain the amplitude of the first-wave component based on satellite observation and statistical results to eliminate unreasonable amplitude bias: Based on the satellite brightness temperature observation data, statistically calculate the climatic average ratio of the first-wave component to the axisymmetric component corresponding to tropical cyclones of different intensities; construct the amplitude correction coefficient of the first-wave component based on the climatic average ratio, and use the amplitude correction coefficient to perform multiplicative correction on the entire original first-wave component field to obtain the amplitude-corrected first-wave component field.

[0014] S4. Objectively calibrate the phase of wave 1 based on the actual wind circle and match the asymmetric distribution of the actual cyclone space: Based on the multi-quadrant wind circle radius in the actual tropical cyclone observation data, rotate the phase of the amplitude-corrected wave 1 component field according to the preset multi-type phase adjustment rules, so that the positive phase of wave 1 corresponds to the large wind circle distribution quadrant and the negative phase corresponds to the small wind circle distribution quadrant, and output the wave 1 component field after amplitude and phase double correction.

[0015] S5. Integrate axisymmetric and corrected 1-wave components and unify intensity matching real-world conditions while preserving the asymmetric relative structure: Linearly superimpose the 0-wave axisymmetric component field and the 1-wave component field after dual amplitude and phase correction to generate a preliminary corrected vortex field; Calculate the overall scaling factor based on the maximum wind speed of the tropical cyclone, and use the same scaling factor to synchronously scale the axisymmetric component field and the dual-corrected 1-wave component field to obtain the final corrected vortex field that maintains the relative proportion of 1-wave unchanged;

[0016] S6. Based on the intensity deviation, iteratively optimize or directly output the forecast initial field, taking into account both the accuracy of the initial field and operational efficiency: compare the maximum wind speed at the cyclone center of the final corrected vortex field with the actual wind speed of the tropical cyclone to determine the magnitude of the intensity deviation; if the intensity deviation exceeds a preset threshold, the final corrected vortex field is substituted back into the WRF numerical model, and steps S2 to S5 are repeated; if the intensity deviation is within the preset threshold, the final corrected vortex field replaces the original vortex field in the global background field to generate a complete initial field for the tropical cyclone, and multi-hour numerical forecasts for the tropical cyclone are carried out based on this initial field.

[0017] Furthermore, in step S2, a three-point smoothing combined cylindrical filtering algorithm is used when separating the total vortex field. The calculation range of the vortex field is limited to the area within a fixed radius of the tropical cyclone center. The large-scale environmental field directly reuses the input global background field, and only the total vortex field is subjected to subsequent correction calculations.

[0018] Furthermore, in step S2, the cylindrical coordinate Fourier decomposition breaks down the vortex element into axisymmetric terms and harmonic terms of each order. The decomposition order covers at least the fourth harmonic, and harmonics above the fourth order are directly discarded and do not participate in subsequent corrections.

[0019] Furthermore, in step S3, the single sample ratio is used to characterize the kinetic energy ratio of the wave component relative to the axisymmetric component; when calculating the climate average ratio, only tropical cyclone samples from open ocean areas far from land and without topographic interference are selected, and the single sample ratio is taken as the average value of the fixed radius area of ​​the cyclone center; the higher the cyclone intensity, the smaller the corresponding climate average ratio value.

[0020] Furthermore, in step S3, the amplitude correction coefficient is calculated by combining the maximum wind speed of the axisymmetric component at 10m, the maximum wind speed of the original wave component at 10m, and the climate average ratio of the current cyclone matching; the original wave component field correction is completed by multiplying the amplitude correction coefficient across the entire domain.

[0021] Furthermore, the preset phase adjustment rules in step S4 include four categories:

[0022] Rule 1: The radius of the four-quadrant wind circle has only one maximum value. Rotate the positive phase of the 1st wave component to the quadrant of the maximum wind circle.

[0023] Rule 2: If the radius of the wind circle in the four quadrants has multiple maximum values ​​and only one minimum value, rotate the negative phase of the 1st wave component to the quadrant with the smallest wind circle.

[0024] Rule 3: The wind circle radius of two adjacent quadrants is the maximum value, and the other two adjacent quadrants are the minimum value. The positive phase is placed in the middle of the two largest quadrants, and the negative phase is placed in the middle of the two smallest quadrants.

