Method and device for calculating drainage basin space surface rainfall by using radar multilayer reflectivity, and medium

Abstract

The invention discloses a method and device for calculating drainage basin space surface rainfall through radar multilayer reflectivity and a medium. The method comprises the steps that the pixel area of each reflectivity unit of each layer of weather radar is calculated; calculating the radar reflectivity space area of each layer; calculating the projection area of each layer of radar reflectivity space area in the watershed range; calculating the rainfall intensity of each radar reflectivity unit by using a radar quantitative rainfall estimation relational expression according to the intensity value of each radar reflectivity unit of each layer; calculating the unit time rainfall of each layer; calculating the total rainfall amount of each layer in the T time period; calculating the drainage basin space surface rainfall of each layer in the T time period; and calculating the total spatial area rainfall of the drainage basin in the T time period. According to the method, the problems of traditional area rainfall data-free areas, watershed crossing, rainfall station density, rainfall intensity distribution, rainfall intensity center deviation or no obvious rainfall intensity distribution are solved, and the time precision, the space precision and the rainfall distribution precision of the basin area rainfall are improved.

Description

Technical Field

[0001] The present invention relates to the technical fields of weather radar, water conservancy and river basin, and more specifically to a method, device and medium for calculating spatial surface rainfall in a river basin by using radar multi-layer reflectivity. Background Art

[0002] Surface rainfall refers to the average precipitation conditions in a specific area or river basin, defined as the amount of precipitation per unit area. It is a very important parameter for flood prevention and control in flood and reservoir scheduling. An important basis for flood prevention and control decision-making is the change of water level and flow. The flow of the river basin, the flood resistance of the river, and the flood storage scale of the reservoir are closely related to the surface rainfall of the river basin. Therefore, carrying out surface rainfall calculation and surface rainfall forecast can better provide an important basis for governments at all levels to organize flood prevention and control and reservoir decisions, and can also provide very important parameters for flood forecasting of water conservancy departments. It is an important means for meteorological departments and water conservancy departments to serve disaster prevention and control and economic construction. The traditional use of ground point rain gauges to calculate basin surface rainfall and compare ground rainfall with the geographical area of ​​the basin has the following main problems: (1) Cross-watershed problem: Using a point rainfall station on one side of the watershed as a representative of part of the area on the other side of the watershed will lead to large errors in the calculation of surface rainfall in each sub-basin; (2) Distribution of ground point rain gauges: Since ground point rain gauges are unevenly distributed in the basin, the precipitation area may be relatively far away from the ground point rain gauges. Therefore, the ground point rain gauges are not representative enough of the precipitation distribution in the sub-basin. (3) Density of ground point rainfall stations: Since the density of ground point rainfall stations is generally between 50 and 100 km 2 There is only one point rain gauge within the range, so the sparse ground point rain gauges provide a low spatial resolution for precipitation observations; (4) Data-free areas: In the mountainous areas within the basin, the terrain is undulating, the landforms are complex and diverse, and the high mountain areas are uninhabited. In many places, it is impossible to build ground point rainfall stations and directly obtain ground point rainfall data. Therefore, there will be large areas of data-free areas within the basin; (5) Rainfall intensity and distribution issues: Due to the large uneven distribution of convective precipitation, using the precipitation at ground point rain gauges to calculate the sub-basin surface rainfall will lead to the deviation of the rainfall intensity center, or there will be no obvious rainfall intensity distribution, and most of the rainfall will be a mixture of convective precipitation.

[0003] (6) Ground point rain gauges measure precipitation that has already fallen to the ground, which has a certain lag in the time scale of flood peak and flood forecasts and flash flood disaster warnings. The emergency response timeline is short, which is not conducive to the implementation of disaster prevention and relief work.

[0004] Weather radar is a primary tool for monitoring and providing early warning of severe convective weather, offering high spatial and temporal resolution for precipitation observations. Weather radar boasts long detection range, high spatial resolution, and the ability to obtain timely precipitation data over large areas. This significantly improves the spatial distribution of precipitation compared to ground-based point rain gauges. Conventional parabolic weather radars have a temporal resolution of minutes, while phased array weather radars offer even higher resolutions, reaching seconds.

