Tropical cyclone rainstorm forecasting method based on conceptual model and physical quantity diagnosis
Through the method based on conceptual models and physical quantification diagnosis, the movement trajectory and path of tropical cyclones are analyzed, the molecular key areas are drawn, and the subjectivity problem in the forecast of tropical cyclone rainstorms is solved, and more accurate forecasts are achieved.
Patent Information
- Application Number
- CN202510299768.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-07-11
AI Technical Summary
The prior art has great subjectivity in the forecast of tropical cyclone rainstorms, which leads to a high probability of missing reports and makes it difficult to achieve accurate forecasts.
Using a method based on conceptual model and physical quantification diagnosis, we use analyzing the moving trajectory and path of tropical cyclones, dividing key molecular areas, combining weather conceptual models and physical quantification diagnosis to determine whether tropical cyclone rainstorms occur, and determining the rainfall area.
It reduces the subjectivity of the forecast, improves the accuracy and accuracy of tropical cyclone rainstorm forecasts, is scientific and practical, and is suitable for tropical cyclone rainstorm forecasts in specific areas.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of weather forecasting, and particularly to a method for forecasting tropical cyclone heavy rain based on a conceptual model and physical quantity diagnosis. Background Art
[0002] A tropical cyclone (TC) is a general term for a non-frontal synoptic-scale vortex generated over the tropical or subtropical ocean surface, with organized convection and a definite cyclonic circulation. A tropical cyclone is the strongest heavy rain weather system, and many extreme heavy rain records at home and abroad are related to tropical cyclone activities. The tropical cyclone heavy rain has a far-reaching influence range and complex and changeable properties, and can often trigger secondary disasters such as floods, landslides, and debris flows, posing a great threat to the safety of human life and property, and has always been the focus and hot spot of concern in the meteorological and water conservancy scientific communities.
[0003] Currently, the general method used for forecasting tropical cyclone heavy rain in operational work is to rely on the forecasting experience of meteorological forecasters to correct numerical forecasts; the forecasting results are highly subjective, and the probability of missing and false alarms is relatively high.
[0004] The Sanmenxia-Huayuankou section in the middle reaches of the Yellow River (the section between Sanmenxia and Huayuankou) is located at the junction of Henan, Shanxi, and Shaanxi provinces. The terrain has large undulations, and the north, west, and south are surrounded by mountains with an elevation of 1000m - 1500m, showing a flared shape with higher elevations in the southwest and northwest and a lower concave in the middle. The precipitation in this section is concentrated, the source is short, the flow is rapid, the flood peak is high, the propagation is fast, and the floods formed by runoff generation and concentration pose the greatest threat to the lower reaches of the Yellow River. Historically, many typical rainstorm floods in the Sanmenxia-Huayuankou section have been closely related to tropical cyclones. For example, from July 14th to 18th, 1958, affected by a tropical cyclone, a westerly trough, and the northwest Pacific subtropical high, persistent heavy rain weather occurred in the Sanmenxia-Huayuankou section, and the Huayuankou Station had the largest flood peak since 1843, causing widespread flooding and levee encroachment below Dongbatou, and most of the levee sections exceeded the guaranteed water level. The "82·8" and "96·8" extremely heavy rain and flood disasters of the Yellow River are also closely related to tropical cyclones. The Huayuankou Station respectively had the second largest flood and the highest historical water level since the station was established. Therefore, establishing an objective and effective method for forecasting tropical cyclone heavy rain in the Sanmenxia-Huayuankou section is an urgent need for flood control and disaster reduction work. Summary of the Invention
[0005] In order to solve the above problems, the present invention proposes a method for forecasting tropical cyclone heavy rain based on a conceptual model and physical quantity diagnosis to reduce the subjectivity of forecasting and improve the accuracy of forecasting tropical cyclone heavy rain.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions:
[0007] A method for forecasting tropical cyclone heavy rain based on a conceptual model and physical quantity diagnosis includes the following steps:
[0008] S1. Analyze the movement trajectory of the tropical cyclone and determine whether it enters the critical impact area;
[0009] S2. If it is determined that the tropical cyclone will enter the critical impact area, then determine the movement path;
[0010] S3. According to the movement path of the tropical cyclone, determine whether it enters the sub-critical areas under each path;
[0011] S4. According to the position where the tropical cyclone enters the sub-critical area, analyze the circulation situation field in combination with the synoptic concept model, and preliminarily judge whether tropical cyclone rainstorms are likely to occur;
[0012] S5. After preliminarily judging that tropical cyclone rainstorms are likely to occur, further diagnose and analyze the physical quantity conditions to finally determine whether tropical cyclone rainstorms will occur; if they will occur, give the rainstorm falling area.
