Rainfall prediction method, device and equipment for plain areas

Abstract

This invention provides a method, apparatus, and equipment for rainfall forecasting in plains areas, relating to the field of weather forecasting technology. The method includes: detecting the circulation pattern of the area to be forecasted to determine if it belongs to a typical rainfall circulation type; if the circulation pattern belongs to a typical rainfall circulation type, obtaining the rainfall triggering conditions corresponding to the circulation type, as well as the low-level jet stream characteristics and vertical wind shear characteristics of the area to be forecasted; if the low-level jet stream characteristics and vertical wind shear characteristics meet the rainfall triggering conditions, determining that rainfall will begin in the area to be forecasted after a set duration, and determining the rainfall intensity level and duration based on the low-level jet stream characteristics and vertical wind shear characteristics. This invention can improve the accuracy of rainfall forecasting in plains areas.

Description

Technical Field

[0001] This invention relates to the field of weather forecasting technology, and in particular to a method, apparatus and equipment for forecasting rainfall in plain areas. Background Technology

[0002] Heavy rain is a major weather event that causes severe disasters such as floods, urban waterlogging, and soaring river levels. Existing meteorological research and forecasts on the disasters caused by heavy rain focus mainly on extreme precipitation caused by orographic uplift in mountainous areas, but neglect the destructive potential of heavy rain in plains areas.

[0003] In related technologies, rainfall forecasting for plains areas mostly remains at the level of qualitative analysis. This results in insufficient accuracy in rainfall forecasting results for plains areas in terms of rainfall intensity quantification, early warning of sudden rainfall events, and prediction of event duration.

[0004] In summary, the relevant technologies have low accuracy in forecasting rainfall in plain areas and cannot effectively cope with disasters such as flooding and sudden rises in river levels caused by heavy rain in plain areas. Summary of the Invention

[0005] This invention provides a method, apparatus, device, and storage medium for rainfall forecasting in plain areas, in order to solve the problem of low rainfall forecast accuracy in plain areas.

[0006] In a first aspect, embodiments of the present invention provide a rainfall forecasting method for plain areas, comprising: Detect the circulation pattern in the area to be forecasted to determine whether it belongs to a typical precipitation circulation type; If the circulation pattern belongs to a typical precipitation circulation type, then obtain the precipitation triggering conditions corresponding to the circulation type, as well as the low-level jet characteristics and vertical wind shear characteristics of the area to be forecasted; If the low-level jet stream characteristics and the vertical wind shear characteristics meet the rainfall triggering conditions, it is determined that rainfall will begin in the forecast area after a set time, and the rainfall intensity level and rainfall duration are determined based on the low-level jet stream characteristics and the vertical wind shear characteristics.

[0007] In one possible implementation, the low-level jet characteristics include: the wind speed of the transition layer, the latitude of the northern end of the isotropic line corresponding to the lower limit of the low-level jet's speed, and the northward lifting speed of the low-level jet. The vertical wind shear features include: vertical wind shear corresponding to the first altitude range, vertical wind shear corresponding to the second altitude range, and vertical wind shear corresponding to the third altitude range; The rainfall triggering conditions include: The wind speed in the transition layer is greater than or equal to a set wind speed; the latitude of the northern end of the isotropic line corresponding to the lower limit of the low-level jet is greater than or equal to a set latitude; the northward lifting speed of the low-level jet is greater than or equal to a set speed; the vertical wind shear corresponding to the first altitude range reaches a first threshold; the vertical wind shear corresponding to the second altitude range reaches a second threshold; and the vertical wind shear corresponding to the third altitude range reaches a third threshold.

[0008] In one possible implementation, the low-level jet characteristics include: the average intensity of the low-level jet in the free atmosphere and the core intensity of the low-level jet in the boundary layer; The vertical wind shear characteristics include: vertical wind shear corresponding to the second altitude range; The determination of rainfall intensity level and duration based on the low-level jet stream characteristics and the vertical wind shear characteristics includes: If the average intensity of the low-level jet in the free atmosphere is greater than or equal to a first average threshold, the intensity of the low-level jet core in the boundary layer is greater than or equal to a first jet core threshold, and the vertical wind shear corresponding to the second altitude range is greater than or equal to a first wind shear threshold, then the rainfall intensity level is determined to be a heavy rainfall level, and the rainfall duration is determined to be greater than or equal to a first duration. If the average intensity of the low-level jet stream in the free atmosphere is less than a first average threshold and greater than or equal to a second average threshold, the intensity of the low-level jet stream core in the boundary layer is less than a first jet stream core threshold and greater than or equal to a second jet stream core threshold, and the vertical wind shear corresponding to the second altitude range is less than a first wind shear threshold and greater than or equal to a second wind shear threshold, then the rainfall intensity level is determined to be a moderate to heavy rainfall level, and the rainfall duration is determined to be less than a first duration and greater than or equal to a second duration. If the average intensity of the low-level jet stream in the free atmosphere is less than the second average threshold or the intensity of the low-level jet stream core in the boundary layer is less than the second jet stream core threshold, and the vertical wind shear corresponding to the second altitude range is less than the second wind shear threshold, then the rainfall intensity level is determined to be a weak rainfall level, and the rainfall duration is determined to be less than the second duration.

[0009] In one possible implementation, the method further includes: Obtain the circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index of the area to be forecasted; The circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index are quantitatively evaluated to obtain quantitative scores for the circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index. The quantitative scores are weighted and summed to obtain the comprehensive score of the region to be predicted; Based on the comprehensive score, the rainfall intensity range corresponding to the area to be forecasted is determined.

[0010] In one possible implementation, typical precipitation circulation types include: upper-level trough type, cold vortex type, typhoon remnant vortex type, and subtropical high type; The circulation pattern is quantitatively evaluated to obtain a quantitative score for the circulation pattern, including: If the circulation pattern belongs to any one of the upper-level trough, the cold vortex, and the typhoon remnant vortex, then the quantitative score of the circulation pattern is determined as the first circulation score. If the circulation pattern belongs to the subtropical high type, then the quantitative score of the circulation pattern is determined as the second circulation score; If the circulation pattern belongs to at least two of the following types: upper-level trough, cold vortex, typhoon remnant vortex, and subtropical high, and the intensity index of the circulation pattern is less than a set intensity threshold, then the quantitative score of the circulation pattern is determined to be the third circulation score. If the circulation pattern does not belong to the typical rainfall circulation type, then the quantitative score of the circulation pattern is determined to be the fourth circulation score; The first circulation score is greater than the second circulation score, the second circulation score is greater than the third circulation score, and the third circulation score is greater than the fourth circulation score.

[0011] In one possible implementation, the height configuration indicators include: wind speed in the free atmosphere, wind speed in the transition layer, and wind speed in the boundary layer; The highly configured indicators are quantitatively evaluated to obtain a quantitative score for the highly configured indicators, including: Detect whether the wind speed in the free atmosphere, the wind speed in the transition layer, and the wind speed in the boundary layer reach the standard value for the low-level jet stream; The quantitative score of the height configuration index is determined based on the number of layers where the wind speed reaches the standard value of the low-level jet stream; the more layers, the higher the quantitative score of the height configuration index. The jet intensity index includes the average jet core intensity corresponding to the maximum value among the free atmospheric wind speed, the transition layer wind speed, and the boundary layer wind speed. The jet flow intensity index is quantitatively evaluated to obtain a quantitative score for the jet flow intensity index, including: The quantitative score of the jet flow intensity index is determined based on the average value of the jet flow core intensity; the higher the average value of the jet flow core intensity, the higher the quantitative score of the jet flow intensity index.

[0012] In one possible implementation, the jet stream location index includes: the latitude of the northern end of the isotropic line corresponding to the lower limit of the low-level jet stream's velocity and the northward lifting velocity of the low-level jet stream. The jet stream location index is quantitatively evaluated to obtain a quantitative score for the jet stream location index, including: If the northern latitude is greater than or equal to the first latitude value, then the northern latitude score is determined to be the first latitude score; If the northern latitude is less than the first latitude value and greater than or equal to the second latitude value, then the northern latitude score is determined to be the second latitude score. If the latitude of the northernmost point is less than the second latitude value, then the score of the latitude of the northernmost point is determined to be the score of the third latitude. If the northward lifting speed is greater than or equal to the first speed, then the score for the northward lifting speed is determined to be the first speed score; If the northward lifting speed is less than the first speed but greater than or equal to the second speed, then the northward lifting speed score is determined to be the second speed score; If the northward lifting speed is less than the second speed, then the score for the northward lifting speed is determined to be the third speed score; The weighted sum of the latitude score at the northern end and the northward shift speed score yields the quantitative score of the jet stream location index.

