Tropical cyclone precipitation analysis method and device based on dynamic mapping of solar sunrise and sunset lines

Abstract

The application relates to the technical field of precipitation analysis, in particular to a tropical cyclone precipitation analysis method and device based on dynamic mapping of a solar dawn and dusk line. In the method, a solar tracking time framework is constructed to convert the UTC time of any latitude and longitude point in the world into STT time coordinates, and then the time sequence reconstruction and daily variation statistics of a tropical cyclone path point and a surrounding precipitation field are carried out. The specific steps comprise the following steps: obtaining high-resolution tropical cyclone path and precipitation data; converting world time information into solar tracking time information; determining a mask region with the tropical cyclone trajectory point as the center; extracting effective precipitation grids in the mask region; taking the solar tracking time information as a label to analyze the data, and obtaining the daily variation information of the tropical cyclone precipitation. The method overcomes the deviation caused by the traditional time framework among different latitudes and longitudes, and can reveal the daily variation law of the tropical cyclone precipitation system under the unified solar tracking time reference framework.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of precipitation analysis, and particularly relates to a tropical cyclone precipitation analysis method and device based on dynamic mapping of solar sunrise and sunset lines. BACKGROUND

[0002] Tropical cyclone (TC) is one of the most significant severe weather systems in the middle and low latitudes of the world, usually accompanied by extreme disaster processes such as strong wind, heavy rain and storm surge, which seriously threatens the life and property safety and the stability of the ecological system in the coastal area. In recent years, with the discussion on the intensity and frequency of tropical cyclones under the background of global warming deepening, the precipitation characteristics, especially the diurnal variation characteristics, have become an important starting point for revealing the internal physical mechanism and energy regulation process.

[0003] In traditional research, the extraction of precipitation diurnal variation is usually based on Universal Time Coordinated (UTC) as a reference time for conversion, or directly calculated in Local Standard Time (LST). However, due to the combined action of the earth's rotation and revolution, the apparent height and incidence angle of the sun at different latitudes change significantly with the seasons, and LST or UTC often cannot synchronously reflect the direct driving effect of solar radiation on atmospheric convection. Especially when analyzing the path of tropical cyclones across multiple latitudes, using the old time frame is easy to mask the real physical rhythm of the convective diurnal variation, leading to deviation in the judgment of spatial evolution law. SUMMARY

[0004] Therefore, the embodiments of the present application are devoted to providing a tropical cyclone precipitation analysis method and device based on dynamic mapping of solar sunrise and sunset lines, so as to more comprehensively and effectively analyze the precipitation and avoid the deviation of the spatial evolution law.

[0005] The present application provides a tropical cyclone precipitation analysis method based on dynamic mapping of solar sunrise and sunset lines, comprising:

[0006] obtaining high-resolution tropical cyclone path and precipitation data; wherein the tropical cyclone path comprises the position and Universal Time Coordinated (UTC) time information of the tropical cyclone; and the precipitation data comprises satellite precipitation product data;

[0007] converting the UTC time information of each path point in the tropical cyclone path into solar tracking time information; specifically comprising: based on the UTC time information, calculating the solar declination angle and the solar direct point, and for each path point, based on the relative relationship between the position information of the path point, the solar declination angle and the solar direct point, determining the solar tracking time information of the path point;

[0008] determine a mask region composed of a circle with a tropical cyclone track point as a center and a first preset value as a radius based on the tropical cyclone path;

[0009] extract effective precipitation grids in the mask region based on the precipitation data, and determine precipitation information and solar time information corresponding to the effective precipitation grids as to-be-analyzed data;

[0010] analyze the to-be-analyzed data with the solar time information as a label to obtain tropical cyclone precipitation diurnal variation information.

[0011] In some embodiments, the satellite precipitation product data is half-hour / 0.1° resolution satellite precipitation product data.

[0012] In some embodiments, the tropical cyclone precipitation diurnal variation information includes an hourly precipitation statistical table, radial profile time series data, cumulative precipitation spatial distribution maps, a solar time precipitation thermal map, and a path superimposed map.