[0013] In some embodiments, in step S1:
[0014] Use numerical forecast products to analyze the movement path of the tropical cyclone during the forecast period and determine whether it enters the critical impact area; wherein, the forecast period is determined according to the required forecast time limit.
[0015] In some embodiments, in step S5: The physical quantity conditions include: moisture, dynamic, and thermal conditions.
[0016] In some embodiments, in step S5:
[0017] The physical quantities used for moisture diagnosis include: specific humidity, relative humidity, and moisture flux divergence;
[0018] The physical quantities used for dynamic diagnosis include: vorticity, divergence, and vertical velocity:
[0019] The physical quantities used for thermal diagnosis include: pseudo-equivalent potential temperature, K-index.
[0020] In some embodiments, in step S5:
[0021] If 10% of the grid points will have rainstorms, it is considered that regional rainstorms will occur;
[0022] Determine the rainstorm falling area according to the positions of the grid points that meet the physical quantity threshold conditions.
[0023] In some embodiments, it is applied to the tropical cyclone rainstorm forecast in the Sanhua area.
[0024] In some embodiments:
[0025] In step S1:
[0026] The range affecting the key area is: 13.5°-35.5°N, 107°-126°E;
[0027] In step S2:
[0028] Determine which category the moving path of the tropical cyclone belongs to among the northward moving type, westward moving type, and turning type;
[0029] In step S3:
[0030] When the moving path is of the northward moving type, delimit Sub-key area 1 and Sub-key area 2;
[0031] If it enters Key area 1, it is considered that the tropical cyclone may have a direct impact of an inverted trough, and if it enters Key area 2, it is considered that the tropical cyclone may have a long-distance impact;
[0032] The range of Sub-key area 1 is: 27.5°-32.5°N, 111.5°-116.5°E;
[0033] The range of Sub-key area 2 is: 20°-27°N, 108.5°-120°E;
[0034] When the moving path is of the westward moving type, delimit Sub-key area 3;
[0035] The range of Sub-key area 3 is: 13.5°-25°N, 107°-122°E;
[0036] When the moving path is of the turning type, delimit Sub-key area 4;
[0037] The range of Sub-key area 4 is: 26.5°-35.5°N, 115°-126°E.
[0038] In some embodiments, in step S4:
[0039] When the moving path is of the northward moving type and the tropical cyclone enters Sub-key area 1, further analyze whether the circulation situation field during the forecast period has the following characteristics according to the synoptic concept model of rainstorms affected by the inverted trough of the northward moving tropical cyclone: At the 500hPa height field, the main center ridge line of the western part of the North Pacific subtropical high is nearly northwest-southeast trending, and the position of the western section of the ridge line is at 35°-40°N; at the same time, there is a high-pressure circulation near Qinghai, forming a situation of two highs confronting each other with the North Pacific subtropical high; the Intertropical Convergence Zone is northward, the tropical low-value systems are active, and there are multiple tropical cyclones coexisting; at the 700hPa, 850hPa or 925hPa height fields, a low-level jet axis is formed between the tropical cyclone and the North Pacific subtropical high, transporting water vapor and energy to the Sanhua area; in addition, the southwest airflow in front of the India-Burma trough transports the water vapor in the Bay of Bengal to the South China Sea and finally converges into the southerly airflow on the east side of the tropical cyclone, forming another water vapor channel;
[0040] When the moving path is of the northward type and the tropical cyclone enters Sub - key Area 2, further analyze whether the circulation situation field in the forecast period has the following characteristics according to the synoptic concept model of heavy rain affected by the northward - moving tropical cyclone: At the 500hPa geopotential height field, the Hetao region and areas south of it are in the trough area. The subtropical high in the western North Pacific and the high - latitude ridge are in phase superposition. The 588dagpm or 584dagpm characteristic line of the subtropical high in the western North Pacific extends westward to the middle and lower reaches of the Yangtze River, and the central ridge line is located at about 27°N; At the 700hPa, 850hPa or 925hPa geopotential height fields, the water vapor from the Bay of Bengal is transported eastward along the south - west airflow in front of the India - Burma trough, converges with the water vapor in the South China Sea, and then advances northward along the southerly airflow between the tropical cyclone and the subtropical high in the western North Pacific, reaching the Sanhua area directly.