[0025] Rule 4: For special scenarios that do not meet the distribution characteristics of the first three categories, retain the original phase of the amplitude correction wave component without rotation.

[0026] Furthermore, in step S5, the axisymmetric component field and the double-corrected 1-wave component field are simultaneously scaled to keep the relative ratio of the 1-wave component to the axisymmetric component constant before and after scaling, without destroying the amplitude correction result of step S3.

[0027] Furthermore, the tropical cyclone observation data input in step S1 includes at least the latitude and longitude of the cyclone center, the maximum sustained wind speed near the ground, and the radius of the 34-knot wind circle in the four quadrants at 6-hour intervals; the satellite brightness temperature observation data is high-resolution brightness temperature data from geostationary meteorological satellites, used to characterize the spatial distribution of tropical cyclone clouds and rain.

[0028] Furthermore, in step S2, the WRF numerical model cyclic integration only uses two nested grids (coarse and medium) for calculation, and the correction variables include air pressure, geopotential height, wind field, temperature, and specific humidity; the inner high-resolution grid is only used in the final 72-hour numerical forecast stage.

[0029] Furthermore, in step S6, the preset intensity deviation threshold is a manual verification parameter. When it is determined that repeated cyclic integration is required, each round of cyclic integration fully executes the vortex splitting, amplitude correction, phase correction, and component superposition process from step S2 to step S5.

[0030] Compared with the prior art, the technical solution disclosed in this invention has the following beneficial effects:

[0031] This invention utilizes two core features: quantitative constraint of wave amplitude using S3 satellite observation statistical ratio and correction of wave phase using S4 real-world wind circle. It constructs an initial vortex that closely matches the actual structure of tropical cyclones, and the forecast accuracy is significantly better than the traditional scheme that only optimizes axisymmetric vortices.

[0032] S3 uses a differentiated 1-wave / axisymmetric ratio to match cyclones of different intensities. Weak cyclones correspond to a high ratio, while strong cyclones correspond to a low ratio. This addresses the technical pain point of systematic overestimation in the intensity forecast of weak tropical cyclones in traditional schemes, without exacerbating the problem of underestimation of the intensity of strong typhoons.

[0033] S4 relies on the JTWC multi-quadrant wind circle to objectively correct the phase of wave 1, so that the distribution of the initial vortex wind area is consistent with the observation, and the simulated precipitation cloud system presents a wave 1 asymmetric distribution that conforms to satellite observation, which greatly improves the authenticity of the initial field cyclone core structure.

[0034] The S6 graded judgment integration / forecasting process balances initial vortex dynamic balance and operational forecasting efficiency. It does not require additional intensive assimilation observations for scarce ocean surfaces. It can generate high-precision initial fields by relying solely on WRF cyclic integration and can be directly used for meteorological operational operations.

[0035] The entire process is standardized and quantified. All correction parameters are based on years of satellite observation statistics, eliminating the need for manual subjective parameter adjustment. The forecast results are highly stable, with good improvement effects, and are suitable for all levels of offshore tropical cyclones in the Northwest Pacific. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1A schematic diagram of the process for initializing the dynamics of a tropical cyclone considering the asymmetry of wave vortexes, provided in an embodiment of the present invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1 As shown, this embodiment uses the WRF 3.8.1 numerical model and selects 75 forecast samples, including Super Typhoon Dujuan in 2015 and 23 tropical cyclones in the Northwest Pacific from 2019 to 2020, to complete batch experimental verification. All steps S1-S6 of claim 1 are fully executed. The detailed operation, parameter explanation, and technical effects of each step are explained below:

[0041] S1: Complete the standardized import of all input data sources and model parameters to build a unified calculation benchmark, i.e., input basic data and numerical model configuration parameters.