[0013] The hourly precipitation statistical table is in CSV format, and the radial profile time series data is in a nested array format.

[0014] In some embodiments, the first preset value ranges from 0 km to 500 km.

[0015] The present application provides a tropical cyclone precipitation analysis device based on dynamic mapping of the solar morning and evening lines, comprising:

[0016] An acquisition module is configured to acquire high-resolution tropical cyclone paths and precipitation data. The tropical cyclone paths include the positions of tropical cyclones and the time information of universal time. The precipitation data includes satellite precipitation product data.

[0017] A conversion module is configured to convert the universal time information of each path point in the tropical cyclone path into solar time information. Specifically, the conversion module is configured to calculate the solar declination angle and the solar direct point based on the universal time information, determine the solar time information of each path point based on the relative relationship between the position information of the path point, the solar declination angle, and the solar direct point, and determine a mask region composed of a circle with a tropical cyclone track point as a center and a first preset value as a radius based on the tropical cyclone path.

[0018] An extraction module is configured to extract effective precipitation grids in the mask region based on the precipitation data, and determine precipitation information and solar time information corresponding to the effective precipitation grids as to-be-analyzed data.

[0019] An analysis module is configured to analyze the to-be-analyzed data with the time information of the sun tracking as a label to obtain the tropical cyclone precipitation diurnal variation information.

[0020] In some embodiments, the satellite precipitation product data is half-hour / 0.1° resolution satellite precipitation product data.

[0021] In some embodiments, the first preset value ranges from 0 km to 500 km.

[0022] The application provides an electronic device, comprising:

[0023] a processor, and a memory for storing a program executable by the processor;

[0024] The processor is configured to realize the tropical cyclone precipitation analysis method based on dynamic mapping of the sun's morning and evening lines by running the program in the memory.

[0025] The application provides a computer readable storage medium, which stores a computer program, and the computer program causes a processor to execute the tropical cyclone precipitation analysis method based on dynamic mapping of the sun's morning and evening lines when the computer program is run by the processor.

[0026] The application provides a computer program product, which comprises a computer program, and the computer program realizes the tropical cyclone precipitation analysis method based on dynamic mapping of the sun's morning and evening lines when the computer program is executed by a processor.

[0027] The application provides a tropical cyclone precipitation analysis method based on dynamic mapping of solar sunrise and sunset lines. First, high-resolution tropical cyclone path and precipitation data are obtained. The tropical cyclone path includes position and Zulu time information of the tropical cyclone. The precipitation data include satellite precipitation product data. The Zulu time information of each path point in the tropical cyclone path is converted into solar tracking time information. Specifically, the solar declination angle and the solar direct point are calculated based on the Zulu time information. For each path point, the solar tracking time information of the path point is determined based on the relative relationship among the position information of the path point, the solar declination angle, and the solar direct point. Based on the tropical cyclone path, a mask region composed of a circle with the tropical cyclone track point as the center and a first preset value as the radius is determined. Based on the precipitation data, the effective precipitation grid in the mask region is extracted, and the precipitation information and the solar tracking time information corresponding to the effective precipitation grid are determined as the data to be analyzed. The data to be analyzed is analyzed with the solar tracking time information as the label to obtain the tropical cyclone precipitation diurnal variation information. In this way, by constructing a solar tracking time (STT) time framework, the time deviation problem caused by different latitudes and longitudes in the traditional method is overcome. Combined with high-resolution tropical cyclone path and precipitation data, the method can accurately align time and space and is suitable for precipitation analysis in the global range. In addition, the extracted tropical cyclone precipitation diurnal variation information can be directly used for physical mechanism research and forecast model improvement, providing a more scientific basis for meteorological research and disaster prevention, and having important scientific application value. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the figures. The drawings provided in connection with the present application are intended to further explain, by way of non-limiting example, the principles of the present application, and constitute a part of this specification. The drawings do not limit the present application and are merely used to explain the present application together with the specification. In the drawings, the same reference numerals refer to the same components or steps throughout the figures.

[0029] Figure 1 is a flowchart of a tropical cyclone precipitation analysis method based on dynamic mapping of solar sunrise and sunset lines provided by an embodiment of the present application.