[0041] In some embodiments, in step S4:
[0042] When the moving path is of the westward type and the tropical cyclone enters Sub - key Area 3, further analyze whether the circulation situation field in the forecast period has the following characteristics according to the synoptic concept model of heavy rain affected by the westward - moving tropical cyclone: At the 500hPa geopotential height field, the eastern part of the Qinghai - Tibet Plateau is controlled by the trough, and the Sanhua area is in front of the trough. The 588dagpm or 584dagpm characteristic line of the subtropical high in the western North Pacific extends westward to areas such as Jiangxi and Anhui, the ridge line is located at about 25°N, and the northern boundary is in the middle and lower reaches of the Yangtze River; At the 700hPa, 850hPa or 925hPa geopotential height fields, the south - west warm and humid airflow in front of the India - Burma trough travels eastward to the South China Sea, converges with the airflow on the south side of the tropical cyclone, and then moves northward along the west side of the subtropical high in the western North Pacific to reach the Sanhua area directly.
[0043] In some embodiments, in step S4:
[0044] When the moving path is of the turning type and the tropical cyclone enters Sub - key Area 4, further analyze whether the circulation situation field in the forecast period has the following characteristics according to the synoptic concept model of heavy rain affected by the turning tropical cyclone: At the 500hPa geopotential height field, the area from east of Lake Baikal to the Sichuan Basin is in the trough area. The subtropical high in the western North Pacific controls the Japan Sea, the ridge line is located at about 33°N, and the tropical cyclone is located on the south - west side of the subtropical high in the western North Pacific; At the 700hPa, 850hPa or 925hPa, an easterly jet stream is formed between the tropical cyclone and the subtropical high in the western North Pacific, transporting the water vapor in the western North Pacific to the Sanhua area.
[0045] If it has the above corresponding characteristics, it is preliminarily judged that tropical cyclone heavy rain may occur in the Sanhua area; if it does not have the above characteristics, it is considered that tropical cyclone heavy rain will not occur in the Sanhua area.
[0046] Compared with the prior art, the present invention provides a method for forecasting tropical cyclone heavy rain based on a conceptual model and physical quantity diagnosis, which has the following beneficial effects.
[0047] 1. In the present invention, the movement trajectory and path of a tropical cyclone are determined, and sub-critical areas of each path are divided; in the sub-critical areas, the circulation situation field is analyzed in combination with the synoptic concept model to preliminarily judge whether heavy rain occurs; further diagnostic analysis is carried out on water vapor, dynamic, and thermal conditions to determine whether tropical cyclone heavy rain occurs; if it will occur, the heavy rain falling area is determined according to the grid positions that meet the physical quantity threshold conditions. The forecasting method of the present invention is scientific and practical, reduces the subjectivity of forecasting, and effectively improves the accuracy of tropical cyclone heavy rain forecasting.
[0048] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification; and to some extent, based on the study of the following text, they will be obvious to those skilled in the art; or, they can be learned from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0049] Figure 1 is a flowchart of the present invention.
[0050] Figure 2 is a schematic diagram of the division of the influence critical area.