[0042] Enter basic data details:

[0043] (1) Global background field: NCEP 0.25° resolution GFS global forecast field, as the basis for large-scale environmental field of WRF model;

[0044] (2) Tropical cyclone observation data: JTWC best track dataset, including cyclone center latitude and longitude, maximum sustained wind speed near the ground, and radius of the 34 knot (17 m / s) wind circle in four quadrants at 6-hour intervals;

[0045] (3) Satellite brightness temperature observation data: 15-channel brightness temperature data with a horizontal resolution of 5km from Sunflower 8 / 9, used to characterize the spatial distribution of cyclonic clouds and rain, and to statistically analyze the ratio of wave 1 to axisymmetric component;

[0046] WRF mode configuration parameter input: three-layer bidirectional nested grid, D01 coarse grid 18km, D02 middle layer 6km, D03 inner layer 2km, 50 vertical layers, top layer pressure 10hPa; the physical scheme is uniformly configured with WSM6 microphysics, Dudhia shortwave radiation, RRTM longwave radiation, YSU boundary layer, and Noah land surface scheme, and the coarse grid is enabled with Kain-Fritsch cumulus parameterization;

[0047] Data filtering rules (manual verification items): Remove tropical cyclone samples with a maximum wind speed at the center of less than 17 m / s, near land terrain, or in the weakening stage, to avoid interference from topography and convection anomalies in the weakening stage on the statistical ratio of wave 1.

[0048] Step S1 technical effect: Unify and standardize the input data source, separate the large-scale environmental field and cyclone vortex variables, ensure that subsequent vortex splitting, statistical ratios and phase correction have a unified objective data benchmark, and eliminate the initial field error caused by the difference of multi-source data.

[0049] S2: Complete vortex field separation and harmonic decomposition, decoupling axisymmetric and 1-wave asymmetric structures, i.e., WRF cyclic integration + vortex field decomposition, extracting 1-wave components.

[0050] Multiple rounds of 6-hour cyclic integration calculation: Only the D01 and D02 grid layers are used to carry out cyclic integration. The correction variables include air pressure, geopotential height, wind field, temperature, and specific humidity to obtain the equilibrium integrated field.

[0051] Separation of environmental field and vortex field: The three-point smoothing + cylindrical filtering algorithm is used to calculate the vortex field within a 600km radius of the cyclone center, separating the large-scale environmental field from the disturbed vortex field. The large-scale environmental field directly uses the original GFS background field, and only the vortex field is corrected.

[0052] Cylindrical Fourier Decomposition: Fourier series decomposition of the vortex field along the azimuth angle, decomposition formula:

[0053]

[0054] In the formula, F represents the meteorological element at a distance r from the center of the tropical cyclone. For cylindrical coordinates, azimuth angle , Here, represents the Fourier coefficients, and n represents the wave number. This paper only decomposes to wave 4; the amplitudes of components with more than 4 waves can be ignored.

[0055] Component splitting output: Outputs the total vortex field, axisymmetric component field, 1-wave component field, and higher-order asymmetric component field respectively.

[0056] Step S2 technical effect: It accurately separates the large-scale background from the cyclone's own vortex, and extracts the one-wave component of the dominant asymmetric structure separately through Fourier decomposition, realizing the decoupling of axisymmetric and asymmetric structures, and providing a basis for subsequent independent correction of component components; it limits the calculation radius to 600km to eliminate irrelevant disturbances in the periphery and reduce the amount of calculation.

[0057] S3: Quantitatively constrain the amplitude of the first-wave component based on satellite observation statistical results to eliminate unreasonable amplitude bias, i.e., satellite observation statistical ratio calculation + first-wave component amplitude correction.

[0058] Climate average ratio statistics: 1525 brightness temperature samples from Northwest Pacific cyclones (center ≥ 450 km from land, avoiding topographic interference) between 2016 and 2021 were selected. The ratio of each sample was calculated using a fixed radius of 360 km. The ratio calculation formula is as follows:

[0059]

[0060] This ratio represents the proportion of kinetic energy of the wave component relative to the axisymmetric component; the higher the intensity of the cyclone, the smaller the corresponding ratio, and the stronger the cyclone tends to be axisymmetric.

[0061] Establish a ratio comparison table for different intensities: Divide the cyclones according to the maximum sustained wind speed gradient to form the standard 1-wave / axisymmetric ratio corresponding to cyclones of different intensities;

[0062] Amplitude correction factor construction, calculation formula:

[0063]

[0064] In the formula The maximum wind speed at 10m for the axisymmetric component. The original wave component has a maximum wind speed of 10m.

