Method and system for identifying cyclones associated with high-altitude cut-off cold vortices

Abstract

The present invention relates to the field of meteorological research, and specifically to a method and system for identifying a high-altitude cut-off cold vortex and a cyclone. The method for identifying a high-altitude cut-off cold vortex and a cyclone of the present invention comprises the following steps: S1, acquiring data; S2, identifying the high-altitude cut-off cold vortex; S3, identifying the cyclone in the same period; S4, matching the cold vortex with the cyclone; S5, outputting the identification result. The method for identifying a high-altitude cut-off cold vortex and a cyclone of the present invention is based on high-resolution reanalysis data and uses computer technology to objectively and efficiently judge whether there is a cyclone in the lower layer when the high-altitude cut-off cold vortex exists, and outputs the identification result, which solves the problems of forecasters' manual judgment of weather systems being time-consuming and labor-intensive, highly subjective, and having limited research time, and provides strong support for the statistical characteristics of long-term series cold vortices and cyclones.

Description

Technical Field

[0001] The invention relates to the field of meteorological research, and in particular to a method and system for identifying a cyclone accompanying a high-altitude cut-off cold vortex. Background Art

[0002] The long-wave trough in the mid- and high-latitude westerlies develops and extends toward the equator until the connection with the cold air in the north is cut off by the warm air, forming an isolated, closed low-pressure vortex with a cold core or cold trough structure, which is called a cut-off low pressure, and is also called a cold vortex. The cut-off cold vortex is a deep, high-altitude cold low pressure, which is strongest in the upper troposphere. The cold vortex mainly provides a favorable circulation background to guide the cold air southward. If there happens to be warm and humid air currents in the lower layer, an unstable stratification with dry and cold upper layers and warm and humid lower layers is formed, which can easily cause high-impact severe convective weather such as hail, thunderstorms, and heavy rains. Therefore, when there is a cold vortex in the upper atmosphere, it is very important to judge whether there are favorable conditions in the lower layer.

[0003] Cyclones can provide favorable conditions for triggering severe convective weather. The southwesterly airflow in front of the cyclone can well guide the warm and humid airflow northward. There is also an obvious cold advection southward in the back of the cyclone. There is a release of condensation latent heat in the ascending area. There may also be several small and medium-scale systems in the cyclone area. At present, most of the existing technologies focus on the single system of high-altitude cut-off cold vortex or ground cyclone. There are few studies that consider cold vortex and cyclone at the same time. However, both can provide favorable conditions for severe convective weather. The weather conditions caused by the superposition of each other may be more complex and severe than that of a single system. Therefore, it is very necessary to combine the two for research.

[0004] In addition, the current existing technology for determining whether there is a cyclone in the background of a cut-off cold vortex is mainly based on manual judgment of individual cases, and there is a lack of objective judgment methods for statistical research on large samples. Summary of the invention

[0005] The purpose of the present invention is to provide a method and system for identifying a high-altitude cut-off cold vortex accompanied by a cyclone. Based on high-resolution reanalysis data, computer technology is used to objectively and efficiently determine whether there is a cyclone in the lower layer when the high-altitude cut-off cold vortex exists, and output the identification results, solving the problems of forecasters' manual judgment of weather systems being time-consuming and laborious, highly subjective, and limited research time.

[0006] In a first aspect, the present invention provides a method for identifying a high-altitude cut-off cold vortex accompanied by a cyclone, comprising the following steps:

[0007] S1. Obtain information;

[0008] S2. Identify the high-altitude cut-off cold vortex;

[0009] S3. Identify cyclones in the same period;

[0010] S4, matching the cold vortex with the cyclone;

[0011] S5. Output the recognition result.

[0012] Accordingly, the second aspect of the present invention provides a high-altitude cut-off cold vortex accompanying cyclone identification system, comprising:

[0013] A data acquisition module, used for acquiring data;

[0014] A high-altitude cut-off cold vortex identification module is used to identify the high-altitude cut-off cold vortex;

[0015] A cyclone identification module is used to identify cyclones in the same period;

[0016] A matching module for matching the cold vortex with the cyclone;

[0017] The result output module is used to output the recognition results.

[0018] Correspondingly, the third aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the computer program is loaded into the processor, the method for identifying a cyclone accompanying a high-altitude cut-off cold vortex is implemented.