[0051] Figure 3 is a schematic diagram of the northward moving path of a tropical cyclone.
[0052] Figure 4 is a schematic diagram of the westward moving path of a tropical cyclone.
[0053] Figure 5 is a schematic diagram of the turning moving path of a tropical cyclone.
[0054] Figure 6 is a schematic diagram of the demarcation of sub-critical area 1.
[0055] Figure 7 is a schematic diagram of the demarcation of sub-critical area 2.
[0056] Figure 8 is a schematic diagram of the demarcation of sub-critical area 3.
[0057] Figure 9 is a schematic diagram of the demarcation of sub-critical area 4. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0058] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.
[0059] Refer toFigure 1 , A tropical cyclone heavy rain forecasting method based on a conceptual model and physical quantity diagnosis, comprising the following steps:
[0060] S1. Analyze the moving track of the tropical cyclone and determine whether it enters the influence key area;
[0061] S2. If it is determined that the tropical cyclone will enter the influence key area, then determine the moving path;
[0062] S3. According to the moving path of the tropical cyclone, determine whether it enters the sub-key areas under each path;
[0063] S4. According to the position where the tropical cyclone enters the sub-key area, analyze the circulation situation field in combination with the synoptic concept model, and preliminarily determine whether tropical cyclone heavy rain may occur;
[0064] S5. After preliminarily determining that tropical cyclone heavy rain may occur, further diagnose and analyze the physical quantity conditions to finally determine whether tropical cyclone heavy rain will occur; if it will occur, give the heavy rain falling area.
[0065] In step S1: Use numerical forecast products (EC, GRAPES_GFS, etc.) to analyze the moving path of the tropical cyclone during the forecast period and determine whether it enters the influence key area.
[0066] Among them, the forecast period is determined according to the required forecast time limit; for example, for a 24-hour forecast, analyze the moving path of the tropical cyclone in the next 24 hours; for a 48-hour forecast, analyze the moving path of the tropical cyclone in the next 48 hours; using numerical forecast products, forecasts within 240 hours can be made.
[0067] In step S5: The physical quantity conditions include: water vapor, dynamic, and thermal conditions.
[0068] Specifically:
[0069] The physical quantities used for water vapor diagnosis include: specific humidity, relative humidity, and water vapor flux divergence;
[0070] The physical quantities used for dynamic diagnosis include: vorticity, divergence, and vertical velocity:
[0071] The physical quantities used for thermal diagnosis include: pseudo-equivalent potential temperature, K index.
[0072] In addition, in step S5:
[0073] If 10% of the grid points in the forecast area will have heavy rain, it is considered that regional heavy rain will occur;
[0074] Determine the heavy rain falling area according to the positions of the grid points that meet the physical quantity threshold conditions.
[0075] It should be noted that the above forecasting method can be used in various regions; correspondingly, in the above forecasting method, the impact key area, movement path, sub-key area, synoptic concept model, and related physical quantity thresholds, etc., are related to the area to be forecast and are set accordingly.
[0076] Apply the above forecasting method to the tropical cyclone heavy rain forecasting in the area between the Three Gorges and the Huaihe River.
[0077] As Figure 2 shown, when conducting tropical cyclone heavy rain forecasting in the area between the Three Gorges and the Huaihe River:
[0078] The range of the impact key area is: 13.5°-35.5°N, 107°-126°E.
[0079] Corresponding to the area between the Three Gorges and the Huaihe River, in step S2:
[0080] Judge which category the movement path of the tropical cyclone belongs to among the northward moving type, westward moving type, and turning type.
[0081] As Figures 3 - 5 shown, it is a schematic diagram of the movement path of the tropical cyclone (derived from the paths of tropical cyclones that caused heavy rain in the area between the Three Gorges and the Huaihe River in history).
[0082] Furthermore, in step S3:
[0083] When the movement path is the northward moving type, delimit sub-key area 1 and sub-key area 2;
[0084] If it enters key area 1, it is considered that the tropical cyclone may produce a reverse trough and have a direct impact;
[0085] If it enters key area 2, it is considered that the tropical cyclone may produce a long-distance impact.