[0013] In one possible implementation, the jet flow pulsation index includes: jet flow core intensity data of the transition layer and the average jet flow core intensity of the transition layer; The jet stream pulsation index is quantitatively evaluated to obtain a quantitative score for the jet stream pulsation index, including: Detect whether there are pulsations in the rapid flow core intensity data; If the jet stream core intensity data exhibits pulsation, the quantitative score of the jet stream pulsation index is determined based on the average value of the jet stream core intensity; the higher the average value of the jet stream core intensity, the higher the quantitative score. The wind shear index includes: vertical wind shear corresponding to the first altitude range, vertical wind shear corresponding to the second altitude range, and a synergistic index; The wind shear index is quantitatively evaluated to obtain a quantitative score for the wind shear index, including: The vertical wind shear corresponding to the first altitude range, the vertical wind shear corresponding to the second altitude range, and the coordination index are respectively tested to see if they meet the standards. The quantitative score of the wind shear index is determined based on the number of times the standard is met; the more times the standard is met, the higher the quantitative score of the wind shear index.

[0014] Secondly, embodiments of the present invention provide a rainfall forecasting device for plains areas, comprising: The detection module is used for: Detect the circulation pattern in the area to be forecasted to determine whether it belongs to a typical precipitation circulation type; If the circulation pattern belongs to a typical precipitation circulation type, then obtain the precipitation triggering conditions corresponding to the circulation type, as well as the low-level jet characteristics and vertical wind shear characteristics of the area to be forecasted; Forecast module, used for: If the low-level jet stream characteristics and the vertical wind shear characteristics meet the rainfall triggering conditions, it is determined that rainfall will begin in the forecast area after a set time, and the rainfall intensity level and rainfall duration are determined based on the low-level jet stream characteristics and the vertical wind shear characteristics.

[0015] Thirdly, embodiments of the present invention provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described in the first aspect or any possible implementation thereof.

[0016] Compared to existing technologies, this invention can determine whether the area to be forecasted is under a rainfall background by analyzing the circulation pattern. Then, based on the characteristics of the low-level jet stream and vertical wind shear, and the corresponding rainfall triggering conditions, a rainfall warning for the area to be forecasted can be issued in advance with a set duration. Furthermore, the rainfall intensity and duration can be quantitatively determined using the characteristics of the low-level jet stream and vertical wind shear, achieving refined and quantitative forecasting of rainfall intensity and duration. Specifically, the large-scale circulation type determines the probability and basic form of rainfall, while the mesoscale characteristics of the low-level jet stream and vertical wind shear are key conditions for triggering rainfall and determining rainfall intensity and duration. This invention organically integrates forecasting factors at different spatial scales, forming a more complete and reliable rainfall judgment mechanism. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the implementation of a rainfall forecasting method for plains areas according to an embodiment of the present invention. Figure 2(a) is a schematic diagram of the circulation pattern of an upper-level trough provided in an embodiment of the present invention; Figure 2(b) is a schematic diagram of the circulation pattern of a cold vortex provided in an embodiment of the present invention; Figure 2(c) is a schematic diagram of the circulation pattern of a typhoon remnant vortex provided in an embodiment of the present invention; Figure 2(d) is a schematic diagram of the circulation pattern of a subtropical high provided in an embodiment of the present invention; Figure 3 This is a flowchart illustrating the implementation of a rainfall forecasting method for plains areas provided in another embodiment of the present invention; Figure 4This is a schematic diagram of the structure of a rainfall forecasting device for plains areas provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0018] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] When using related technologies to forecast rainfall in plains areas, most of them remain at the level of qualitative analysis. This results in insufficient accuracy in rainfall forecasts for plains areas in terms of rainfall intensity quantification, early warning of sudden rainfall events, and prediction of event duration.

[0020] To improve the accuracy of rainfall forecasts in plain areas, this invention determines the possibility of rainfall by detecting whether the circulation pattern of the area to be forecasted belongs to a typical rainfall circulation type. Then, it uses low-level jet characteristics and vertical wind shear characteristics to pre-set the duration of rainfall warnings for the area to be forecasted. Furthermore, it can also use low-level jet characteristics and vertical wind shear characteristics to quantitatively determine the rainfall intensity level and rainfall duration, thereby achieving refined and quantitative forecasts of rainfall intensity level and rainfall duration.

[0021] See Figure 1 The document illustrates a flowchart of the rainfall forecasting method for plains areas provided in an embodiment of the present invention, detailed below: Step 101: Detect the circulation pattern of the area to be forecasted to determine whether it belongs to a typical precipitation circulation type.

[0022] In this embodiment of the invention, the 500 hPa circulation pattern of the area to be forecasted can be obtained, and it can be detected whether the 500 hPa circulation pattern belongs to a typical precipitation circulation type. Typical precipitation circulation types include: upper-level trough type, cold vortex type, typhoon remnant vortex type, and subtropical high type. The 500 hPa circulation patterns corresponding to different typical precipitation circulation types are shown in Figures 2(a) to 2(d).

[0023] Understandably, if the 500 hPa circulation pattern of the area to be forecasted belongs to any of the typical precipitation circulation types mentioned above, then it is determined that there is a possibility of precipitation in the area, and the following steps can be performed to check whether the precipitation triggering conditions are met, and to further determine the rainfall intensity and duration. If the 500 hPa circulation pattern of the area to be forecasted does not belong to any of the typical precipitation circulation types mentioned above, then it is determined that there is no possibility of precipitation in the area, and no further steps are required.

[0024] Step 102: If the circulation pattern belongs to a typical precipitation circulation type, then obtain the precipitation triggering conditions corresponding to the circulation type, as well as the low-level jet characteristics and vertical wind shear characteristics of the area to be forecasted.

[0025] Low-level jet characteristics can include, but are not limited to, various dimensions of low-level jet information such as wind speed in the transition layer, the latitude of the northern end of the isotropic lines corresponding to the lower limit of the low-level jet speed, the northward lifting speed of the low-level jet, the average intensity of the low-level jet in the free atmosphere, and the core intensity of the low-level jet in the boundary layer.

[0026] In this embodiment of the invention, the altitude of the low-level jet stream is divided into the free atmosphere (700 hPa), the transition layer (850 hPa), and the boundary layer (925 hPa). For each layer, if the wind speed in that layer is greater than or equal to the lower speed limit of the low-level jet stream, it is determined to be a low-level jet stream. For example, the lower speed limit of the low-level jet stream can be 12 m / s. Correspondingly, the isotropic lines corresponding to the lower speed limit of the low-level jet stream are the 12 m / s isotropic lines.

[0027] The northward velocity of the low-level jet stream refers to the northward movement speed of the isotropic line (i.e., the 12 m / s isotropic line) corresponding to the lower limit of the low-level jet stream velocity.

[0028] The average intensity of the low-level jet stream in the free atmosphere refers to the average wind speed in the region within the free atmosphere where the wind speed is greater than or equal to the lower limit of the low-level jet stream speed (i.e., 12 m / s).

[0029] The intensity of the low-level jet core in the boundary layer refers to the wind speed at the location of the maximum wind speed (i.e., the jet core) within the jet region (i.e., the region with wind speeds greater than or equal to 12 m / s) in the boundary layer.

[0030] In plains areas, the moisture required for rainfall depends entirely on external transport, with low-level jet streams being the primary moisture carriers. The warm, moist air transported by these jet streams accumulates in the plains, forming a highly unstable layer with cold air (such as cold fronts or the dry, cold air behind cold vortices). This unstable layer, with its lower warm and moist lower layer and middle dry and cold middle layer, has a vertical structure that allows for the rapid accumulation of convective potential energy, storing energy for convective bursts (i.e., rainfall).