[0005] The present invention provides a method, device, and medium for calculating spatial surface rainfall in a watershed using radar multi-layer reflectivity to solve at least one of the following technical problems: (1) Solve the problem of no data areas at ground point rainfall stations; (2) Solve the problem of insufficient representativeness of ground point rainfall stations; (3) Solve the problem of insufficient spatial distribution of precipitation at ground point rain gauges; (4) Solve the problem of low temporal and spatial resolution of precipitation observations due to the sparse distribution of ground point rain gauges; (5) Solve the problem of short timeline for ground point rainfall stations to predict flood peaks and floods in the basin and torrent disaster warnings. Summary of the Invention

[0006] The present invention is provided to solve the above-mentioned problems existing in the prior art. Therefore, a method, device, and medium for calculating spatial surface rainfall in a watershed using multi-layer radar reflectivity are needed to realize the calculation of spatial surface rainfall in a watershed using multi-layer weather radar reflectivity. The multi-layer weather radar reflectivity Z within a set spatial range is extracted based on the geographical watershed surface. Data quality control is performed (non-precipitation meteorological echoes are removed). The spatial surface rainfall of each layer of the watershed is first calculated. The calculation process is as follows: the pixel area of ​​each radar reflectivity unit is calculated, the spatial area of ​​each radar reflectivity layer is calculated, the spatial area of ​​each radar reflectivity layer is projected, the size of the Z value of each radar reflectivity unit is determined, and the reflectivity factor Z is calculated using the reflectivity Z. e , according to the radar quantitative precipitation estimation relationship Z e -I calculates the precipitation intensity I of each reflectivity unit, calculates the precipitation q per unit time t, and then accumulates it over a period of time T to obtain the total spatial precipitation Q. The ratio of the total spatial precipitation Q to the projection S of the radar reflectivity spatial area or the basin's geographical area is the basin spatial surface rainfall of the current layer. The radar's multiple layers of basin spatial surface rainfall are then superimposed to obtain the total basin spatial surface rainfall above the corresponding area of ​​the basin.

[0007] According to a first aspect of the present invention, a method for calculating spatial surface rainfall in a watershed using radar multi-layer reflectivity is provided, the method comprising: The pixel area of ​​each reflectivity unit of each layer of weather radar is calculated based on the distance between each reflectivity unit and the weather radar, the range resolution of radar detection, and the radar beamwidth; The radar reflectivity spatial area of ​​each layer is calculated based on the pixel area of ​​each reflectivity unit of each layer of weather radar; Calculate the projection area of ​​each layer of radar reflectivity space area into the watershed according to the spatial area of ​​each layer of radar reflectivity; According to the intensity value of each radar reflectivity unit in each layer, the precipitation intensity of each radar reflectivity unit is calculated using the radar quantitative precipitation estimation relationship; The precipitation per unit time of each layer is calculated based on the precipitation intensity of each radar reflectivity unit; Calculate the rainfall per unit time for each layer T The total amount of precipitation during the time period; According to the projection area of ​​each layer of radar reflectivity space to the basin range, each layer T Calculation of total precipitation during the time period and the geographical area of ​​the basin T The spatial surface rainfall of the watershed at each layer within the time period; according to T Calculation of spatial surface rainfall in each layer of the watershed within a time period T The total area rainfall in the watershed during the time period.

[0008] Furthermore, the pixel area of ​​each reflectivity unit of each layer of weather radar is calculated according to the distance between each reflectivity unit and the weather radar, the range resolution of radar detection, and the radar beamwidth using the following formula: (1) Where: is the pixel area of ​​each reflectivity unit, is the distance of each reflectivity unit from the weather radar, is the range resolution of radar detection, is the radar beam width, and n is the number of radar reflectivity units in each layer.

[0009] Furthermore, the radar reflectivity spatial area of ​​each layer is calculated according to the pixel area of ​​each reflectivity unit of each layer of weather radar using the following formula: (2) Where: is the number of reflectivity units, is the pixel area of ​​each reflectivity unit, S K is the radar reflectivity space area of ​​each layer.