[0086] When the movement path is the westward moving type, delimit sub-key area 3.
[0087] When the movement path is the turning type, delimit sub-key area 4.
[0088] As Figures 6 - 9 shown; it is a schematic diagram of the delimitation of each sub-key area.
[0089] Among them:
[0090] The range of sub-key area 1 is: 27.5°-32.5°N, 111.5°-116.5°E;
[0091] The range of sub-key area 2 is: 20°-27°N, 108.5°-120°E;
[0092] The range of sub-key area 3 is: 13.5°-25°N, 107°-122°E;
[0093] The range of the sub-critical area 4 is: 26.5°-35.5°N, 115°-126°E.
[0094] Correspondingly, in step S4, judgment conditions are set for the corresponding triple-flower intervals.
[0095] As Figure 6 shown; when the moving path is of the northward type and the tropical cyclone enters the sub-critical area 1, further analyze whether the circulation situation field in the forecast period has the following characteristics according to the synoptic concept model of the rainstorm affected by the inverted trough of the northward tropical cyclone:
[0096] On the 500hPa geopotential height field, the main ridge line of the western part of the Western Pacific Subtropical High (WPSH) is nearly northwest-southeast, and the position of the western section of the ridge line is at 35°-40°N; at the same time, there is a high-pressure circulation near Qinghai, forming a situation of two highs confronting each other with the Western Pacific Subtropical High; the Intertropical Convergence Zone is located northward, and tropical low-value systems are active, with multiple tropical cyclones coexisting; on the 700hPa, 850hPa or 925hPa geopotential height fields, a low-level jet axis is formed between the tropical cyclone and the Western Pacific Subtropical High, transporting water vapor and energy to the triple-flower intervals; in addition, the southwest airflow in front of the India-Burma trough transports the water vapor in the Bay of Bengal to the South China Sea and finally converges into the southerly airflow on the east side of the tropical cyclone, forming another water vapor channel.
[0097] As Figure 7 shown; when the moving path is of the northward type and the tropical cyclone enters the sub-critical area 2, further analyze whether the circulation situation field in the forecast period has the following characteristics according to the synoptic concept model of the rainstorm affected by the long-distance influence of the northward tropical cyclone:
[0098] On the 500hPa geopotential height field, the area south of and including the Hetao region is a trough area, and the Western Pacific Subtropical High is in phase superposition with the mid-high latitude high-pressure ridge. The 588dagpm (geopotential decameters) or 584dagpm characteristic line of the Western Pacific Subtropical High extends westward to the middle and lower reaches of the Yangtze River, and the central ridge line is located at about 27°N; on the 700hPa, 850hPa or 925hPa geopotential height fields, the water vapor from the Bay of Bengal is transported eastward along the southwest airflow in front of the India-Burma trough, converges with the water vapor in the South China Sea, and then advances northward along the southerly airflow between the tropical cyclone and the Western Pacific Subtropical High, reaching the triple-flower intervals directly.
[0099] As Figure 8 shown; when the moving path is of the westward type and the tropical cyclone enters the sub-critical area 3, further analyze whether the circulation situation field in the forecast period has the following characteristics according to the synoptic concept model of the rainstorm affected by the westward tropical cyclone:
[0100] At the 500 hPa geopotential height field, the eastern part of the Qinghai-Tibet Plateau is controlled by a trough, and the Sanhua area is located in front of the trough. The 588 dagpm or 584 dagpm characteristic line of the Western Pacific subtropical high extends westward to Jiangxi and Anhui, the ridge line is located around 25°N, and the northern boundary is in the middle and lower reaches of the Yangtze River. At the 700 hPa, 850 hPa or 925 hPa geopotential height fields, the southwest warm and moist airflow in front of the India-Burma trough moves eastward to the South China Sea. After converging with the airflow on the south side of the tropical cyclone, it moves northward along the west side of the Western Pacific subtropical high directly to the Sanhua area.