[0030] Figure 2 is a flowchart of a tropical cyclone precipitation analysis method based on dynamic mapping of solar sunrise and sunset lines provided by another embodiment of the present application.

[0031] Figure 3 is a structural diagram of a device for analyzing tropical cyclone precipitation based on dynamic mapping of solar sunrise and sunset lines provided by an embodiment of the present application.

[0032] Figure 4Figure 1 is a schematic diagram of an electronic device structure according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0034] The present application aims to provide a tropical cyclone precipitation diurnal variation analysis method based on dynamic mapping of solar sunrise and sunset lines, to solve the problems of non-uniform time frame and difficulty in decoupling physical mechanisms in current global tropical cyclone precipitation diurnal variation research.

[0035] The technical solution comprises the following steps: s1: obtaining high-resolution tropical cyclone path and precipitation data: using the tropical cyclone best path dataset (such as IBTrACS) to obtain the position and time information of each tropical cyclone at UTC; obtaining half-hour / 0.1° resolution IMERG satellite precipitation products; accurately matching the tropical cyclone path points and IMERG precipitation data in time and space. s2: converting UTC time to solar tracking time (STT): using the latitude and longitude of the track point and the UTC time, calculating the solar declination and the solar direct point; establishing a coordinate system with the antipodal point as the pole for mapping; dividing the solar tracking time zone for each track point and generating its corresponding STT time label. s3: extracting the radial structure of tropical cyclone precipitation and the association with solar tracking time: taking each track point as the center, constructing a 50km influence radius; using the Haversine algorithm to calculate the spherical distance from the center point; extracting the corresponding precipitation grid, calculating: 50km average precipitation; radial ring distribution (every 25km one grade); and classifying the precipitation into the corresponding STT hour segment. s4: statistics and output of STT hourly scale precipitation diurnal variation curve: all track points are grouped according to the solar tracking time hour; calculating the average precipitation and sample size of each hour segment; outputting the global statistical table and regional distribution diagram of precipitation diurnal variation; supporting further superimposing city boundaries, sea-land distribution, tropical sea temperature field, etc.

[0036] Compared with the prior art, the present application has the following significant technical effects: based on the time axis of the time information of the sun tracking, the deviation of the periodic identification of precipitation caused by the traditional UTC or LST between different latitudes and longitudes is avoided; high-resolution physical alignment: combined with the IMERG satellite data and the TC center path, the precipitation structure has the characteristics of spatial scale and time precision; strong global applicability: suitable for tropical cyclones in any latitude range, with universality and scalability, such as also applicable to the analysis of tropical cyclone intensity, convection or wind field diurnal variation characteristics; mechanism revealing and modeling improvement: the diurnal variation extraction result can be directly used for tropical cyclone precipitation physical mechanism research, diurnal variation simulation improvement and machine learning model training, etc.

[0037] After introducing the basic principles of the present application, various non-limiting embodiments of the present application will be specifically introduced with reference to the accompanying drawings.

[0038] Figure 1 is a flowchart of a tropical cyclone precipitation analysis method based on dynamic mapping of the sun's sunrise and sunset line according to an embodiment of the present application. As shown in the figure, the method includes the following contents. Figure 1

[0039] Step S110, obtaining high-resolution tropical cyclone path and precipitation data; wherein the tropical cyclone path includes the position of the tropical cyclone and the universal time information; the precipitation data includes satellite-based precipitation product data;

[0040] First, we need to obtain high-resolution tropical cyclone path data and precipitation data. The tropical cyclone path data includes the position information (such as latitude and longitude) of the tropical cyclone at different time points and the corresponding universal time (UTC) information. These data can be obtained from authoritative meteorological databases such as the International Tropical Cyclone Path Archiving Database (IBTrACS). At the same time, we also need to obtain satellite-based precipitation product data, which provides high-resolution precipitation information, usually with a resolution of half an hour / 0.1°. These data can be obtained from the IMERG (Integrated Multi-satellite Retrievals for GPM) product of the Global Precipitation Measurement (GPM) mission. By accurately matching the tropical cyclone path points with the satellite precipitation data in time and space, it is ensured that each path point has corresponding precipitation data.