[0010] Furthermore, the projection area of ​​each layer of radar reflectivity space onto the ground is calculated based on the radar reflectivity space area of ​​each layer using the following formula: S T : (3) Where: is the radar reflectivity space area, It is a calculation method for projecting the radar reflectivity space area onto the ground watershed.

[0011] Furthermore, the radar quantitative precipitation estimation relationship is expressed as: The precipitation intensity of each radar reflectivity unit is calculated using the following formula based on the intensity value of each radar reflectivity unit in each layer and the radar quantitative precipitation estimation relationship: (4) (5) Where: is the radar reflectivity unit intensity value, A and b are coefficients, is the precipitation intensity in the radar reflectivity unit, The reflectivity factor corresponding to the intensity of the radar reflectivity unit Furthermore, the rainfall per unit time of each layer is calculated based on the precipitation intensity of each radar reflectivity unit, including: Unit time per layer Precipitation is the sum of all precipitation intensities in this layer, and the calculation formula is: (6) Where: is the precipitation intensity in the radar reflectivity unit, is the number of radar reflectivity units, is the temporal resolution of radar detection.

[0012] Furthermore, the precipitation per unit time of each layer is calculated. T The total amount of precipitation during the time period, including: Each layer Total precipitation during the time period is the precipitation per unit time The time integral of is calculated as: (7) Where: is the precipitation intensity in the radar reflectivity unit, is the number of radar reflectivity units per unit time t, is the time resolution of radar detection, The duration of precipitation.

[0013] Furthermore, according to the projection area of ​​each layer of radar reflectivity space onto the ground, each layer T Calculation of total precipitation during the time period and the geographical area of ​​the basin T The spatial surface rainfall of the watershed at each layer within the time period includes: Calculated by the following formula The spatial surface rainfall of each layer in the watershed during the time period : (8) Where: for The total amount of precipitation during the time period, is the projection of the radar reflectivity space area within the watershed, is the geographical area of ​​the basin; when When the projected area of ​​each layer of radar combined reflectivity space within the watershed is used Calculate spatial surface rainfall in the watershed; when When using the basin's geographic area Calculate the spatial surface rainfall of the watershed.

[0014] according to T Calculation of spatial surface rainfall in each layer of the watershed within a time period T The total area rainfall in the watershed during the time period, including: Total rainfall in the basin space within the time period is the spatial rainfall of each layer of the watershed The sum is calculated as follows: (9) Where: is the number of radar reflectivity layers.

[0015] According to a second aspect of the present invention, there is provided a device for calculating spatial surface rainfall in a watershed using radar multi-layer reflectivity, the device comprising: A first calculation module is configured to calculate the pixel area of ​​each reflectivity unit of each layer of weather radar based on the distance between each reflectivity unit and the weather radar, the range resolution of radar detection, and the radar beam width; A second calculation module is configured to calculate the radar reflectivity spatial area of ​​each layer according to the pixel area of ​​each reflectivity unit of each layer of weather radar; The third calculation module is configured to calculate the projection area of ​​each layer of radar reflectivity space area into the watershed according to each layer of radar reflectivity space area; a fourth calculation module configured to calculate the precipitation intensity of each radar reflectivity unit according to the intensity value of each radar reflectivity unit in each layer using a radar quantitative precipitation estimation relationship; a fifth calculation module, configured to calculate the precipitation per unit time of each layer according to the precipitation intensity of each radar reflectivity unit; The sixth calculation module is configured to calculate the rainfall per unit time of each layer. T The total amount of precipitation during the time period; The seventh calculation module is configured to calculate the projected area of ​​each layer of radar reflectivity space to the watershed range, T Calculation of total precipitation during the time period and the geographical area of ​​the basin T The spatial surface rainfall of the watershed at each layer within the time period; The eighth computing module is configured to T Calculation of spatial surface rainfall in each layer of the watershed within a time period T The total area rainfall in the watershed during the time period.

[0016] According to a third aspect of the present invention, a readable storage medium is provided, wherein the readable storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the method described above.