[0101] As Figure 9 shown; when the moving path is of the turning type and the tropical cyclone enters the sub-critical area 4, then further analyze whether the circulation situation field has the following characteristics during the forecast period according to the synoptic concept model of the turning tropical cyclone affecting heavy rain:
[0102] At the 500 hPa geopotential height field, the area from east of Lake Baikal to the Sichuan Basin is a trough area, the Western Pacific subtropical high controls the Sea of Japan, the ridge line is located around 33°N, and the tropical cyclone is located on the southwest side of the Western Pacific subtropical high. At the 700 hPa, 850 hPa or 925 hPa geopotential height fields, an easterly jet forms between the tropical cyclone and the Western Pacific subtropical high, transporting the water vapor in the Western Pacific to the Sanhua area.
[0103] If it has the above corresponding characteristics, then initially judge that tropical cyclone heavy rain may occur in the Sanhua area; if it does not have the above characteristics, then it is considered that tropical cyclone heavy rain will not occur in the Sanhua area.
[0104] In step S5: After initially judging that tropical cyclone heavy rain may occur, further conduct diagnostic analysis on the water vapor, dynamic, and thermodynamic conditions in the Sanhua area to finally determine whether tropical cyclone heavy rain will occur in the Sanhua area; if it will occur, determine the heavy rain falling area according to the grid positions that meet the physical quantity threshold conditions.
[0105] Specifically:
[0106] The physical quantities used for water vapor diagnosis include: specific humidity, relative humidity, and water vapor flux divergence at the 700 hPa, 850 hPa, and 925 hPa height levels;
[0107] The physical quantities used for dynamic diagnosis include: vorticity and divergence at the 200 hPa and 850 hPa height levels, and vertical velocity at the 850 hPa height level;
[0108] The physical quantities used for thermodynamic diagnosis include: pseudo-equivalent potential temperature at the 850 hPa height level, and the difference in pseudo-equivalent potential temperature between the 850 hPa and 500 hPa height levels, and K index.
[0109] Among them, the above physical quantities are directly obtained from numerical prediction products (EC, GRAPES_GFS, etc.) or calculated.
[0110] After obtaining the values of the above 17 physical quantities at each grid point within the Sanhua interval area:
[0111] If the maximum value (when the physical quantity value is positive) or the minimum value (when the physical quantity value is negative) of 10 physical quantities at a certain grid point reaches the threshold within the prediction period (such as 24h), it is considered that heavy rain will occur at this grid point.
[0112] It should be noted that among the 10 physical quantities that reach the threshold, there is at least one physical quantity representing water vapor, dynamic, and thermodynamic conditions.
[0113] If 10% of the grid points within the Sanhua interval area will have heavy rain, it is considered that regional heavy rain will occur in the Sanhua interval; and the heavy rain falling area is determined according to the positions of the grid points that meet the physical quantity threshold conditions.
[0114] Specifically, the threshold of the physical quantity is determined by the box plot method.
[0115] That is, the information of all meteorological stations with tropical cyclone heavy rain in the Sanhua interval in history is statistically analyzed. Using ERA5 reanalysis data, box plot analysis is carried out on the maximum or minimum values of 17 physical quantities at each heavy rain station on the heavy rain day, and the threshold is defined as the lower quartile or the upper quartile in the box plot.
[0116] Among them, when the physical quantity value is positive, the threshold is defined as the upper quartile in the box plot; when the physical quantity value is negative, the threshold is defined as the lower quartile in the box plot.
[0117] The thresholds of each physical quantity are shown in the following table.
[0118]
[0119] Table 1 Thresholds of Physical Quantities for Water Vapor Conditions
[0120]
[0121] Table 2 Thresholds of Physical Quantities for Dynamic Conditions ( / means no threshold is given, the same below)
[0122]
[0123] Table 3 Thresholds of Physical Quantities for Thermodynamic Conditions
[0124] In the present invention, the movement trajectory and path of a tropical cyclone are analyzed, and sub-critical areas of each path are divided; in the sub-critical areas, it is preliminarily determined whether heavy rain occurs by combining a synoptic concept model; after it is preliminarily determined that tropical cyclone heavy rain may occur, the physical quantity conditions (water vapor, dynamics, thermodynamics) are further diagnosed and analyzed to determine whether tropical cyclone heavy rain occurs; if it will occur, the heavy rain fall area is determined according to the grid point positions that meet the physical quantity threshold conditions; the forecasting method of the present invention is scientific and practical, reduces the subjectivity of forecasting, and effectively improves the accuracy of tropical cyclone heavy rain forecasting.