[0065] One-wave amplitude correction calculation: The original one-wave component is multiplied across the entire domain by a correction factor to complete the correction. The correction formula is as follows:

[0066] Step S3 technical effect: Based on years of satellite observation and objective statistics, the intensity standard ratio is obtained. The correction coefficient is converted by the square root of kinetic energy to avoid over- or under-correction of wave amplitude. The weak cyclone is matched with a high ratio to amplify the asymmetric structure, which directly alleviates the defect of overestimating the intensity of weak cyclones in traditional schemes. The strong cyclone is matched with a low ratio to suppress excessive asymmetry, maintain the axisymmetric characteristics of strong typhoons, and adapt to cyclones of all intensity levels.

[0067] S4: Based on the actual wind circle, objectively calibrate the phase of wave 1, matching the asymmetric distribution of the actual cyclone space. That is, correct the phase of wave 1 component based on the actual four-quadrant wind circle radius. The correction is based on the 34-knot wind circle radius R34 of the four quadrants (Northeast, Southeast, Southwest, and Northwest) output by JTWC, and four types of standardized phase rotation rules are set:

[0068] Maximum value of R34 in a single quadrant: Rotate the positive phase of wave component 1 to the quadrant with the maximum wind circle;

[0069] Multi-quadrant R34 maximum value, single-quadrant minimum value: rotate the negative phase of the wave component to the minimum wind circle quadrant;

[0070] The R34 values ​​are maximized in two adjacent quadrants and minimized in two adjacent quadrants: positive phase is placed in the middle of the two largest quadrants, and negative phase is placed in the middle of the two smallest quadrants.

[0071] Other special distribution scenarios: retain the original wave phase unchanged;

[0072] After phase rotation is completed, the output is a single-wave component field with double correction of amplitude and phase.

[0073] Step S4 technical results: The phase of wave 1 matches the actual strong wind area, and the initial vortex four-quadrant wind circle distribution fits the JTWC observation; taking Typhoon Dujuan as an example, the large wind circle in the southwest quadrant expands significantly after correction, which is consistent with the four-quadrant R34 distribution recorded by JTWC; the simulated cloud top brightness temperature shows a wave 1 asymmetric shape, which is highly consistent with the cloud system distribution of Himawari-8 / 9 satellites.

[0074] S5: Integrates axisymmetric and corrected 1-wave components and unifies intensity matching, while preserving the asymmetric relative structure; that is, component superposition + overall intensity scaling correction.

[0075] Vortex field superposition: The axisymmetric component field and the amplitude-phase corrected 1-wave component field are linearly superimposed to generate a preliminary corrected vortex field;

[0076] Overall intensity scaling: Calculate the scaling factor between the maximum wind speed at the center of the preliminary corrected vortex field and the actual wind speed in JTWC. Multiply the axisymmetric component and the 1-wave component by the scaling factor simultaneously to ensure that the relative ratio of 1-wave / axisymmetric remains unchanged, thus obtaining the final corrected vortex field.

[0077] The technical effect of step S5 is that the axisymmetric main circulation of the cyclone and the asymmetric wave disturbance are completely preserved after superposition; the synchronous scaling mechanism maintains the relative proportion of the corrected wave and avoids the overall scaling of intensity from destroying the amplitude correction effect of step S3, thus balancing the vortex dynamic structure.

[0078] S6: Based on the intensity deviation, iterative optimization or direct output of the forecast initial field is performed, balancing the accuracy of the initial field and operational efficiency. That is, the intensity deviation is determined, and the forecast is split into cyclic integration or 72-hour forecast.

[0079] Deviation Judgment Threshold (Manual Verification Item): Set the threshold for the difference between the maximum wind speed of the corrected vortex and the actual wind speed;

[0080] Branch 1: If the intensity deviation exceeds the threshold, replace the initial vortex of the WRF mode with the final corrected vortex field, perform a new round of 6-hour cyclic integration, and repeat the S2-S5 correction process.

[0081] Branch 2: If the intensity deviation is within the threshold range, the original GFS vortex field will be replaced by the final corrected vortex field to generate a complete tropical cyclone initial field, and the WRF model 72-hour tropical cyclone numerical forecast will be directly started.