[0031] Rainfall formation also requires lifting conditions. Low-level jet streams can provide power through three mechanisms: First, convergence to the left of the jet stream axis: the left side of the low-level jet stream axis is a cyclonic shear zone, and wind speed shear leads to horizontal convergence, triggering vertical upward motion; second, orographic lifting: when the low-level jet stream encounters a windward slope, it is forced to lift up along the slope; third, lifting due to the convergence of warm and cold air: the convergence of warm and moist jet streams with cold air forms a front, and the lifting of the front further strengthens vertical motion, maintaining the continuous development of convection.

[0032] As described above, low-level jet streams are an important condition for determining whether rainfall will occur in plain areas. In this embodiment of the invention, rainfall triggering conditions can be constructed by using low-level jet stream characteristics, and low-level jet stream characteristics of the area to be forecasted can be obtained to detect whether the area to be forecasted meets the rainfall triggering conditions.

[0033] Vertical wind shear characteristics may include, but are not limited to, vertical wind shear corresponding to different altitude ranges, such as vertical wind shear corresponding to the first altitude range, the second altitude range, and the third altitude range.

[0034] Here, the first altitude range can be 0-1km, the second altitude range can be 0-3km, and the third altitude range can be 0-6km.

[0035] The embodiments of the present invention can be based on Calculate the vertical wind shear for each altitude range.

[0036] in, This indicates the vertical wind shear corresponding to a range of altitudes. This represents the difference between the upper and lower limits of an altitude range. Wind speed at upper altitude limit Wind speed indicating the lower limit of altitude. This indicates a difference in wind direction.

[0037] Vertical wind shear tilts the updrafts from cumulonimbus clouds, promoting the continuous entrainment of warm, moist air from the environment and providing matter and energy for the maintenance of convective systems. It is a key dynamic condition for the intensification and persistence of rainfall. Among these, the vertical wind shear at 0-1 km has the strongest indicative significance for the onset of rainfall; it shows a significant increasing trend 6 hours before rainfall occurs. The vertical wind shear at 0-3 km is most sensitive to fluctuations in rainfall intensity during the rainfall process. The vertical wind shear at 0-6 km has the lowest overall shear intensity, but it changes in tandem with rainfall intensity, consistently increasing as rainfall intensity increases; although its indicative significance for rainfall intensity is weaker than that of low-level shear, it can serve as an auxiliary signal.

[0038] Based on the above, vertical wind shear is a crucial condition for determining whether rainfall will occur, its intensity, and its duration in plain areas. This embodiment of the invention can construct rainfall triggering conditions using vertical wind shear characteristics and obtain the vertical wind shear characteristics of the area to be forecasted, which can then be used to detect whether the area meets the rainfall triggering conditions. Furthermore, the rainfall intensity and duration can be further determined based on the vertical wind shear characteristics.

[0039] In some embodiments, rainfall triggering conditions may include: The wind speed in the transition layer is greater than or equal to the set wind speed; the latitude of the northern end of the isotropic line corresponding to the lower limit of the speed of the low-level jet is greater than or equal to the set latitude; the northward lifting speed of the low-level jet is greater than or equal to the set speed; the vertical wind shear corresponding to the first altitude range reaches the first threshold; the vertical wind shear corresponding to the second altitude range reaches the second threshold; and the vertical wind shear corresponding to the third altitude range reaches the third threshold.

[0040] Here, the wind speed, latitude, velocity, first threshold, second threshold, and third threshold can be determined based on the typical rainfall circulation type and the geographical location of the area to be forecasted. This embodiment of the invention does not impose specific limitations on these parameters.

[0041] It is important to clarify that the above-mentioned rainfall triggering conditions apply to all typical rainfall circulation types. The difference between typical rainfall circulation types only affects the values ​​of the set wind speed, set latitude, set velocity, first threshold, second threshold, and third threshold in the rainfall triggering conditions.

[0042] In this embodiment of the invention, historical rainfall data of the area to be forecasted can be pre-compiled, and rainfall samples covering four typical rainfall circulation types—upper-level trough, typhoon remnant, cold vortex, and subtropical high—can be selected from them. The low-level jet stream characteristics and vertical wind shear characteristics of each rainfall sample corresponding to a set time before rainfall can be statistically analyzed, thereby determining the values ​​of the set wind speed, set latitude, set velocity, first threshold, second threshold, and third threshold.

[0043] For example, the characteristics of the low-level jet stream and vertical wind shear corresponding to the 6 hours before rainfall for each rainfall sample can be statistically analyzed, and the values ​​of the set wind speed, set latitude, set velocity, first threshold, second threshold and third threshold in the rainfall triggering conditions can be determined by calculating the average value of each low-level jet stream and vertical wind shear characteristics.

[0044] Taking the Beijing-Tianjin-Hebei Plain as an example, the rainfall triggering conditions corresponding to different typical rainfall circulation types are shown in Table 1.

[0045] Table 1. Different typical rainfall circulation types and their corresponding rainfall triggering conditions

[0046] Step 103: If the characteristics of the low-level jet stream and the vertical wind shear meet the conditions for triggering rainfall, then it is determined that rainfall will begin in the forecast area after a set time, and the rainfall intensity level and duration are determined based on the characteristics of the low-level jet stream and the vertical wind shear.

[0047] It is understandable that the above-mentioned rainfall triggering conditions are obtained by statistically analyzing the low-level jet stream characteristics and vertical wind shear characteristics of each rainfall sample at a set time before rainfall. Accordingly, when the current low-level jet stream characteristics and vertical wind shear characteristics of the area to be forecasted meet the rainfall triggering conditions, it is determined that rainfall will begin in the area to be forecasted after the set time.

[0048] Taking Table 1 above as an example, if the 500pHa circulation pattern in the Beijing-Tianjin-Hebei region belongs to any one of the following types: upper-level trough, typhoon remnant, cold vortex, or subtropical high, and the characteristics of the low-level jet stream and vertical wind shear meet the corresponding rainfall triggering conditions, then it is determined that rainfall will begin in the Beijing-Tianjin-Hebei region 6 hours later.

[0049] After determining that rainfall is about to begin in the area to be forecasted, this embodiment of the invention can further forecast the rainfall intensity and duration based on the characteristics of the low-level jet stream and vertical wind shear, so as to achieve refined rainfall forecasting.

[0050] Besides determining whether rainfall will occur in plains areas, low-level jet streams can also determine the duration of rainfall, and are key to sustained heavy rainfall. Here, the stability of the jet stream depends on large-scale systems (e.g., the position of the subtropical high, the typhoon path, and the movement speed of the upper-level trough). If the subtropical high is stable and the typhoon moves slowly westward, the jet stream can be maintained for 24-48 hours, with a continuous supply of moisture and dynamic conditions, resulting in a long duration of rainfall.

[0051] The low-level jet stream, acting as a conduit for warm, moist air currents, continuously supplies water vapor and unstable energy. Simultaneously, it triggers convection through low-level convergence and uplift, serving as the "energy and water vapor source" for precipitation. Vertical wind shear, through vertical wind variations (wind speed / direction), maintains convective organization—moderate shear separates rising / descending air currents, preventing rapid convective dissipation, while strong shear promotes the merging of convective cells into mesoscale systems, prolonging the duration of rainfall. Furthermore, shear intensity determines the rate of convective development, influencing raindrop condensation and growth efficiency, thus regulating rainfall intensity. The low-level jet stream provides the "material basis," while vertical wind shear determines the "duration and intensity" of convection. When these two are matched (e.g., the jet stream delivers sufficient water vapor + moderate shear maintains convection), strong and persistent rainfall is easily formed; conversely, rainfall intensity is weak or duration is short.

[0052] As described above, the low-level jet stream and vertical wind shear jointly influence the rainfall intensity and duration. This embodiment of the invention, based on the determination that rainfall is imminent in the forecast area, further determines the rainfall intensity and duration of the forecast area according to the characteristics of the low-level jet stream and vertical wind shear.