[0017] The present invention has at least the following beneficial effects: 1. The present invention can improve the temporal resolution and spatial resolution of basin surface rainfall calculation, and can solve the problems of data-free areas in the basin, cross-watershed problems in the basin, density of rain gauges, precipitation intensity distribution in the basin, deviation of precipitation intensity center or the absence of obvious precipitation intensity distribution. It can improve the temporal accuracy, spatial accuracy and spatial distribution accuracy of basin surface rainfall calculation.

[0018] 2. The present invention can advance the timeline of flood peak, flood forecast and prediction, and flash flood disaster warning in the basin, increase the length of flood peak, flood forecast and prediction flood prevention services, and flash flood disaster warning emergency response time, and improve the actual work efficiency of disaster prevention and relief. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram showing the principle of a method for calculating spatial surface rainfall in a watershed using radar multi-layer reflectivity according to an embodiment of the present invention is shown.

[0020] Figure 2 A flow chart of a method for calculating spatial surface rainfall in a watershed using radar multi-layer reflectivity according to an embodiment of the present invention is shown.

[0021] Figure 3The structure diagram of a device for calculating spatial surface rainfall in a watershed using radar multi-layer reflectivity according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are further described in detail below with reference to the accompanying drawings and specific embodiments, but are not intended to limit the present invention. For the various steps described herein, if there is no necessity for a contextual relationship between each other, the order in which they are described as examples herein should not be regarded as limiting, and those skilled in the art should know that they can be adjusted in order as long as the logic between them is not destroyed, resulting in the inability to implement the entire process.

[0023] Figure 1 The schematic diagram of the principle of a method for calculating spatial surface rainfall of a watershed using radar multi-layer reflectivity according to an embodiment of the present invention is shown. The embodiment of the present invention provides a method for calculating spatial surface rainfall of a watershed using radar multi-layer reflectivity. Figure 1 As shown in Figure 2, this method needs to be applied to the existing weather radar system when it is implemented. Figure 1 The figure shows the multiple layers of radar reflectivity units corresponding to the weather radar system. Each layer of radar reflectivity units corresponds to a radar reflectivity unit area projection. The figure shows the first layer of radar reflectivity units, the second layer of radar reflectivity units, the third layer of radar reflectivity units and the nth layer of radar reflectivity units.

[0024] based on Figure 1 The principle diagram of the method shown is that the method uses the multi-layer reflectivity of weather radar to calculate the spatial surface rainfall over the basin. The multi-layer reflectivity Z of weather radar within the set spatial range is extracted according to the geographical basin surface, and data quality control is performed (non-precipitation meteorological echoes are removed). The spatial surface rainfall of each layer of the basin is first calculated. The calculation process is as follows: the pixel area of ​​each layer of radar reflectivity unit is calculated, the spatial area of ​​each layer of radar reflectivity is calculated, the spatial area of ​​the radar reflectivity of each layer is projected, the size of the Z value of each radar reflectivity unit is determined, and the reflectivity factor Z is calculated using the reflectivity Z e , according to the radar quantitative precipitation estimation relationship Z e -I calculates the precipitation intensity I of each reflectivity unit, calculates the precipitation q per unit time t, and then accumulates it over a period of time T to obtain the total spatial precipitation Q. The ratio of the total spatial precipitation Q to the projection S of the radar reflectivity spatial area or the basin's geographical area is the basin spatial surface rainfall of the current layer. The radar's multiple layers of basin spatial surface rainfall are then superimposed to obtain the total basin spatial surface rainfall above the corresponding area of ​​the basin.

[0025] In the present invention, the weather radar multi-layer reflectivity can be the multi-layer reflectivity of different elevation layers of a single radar, or it can be the multi-layer reflectivity of different elevation layers fused from multiple radars. This embodiment uses the reflectivity of weather radar at different detection elevation angles. Due to different radar elevation angles, the reflectivity area corresponding to each elevation layer is different, and the area of ​​each reflectivity pixel unit in each elevation layer is also different. This embodiment first calculates the spatial surface rainfall of the watershed using the radar reflectivity of each layer, and then calculates the total spatial surface rainfall of the watershed by summing the two.

[0026] Figure 2 FIG. 4 shows a flow chart of a method for calculating spatial surface rainfall in a watershed using radar multi-layer reflectivity according to an embodiment of the present invention. Figure 2 As shown, the method includes steps S100-S800, which are described in detail as follows.