[0041] Step S120, converting the universal time information of each path point in the tropical cyclone path into sun tracking time information; specifically including: based on the universal time information, calculating the solar declination angle and the sun's direct point, for each path point, based on the relative relationship of the position information of the path point, the solar declination angle and the sun's direct point, determining the sun tracking time information of the path point;​

[0042] Next, for each path point in the tropical cyclone path, we need to convert its universal time information into solar tracking time (STT) information. This conversion process includes the following detailed steps:

[0043] Calculate the solar declination angle: Calculate the solar declination angle according to the current date in the year.

[0044] Determine the subsolar point: Calculate the longitude of the subsolar point according to the current UTC time UTC_time. The latitude of the subsolar point is the calculated solar declination angle.

[0045] Determine the antipode coordinates: For each path point, calculate the coordinates of its antipode:

[0046] Convert to spherical Cartesian coordinates: Convert the geographic coordinates (ϕ,λ) of each path point to spherical Cartesian coordinates (x,y,z):

[0047] Rotate the coordinate system: Take the antipode as the new pole and perform a three-dimensional rotation.

[0048] Convert the spherical Cartesian coordinates (x,y,z) of the path point to new coordinates (x′,y′,z′) through the rotation matrix R;

[0049] Convert back to spherical coordinates: Convert the rotated coordinates (x′,y′,z′) back to spherical coordinates (ϕ′,λ′);

[0050] Convert λ′ to angular measure and ensure it is within the range [-180,180];

[0051] Calculate the STT value: Translate the subsolar point to a rotated longitude of 180° and define a translation function;

[0052] Normalize λshifted to the interval [-180,180];

[0053] Calculate the final STT value according to the time zone of every 15°: Ensure that the STT value is within the range [0, 23];

[0054] Step S130, based on the tropical cyclone path, determine a mask region composed of circles with the tropical cyclone track points as centers and a first preset value as radii;

[0055] Based on the tropical cyclone path, a circular region is determined as a mask region centered at each trajectory point. The radius of this circular region is set to a preset value, usually between 0 km and 500 km. The purpose of the mask region is to limit the geographical scope of the analysis, ensuring that the analysis is focused within the specific area related to the tropical cyclone. In this way, the interference of irrelevant data can be reduced, improving the efficiency and accuracy of the analysis.

[0056] Step S140, based on the precipitation data, extracting the effective precipitation grid in the mask region, and determining the corresponding precipitation information and solar tracking time information of the effective precipitation grid as the data to be analyzed;

[0057] Using the obtained satellite precipitation data, the effective precipitation grid within the mask region is extracted. The specific steps are as follows:

[0058] Calculate the spherical distance: for each path point, use the Haversine formula to calculate the spherical distance between all precipitation grid points within the mask region and the path point.

[0059] Extract the effective precipitation grid: select the precipitation grid points with a spherical distance within the preset radius range as the effective precipitation grid. For each effective precipitation grid, extract its corresponding precipitation information, including precipitation amount and other data. Determine the STT time information: associate the precipitation information of each effective precipitation grid with the corresponding STT time information to form the data to be analyzed. These data will be used in the subsequent analysis process.

[0060] Step S150, using the solar tracking time information as a label to analyze the data to be analyzed, and obtaining the tropical cyclone precipitation diurnal variation information.

[0061] Finally, the extracted data to be analyzed is analyzed with the solar tracking time information as a label. The specific steps are as follows:

[0062] Group statistics: group all effective precipitation grids by STT time information, with each time period (such as every hour) as a group.

[0063] Calculate the average precipitation: for each time period, calculate the average precipitation of all effective precipitation grids in that time period.

[0064] Generate analysis results: according to the statistical results, generate the diurnal variation information of tropical cyclone precipitation, including hourly precipitation statistics table, radial profile time series data, cumulative precipitation spatial distribution map, solar time precipitation thermal map and path superposition map, etc. These information helps to better understand the rules and characteristics of tropical cyclone precipitation, and provides scientific basis for meteorological research and disaster prevention.