[0082] Step S6 technical effects: Dynamically balances the initial vortex dynamic structure with operational forecast efficiency; continuously iterates and optimizes the vortex when the intensity deviation is large, ensuring the accuracy of the initial field; forecasts are directly carried out during intensity matching observations, reducing meaningless cyclic integration and adapting to the real-time forecasting needs of meteorological operations. 3.2 Comparative Experiment Example: Two parallel control experiments were set up, with unified input data and model parameters, distinguishing only the vortex initialization scheme:

[0083] Control group AX (traditional scheme): only S1-S2 are performed, only the axisymmetric component is retained to construct the initial vortex, and there are no amplitude and phase correction steps for wave 1 component;

[0084] Experimental group AX-WN1 (the scheme of this invention): Complete all steps S1-S6, and introduce 1 wave vortex asymmetric correction;

[0085] The experiment included 75 sets of forecast times for tropical cyclones in the Northwest Pacific, with a forecast duration of 72 hours. The results showed that the track forecast error of the experimental group was reduced by 17.8% and the intensity forecast error was reduced by 6.8% compared with the control group. The improvement effect passed the 98% significance test. The track improvement effect of tropical storm level was the most significant, the intensity correction effect of strong tropical storm level was the best, and the overestimation of weak cyclone intensity was significantly improved.

[0086] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0087] The block diagrams of devices, apparatuses, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0088] It should also be noted that in the apparatus, device, and method of the present invention, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of the present invention.

[0089] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0090] It should be understood that the qualifying terms "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present invention are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of the present invention.

[0091] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A method for initializing the dynamics of a tropical cyclone considering the asymmetry of a single-wave vortex, characterized in that, Includes the following steps: S1. Complete the standardized import of all input data sources and model parameters to build a unified calculation benchmark: input basic data and numerical model configuration parameters; the basic data includes global background field, tropical cyclone observation data, and satellite brightness temperature observation data; the numerical model is a multi-layer bidirectional nested grid WRF numerical model. S2. Complete vortex field separation and harmonic decomposition to decouple axisymmetric and 1-wave asymmetric structures: Perform multiple rounds of 6-hour cyclic integration based on the WRF numerical model to obtain the integral full field; separate the integral full field into a large-scale environmental field and a total vortex field within a limited radius; perform cylindrical coordinate Fourier decomposition on the total vortex field to obtain the 0-wave axisymmetric component field and the multi-order Fourier harmonic asymmetric component field, and extract the 1-wave component field as the dominant component of the asymmetric structure; S3. Quantitatively constrain the amplitude of the first wave component based on satellite observation and statistical results to eliminate unreasonable amplitude bias: Based on the satellite brightness temperature observation data, statistically calculate the climatic average ratio of the first wave component to the axisymmetric component corresponding to tropical cyclones of different intensities. Based on the climate average ratio, an amplitude correction coefficient for the first wave component is constructed. The amplitude correction coefficient is then used to perform a multiplicative correction on the entire original first wave component field to obtain the amplitude-corrected first wave component field. S4. Objectively calibrate the phase of wave 1 based on the actual wind circle and match the asymmetric distribution of the actual cyclone space: Based on the multi-quadrant wind circle radius in the actual tropical cyclone observation data, rotate the phase of the amplitude-corrected wave 1 component field according to the preset multi-type phase adjustment rules, so that the positive phase of wave 1 corresponds to the large wind circle distribution quadrant and the negative phase corresponds to the small wind circle distribution quadrant, and output the wave 1 component field after amplitude and phase double correction. S5. Integrate axisymmetric and corrected 1-wave components and unify intensity matching real-world conditions while preserving the asymmetric relative structure: Linearly superimpose the 0-wave axisymmetric component field and the 1-wave component field after dual amplitude and phase correction to generate a preliminary corrected vortex field; Calculate the overall scaling factor based on the maximum wind speed of the tropical cyclone, and use the same scaling factor to synchronously scale the axisymmetric component field and the dual-corrected 1-wave component field to obtain the final corrected vortex field that maintains the relative proportion of 1-wave unchanged; S6. Based on the intensity deviation, iteratively optimize or directly output the forecast initial field, taking into account both the accuracy of the initial field and operational efficiency: compare the maximum wind speed at the cyclone center of the final corrected vortex field with the actual wind speed of the tropical cyclone to determine the magnitude of the intensity deviation; if the intensity deviation exceeds a preset threshold, the final corrected vortex field is substituted back into the WRF numerical model, and steps S2 to S5 are repeated; if the intensity deviation is within the preset threshold, the final corrected vortex field replaces the original vortex field in the global background field to generate a complete initial field for the tropical cyclone, and multi-hour numerical forecasts for the tropical cyclone are carried out based on this initial field.