[0053] In some embodiments, if the average intensity of the low-level jet in the free atmosphere is greater than or equal to a first average threshold, the intensity of the low-level jet core in the boundary layer is greater than or equal to a first jet core threshold, and the vertical wind shear corresponding to the second altitude range is greater than or equal to a first wind shear threshold, then the rainfall intensity level is determined to be a heavy rainfall level, and the rainfall duration is determined to be greater than or equal to a first duration. If the average intensity of the low-level jet in the free atmosphere is less than the first average threshold and greater than or equal to the second average threshold, the intensity of the low-level jet core in the boundary layer is less than the first jet core threshold and greater than or equal to the second jet core threshold, and the vertical wind shear corresponding to the second altitude range is less than the first wind shear threshold and greater than or equal to the second wind shear threshold, then the rainfall intensity level is determined to be moderate to heavy rainfall, and the rainfall duration is determined to be less than the first duration and greater than or equal to the second duration. If the average intensity of the low-level jet stream in the free atmosphere is less than the second average threshold or the intensity of the low-level jet stream core in the boundary layer is less than the second jet stream core threshold, and the vertical wind shear corresponding to the second altitude range is less than the second wind shear threshold, then the rainfall intensity level is determined to be a weak rainfall level, and the rainfall duration is determined to be less than the second duration.

[0054] In this embodiment of the invention, the rainfall intensity level, rainfall duration, and corresponding low-level jet stream characteristics and vertical wind shear characteristics of each rainfall sample can be statistically analyzed to determine the values ​​of the first average threshold, the first jet stream core threshold, the first wind shear threshold, the second average threshold, the second jet stream core threshold, and the second wind shear threshold.

[0055] For example, embodiments of the present invention can determine the values ​​of a first average threshold, a first jet core threshold, and a first wind shear threshold by calculating the average values ​​of the low-level jet stream characteristics and vertical wind shear characteristics corresponding to rainfall samples of heavy rainfall intensity and rainfall duration greater than a first duration. Similarly, the values ​​of a second average threshold, a second jet core threshold, and a second wind shear threshold can be determined by calculating the average values ​​of the corresponding low-level jet stream characteristics and vertical wind shear characteristics corresponding to rainfall samples of moderate to heavy rainfall intensity and rainfall duration less than the first duration but greater than or equal to a second duration.

[0056] Taking the Beijing-Tianjin-Hebei Plain as an example, the embodiments of the present invention can determine the rainfall intensity level and rainfall duration according to Table 2 below.

[0057] Table 2

[0058] In this embodiment of the invention, if the rainfall intensity is greater than or equal to 40 mm / h, it is determined to be heavy rainfall. If the rainfall intensity is greater than or equal to 20 mm / h but less than 40 mm / h, it is determined to be moderate to heavy rainfall. If the rainfall intensity is less than 20 mm / h, it is determined to be light rainfall. The first duration is 4 hours, and the second duration is 2 hours.

[0059] Compared to existing technologies, this invention can determine whether the area to be forecasted is under a rainfall background by analyzing the circulation pattern. Then, based on the characteristics of the low-level jet stream and vertical wind shear, and the corresponding rainfall triggering conditions, a rainfall warning for the area to be forecasted can be issued in advance with a set duration. Furthermore, the rainfall intensity and duration can be quantitatively determined using the characteristics of the low-level jet stream and vertical wind shear, achieving refined and quantitative forecasting of rainfall intensity and duration. Specifically, the large-scale circulation type determines the probability and basic form of rainfall, while the mesoscale characteristics of the low-level jet stream and vertical wind shear are key conditions for triggering rainfall and determining rainfall intensity and duration. This invention organically integrates forecasting factors at different spatial scales, forming a more complete and reliable rainfall judgment mechanism.

[0060] Considering that the above embodiments define rainfall intensity levels too broadly for precise rainfall intensity forecasting, another embodiment of the present invention provides a novel rainfall forecasting method for plain areas, enabling precise rainfall intensity forecasting. See also... Figure 3 The rainfall forecasting method includes: Step 301: Obtain the circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index of the area to be forecasted.

[0061] Here, the circulation pattern refers to the 500 pHa circulation pattern. Altitude configuration indicators include: wind speeds in the free atmosphere, transition layer, and boundary layer. Jet intensity indicators include: the average jet core intensity corresponding to the maximum values ​​of the wind speeds in the free atmosphere, transition layer, and boundary layer. Jet location indicators include: the latitude of the northern end of the isotropic lines corresponding to the lower limit of the low-level jet velocity and the northward shift velocity of the low-level jet. Jet pulsation indicators include: jet core intensity data in the transition layer and the average jet core intensity in the transition layer. Wind shear indicators include: vertical wind shear corresponding to the first altitude range, vertical wind shear corresponding to the second altitude range, and the coordination index.

[0062] The average intensity of the jet stream core refers to the average wind speed in the region where the jet stream core is located. In this embodiment of the invention, the region within a set distance from the jet stream core can be defined as the region where the jet stream core is located. The value of the set distance can be determined according to the actual situation and is not specifically limited here.

[0063] The jet stream core intensity data of the transition layer refers to the time series data of the jet stream core intensity of the transition layer. In this embodiment of the invention, the jet stream core intensity of the transition layer can be collected at unit time intervals (e.g., 1 hour) within a set time period (e.g., 24 hours) to form the time series data of the jet stream core intensity of the transition layer.

[0064] The synergy index refers to the correlation between vertical wind shear and convective available potential energy corresponding to 0-3km. It can reflect the degree of matching between rainfall dynamic conditions (i.e., vertical wind shear corresponding to 0-3km) and thermal conditions (i.e., convective available potential energy), and is used to improve the accuracy of rainfall intensity prediction.

[0065] The formula for calculating the synergy index can be expressed as: ; in, Indicates the synergy index. This indicates the vertical wind shear corresponding to 0-3km. This represents the convective effective potential energy.

[0066] According to statistics, When the value is ≥8, the probability of rainfall intensity ≥20 mm / h is ≥85%; when the value is ≤6, the probability of rainfall intensity ≥20 mm / h is ≥85%. At times <8:00, the probability of rainfall intensity being 10-20 mm / h is ≥78%; When the rainfall intensity is less than 6 mm / h, the probability of occurrence is ≥82%.

[0067] Step 302: Quantitatively evaluate the circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index respectively to obtain quantitative scores for the circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index.

[0068] In some embodiments, the quantitative assessment process for circulation patterns is as follows: If the circulation pattern belongs to any of the following types: upper-level trough, cold vortex, and typhoon remnant, then the quantitative score of the circulation pattern is determined as the first circulation score; if the circulation pattern belongs to the subtropical high, then the quantitative score of the circulation pattern is determined as the second circulation score; if the circulation pattern belongs to at least two of the following types: upper-level trough, cold vortex, typhoon remnant, and subtropical high, and the intensity index of the circulation pattern is less than the set intensity threshold, then the quantitative score of the circulation pattern is determined as the third circulation score; if the circulation pattern does not belong to the typical precipitation circulation type, then the quantitative score of the circulation pattern is determined as the fourth circulation score.

[0069] Among them, the first circulation score is greater than the second circulation score, the second circulation score is greater than the third circulation score, and the third circulation score is greater than the fourth circulation score.

[0070] In this embodiment of the invention, the circulation characteristics of the 500 pHa circulation pattern in the area to be predicted can be extracted, and it can be detected whether the circulation characteristics meet the criteria of a typical precipitation circulation type, thereby determining whether the 500 pHa circulation pattern in the area to be predicted belongs to a typical precipitation circulation type.

[0071] For upper-level troughs, the presence of a trough line, the strength of the trough line meeting the standard, and the location of the trough line entering a critical position can be detected within the 500 pHa circulation pattern of the area to be predicted. Understandably, if all the above conditions are met, the 500 pHa circulation pattern of the area to be predicted is determined to be an upper-level trough.

[0072] For cold vortex patterns, it can be determined whether closed contour lines exist in the 500 pHa circulation pattern of the region to be predicted, and whether a significant low-temperature center exists near the closed low-pressure center. Understandably, if all the above conditions are met, the 500 pHa circulation pattern of the region to be predicted is determined to be a cold vortex pattern.