[0019] Correspondingly, the fourth aspect of the present invention provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, it implements the method for identifying a cyclone accompanied by a high-altitude cut-off cold vortex as described above.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention first establishes an objective identification method to identify the high-altitude cut-off cold vortex process and the low-level cyclone process respectively; secondly, the cold vortex process and the cyclone process in the same period are matched; finally, the judgment result and related charts of whether there is a cyclone in the low layer under the cold vortex background are output. The present invention solves the problems of forecasters' manual judgment of weather systems being time-consuming and laborious, highly subjective, and having limited research time, and provides strong support for the statistical characteristics of long-term series cold vortices and cyclones. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the process of the present invention.

[0023] Figure 2 This is a schematic diagram of the operation of the electronic device proposed by the present invention. DETAILED DESCRIPTION

[0024] The most common high-altitude cut-off cold vortex in China is the Northeast Cold Vortex, and the Jianghuai cyclone is also a relatively typical cyclone type. The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation cases. It should be noted that the embodiments described here are only for illustration and are not intended to limit the present invention.

[0025] Existing technologies mostly focus on a single system of high-altitude cold vortex or low-level cyclone, and rarely combine the two. When judging whether there is a cyclone against the background of a cold vortex, it is mainly based on manual judgment of individual cases, and lacks statistical research on large samples.

[0026] Based on this, the present invention proposes a method for identifying a high-altitude cut-off cold vortex accompanied by a cyclone. The flow chart is as follows: Figure 1 As shown, the specific steps include:

[0027] S1. Obtain data, including reanalysis data grid data and typhoon path data; specifically:

[0028] Reanalysis data can come from the fifth generation of global weather and climate reanalysis data ERA5 from the European Centre for Medium-Range Weather Forecasts (ECMWF), with a spatial resolution of 0.25°×0.25° and a temporal resolution of 1h, including 500hPa geopotential height field and temperature field, and sea level pressure field;

[0029] Typhoon path data can come from the best path data set of the Shanghai Typhoon Institute of the China Meteorological Administration, including the longitude and latitude information of the typhoon center, with a spatial resolution of 0.1°×0.1° and a temporal resolution of 3h or 6h;

[0030] In order to ensure the correct positioning of the system center at the boundary, based on the definitions of the Northeast Cold Vortex and the Jianghuai Cyclone, the initial identification range was widened by 15° in four directions.

[0031] S2. Objectively identify the northeastern cold vortex; specifically:

[0032] 1) For the 500hPa geopotential height field, if the geopotential height value of a point is less than or equal to the surrounding 8 grid points, then the point is the local minimum value and is regarded as a candidate point;

[0033] 2) Preliminary screening of candidate points. If there are multiple candidate points within the range of 10°×10°, only the point with the lowest geopotential height is retained and the others are discarded; points that are not within the definition of the northeastern cold vortex are also discarded;

[0034] 3) With the candidate point as the center and 15° as the radius, calculate the temperature centroid of the 500hPa temperature field; if the distance between the temperature centroid and the candidate point is less than 500km, the candidate point is the center of the cold vortex;

[0035] 4) Track the center of the cold vortex. The centers of the cold vortex at two adjacent moments are considered to be the same cold vortex process if the distance between them in the longitudinal direction does not exceed 2° and the distance between them in the latitudinal direction does not exceed 3°.

[0036] 5) If there are multiple cold vortex centers that meet the tracking conditions at the next adjacent moment based on the current moment, then at the next adjacent moment, the cold vortex center with the closest longitude and latitude to the current moment and the smallest absolute difference in potential height is preferentially selected;

[0037] 6) Eliminate the false processes caused by northward-moving degenerate typhoons, where the distance between the cold vortex center and the typhoon center is less than 500 km and lasts for at least 6 hours;

[0038] 7) Screen and retain the northeastern cold vortex processes with a duration greater than or equal to 3 days.

[0039] S3. Objectively identify the Jianghuai cyclone during the same period; specifically:

[0040] 1) For the sea level pressure field, if the pressure value of a certain point is lower than that of the eight adjacent grid points, and the pressure center is less than 1015hPa, then this point is the potential cyclone center;

[0041] 2) Calculate the average pressure Laplace within 4° extending outward from the potential cyclone center using the following formula:

[0042]

[0043] where x i is the longitude, y j is latitude, p(x i ,y j ) is the longitude x i , latitude is y j The sea level pressure value corresponding to the point, based on a resolution of 0.25°, the maximum value of i and j is 17;

[0044] 3) If the central pressure value is less than 995hPa or If at least one closed contour line can be found, it is the cyclone center; within the range of 500km×500km, at most one cyclone center is retained; points that are not within the definition of the Jianghuai cyclone are also discarded;

[0045] 4) Track the cyclone center. The cyclone centers at two adjacent moments are considered to be in the same process if the distance between them in the longitudinal direction does not exceed 2° and the distance between them in the latitudinal direction does not exceed 3°.