[0027] The geographical area of ​​the basin is The geographical area of ​​the basin can be the entire basin area or the sub-basin area. The distance resolution of weather radar detection is , the radar beam width is , the time resolution of radar detection is , the number of radar reflectivity layers within the set spatial range above the basin is , the area of ​​each layer of radar reflectivity space is , the number of weather radar reflectivity units is , the distance between each reflectivity unit and the weather radar is , the projection of the radar reflectivity space area is , the spatial rainfall in the basin is .

[0028] Step S100 , calculating the pixel area of ​​each reflectivity unit of each layer of weather radar according to the distance between each reflectivity unit and the weather radar, the range resolution of radar detection, and the radar beam width.

[0029] Specifically, calculate the pixel area of ​​each reflectivity unit of each layer of weather radar The formula is: (1) Where: The pixel area of ​​each reflectivity unit (unit: square meters 2 ), is the distance between each reflectivity unit and the weather radar (unit: m), is the range resolution of radar detection (unit: meter), is the radar beamwidth (unit: degrees).

[0030] Step S200 , calculating the radar reflectivity spatial area of ​​each layer according to the pixel area of ​​each reflectivity unit of each layer of weather radar.

[0031] Specifically, calculate the radar reflectivity spatial area of ​​each layer The formula is: (2) Where: is the number of reflectivity units.

[0032] Step S300 : calculating the projection area of ​​each radar reflectivity spatial area onto the watershed according to each radar reflectivity spatial area.

[0033] Specifically, calculate the projection area of ​​each layer of radar reflectivity space area into the watershed range The formula is: (3) Where: is the radar reflectivity space area (unit: square meters m 2 ), It is a calculation method for projecting the radar reflectivity space area onto the ground watershed.

[0034] Step S400 , according to the intensity value of each radar reflectivity unit in each layer, the precipitation intensity of each radar reflectivity unit is calculated using a radar quantitative precipitation estimation relationship.

[0035] Specifically, determine the intensity value of each radar reflectivity unit in each layer The size of the radar quantitative precipitation estimation relationship is used , calculate the precipitation intensity for each radar reflectivity cell : (4) (5) In formulas (4) and (5): is the radar reflectivity unit intensity value (unit: dBZ), A and b are coefficients, is the precipitation intensity in radar reflectivity units (unit: mm), The reflectivity factor corresponding to the intensity of the radar reflectivity unit (unit: mm 6 / m 3 ).

[0036] Step S500 , calculating the rainfall per unit time for each layer according to the precipitation intensity of each radar reflectivity unit.

[0037] Specifically, each layer unit time Precipitation is the sum of all precipitation intensities in this layer, and the calculation formula is: (6) Where: is the precipitation intensity in radar reflectivity units (unit: mm), is the number of radar reflectivity units, is the temporal resolution of radar detection.

[0038] Step S600, calculate the rainfall per unit time for each layer T The total amount of precipitation during the time period.

[0039] Specifically, each layer Total precipitation during the time period is the precipitation per unit time The time integral of is calculated as: (7) Where: is the precipitation intensity in radar reflectivity units (unit: mm), is the number of radar reflectivity units per unit time t, is the time resolution of radar detection, The duration of precipitation.

[0040] Step S700: Based on the projection area of ​​each layer of radar reflectivity space to the watershed, each layer T Calculation of total precipitation during the time period and the geographical area of ​​the basin T The spatial surface rainfall of the watershed at each layer during the time period.

[0041] Specifically, The spatial surface rainfall of each layer in the watershed during the time period The calculation formula is: (8) Where: for The total amount of precipitation during the time period (unit: mm), is the projection of the radar reflectivity space area within the watershed (unit: square meters m 2 ), is the geographical area of ​​the basin (unit: square meters 2 ).

[0042] when When the projected area of ​​each layer of radar combined reflectivity space within the watershed is used Calculate spatial surface rainfall in the watershed; when When using the basin's geographic area Calculate the spatial surface rainfall of the watershed.

[0043] Step S800, according to T Calculation of spatial surface rainfall in each layer of the watershed within a time period T The total area rainfall in the watershed during the time period.