[0073] For typhoon remnant patterns, the 500 pHa circulation pattern in the forecast area can be analyzed based on the typhoon track forecast to determine whether it represents the remnant circulation after landfall of the typhoon, and whether the circulation pattern is warm, isolated low-pressure, or a deep trough. Understandably, if all the above conditions are met, the 500 pHa circulation pattern in the forecast area is determined to be a typhoon remnant pattern.

[0074] For subtropical high-pressure systems, it can be determined whether the 588 dagpm contour line of the main body of the subtropical high extends westward to the key area. If it is confirmed that the 588 dagpm contour line of the main body of the subtropical high extends westward to the key area, then the 500 pHa circulation pattern in the area to be predicted is determined to be of the subtropical high-pressure type.

[0075] It should be noted that if the 500 pHa circulation pattern of the area to be predicted simultaneously meets at least two of the above types, but the intensity index of each type is low (e.g., low trough intensity, indistinct low temperature center, excessively high central pressure of the circulation pattern, 588 contour line extending westward to the edge of the key area, etc.), then it is determined that the 500 pHa circulation pattern of the area to be predicted is fuzzy and a weak circulation system exists.

[0076] This invention can employ gradient quantization to unify the quantization score to a [0, 10] scale. When the circulation pattern can be accurately classified and determined to be any of the following types: upper-level trough, cold vortex, or typhoon remnant, the quantization score is determined as the first circulation score (e.g., 10 points). When the circulation pattern can be accurately fractalized and determined to be a subtropical high, the quantization score is determined as the second circulation score (e.g., 7 points). When the circulation pattern is ambiguous and a weak circulation system exists, the quantization score is determined as the third circulation score (e.g., 5 points). When the circulation pattern does not belong to any of the following types: upper-level trough, cold vortex, typhoon remnant, or subtropical high, the quantization score is determined as the fourth circulation score (e.g., 0 points).

[0077] Circulation patterns provide support for large-scale precipitation circulation and are a necessary condition for rainfall. If the quantitative score of the circulation pattern is 0, meaning the circulation pattern does not belong to a typical precipitation circulation background, then it is determined that there will be no rainfall in the area to be forecasted, and no further steps are required.

[0078] Altitude configuration indicators include wind speeds in the free atmosphere, transition layer, and boundary layer. These reflect the configuration of the jet stream axis across multiple altitudes, thus determining the efficiency of water vapor / energy transport and are crucial factors for precipitation. In some embodiments, the quantitative evaluation process for altitude configuration indicators is as follows: The system detects whether the wind speeds in the free atmosphere, transition layer, and boundary layer reach the standard values ​​for the low-level jet stream. Based on the number of layers where the wind speed reaches the standard value for the low-level jet stream, the quantitative score of the altitude configuration index is determined; the more layers, the higher the quantitative score of the altitude configuration index.

[0079] Here, the standard value for the low-level jet stream can be the lower limit of its speed, i.e., 12 m / s. Similarly, following a gradient quantization method, the quantization score is standardized to a [0-10] point scale. If the wind speeds at all three levels reach the standard value for the low-level jet stream, the quantization score is determined as the first altitude score (e.g., 10 points). If the wind speeds at any two levels reach the standard value for the low-level jet stream, the quantization score is determined as the second altitude score (e.g., 9 points). If the wind speed at one level reaches the standard value for the low-level jet stream, the quantization score is determined as the third altitude score (e.g., 7 points). If the wind speeds at all three levels do not reach the standard value for the low-level jet stream, the quantization score is determined as the fourth altitude score (e.g., 0 points).

[0080] The jet stream intensity index includes the average jet stream core intensity corresponding to the maximum value among the free atmospheric wind speed, transition layer wind speed, and boundary layer wind speed. This directly determines the water vapor transport intensity and upward motion kinetic energy, and is a core driving condition. In some embodiments, the quantitative evaluation process for the jet stream intensity index is as follows: The quantitative score of the jet flow intensity index is determined based on the average value of the jet flow core intensity; the higher the average value of the jet flow core intensity, the higher the quantitative score of the jet flow intensity index.

[0081] First, identify the layer with the highest wind speed among 700hPa, 850hPa, and 925hPa. Then, calculate the average jet core intensity of that layer. Finally, use gradient quantization to determine the quantization score.

[0082] For example, when the average intensity of the jet stream core is ≥24 m / s (i.e., extreme jet stream), the quantified score is determined as the first intensity score (e.g., 10 points). When the average intensity of the jet stream core is greater than or equal to 18 m / s and less than 24 m / s (i.e., strong jet stream), the quantified score is determined as the second intensity score (e.g., 9 points). When the average intensity of the jet stream core is greater than or equal to 15 m / s and less than 18 m / s (i.e., moderate jet stream), the quantified score is determined as the third intensity score (e.g., 7 points). When the average intensity of the jet stream core is greater than or equal to 12 m / s and less than 15 m / s (i.e., weak jet stream), the quantified score is determined as the fourth intensity score (e.g., 5 points). When the average intensity of the jet stream core is less than 12 m / s (i.e., no jet stream), the quantified score is determined as the fifth intensity score (e.g., 0 points).

[0083] The key indicators of jet stream location include the latitude of the northern end of the isotropic lines (i.e., the jet stream axis) corresponding to the lower limit of the jet stream's velocity, and the northward shifting velocity of the jet stream. The northern end of the jet stream axis and its northward shifting velocity determine the area and duration of precipitation impact. Jet stream location indicators are crucial factors influencing rainfall.

[0084] In some embodiments, the process of quantifying and evaluating the jet stream location index is as follows: First, the aforementioned northern latitude and northward shift velocity are quantitatively assessed, yielding corresponding scores for the northern latitude and northward shift velocity. Next, the northern latitude and northward shift velocity scores are weighted and summed to obtain a quantitative score for the jet stream location index. For example, the weight corresponding to the northern latitude score can be 0.85, and the weight corresponding to the northward shift velocity score can be 0.15.

[0085] Specifically, if the latitude of the northernmost point is greater than or equal to the first latitude value, then the latitude score of the northernmost point is determined as the first latitude score; if the latitude of the northernmost point is less than the first latitude value but greater than or equal to the second latitude value, then the latitude score of the northernmost point is determined as the second latitude score; if the latitude of the northernmost point is less than the second latitude value, then the latitude score of the northernmost point is determined as the third latitude score.

[0086] Here, the first latitude value can be simply understood as the effective location influencing rainfall in the area to be forecasted. The second latitude value can be simply understood as the starting point where the jet stream begins to influence rainfall in the area to be forecasted. If the northern latitude is greater than or equal to the first latitude value, it proves that the jet stream axis completely influences rainfall in the area to be forecasted. If the northern latitude is less than the first latitude value but greater than or equal to the second latitude value, it proves that the jet stream axis begins to influence rainfall in the area to be forecasted. If the northern latitude is less than the second latitude value, it proves that the jet stream axis cannot influence rainfall in the area to be forecasted.

[0087] Taking the Beijing-Tianjin-Hebei Plain as an example, if the northern latitude is greater than or equal to 36°N, then the northern latitude score is determined as the first latitude score (e.g., 10 points). If the northern latitude is less than 36°N but greater than or equal to 33°N, then the northern latitude score is determined as the second latitude score (e.g., 5 points). If the northern latitude is less than 33°N, then the northern latitude score is determined as the third latitude score (e.g., 0 points).

[0088] If the northward lifting speed is greater than or equal to the first speed, then the northward lifting speed score is determined as the first speed score; if the northward lifting speed is less than the first speed but greater than or equal to the second speed, then the northward lifting speed score is determined as the second speed score; if the northward lifting speed is less than the second speed, then the northward lifting speed score is determined as the third speed score.

[0089] For example, if the northward shift speed is greater than or equal to 4° / 6h, the northward shift speed score is determined as the first speed score (e.g., 10 points). If the northward shift speed is less than 4° / 6h but greater than or equal to 2° / 6h, the northward shift speed score is determined as the second speed score (e.g., 6 points). If the northward shift speed is less than 2° / 6h, the northward shift speed score is determined as the third speed score (e.g., 0 points).