[0046] 5) If there are multiple cyclone centers that meet the tracking conditions at the next moment based on the current moment, then at the next moment, the cyclone center with the shortest longitude and latitude distance to the current moment and the smallest absolute pressure difference is preferentially selected;

[0047] 6) Eliminate false processes caused by typhoons; a false typhoon is defined as a cyclone whose center is less than 500 km from the typhoon center and lasts for at least 6 hours;

[0048] 7) Screen and retain the Jianghuai cyclone processes with a duration of 1 day or more;

[0049] S4. Match the Northeast Cold Vortex with the Jianghuai Cyclone; specifically:

[0050] 1) Calculate the maximum radius r1 of the cold vortex system, that is, the average distance from the center of the cold vortex to the outermost closed contour line;

[0051] 2) Calculate the maximum radius r2 of the cyclone system, that is, the average distance from the cyclone center to the outermost closed contour line. The radius difference between two adjacent closed contour lines of the cyclone system must be less than 500 km;

[0052] 3) Calculate the actual distance d1 between the center of the cold vortex and the center of the cyclone at the same time, the formula is as follows:

[0053] d1=R·arcos[cos(y H )·cos(y c )·cos(x H -x c )+sin(y H )·sin(y c )];

[0054] Where R is the radius of the earth, (x H ,y H ) is the latitude and longitude coordinates of the cold vortex center, (x c ,y c ) are the longitude and latitude coordinates of the cyclone center, which need to be converted into radians during calculation;

[0055] 4) Calculate the relative distance d2 between the cold vortex center and the cyclone center at the same time, the formula is as follows:

[0056]

[0057] 5) If d1<500km, or d1<1500km and d2<0.6, it is considered that the cold vortex can match the cyclone at this moment; if it can match multiple cyclone centers, the one with the closest actual distance is selected.

[0058] The matching results of the Northeast Cold Vortex and the Jianghuai Cyclone need to be quality controlled. The specific steps include:

[0059] 1) Taking the cold vortex process as the benchmark, calculate the total number of synoptic moments n1 when the cold vortex matches the cyclone;

[0060] 2) Calculate the total number of meteorological moments n2 that satisfy the condition d1 < 1000 km;

[0061] 3) If n2 / n1>0.3 and it lasts for at least two consecutive meteorological moments, the match is considered correct and the Jianghuai cyclone exists in the lower layer of the cold vortex process.

[0062] S5. The output recognition results include a data set and an atlas;

[0063] The data set includes at least one of the following data sets:

[0064] 1) Northeast cold vortex process data set, including the latitude, longitude and geopotential height values ​​of the cold vortex center every hour;

[0065] 2) Jianghuai cyclone process dataset, including the longitude and latitude of the cyclone center and sea level pressure values ​​every hour;

[0066] 3) Determine the northeastern cold vortex process accompanying the Jianghuai cyclone in the low layer after screening, including the longitude and latitude of the cold vortex center, the potential height value, the longitude and latitude of the cyclone center, the sea level pressure value, and the actual distance between the cold vortex center and the cyclone center.

[0067] The data set includes at least one of the following data sets:

[0068] 1) 500hPa circulation situation map of the northeastern cold vortex at a single moment, including the potential height field, temperature field and the position of the cold vortex center;

[0069] 2) The position distribution of the cold vortex center of a single cold vortex process hour by hour, that is, the moving path diagram of the cold vortex center;

[0070] 3) The sea level pressure field of the Jianghuai cyclone and the position of the cyclone center at a single moment;

[0071] 4) The hourly position distribution of the cyclone center of a single Jianghuai cyclone process, i.e., the moving path diagram of the cyclone center;

[0072] 5) When a cold vortex and a cyclone exist at the same time, the position diagram of the cyclone center relative to the cold vortex center.

[0073] On the basis of the above-mentioned embodiments, a second aspect of the present invention provides a method system for identifying a high-altitude cut-off cold vortex accompanied by a cyclone, comprising:

[0074] A data acquisition module, used for acquiring data;

[0075] A high-altitude cut-off cold vortex identification module is used to identify the high-altitude cut-off cold vortex;

[0076] A cyclone identification module is used to identify cyclones in the same period;

[0077] A matching module for matching the cold vortex with the cyclone;

[0078] The result output module is used to output the recognition results.

[0079] In this embodiment, the working method of each module can be as described above and will not be repeated here.

[0080] like Figure 2 As shown, an embodiment of the third aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the computer program is loaded into the processor, the method for identifying a cyclone accompanying a high-altitude cut-off cold vortex is implemented according to the method described above.

[0081] Optionally, the electronic device may include an input device A1, a processor A2, a storage A3, and an output device A4.