[0044] Specifically, Total rainfall in the basin space within the time period is the spatial rainfall of each layer of the watershed The sum is calculated as follows: (9) Where: is the number of radar reflectivity layers.

[0045] The embodiment of the present invention also provides a device for calculating the spatial surface rainfall of a watershed using radar multi-layer reflectivity, such as Figure 3 As shown, the device 300 includes: The first calculation module 301 is configured to calculate the pixel area of ​​each reflectivity unit of each layer of weather radar based on the distance between each reflectivity unit and the weather radar, the range resolution of the radar detection, and the radar beam width; The second calculation module 302 is configured to calculate the radar reflectivity spatial area of ​​each layer according to the pixel area of ​​each reflectivity unit of each layer of weather radar; The third calculation module 303 is configured to calculate the projection area of ​​each layer of radar reflectivity spatial area into the watershed according to each layer of radar reflectivity spatial area; The fourth calculation module 304 is configured to calculate the precipitation intensity of each radar reflectivity unit according to the intensity value of each radar reflectivity unit in each layer using a radar quantitative precipitation estimation relationship; a fifth calculation module 305 configured to calculate the precipitation per unit time of each layer according to the precipitation intensity of each radar reflectivity unit; The sixth calculation module 306 is configured to calculate the rainfall per unit time of each layer. T The total amount of precipitation during the time period; The seventh calculation module 307 is configured to calculate the projected area of ​​each layer of radar reflectivity space area to the watershed range, each layer T Calculation of total precipitation during the time period and the geographical area of ​​the basin T The spatial surface rainfall of the watershed at each layer within the time period; The eighth calculation module 308 is configured to T Calculation of spatial surface rainfall in each layer of the watershed within a time period T The total area rainfall in the watershed during the time period.

[0046] In some embodiments, the first calculation module is further configured to calculate the pixel area of ​​each reflectivity unit of each layer of weather radar according to the distance between each reflectivity unit and the weather radar, the range resolution of radar detection, and the radar beam width using the following formula: (1) Where: is the pixel area of ​​each reflectivity unit, is the distance of each reflectivity unit from the weather radar, is the range resolution of radar detection, is the radar beam width, and n is the number of radar reflectivity units in each layer.

[0047] In some embodiments, the second calculation module is further configured to calculate the radar reflectivity spatial area of ​​each layer according to the pixel area of ​​each reflectivity unit of each layer of weather radar using the following formula: (2) Where: is the number of reflectivity units, is the pixel area of ​​each reflectivity unit, S K is the radar reflectivity space area of ​​each layer.

[0048] In some embodiments, the third calculation module is further configured to calculate the projection area of ​​each layer of radar reflectivity space area into the watershed according to the following formula: S T : (3) Where: is the radar reflectivity space area, It is a calculation method for projecting the radar reflectivity space area onto the ground watershed.

[0049] In some embodiments, the radar quantitative precipitation estimation relationship is expressed as: The fourth calculation module is further configured to calculate the precipitation intensity of each radar reflectivity unit according to the intensity value of each radar reflectivity unit in each layer using the radar quantitative precipitation estimation relationship using the following formula: (4) (5) Where: is the radar reflectivity unit intensity value, A and b are coefficients, is the precipitation intensity in the radar reflectivity unit, The reflectivity factor corresponding to the intensity of the radar reflectivity unit In some embodiments, the fifth computing module is further configured to: Unit time per layer Precipitation is the sum of all precipitation intensities in this layer, and the calculation formula is: (6) Where: is the precipitation intensity in the radar reflectivity unit, is the number of radar reflectivity units, is the temporal resolution of radar detection.

[0050] In some embodiments, the sixth computing module is further configured to: Each layer Total precipitation during the time period is the precipitation per unit time The time integral of is calculated as: (7) Where: is the precipitation intensity in the radar reflectivity unit, is the number of radar reflectivity units per unit time t, is the time resolution of radar detection, The duration of precipitation.