[0065] Through the above detailed steps, the method can more accurately analyze the diurnal variation of tropical cyclone precipitation, overcoming the problems caused by the lack of unified time frame and insufficient data resolution in traditional methods.

[0066] Specifically, the satellite precipitation product data is specifically: half-hour / 0.1° resolution satellite precipitation product data.

[0067] The tropical cyclone precipitation diurnal variation information specifically includes: hourly precipitation statistics table, radial profile time series data, cumulative precipitation spatial distribution map, solar time precipitation thermal map and path superposition map; wherein the hourly precipitation statistics table is in CSV format, and the radial profile time series data is in nested array format.

[0068] The tropical cyclone precipitation diurnal variation information specifically includes the following forms of data output, which helps to analyze and understand the characteristics and rules of tropical cyclone precipitation from different angles:

[0069] The format of the hourly precipitation statistics table is CSV format, which records the average precipitation in each solar tracking time (STT) period. Each row represents a time period (such as every hour), and the columns include time period labels (STT time), average precipitation, sample size, etc. For example, the table may show that between STT time 12:00 and 13:00, the average precipitation is 5.2 mm, and the sample size is 30 valid precipitation grids.

[0070] Through hourly precipitation statistics, the diurnal variation of tropical cyclone precipitation can be clearly observed, and the peak and trough periods of precipitation intensity can be identified, which helps to understand the diurnal periodicity of precipitation.

[0071] The format of the radial profile time series data is nested array format. This data format provides the time series variation of tropical cyclone precipitation at different radial distances. Taking the tropical cyclone track point as the center, according to the preset radial distance (such as every 25 kilometers a ring), the average precipitation of each ring in different STT time periods is recorded. For example, the data may show that between STT time 12:00 and 13:00, the average precipitation of the ring 50 kilometers away from the center is 4.5 mm, and the average precipitation of the ring 100 kilometers away from the center is 3.0 mm.

[0072] Radial profile time series data helps to analyze the spatial distribution characteristics of precipitation and its changes over time, revealing how precipitation intensity changes with increasing distance from the center of the tropical cyclone, which is of great significance for understanding the structure and dynamics of the tropical cyclone.

[0073] Cumulative Precipitation Spatial Distribution Map: This map shows the spatial distribution of cumulative precipitation around the tropical cyclone path within a specific time period, such as a day or the entire lifetime of the tropical cyclone. Different colors or contour lines represent different levels of precipitation, visually displaying high and low value areas and the unevenness of precipitation distribution.

[0074] Through the cumulative precipitation spatial distribution map, the main impact areas of tropical cyclone precipitation can be quickly identified, and the precipitation risk in different regions can be assessed, providing a basis for disaster prevention and resource management.

[0075] Solar Time Precipitation Thermograph: The thermograph represents the size of the precipitation with the depth of color, the horizontal axis is the solar tracking time (STT), and the vertical axis is the different positions on the tropical cyclone path (which can be latitude, longitude or distance from the center). On the graph, the deeper the color, the greater the precipitation, and the lighter the color, the smaller the precipitation, thus visually displaying the trend of precipitation change in time and space. The solar time precipitation thermograph can visually display the daily variation of tropical cyclone precipitation and the difference in precipitation intensity at different positions, helping to identify the spatiotemporal characteristics of precipitation and provide strong support for weather forecasting and research.

[0076] Path Overlay Map: The path overlay map superimposes the movement path of the tropical cyclone on the precipitation distribution map, clearly showing the position of the tropical cyclone at different time points and its relationship with the precipitation distribution. Different colors or symbols can be used to represent different time points, and precipitation contours or color changes can be marked. The path overlay map helps to analyze the impact of the movement path of the tropical cyclone on the precipitation distribution and understand how precipitation changes with the movement of the tropical cyclone, which is of great value for studying the dynamic mechanism of the tropical cyclone and the formation process of precipitation.

[0077] Through these detailed information on the daily variation of tropical cyclone precipitation, researchers and meteorologists can have a more comprehensive and in-depth understanding of the characteristics and rules of tropical cyclone precipitation, thereby improving the prediction ability and disaster response capacity of tropical cyclone precipitation.