[0090] Jet pulsations can trigger enhanced convection and intensify rainfall, acting as a secondary enhancement condition for rainfall. In some embodiments, jet pulsation indices include: jet core intensity data of the transition layer and the average jet core intensity of the transition layer. The quantitative evaluation process for jet pulsation indices is as follows: The system detects whether there is pulsation in the jet stream core intensity data. If pulsation is found, the quantitative score of the jet stream pulsation index is determined based on the average value of the jet stream core intensity. The higher the average value of the jet stream core intensity, the higher the quantitative score.

[0091] Based on the above, the jet stream core intensity data is the time series data of the jet stream core intensity. Embodiments of the present invention can determine the presence of pulsations by identifying peaks in the time series data. It is understood that if the time series data contains at least one peak, then pulsations are determined to exist.

[0092] Based on the confirmed presence of pulsation, a gradient quantification method can be used for assessment: If the average jet stream intensity is greater than or equal to 4 m / s / 3 h (i.e., strong pulsation), the quantification score is 10 points. If the average jet stream intensity is less than 4 m / s / 3 h but greater than or equal to 1 m / s / 3 h (i.e., medium pulsation), the quantification score is 9 points. If the average jet stream intensity is less than 1 m / s / 3 h but greater than 0 m / s / 3 h (i.e., weak pulsation), the quantification score is 8 points. If the average jet stream intensity is equal to 0 m / s / 3 h, the quantification score is 0 points. If no pulsation is confirmed, the quantification score for the jet stream pulsation index can be directly set to 0 points.

[0093] In some embodiments, wind shear indices include: vertical wind shear corresponding to a first elevation range, vertical wind shear corresponding to a second elevation range, and a synergistic index. Wind shear indices affect the degree of convection organization; strong shear is conducive to the maintenance of heavy precipitation and is an important condition for rainfall.

[0094] The quantitative evaluation process for wind shear index is as follows: The vertical wind shear and the synergistic index corresponding to the first and second altitude ranges are tested to see if they meet the standards. The quantitative score of the wind shear index is determined based on the number of standards met. The more standards met, the higher the quantitative score of the wind shear index.

[0095] In this embodiment of the invention, the quantization score is standardized to a [0, 10] score system using a gradient quantization method: if the vertical wind shear for 0-1km, the vertical wind shear for 0-3km, and the coordination index all meet their respective set standards, the quantization score is determined as the first shear score (e.g., 10 points). If any two items meet their respective set standards, the quantization score is determined as the second shear score (e.g., 7 points). If only one item meets its corresponding set standard, the quantization score is determined as the third shear score (e.g., 4 points). If none of them meet their respective standards, the quantization score is determined as the fourth shear score (e.g., 0 points).

[0096] Step 303: The quantitative scores are weighted and summed to obtain the comprehensive score of the area to be predicted.

[0097] In this embodiment of the invention, a weighted summation method combining the analytic hierarchy process (AHP) and the entropy weighting method is used to assign weights to each quantitative score, thus obtaining the weight of each quantitative score. Then, the quantitative scores are weighted and summed to obtain the final comprehensive score.

[0098] In this embodiment of the invention, the subjective weights corresponding to each indicator can be obtained by first using the analytic hierarchy process (AHP). For example, the subjective weight of the circulation pattern is 0.22, the subjective weight of the height configuration indicator is 0.16, the subjective weight of the jet stream intensity indicator is 0.23, the subjective weight of the jet stream location indicator is 0.15, the subjective weight of the jet stream pulsation indicator is 0.14, and the subjective weight of the wind shear indicator is 0.1.

[0099] Next, the objective weights corresponding to each indicator are obtained using the entropy weight method: for example, the objective weight of circulation pattern is 0.15, the objective weight of height configuration indicator is 0.2, the objective weight of jet intensity indicator is 0.27, the objective weight of jet location indicator is 0.18, the objective weight of jet pulsation indicator is 0.07, and the objective weight of wind shear indicator is 0.13.

[0100] Finally, a weighted average method is used to superimpose the subjective and objective weights: for example, the subjective weight accounts for 0.4 and the objective weight accounts for 0.6. The final weights of each indicator are as follows: the weight of circulation pattern is 0.18, the weight of height configuration indicator is 0.22, the weight of jet stream intensity indicator is 0.25, the weight of jet stream location indicator is 0.17, the weight of jet stream pulsation indicator is 0.08, and the subjective weight of wind shear indicator is 0.1.

[0101] Step 304: Determine the rainfall intensity interval corresponding to the area to be forecasted based on the comprehensive score.

[0102] It should be noted that the higher the overall score, the greater the corresponding rainfall intensity, and consequently, the larger the rainfall intensity range. For example, the embodiments of the present invention delineate... point Five rainfall intensity ranges: 0-10 mm / h, 10-20 mm / h, 20-30 mm / h, 30-50 mm / h, and greater than or equal to 50 mm / h.

[0103] Still using the [0,10] scale, the embodiment of the present invention can determine the rainfall intensity interval corresponding to the area to be forecasted based on Table 3: Table 3. Different comprehensive scores and their corresponding rainfall intensity ranges

[0104] According to Table 3, if the overall score of the area to be forecasted is less than 4 points, the rainfall intensity of the area is determined to be greater than or equal to 0 and less than 10 mm / h. If the overall score of the area to be forecasted is greater than or equal to 4 points and less than 5.5 points, the rainfall intensity of the area is determined to be greater than or equal to 10 mm / h and less than 20 mm / h. If the overall score of the area to be forecasted is greater than or equal to 5.5 points and less than 7 points, the rainfall intensity of the area is determined to be greater than or equal to 20 mm / h and less than 30 mm / h. If the overall score of the area to be forecasted is greater than or equal to 7 points and less than 8.5 points, the rainfall intensity of the area is determined to be greater than or equal to 30 mm / h and less than 50 mm / h. If the overall score of the area to be forecasted is greater than or equal to 8.5 points, the rainfall intensity of the area is determined to be greater than or equal to 50 mm / h.

[0105] The embodiments of the present invention quantify and evaluate circulation patterns, height configuration indicators, jet stream intensity indicators, jet stream location indicators, jet stream pulsation indicators, and wind shear indicators, respectively, which can achieve accurate quantitative classification of precipitation intensity and significantly improve the precision and accuracy of forecasts.

[0106] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0107] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0108] Figure 4 A schematic diagram of a rainfall forecasting device for plains areas provided in an embodiment of the present invention is shown. For ease of explanation, only the parts relevant to the embodiment of the present invention are shown, and are described in detail below: like Figure 4 As shown, the rainfall forecasting device 4 for plains areas includes a detection module 41 and a forecasting module 42.

[0109] Detection module 41 is used for: Detect the circulation pattern in the area to be forecasted to determine whether it belongs to a typical precipitation circulation type; If the circulation pattern belongs to a typical precipitation circulation type, then obtain the precipitation triggering conditions corresponding to the circulation type, as well as the low-level jet characteristics and vertical wind shear characteristics of the area to be forecasted; Forecast module 42 is used for: If the characteristics of the low-level jet stream and the vertical wind shear meet the conditions for triggering rainfall, then it is determined that rainfall will begin in the forecast area after a set time, and the rainfall intensity level and duration are determined based on the characteristics of the low-level jet stream and the vertical wind shear.

[0110] Optionally, the characteristics of the low-level jet stream include: the wind speed in the transition layer, the latitude of the northern end of the isotropic lines corresponding to the lower limit of the low-level jet stream speed, and the northward lifting speed of the low-level jet stream. Vertical wind shear characteristics include: vertical wind shear corresponding to the first altitude range, vertical wind shear corresponding to the second altitude range, and vertical wind shear corresponding to the third altitude range; Rainfall triggering conditions include: The wind speed in the transition layer is greater than or equal to the set wind speed; the latitude of the northern end of the isotropic line corresponding to the lower limit of the speed of the low-level jet is greater than or equal to the set latitude; the northward lifting speed of the low-level jet is greater than or equal to the set speed; the vertical wind shear corresponding to the first altitude range reaches the first threshold; the vertical wind shear corresponding to the second altitude range reaches the second threshold; and the vertical wind shear corresponding to the third altitude range reaches the third threshold.