[0082] In one application scenario, the acquired reanalysis data grid point data and typhoon path data can be input into the device through the input device A1, and the data can be submitted to the processor A2 for data processing;

[0083] After receiving the reanalysis data grid data and typhoon path data from the input device A1, the processor A2 processes the received data and obtains the recognition result. Finally, the processor A2 submits the obtained recognition result to the storage A3;

[0084] After receiving the result from the processor A2, the storage A3 stores the result and submits it to the output device A4;

[0085] After receiving the calculation result from the storage, the output device A4 outputs the output result.

[0086] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for identifying a cyclone accompanying a high-altitude cut-off cold vortex as described above.

[0087] In summary, the present invention first establishes an objective identification method to identify the high-altitude cut-off cold vortex process and the low-level cyclone process respectively; secondly, the cold vortex process and the cyclone process in the same period are matched; finally, the judgment result and related charts of whether there is a cyclone in the low layer under the cold vortex background are output. The present invention solves the problems of forecasters' manual judgment of weather systems being time-consuming and laborious, highly subjective, and having limited research time, and provides strong support for the statistical characteristics of long-term series cold vortices and cyclones.

Claims

1. A method for identifying a high-altitude cut-off cold vortex accompanied by a cyclone, characterized in that: The steps include: S1. Obtain information; S2. Identify the high-altitude cut-off cold vortex; S3. Identify cyclones in the same period; S4, matching the cold vortex with the cyclone; S5, output recognition results; in In S4, matching the cold vortex with the cyclone comprises the following steps: Calculate the maximum radius r1 of the cold vortex system, that is, the average distance from the center of the cold vortex to the outermost closed contour line; Calculate the maximum radius r2 of the cyclone system, that is, the average distance from the cyclone center to the outermost closed contour line. The radius difference between two adjacent closed contour lines of the cyclone system must be less than 500 km. Calculate the actual distance d1 between the center of the cold vortex and the center of the cyclone at the same moment using the following formula: ； Where R is the radius of the Earth, ( , ) is the longitude and latitude coordinates of the cold vortex center, ( , ) are the longitude and latitude coordinates of the cyclone center, which need to be converted into radians during calculation; Calculate the relative distance d2 between the cold vortex center and the cyclone center at the same time, the formula is as follows: ； If d1<500km, or d1<1500km and d2<0.6, it is considered that the cold vortex can match the cyclone at this moment; if it can match multiple cyclone centers, the one with the closest actual distance is selected.

2. The method for identifying a high-altitude cut-off cold vortex accompanied by a cyclone according to claim 1, characterized in that: In said S1, the acquired data include reanalysis data grid data and typhoon path data; The reanalysis data grid data include: 500hPa geopotential height field and temperature field, spatial resolution 0.25°×0.25°, time resolution 1h; Sea level pressure field, with a spatial resolution of 0.25°×0.25° and a temporal resolution of 1 hour; and The typhoon path data includes: longitude and latitude information of the typhoon center, spatial resolution 0.1°×0.1°, and time resolution 3h or 6h.

3. The method for identifying a high-altitude cut-off cold vortex accompanied by a cyclone according to claim 1, characterized in that: In S2, the step of identifying the high-altitude cut-off cold vortex includes: For the 500hPa geopotential height field, if the geopotential height value of a point is less than or equal to the surrounding eight grid points, then the point is the local minimum and is considered a candidate point; The candidate points were preliminarily screened. If there were multiple candidate points within the range of 10°×10°, only the point with the lowest potential height was retained and the others were discarded. With the candidate point as the center and 15° as the radius, calculate the temperature centroid of the temperature field on the same isobaric surface; if the distance between the temperature centroid and the candidate point is less than 500km, the candidate point is the center of the cold vortex; The cold vortex center is tracked. The cold vortex centers at two adjacent moments are considered to be the same cold vortex process if the distance between them in the longitudinal direction does not exceed 2° and the distance in the latitudinal direction does not exceed 3°. If there are multiple cold vortex centers that meet the tracking conditions at the next adjacent moment based on the current moment, then at the next adjacent moment, the cold vortex center with the shortest longitude and latitude distance to the cold vortex center at the current moment and the smallest absolute difference in potential height is preferentially selected; Eliminate the false processes caused by northward-moving degenerate typhoons; the false processes are those in which the distance between the cold vortex center and the typhoon center is less than 500 km and lasts for at least 6 hours; Filter and retain the northeastern cold vortex processes with a duration of 3 days or more.