[0078] Further, the first preset value is in the range of 0 km to 500 km. In this application, the first preset value refers to a parameter used to determine the radius of the mask area. This parameter plays a key role in analyzing tropical cyclone precipitation, as it defines the analysis range around the tropical cyclone track point. Specifically, the first preset value is in the range of 0 km to 500 km. The following is a detailed description of this value range:

[0079] The first preset value is a key parameter that defines the radius of the circular mask region centered on the tropical cyclone track point. This radius determines the geographical scope of the analysis, ensuring that the analysis is focused within the specific area related to the tropical cyclone while reducing the interference of irrelevant data.

[0080] The selection of 0km to 500km as the value range of the first preset value is based on the following considerations: Typical influence range of tropical cyclones: The influence range of tropical cyclones is usually within thousands of kilometers, especially in the case of strong tropical cyclones (such as hurricanes or typhoons). Studies have shown that the precipitation influence range of tropical cyclones is usually between 0km and 500km. This range can cover the main precipitation area of tropical cyclones, while avoiding excessive expansion of the analysis range, reducing computational complexity and data processing volume. Data resolution and analysis accuracy: The selection of 0km to 500km range can ensure that the analysis results have sufficient accuracy and reliability under high-resolution data (such as half-hour / 0.1° resolution satellite precipitation product data). This range can capture the main characteristics of tropical cyclone precipitation without missing important information due to too small a range. In practical applications, meteorological forecasting and disaster prevention require analysis within a reasonable range to ensure that the analysis results have practical significance. The 0km to 500km range can meet these needs, providing sufficient information for assessing the impact of tropical cyclone precipitation while avoiding unnecessary calculations and data processing.

[0081] In practical applications, the specific value of the first preset value can be adjusted according to specific research goals and data conditions. For example: 0km: suitable for detailed analysis in a smaller range, which can more accurately capture the local characteristics of tropical cyclone precipitation. 500km: suitable for comprehensive analysis in a larger range, which can provide a more comprehensive precipitation distribution, suitable for large-scale meteorological research and disaster assessment.

[0082] Suppose we are analyzing the precipitation characteristics of a strong tropical cyclone and choose 500km as the first preset value. This means that a circular mask region with a radius of 500km is constructed centered on the tropical cyclone track point. Within this region, all valid precipitation grids are extracted and further analyzed. In this way, the analysis can be focused within the main influence range of the tropical cyclone while reducing the interference of irrelevant data. The value range of the first preset value is 0km to 500km, which is selected based on the typical influence range of tropical cyclones, data resolution, and practical application needs. By reasonably selecting the first preset value, the analysis results can have sufficient accuracy and reliability, while meeting the practical needs of meteorological research and disaster prevention.

[0083] The following will combine Figure 2 to further illustrate the schemes provided in the present application:

[0084] The application provides a tropical cyclone precipitation diurnal variation analysis method based on solar sunrise and sunset line dynamic mapping. The core idea is to use solar tracking time (STT) as the time reference framework to extract and statistically analyze the global tropical cyclone precipitation field in space and time, and then reveal the diurnal rhythm of the precipitation system.

[0085] Step 1, obtain the global tropical cyclone path data set, such as the International Best Track Archive for Climate Stewardship (IBTrACS), which contains the central latitude and longitude, UTC time, intensity level and other information of each tropical cyclone at different time steps, and convert it to a standard datetime object and set it to the coordinated universal time (UTC) time zone. On this basis, the global half-hour 0.1° resolution satellite precipitation product GPM IMERG Final Run data is introduced, and according to the time of the path point, the " / Grid / precipitation" data layer in the corresponding time precipitation data file is accurately read, and the corresponding longitude and latitude grid (lon / lat) is extracted, and the tropical cyclone path point and IMERG precipitation data are accurately matched in time and space.