[0111] Optionally, low-level jet characteristics include: the average intensity of the low-level jet in the free atmosphere and the intensity of the low-level jet core in the boundary layer; Vertical wind shear characteristics include: vertical wind shear corresponding to the second altitude range; Forecast module 42 is specifically used for: If the average intensity of the low-level jet in the free atmosphere is greater than or equal to the first average threshold, the intensity of the low-level jet core in the boundary layer is greater than or equal to the first jet core threshold, and the vertical wind shear corresponding to the second altitude range is greater than or equal to the first wind shear threshold, then the rainfall intensity level is determined to be a heavy rainfall level, and the rainfall duration is determined to be greater than or equal to the first duration. If the average intensity of the low-level jet in the free atmosphere is less than the first average threshold and greater than or equal to the second average threshold, the intensity of the low-level jet core in the boundary layer is less than the first jet core threshold and greater than or equal to the second jet core threshold, and the vertical wind shear corresponding to the second altitude range is less than the first wind shear threshold and greater than or equal to the second wind shear threshold, then the rainfall intensity level is determined to be moderate to heavy rainfall, and the rainfall duration is determined to be less than the first duration and greater than or equal to the second duration. If the average intensity of the low-level jet stream in the free atmosphere is less than the second average threshold or the intensity of the low-level jet stream core in the boundary layer is less than the second jet stream core threshold, and the vertical wind shear corresponding to the second altitude range is less than the second wind shear threshold, then the rainfall intensity level is determined to be a weak rainfall level, and the rainfall duration is determined to be less than the second duration.

[0112] Optionally, the forecast module 42 is also used for: Obtain the circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index of the area to be forecasted; The circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index were quantitatively evaluated to obtain quantitative scores for the circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index. The quantitative scores are weighted and summed to obtain the comprehensive score of the area to be predicted. Based on the overall score, the rainfall intensity range corresponding to the area to be forecasted is determined.

[0113] Optional, typical precipitation circulation types include: upper-level trough type, cold vortex type, typhoon remnant type, and subtropical high type; Forecast module 42 is specifically used for: If the circulation pattern belongs to any of the following types: upper-level trough, cold vortex, and typhoon remnant vortex, then the quantitative score of the circulation pattern is determined as the first circulation score. If the circulation pattern is of the subtropical high type, then the quantitative score of the circulation pattern is determined as the second circulation score; If the circulation pattern belongs to at least two of the following types: upper-level trough, cold vortex, typhoon remnant vortex, and subtropical high, and the intensity index of the circulation pattern is less than the set intensity threshold, then the quantitative score of the circulation pattern is determined as the third circulation score. If the circulation pattern does not belong to the typical rainfall circulation type, then the quantitative score of the circulation pattern is determined to be the fourth circulation score; The first circulation score is greater than the second circulation score, the second circulation score is greater than the third circulation score, and the third circulation score is greater than the fourth circulation score.

[0114] Optional height configuration parameters include: wind speed in the free atmosphere, wind speed in the transition layer, and wind speed in the boundary layer; Forecast module 42 is specifically used for: The test measures whether the wind speeds in the free atmosphere, the transition layer, and the boundary layer meet the standard values ​​for the low-level jet stream. The quantitative score of the height configuration index is determined based on the number of layers where the wind speed reaches the standard value of the low-level jet stream; the more layers, the higher the quantitative score of the height configuration index.

[0115] Optionally, the jet intensity index includes: the average jet core intensity corresponding to the maximum value among the free atmosphere wind speed, transition layer wind speed and boundary layer wind speed; Forecast module 42 is specifically used for: The quantitative score of the jet flow intensity index is determined based on the average value of the jet flow core intensity; the higher the average value of the jet flow core intensity, the higher the quantitative score of the jet flow intensity index.

[0116] Optional indicators of jet stream location include: the latitude of the northern end of the isotropic line corresponding to the lower limit of the jet stream speed and the northward lifting speed of the jet stream. Forecast module 42 is specifically used for: If the latitude of the northernmost point is greater than or equal to the value of the first latitude, then the score of the latitude of the northernmost point is determined to be the score of the first latitude. If the northern latitude is less than the first latitude value but greater than or equal to the second latitude value, then the northern latitude score is determined to be the second latitude score. If the latitude of the northernmost point is less than the second latitude value, then the score for the latitude of the northernmost point is determined to be the score for the third latitude. If the northward lifting speed is greater than or equal to the first speed, then the northward lifting speed score is determined as the first speed score; If the northward lifting speed is less than the first speed but greater than or equal to the second speed, then the northward lifting speed score is determined to be the second speed score; If the northward lifting speed is less than the second speed, then the score for the northward lifting speed is determined to be the score for the third speed. The quantitative score of the jet stream location index is obtained by weighting and summing the latitude score at the northern end and the northward velocity score.

[0117] Optional parameters for jet pulsation include: jet core intensity data of the transition layer and the average jet core intensity of the transition layer; Forecast module 42 is specifically used for: Detect whether there are pulsations in the nuclear intensity data of the rapid flow; If there are pulsations in the jet stream core intensity data, the quantitative score of the jet stream pulsation index is determined based on the average value of the jet stream core intensity; the higher the average value of the jet stream core intensity, the higher the quantitative score.

[0118] Optional wind shear indices include: vertical wind shear corresponding to the first altitude range, vertical wind shear corresponding to the second altitude range, and synergistic index; Forecast module 42 is specifically used for: The vertical wind shear and the synergy index corresponding to the first and second altitude ranges were tested to see if they met the standards. The quantitative score of the wind shear index is determined based on the number of compliances; the more compliances, the higher the quantitative score of the wind shear index.

[0119] This device embodiment can be used in the above method embodiment, and its technical principle and implementation effect are the same as those of the above method embodiment, so it will not be repeated here.

[0120] Figure 5 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. For example... Figure 5As shown, the electronic device 5 of this embodiment includes a processor 50 and a memory 51. The memory 51 stores a computer program 52. When the processor 50 executes the computer program 52, it implements the steps in the various method embodiments described above. Alternatively, when the processor 50 executes the computer program 52, it implements the functions of each module / unit in the various device embodiments described above.

[0121] For example, computer program 52 may be divided into one or more modules / units, which are stored in memory 51 and executed by processor 50 to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of computer program 52 in electronic device 5.

[0122] Electronic device 5 may include, but is not limited to, processor 50 and memory 51. Those skilled in the art will understand that... Figure 5 This is merely an example of electronic device 5 and does not constitute a limitation on electronic device 5. It may include more or fewer components than shown, or combine certain components, or different components. For example, electronic device 5 may also include input / output devices, network access devices, buses, etc.

[0123] The processor 50 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0124] The memory 51 can be an internal storage unit of the electronic device 5, such as a hard disk or RAM. The memory 51 can also be an external storage device of the electronic device 5, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory 51 can include both internal and external storage units of the electronic device 5. The memory 51 is used to store the computer program 52 and other programs and data required by the electronic device 5. The memory 51 can also be used to temporarily store data that has been output or will be output.

[0125] For the sake of simplicity and clarity, only the above-described functional modules / units are used as examples. In practical applications, the functions described above can be assigned to different functional modules / units as needed. These modules / units can be implemented in hardware, software, or a combination of both.

[0126] This invention also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the methods described in the above-described method embodiments.

[0127] This invention also provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the methods described in the above-described method embodiments.

[0128] Computer programs include computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0129] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not detailed or described in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Unless otherwise specified or in conflict with logic, the terminology and / or descriptions between different embodiments are consistent and can be referenced interchangeably. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0130] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for forecasting rainfall in plain areas, characterized in that, include: Detect the circulation pattern in the area to be forecasted to determine whether it belongs to a typical precipitation circulation type; If the circulation pattern belongs to a typical precipitation circulation type, then obtain the precipitation triggering conditions corresponding to the circulation type, as well as the low-level jet characteristics and vertical wind shear characteristics of the area to be forecasted; If the low-level jet stream characteristics and the vertical wind shear characteristics meet the rainfall triggering conditions, it is determined that rainfall will begin in the forecast area after a set time, and the rainfall intensity level and rainfall duration are determined based on the low-level jet stream characteristics and the vertical wind shear characteristics.