2. The tropical cyclone dynamic initialization method considering the asymmetry of wave vortex as described in claim 1, characterized in that, In step S2, a three-point smoothing combined cylindrical filtering algorithm is used to separate the total vortex field. The calculation range of the vortex field is limited to the region within a fixed radius of the tropical cyclone center. The large-scale environmental field directly reuses the input global background field, and only the total vortex field is subjected to subsequent correction calculations.

3. The tropical cyclone dynamic initialization method considering the asymmetry of wave vortex as described in claim 1, characterized in that, In step S2, the cylindrical coordinate Fourier decomposition breaks down the vortex element into axisymmetric terms and harmonic terms of each order. The decomposition order covers at least the fourth harmonic, and harmonics above the fourth order are directly discarded and do not participate in subsequent correction.

4. The tropical cyclone dynamic initialization method considering the asymmetry of wave vortex as described in claim 1, characterized in that, In step S3, the single sample ratio is used to characterize the kinetic energy ratio of the wave component relative to the axisymmetric component; when calculating the climate average ratio, only open ocean tropical cyclone samples far from land and without topographic interference are selected, and the single sample ratio is the average value of the fixed radius area of ​​the cyclone center; the higher the cyclone intensity, the smaller the corresponding climate average ratio value.

5. The tropical cyclone dynamic initialization method considering the asymmetry of wave vortex as described in claim 1, characterized in that, In step S3, the amplitude correction coefficient is calculated by combining the maximum wind speed of the axisymmetric component at 10m, the maximum wind speed of the original wave component at 10m, and the climate average ratio of the current cyclone matching; the original wave component field correction is completed by multiplying the amplitude correction coefficient across the entire domain.

6. The tropical cyclone dynamic initialization method considering the asymmetry of wave vortex as described in claim 1, characterized in that, The preset phase adjustment rules in step S4 include four categories: Rule 1: The radius of the four-quadrant wind circle has only one maximum value. Rotate the positive phase of the 1st wave component to the quadrant of the maximum wind circle. Rule 2: If the radius of the wind circle in the four quadrants has multiple maximum values ​​and only one minimum value, rotate the negative phase of the 1st wave component to the quadrant with the smallest wind circle. Rule 3: The wind circle radius of two adjacent quadrants is the maximum value, and the other two adjacent quadrants are the minimum value. The positive phase is placed in the middle of the two largest quadrants, and the negative phase is placed in the middle of the two smallest quadrants. Rule 4: For special scenarios that do not meet the distribution characteristics of the first three categories, retain the original phase of the amplitude correction wave component without rotation.

7. The tropical cyclone dynamic initialization method considering the asymmetry of wave vortex as described in claim 1, characterized in that, In step S5, the axisymmetric component field and the double-corrected 1-wave component field are simultaneously scaled to keep the relative ratio of the 1-wave component to the axisymmetric component constant before and after scaling, without destroying the amplitude correction result of step S3.

8. The tropical cyclone dynamic initialization method considering the asymmetry of wave vortex as described in claim 1, characterized in that, The tropical cyclone observation data input in step S1 includes at least the latitude and longitude of the cyclone center, the maximum sustained wind speed near the ground, and the radius of the 34-knot wind circle in the four quadrants at 6-hour intervals; the satellite brightness temperature observation data is high-resolution brightness temperature data from geostationary meteorological satellites, used to characterize the spatial distribution of tropical cyclone convective precipitation.

9. The tropical cyclone dynamic initialization method considering the asymmetry of wave vortex as described in claim 1, characterized in that, In step S2, the WRF numerical model cyclic integration only uses two nested grids (coarse and medium) for calculation, and the correction variables include air pressure, geopotential height, wind field, temperature, and specific humidity; the inner high-resolution grid is only used in the final 72-hour numerical forecast stage.

10. The tropical cyclone dynamic initialization method considering the asymmetry of wave vortex as described in claim 1, characterized in that, In step S6, the preset intensity deviation threshold is a manual verification parameter. When it is determined that repeated cyclic integration is required, each round of cyclic integration will fully execute the vortex splitting, amplitude correction, phase correction, and component superposition process from step S2 to step S5.

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