[0125] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.
[0126] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.
Claims
1. A tropical cyclone heavy rain forecasting method based on a conceptual model and physical quantity diagnosis, characterized in that, It includes the following steps: S1. Analyze the moving track of the tropical cyclone and determine whether it enters the key impact area; S2. If it is determined that the tropical cyclone will enter the key impact area, then judge the moving path; S3. According to the moving path of the tropical cyclone, determine whether it enters the sub-key areas under each path; S4. According to the position where the tropical cyclone enters the sub-key area, analyze the circulation situation field in combination with the synoptic concept model, and preliminarily judge whether tropical cyclone rainstorms may occur; S5. After preliminarily judging that tropical cyclone rainstorms may occur, further conduct diagnostic analysis on physical quantity conditions to finally determine whether tropical cyclone rainstorms will occur; if they will occur, give the rainstorm falling area.
2. The tropical cyclone heavy rain forecasting method based on concept model and physical quantity diagnosis according to claim 1, characterized in that In step S1: Use numerical forecast products to analyze the moving path of the tropical cyclone during the forecast period and determine whether it enters the key impact area; among them, the forecast period is determined according to the required forecast time limit.
3. The tropical cyclone heavy rain forecasting method based on concept model and physical quantity diagnosis according to claim 1, wherein In step S5: The physical quantity conditions include: water vapor, dynamic, and thermal conditions.
4. The tropical cyclone heavy rain forecasting method based on concept model and physical quantity diagnosis according to claim 3, wherein In step S5: The physical quantities used for water vapor diagnosis include: specific humidity, relative humidity, and water vapor flux divergence; The physical quantities used for dynamic diagnosis include: vorticity, divergence, and vertical velocity: The physical quantities used for thermal diagnosis include: pseudo-equivalent potential temperature, K index.
5. The tropical cyclone heavy rain forecasting method based on concept model and physical quantity diagnosis according to claim 1, wherein In step S5: If 10% of the grid points in the forecast area will have rainstorms, it is considered that regional rainstorms will occur; Determine the rainstorm falling area according to the positions of the grid points that meet the physical quantity threshold conditions.
6. The tropical cyclone heavy rain forecasting method based on concept model and physical quantity diagnosis according to any one of claims 1-5, characterized in that Applied to the tropical cyclone rainstorm forecast in the Sanhua River Basin.
7. The tropical cyclone rainstorm forecast method based on the concept model and physical quantity diagnosis according to claim 6, characterized in that: In step S1: The range of the key impact area is: 13.5° - 35.5°N, 107° - 126°E; In step S2: Judge which category the moving path of the tropical cyclone belongs to among the northward moving category, westward moving category, and turning category; In step S3: When the moving path is the northward moving category, delimit sub-key area 1 and sub-key area 2; The range of sub-key area 1 is: 27.5° - 32.5°N, 111.5° - 116.5°E; The range of sub-key area 2 is: 20° - 27°N, 108.5° - 120°E; If it enters sub-key area 1, it is considered that the tropical cyclone may have a direct impact on the inverted trough; If it enters sub-key area 2, it is considered that the tropical cyclone may have a long-distance impact; When the moving path is the westward moving category, delimit sub-key area 3; The range of sub-key area 3 is: 13.5° - 25°N, 107° - 122°E; When the moving path is the turning category, delimit sub-key area 4; The range of sub-key area 4 is: 26.5° - 35.5°N, 115° - 126°E.