[0051] In some embodiments, the seventh computing module is further configured to: Calculated by the following formula The spatial surface rainfall of each layer in the watershed during the time period : (8) Where: for The total amount of precipitation during the time period, is the projection of the radar reflectivity space area within the watershed, is the geographical area of ​​the basin; when When the projected area of ​​each layer of radar combined reflectivity space within the watershed is used Calculate spatial surface rainfall in the watershed; when When using the basin's geographic area Calculate the spatial surface rainfall of the watershed.

[0052] The eighth computing module is further configured to: Total areal rainfall of the basin space in the time period Areal rainfall of the basin space for each layer The sum, the calculation formula is: (9) In the formula, Z is the number of radar reflectivity layers.

[0053] It should be noted that the various device structures described in the embodiments belong to the same technical concept as the methods described above, and achieve the same technical effects through the same principles, which will not be described here.

[0054] The embodiment of the application further provides a readable storage medium, the readable storage medium stores one or more programs, the one or more programs can be executed by one or more processors to implement the method described in any of the above embodiments.

[0055] In addition, although the exemplary embodiments have been described herein, the scope of their range includes any and all embodiments based on the present application with equivalent elements, modifications, omissions, combinations (for example, solutions of various embodiments are crossed), adaptations or changes. The elements in the claims will be broadly interpreted based on the language adopted in the claims, and are not limited to the examples described in the specification or during the implementation of the application, and the examples will be interpreted as non-exclusive. Therefore, the specification and examples are intended to be considered only as examples, and the true scope and spirit are indicated by the following claims and the full scope of their equivalents.

[0056] The above description is intended to be illustrative rather than limiting. For example, the above examples (or one or more aspects thereof) can be used in combination with each other. For example, other embodiments can be used by those of ordinary skill in the art in view of the foregoing description. In addition, in the above detailed description, various features can be grouped together in one or more embodiments to simplify the application. This should not be interpreted as an intent to require one or more claimed applications to have all the features of a particular embodiment. On the contrary, subject matter application can be less than all the features of a particular embodiment. Therefore, the following claims are incorporated into the detailed description as examples or embodiments, where each claim is independently a separate embodiment, and it is contemplated that these embodiments can be combined with each other in various combinations or permutations. The scope of the application should be determined with reference to the appended claims and the full scope of equivalents to which they are entitled.

Claims

1. A method for calculating spatial surface rainfall in a watershed using radar multi-layer reflectivity, characterized in that: The method comprises: The pixel area of ​​each reflectivity unit of each layer of weather radar is calculated based on the distance between each reflectivity unit and the weather radar, the range resolution of radar detection, and the radar beamwidth; The radar reflectivity spatial area of ​​each layer is calculated based on the pixel area of ​​each reflectivity unit of each layer of weather radar; Calculate the projection area of ​​each layer of radar reflectivity space area into the watershed according to the spatial area of ​​each layer of radar reflectivity; According to the intensity value of each radar reflectivity unit in each layer, the precipitation intensity of each radar reflectivity unit is calculated using the radar quantitative precipitation estimation relationship; The precipitation per unit time of each layer is calculated based on the precipitation intensity of each radar reflectivity unit; Calculate the rainfall per unit time for each layer T The total amount of precipitation during the time period; According to the projection area of ​​each layer of radar reflectivity space to the basin range, each layer T Calculation of total precipitation during the time period and the geographical area of ​​the basin T The spatial surface rainfall of the watershed at each layer within the time period; according to T Calculation of spatial surface rainfall in each layer of the watershed within a time period T The total area rainfall in the watershed during the time period.

2. The method according to claim 1, characterized in that The pixel area of ​​each reflectivity unit of each layer of weather radar is calculated according to the distance between each reflectivity unit and the weather radar, the range resolution of radar detection, and the radar beamwidth using the following formula: （1） Where: is the pixel area of ​​each reflectivity unit, is the distance of each reflectivity unit from the weather radar, is the range resolution of radar detection, is the radar beam width, and n is the number of radar reflectivity units in each layer.

3. The method according to claim 1, characterized in that The radar reflectivity spatial area of ​​each layer is calculated based on the pixel area of ​​each reflectivity unit of each layer of weather radar using the following formula: （2） Where: is the number of reflectivity units, is the pixel area of ​​each reflectivity unit, S K is the radar reflectivity space area of ​​each layer.