[0086] Step 2, in order to accurately describe the precipitation rhythm under the influence of solar radiation, the UTC time of each track point needs to be converted to solar tracking time (STT). The conversion process includes four steps:

[0087] Step 2.1, calculate the current solar declination angle, unit: degree, calculation formula:

[0088]

[0089] Where is the solar declination angle, is the day of the year, 81 is about the spring equinox (March 21);

[0090] Step 2.2, calculate the solar direct point, set the current UTC time as:

[0091]

[0092] Then the longitude of the solar direct point is:

[0093]

[0094] The longitude is normalized to the interval :

[0095]

[0096] The latitude of the sun's direct point is:

[0097]

[0098] where, is the UTC time, hour is the hour, min is the minute, and sec is the second, is the longitude of the sun's direct point, is the latitude of the sun's direct point.

[0099] Step 2.3, define the antipodal point coordinates:

[0100]

[0101] and normalize:

[0102]

[0103] Then rotate the coordinates to the coordinate system with the antipodal point as the pole; given the coordinates of any point on the earth's surface , first convert to the spherical Cartesian coordinate system:

[0104]

[0105] Consider the antipodal point as the new pole and perform a three-dimensional rotation (polar shift):

[0106]

[0107] Convert back to the spherical coordinate (after rotation):

[0108]

[0109] and convert to the angle system.

[0110] where, is the (latitude, longitude) of the antipodal point, is the coordinates (latitude, longitude) of any point on the earth's surface, is the three-dimensional Cartesian coordinate on the unit sphere, is the new coordinate after rotation, is the spherical coordinate (latitude, longitude) after rotation.

[0111] Step 2.4, translate the sub-sun point to a rotated longitude of 180°, and the longitude of the rotated sub-sun point is recorded as To center it (i.e. STT = 12 corresponds to a rotated longitude of 180°), we do an angular translation, defining the translation function:

[0112]

[0113] and normalize so that all longitudes :

[0114]

[0115] Then we follow the time zones of 1 hour per 15°:

[0116]

[0117] This is the final Solar Tracking Time (STT) value, ranging from [0, 23].

[0118] where is the translation function, is the rotated longitude, is the rotated longitude of the sub-solar point, is the translation angle, is the final longitude after translation and normalization, is the normalization function, mod denotes the modulo operation, i.e. the remainder after division of two numbers.

[0119] Step 3, construct a circular precipitation extraction mask region with a radius of 500 km centered on the typhoon track point, and extract all valid precipitation grids within it:

[0120]

[0121] Using the central latitude and longitude of the track point and the latitude and longitude of the precipitation data grid points, the spherical distance is calculated using the Haversine formula:

[0122]

[0123] where is the mask region with a radius of 500 km, is the latitude and longitude of the geographical grid, is the distance from the point to the sphere, R = 6371 km is the average radius of the Earth, , and , are the latitudes and longitudes (in radians) of the grid points and the track center point, respectively.

[0124] All valid precipitation values P(x, y) ≥ 0.1 mm / h are extracted from the area A500, and the average precipitation intensity is:

[0125]

[0126] where is the average precipitation intensity in the 50 km area, is the number of valid grid points that meet the conditions.

[0127] Further divide it into 20 25 km wide radial ring bands, each with a width of 25 km, and define the rth ring band area as:

[0128]

[0129] The average precipitation intensity in each ring band is counted respectively, and the average precipitation intensity of the rth ring band is:

[0130]

[0131] where, is the rth ring band area, is the ring band width, is the number of valid precipitation grids in the rth ring.

[0132] Thus, the radial precipitation profile of the path point is constructed.

[0133] Step 4, process all tropical cyclone path points point by point, take the STT hour (0-23h) it belongs to as the classification label, and on this basis, count the average precipitation (such as 500 km circular area average) and the number of samples corresponding to all path points in each STT hour, and construct the following function form:

[0134]

[0135] where, is the average precipitation intensity corresponding to h time, is the number of valid path points in this period, is the regional average precipitation value of the ith path point. According to this, the average daily precipitation variation curve in the global range with the sun tracking time as the horizontal axis can be drawn, so as to reveal the systematic daily variation law of precipitation activity under the influence of the relative position of the sun.