4. The method for identifying a high-altitude cut-off cold vortex accompanied by a cyclone according to claim 1, characterized in that: In S3, the step of identifying the cyclone in the same period includes: For the sea level pressure field, if the pressure value of a certain point is lower than that of the eight adjacent grid points, and the pressure center is less than 1015hPa, then the point is the potential cyclone center; The Laplace average pressure within a 4° radius extending outward from the center of a potential cyclone is calculated using the following formula: ； in is the longitude, is the latitude, The longitude is , latitude is The sea level pressure value corresponding to the point, based on a resolution of 0.25°, the maximum value of i and j is 17; If the central pressure value is less than 995hPa or , and at least one closed contour line can be found, then it is the cyclone center; within the range of 500km×500km, at most one cyclone center can be retained; Track the cyclone center; the cyclone centers at two adjacent moments are considered to be in the same process if the distance between them in the longitudinal direction does not exceed 2° and the distance between them in the latitudinal direction does not exceed 3°; If there are multiple cyclone centers that meet the tracking conditions at the next moment based on the current moment, then at the next moment, the cyclone center with the shortest longitude and latitude distance to the current moment and the smallest absolute pressure difference is preferentially selected; Eliminate the false processes caused by typhoons; the false process is when the distance between the cyclone center and the typhoon center is less than 500km and lasts for at least 6 hours; Cyclone processes with a duration of 1 day or more are screened and retained.

5. The method for identifying a high-altitude cut-off cold vortex accompanied by a cyclone according to claim 1, characterized in that: The step S4 also includes quality control of the matching results, and the specific steps include: Taking the cold vortex process as the benchmark, calculate the total number of synoptic moments n1 when the cold vortex matches the cyclone; Calculate the total number of synoptic moments n2 that satisfy the condition d1 < 1000 km; If n2 / n1>0.3 and is maintained for at least two consecutive meteorological moments, the match is considered correct and a cyclone exists in the lower layer of the cold vortex process.

6. The method for identifying a high-altitude cut-off cold vortex accompanied by a cyclone according to claim 1, characterized in that: In said S5, the output recognition result includes a data set and an atlas; wherein The data set includes at least one of the following data sets: Cold vortex process data set, including the longitude and latitude and potential height values ​​of the cold vortex center every hour; Cyclone process dataset, including the hourly longitude and latitude of the cyclone center and sea level pressure values; Determine the cold vortex process of the low-level accompanying cyclone after screening, including the longitude and latitude of the cold vortex center, the potential height value, the longitude and latitude of the cyclone center, the sea level pressure value, and the actual distance between the cold vortex center and the cyclone center; The atlas includes at least one of the following atlases: The 500hPa circulation situation diagram of the cold vortex at a single moment, including the potential height field, temperature field and the position of the cold vortex center; The position distribution of the cold vortex center of a single cold vortex process hour by hour, that is, the moving path diagram of the cold vortex center; The cyclone sea level pressure field and the location of the cyclone center at a single moment; The hourly position distribution of the cyclone center of a single cyclone process, that is, the movement path diagram of the cyclone center; A diagram showing the position of the cyclone center relative to the cold vortex center when a cold vortex and a cyclone exist at the same time.

7. A high-altitude cut-off cold vortex accompanying cyclone identification system, characterized in that: include: A data acquisition module, used for acquiring data; A high-altitude cut-off cold vortex identification module is used to identify the high-altitude cut-off cold vortex; A cyclone identification module is used to identify cyclones in the same period; A matching module for matching the cold vortex with the cyclone; A result output module, used to output the recognition result; in Matching a cold vortex with a cyclone involves the following steps: Calculate the maximum radius r1 of the cold vortex system, that is, the average distance from the center of the cold vortex to the outermost closed contour line; Calculate the maximum radius r2 of the cyclone system, that is, the average distance from the cyclone center to the outermost closed contour line. The radius difference between two adjacent closed contour lines of the cyclone system must be less than 500 km. Calculate the actual distance d1 between the center of the cold vortex and the center of the cyclone at the same moment using the following formula: ； Where R is the radius of the Earth, ( , ) is the longitude and latitude coordinates of the cold vortex center, ( , ) are the longitude and latitude coordinates of the cyclone center, which need to be converted into radians during calculation; Calculate the relative distance d2 between the cold vortex center and the cyclone center at the same time, the formula is as follows: ； If d1<500km, or d1<1500km and d2<0.6, it is considered that the cold vortex can match the cyclone at this moment; if it can match multiple cyclone centers, the one with the closest actual distance is selected.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is loaded into a processor, the method for identifying a cyclone accompanying a high-altitude cut-off cold vortex according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for identifying a cyclone accompanying a high-altitude cut-off cold vortex according to any one of claims 1 to 6 is implemented.

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