8. The tropical cyclone heavy rain forecasting method based on concept model and physical quantity diagnosis according to claim 7, characterized in that In step S4: When the moving path is of the northward type and the tropical cyclone enters Sub - key Area 1, further analyze whether the circulation situation field in the forecast period has the following characteristics according to the synoptic concept model of heavy rain affected by the inverted trough of the northward - moving tropical cyclone: On the 500hPa geopotential height field, the main ridge line of the western part of the subtropical high in the western North Pacific is nearly northwest - southeast, and the position of the western - segment ridge line is at 35° - 40°N; meanwhile, there is a high - pressure circulation near Qinghai, forming a situation of two highs confronting each other with the subtropical high in the western North Pacific; the Inter - Tropical Convergence Zone is northward, tropical low - value systems are active, and there are multiple tropical cyclones coexisting; on the 700hPa, 850hPa or 925hPa geopotential height fields, a low - level jet axis is formed between the tropical cyclone and the subtropical high in the western North Pacific, transporting water vapor and energy to the Sanhua area; in addition, the southwest airflow in front of the India - Burma trough transports the water vapor in the Bay of Bengal to the South China Sea and finally converges into the southerly airflow on the east side of the tropical cyclone, forming another water - vapor channel. When the moving path is of the northward type and the tropical cyclone enters Sub - key Area 2, further analyze whether the circulation situation field in the forecast period has the following characteristics according to the synoptic concept model of heavy rain affected by the long - distance influence of the northward - moving tropical cyclone: On the 500hPa geopotential height field, the Hetao region and the areas south of it are in the trough area, the subtropical high in the western North Pacific and the mid - high - latitude high - pressure ridge are in phase superposition, and the 588dagpm or 584dagpm characteristic line of the subtropical high in the western North Pacific extends westward to the middle and lower reaches of the Yangtze River, and the central ridge line is located at about 27°N; on the 700hPa, 850hPa or 925hPa geopotential height fields, the water vapor from the Bay of Bengal is transported eastward along the southwest airflow in front of the India - Burma trough, converges with the water vapor in the South China Sea, and then advances northward along the southerly airflow between the tropical cyclone and the subtropical high in the western North Pacific, reaching the Sanhua area directly.
9. The tropical cyclone heavy rain forecasting method based on concept model and physical quantity diagnosis according to claim 7, characterized in that In step S4: When the moving path is of the westward type and the tropical cyclone enters Sub - key Area 3, further analyze whether the circulation situation field in the forecast period has the following characteristics according to the synoptic concept model of heavy rain affected by the westward - moving tropical cyclone: On the 500hPa geopotential height field, the eastern part of the Qinghai - Tibet Plateau is controlled by a trough, the Sanhua area is in front of the trough, the 588dagpm or 584dagpm characteristic line of the subtropical high in the western North Pacific extends westward to Jiangxi and Anhui areas, the ridge line is located at about 25°N, and the northern boundary is in the middle and lower reaches of the Yangtze River region; on the 700hPa, 850hPa or 925hPa geopotential height fields, the southwest warm and humid airflow in front of the India - Burma trough travels eastward to the South China Sea, converges with the airflow on the south side of the tropical cyclone, and then moves northward along the west side of the subtropical high in the western North Pacific to reach the Sanhua area directly.
10. The tropical cyclone heavy rain forecasting method based on concept model and physical quantity diagnosis according to claim 7, characterized in that In step S4: When the moving path is a turning type and the tropical cyclone enters the sub-critical area 4, it is further analyzed according to the synoptic concept model of the rainstorm affected by the turning tropical cyclone whether the circulation situation field has the following characteristics during the forecast period: on the 500hPa height field, there is a trough area from east of Lake Baikal to the Sichuan Basin, the Northwest Pacific subtropical high controls the Sea of Japan, the ridge line is located at about 33°N, and the tropical cyclone is located on the southwest side of the Northwest Pacific subtropical high; on the 700hPa, 850hPa or 925hPa, an easterly jet stream is formed between the tropical cyclone and the Northwest Pacific subtropical high, transporting the water vapor in the Northwest Pacific to the area between the Three Rivers.