4. The method according to claim 1, wherein The projection area of ​​each layer of radar reflectivity space area onto the ground basin is calculated based on the following formula: S T : （3） Where: is the radar reflectivity space area of ​​each layer, It is a calculation method for projecting the spatial area of ​​each layer of radar reflectivity onto the ground watershed.

5. The method according to claim 1, wherein The radar quantitative precipitation estimation relationship is expressed as: The precipitation intensity of each radar reflectivity unit is calculated using the following formula based on the intensity value of each radar reflectivity unit in each layer and the radar quantitative precipitation estimation relationship: （4） （5） Where: is the radar reflectivity unit intensity value, A and b are coefficients, is the precipitation intensity in the radar reflectivity unit, is the reflectivity factor corresponding to the intensity of the radar reflectivity unit.

6. The method according to claim 1, characterized in that The precipitation per unit time of each layer is calculated based on the precipitation intensity of each radar reflectivity unit, including: Unit time per layer Precipitation is the sum of all precipitation intensities in this layer, and the calculation formula is: （6） Where: is the precipitation intensity in the radar reflectivity unit, Unit time The number of radar reflectivity units, is the temporal resolution of radar detection.

7. The method according to claim 1, characterized in that Calculate the rainfall per unit time for each layer T Total precipitation for the time period, including: Each layer Total precipitation during the time period is the precipitation per unit time The time integral of is calculated as: （7） Where: is the precipitation intensity in the radar reflectivity unit, is the number of radar reflectivity units per unit time t, is the time resolution of radar detection, The duration of precipitation.

8. The method according to claim 1, characterized in that According to the projection area of ​​each layer of radar reflectivity space to the basin range, each layer T Calculation of total precipitation during the time period and the geographical area of ​​the basin T The spatial surface rainfall of the watershed at each layer within the time period includes: Calculated by the following formula The spatial surface rainfall of each layer in the watershed during the time period : （8） Where: for The total amount of precipitation during the time period, is the projection of the spatial area of ​​each layer of radar reflectivity within the watershed, is the geographical area of ​​the basin; when When the projected area of ​​each layer of radar combined reflectivity space within the watershed is used Calculate spatial surface rainfall in the watershed; when When using the basin's geographic area Calculate the spatial surface rainfall of the watershed.

9. According to T Calculation of spatial surface rainfall in each layer of the watershed within a time period T The total area rainfall in the watershed during the time period, including: Total rainfall in the basin space within the time period is the spatial rainfall of each layer of the watershed The sum is calculated as follows: （9） Where: is the number of radar reflectivity layers.

10. A device for calculating spatial surface rainfall in a watershed using radar multi-layer reflectivity, characterized in that: The device comprises: A first calculation module is configured to calculate the pixel area of ​​each reflectivity unit of each layer of weather radar based on the distance between each reflectivity unit and the weather radar, the range resolution of radar detection, and the radar beam width; A second calculation module is configured to calculate the radar reflectivity spatial area of ​​each layer according to the pixel area of ​​each reflectivity unit of each layer of weather radar; The third calculation module is configured to calculate the projection area of ​​each layer of radar reflectivity space area into the watershed according to each layer of radar reflectivity space area; a fourth calculation module configured to calculate the precipitation intensity of each radar reflectivity unit according to the intensity value of each radar reflectivity unit in each layer using a radar quantitative precipitation estimation relationship; a fifth calculation module, configured to calculate the precipitation per unit time of each layer according to the precipitation intensity of each radar reflectivity unit; The sixth calculation module is configured to calculate the rainfall per unit time of each layer. T The total amount of precipitation during the time period; The seventh calculation module is configured to calculate the projected area of ​​each layer of radar reflectivity space to the watershed range, T Calculation of total precipitation during the time period and the geographical area of ​​the basin T The spatial surface rainfall of the watershed at each layer within the time period; The eighth computing module is configured to T Calculation of spatial surface rainfall in each layer of the watershed within a time period T The total area rainfall in the watershed during the time period. 11 . A non-transitory computer-readable storage medium storing instructions, which, when executed by a processor, executes the method according to claim 1 .

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