2. The rainfall forecasting method for plain areas according to claim 1, characterized in that, The characteristics of the low-level jet stream include: the wind speed of the transition layer, the latitude of the northern end of the isotropic line corresponding to the lower limit of the low-level jet stream speed, and the northward lifting speed of the low-level jet stream. The vertical wind shear features include: vertical wind shear corresponding to the first altitude range, vertical wind shear corresponding to the second altitude range, and vertical wind shear corresponding to the third altitude range; The rainfall triggering conditions include: The wind speed in the transition layer is greater than or equal to a set wind speed; the latitude of the northern end of the isotropic line corresponding to the lower limit of the low-level jet is greater than or equal to a set latitude; the northward lifting speed of the low-level jet is greater than or equal to a set speed; the vertical wind shear corresponding to the first altitude range reaches a first threshold; the vertical wind shear corresponding to the second altitude range reaches a second threshold; and the vertical wind shear corresponding to the third altitude range reaches a third threshold.

3. The rainfall forecasting method for plain areas according to claim 1, characterized in that, The low-level jet characteristics include: the average intensity of the low-level jet in the free atmosphere and the core intensity of the low-level jet in the boundary layer; The vertical wind shear characteristics include: vertical wind shear corresponding to the second altitude range; The determination of rainfall intensity level and duration based on the low-level jet stream characteristics and the vertical wind shear characteristics includes: If the average intensity of the low-level jet in the free atmosphere is greater than or equal to a first average threshold, the intensity of the low-level jet core in the boundary layer is greater than or equal to a first jet core threshold, and the vertical wind shear corresponding to the second altitude range is greater than or equal to a first wind shear threshold, then the rainfall intensity level is determined to be a heavy rainfall level, and the rainfall duration is determined to be greater than or equal to a first duration. If the average intensity of the low-level jet stream in the free atmosphere is less than a first average threshold and greater than or equal to a second average threshold, the intensity of the low-level jet stream core in the boundary layer is less than a first jet stream core threshold and greater than or equal to a second jet stream core threshold, and the vertical wind shear corresponding to the second altitude range is less than a first wind shear threshold and greater than or equal to a second wind shear threshold, then the rainfall intensity level is determined to be a moderate to heavy rainfall level, and the rainfall duration is determined to be less than a first duration and greater than or equal to a second duration. If the average intensity of the low-level jet stream in the free atmosphere is less than the second average threshold or the intensity of the low-level jet stream core in the boundary layer is less than the second jet stream core threshold, and the vertical wind shear corresponding to the second altitude range is less than the second wind shear threshold, then the rainfall intensity level is determined to be a weak rainfall level, and the rainfall duration is determined to be less than the second duration.

4. The rainfall forecasting method for plain areas according to any one of claims 1-3, characterized in that, The method further includes: Obtain the circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index of the area to be forecasted; The circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index are quantitatively evaluated to obtain quantitative scores for the circulation pattern, height configuration index, jet stream intensity index, jet stream location index, jet stream pulsation index, and wind shear index. The quantitative scores are weighted and summed to obtain the comprehensive score of the region to be predicted; Based on the comprehensive score, the rainfall intensity range corresponding to the area to be forecasted is determined.

5. The rainfall forecasting method for plain areas according to claim 4, characterized in that, Typical precipitation circulation types include: upper-level trough type, cold vortex type, typhoon remnant type, and subtropical high type; The circulation pattern is quantitatively evaluated to obtain a quantitative score for the circulation pattern, including: If the circulation pattern belongs to any one of the upper-level trough, the cold vortex, and the typhoon remnant vortex, then the quantitative score of the circulation pattern is determined as the first circulation score. If the circulation pattern belongs to the subtropical high type, then the quantitative score of the circulation pattern is determined as the second circulation score; If the circulation pattern belongs to at least two of the following types: upper-level trough, cold vortex, typhoon remnant vortex, and subtropical high, and the intensity index of the circulation pattern is less than a set intensity threshold, then the quantitative score of the circulation pattern is determined to be the third circulation score. If the circulation pattern does not belong to the typical rainfall circulation type, then the quantitative score of the circulation pattern is determined to be the fourth circulation score; The first circulation score is greater than the second circulation score, the second circulation score is greater than the third circulation score, and the third circulation score is greater than the fourth circulation score.

6. The rainfall forecasting method for plain areas according to claim 4, characterized in that, The height configuration indicators include: wind speed in the free atmosphere, wind speed in the transition layer, and wind speed in the boundary layer; The highly configured indicators are quantitatively evaluated to obtain a quantitative score for the highly configured indicators, including: Detect whether the wind speed in the free atmosphere, the wind speed in the transition layer, and the wind speed in the boundary layer reach the standard value for the low-level jet stream; The quantitative score of the height configuration index is determined based on the number of layers where the wind speed reaches the standard value of the low-level jet stream; the more layers, the higher the quantitative score of the height configuration index. The jet intensity index includes the average jet core intensity corresponding to the maximum value among the free atmospheric wind speed, the transition layer wind speed, and the boundary layer wind speed. The jet flow intensity index is quantitatively evaluated to obtain a quantitative score for the jet flow intensity index, including: The quantitative score of the jet flow intensity index is determined based on the average value of the jet flow core intensity; the higher the average value of the jet flow core intensity, the higher the quantitative score of the jet flow intensity index.

7. The rainfall forecasting method for plain areas according to claim 4, characterized in that, The jet stream location indicators include: the latitude of the northern end of the isotropic line corresponding to the lower limit of the low-level jet stream speed and the northward lifting speed of the low-level jet stream. The jet stream location index is quantitatively evaluated to obtain a quantitative score for the jet stream location index, including: If the northern latitude is greater than or equal to the first latitude value, then the northern latitude score is determined to be the first latitude score; If the northern latitude is less than the first latitude value and greater than or equal to the second latitude value, then the northern latitude score is determined to be the second latitude score. If the latitude of the northernmost point is less than the second latitude value, then the score of the latitude of the northernmost point is determined to be the score of the third latitude. If the northward lifting speed is greater than or equal to the first speed, then the score for the northward lifting speed is determined to be the first speed score; If the northward lifting speed is less than the first speed but greater than or equal to the second speed, then the northward lifting speed score is determined to be the second speed score; If the northward lifting speed is less than the second speed, then the score for the northward lifting speed is determined to be the third speed score; The weighted sum of the latitude score at the northern end and the northward shift speed score yields the quantitative score of the jet stream location index.

8. The rainfall forecasting method for plain areas according to claim 4, characterized in that, The rapid flow pulsation index includes: rapid flow core intensity data of the transition layer and the average value of the rapid flow core intensity of the transition layer; The jet stream pulsation index is quantitatively evaluated to obtain a quantitative score for the jet stream pulsation index, including: Detect whether there are pulsations in the rapid flow core intensity data; If the jet stream core intensity data exhibits pulsation, the quantitative score of the jet stream pulsation index is determined based on the average value of the jet stream core intensity; the higher the average value of the jet stream core intensity, the higher the quantitative score. The wind shear index includes: vertical wind shear corresponding to the first altitude range, vertical wind shear corresponding to the second altitude range, and a synergistic index; The wind shear index is quantitatively evaluated to obtain a quantitative score for the wind shear index, including: The vertical wind shear corresponding to the first altitude range, the vertical wind shear corresponding to the second altitude range, and the coordination index are respectively tested to see if they meet the standards. The quantitative score of the wind shear index is determined based on the number of times the standard is met; the more times the standard is met, the higher the quantitative score of the wind shear index.

9. A rainfall forecasting device for plains areas, characterized in that, include: The detection module is used for: Detect the circulation pattern in the area to be forecasted to determine whether it belongs to a typical precipitation circulation type; If the circulation pattern belongs to a typical precipitation circulation type, then obtain the precipitation triggering conditions corresponding to the circulation type, as well as the low-level jet characteristics and vertical wind shear characteristics of the area to be forecasted; Forecast module, used for: If the low-level jet stream characteristics and the vertical wind shear characteristics meet the rainfall triggering conditions, it is determined that rainfall will begin in the forecast area after a set time, and the rainfall intensity level and rainfall duration are determined based on the low-level jet stream characteristics and the vertical wind shear characteristics.

10. An electronic device, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method as described in any one of claims 1 to 8.

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