[0136] To enhance practicability, the method also supports output of various structured results, including hourly precipitation statistical table (in CSV format), radial profile time series data (nested array), cumulative precipitation spatial distribution map, solar time precipitation thermal map and path superimposed map, etc., so as to facilitate further use in climate rule extraction, tropical cyclone structure research and precipitation unevenness evaluation.

[0137] In summary, the application uses solar time as a unified time coordinate, and solves the problem of precipitation recognition deviation of different longitude path points in the traditional UTC framework by accurate path matching and high-resolution precipitation extraction, combined with spherical distance modeling and astronomical time correction, to provide a new idea and tool for physical understanding and modeling of tropical cyclone precipitation.

[0138] Exemplary device

[0139] The device embodiment of the application can be used to execute the method embodiment of the application. For details not disclosed in the device embodiment of the application, please refer to the method embodiment of the application.

[0140] Figure 3 Fig. 1 shows a block diagram of a tropical cyclone precipitation analysis device based on dynamic mapping of solar dawn and dusk lines according to an embodiment of the application. As shown in the figure, Figure 3 The device comprises:

[0141] The acquisition module 31 is configured to acquire high-resolution tropical cyclone path and precipitation data. The tropical cyclone path comprises position and Zulu time information of the tropical cyclone. The precipitation data comprises satellite precipitation product data.

[0142] The conversion module 32 is configured to convert the Zulu time information of each path point in the tropical cyclone path into solar tracking time information. The specific steps are as follows: based on the Zulu time information, the solar declination angle and the solar direct point are calculated; for each path point, the solar tracking time information of the path point is determined based on the relative relationship between the position information of the path point, the solar declination angle and the solar direct point; the determination module is configured to determine a mask region composed of a circle with the track point of the tropical cyclone as the center and a first preset value as the radius based on the tropical cyclone path.

[0143] The extraction module 33 is configured to extract effective precipitation grids in the mask region based on the precipitation data, and determine the precipitation information and solar tracking time information corresponding to the effective precipitation grids as the analysis data.

[0144] The analysis module 34 is configured to analyze the analysis data with the solar tracking time information as the label to obtain the tropical cyclone precipitation diurnal variation information.

[0145] In some embodiments, the satellite precipitation product data is: satellite precipitation product data with a resolution of half an hour / 0.1°.

[0146] In some embodiments, the first preset value ranges from 0 km to 500 km.

[0147] Below, for reference Figure 4 This describes an electronic device according to embodiments of the present application. Figure 4 A block diagram of an electronic device according to an embodiment of this application is illustrated.

[0148] like Figure 4 As shown, the electronic device 400 includes one or more processors 410 and memory 420.

[0149] The processor 410 may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device 400 to perform desired functions.

[0150] The memory 420 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 410 may execute the program instructions to implement the tropical cyclone precipitation analysis method based on dynamic mapping of the solar terminator described in the various embodiments of this application above, and / or other desired functions. Various contents, such as category correspondences, may also be stored in the computer-readable storage medium.

[0151] In one example, the electronic device 400 may also include an input device 430 and an output device 440, which are interconnected via a bus system and / or other forms of connection mechanism (not shown).

[0152] In addition, the input device 430 may also include, for example, a keyboard, mouse, interface, etc. The output device 440 can output various information to the outside, including analysis results, etc. The output device 440 may include, for example, a display, speaker, printer, and communication network and its connected remote output devices, etc.

[0153] Of course, for the sake of simplicity, Figure 4Only some of the components of the electronic device related to the present application are shown, and components such as a bus, an input / output interface, and the like are omitted. In addition to this, the electronic device can include any other appropriate components according to a specific application.

[0154] In addition to the methods and the device described above, an embodiment of the present application can also be a computer program product, which includes computer program instructions, which, when executed by a processor, cause the processor to perform the steps of the tropical cyclone precipitation analysis method based on dynamic mapping of the solar morning / evening line according to various embodiments of the present application described in the above "Exemplary Method" section of the present specification.

[0155] The computer program product can be written in any combination of one or more programming languages, including an object oriented programming language such as Python, Java, C++, and the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device or entirely on the remote computing device or server.

[0156] In addition, an embodiment of the present application can also be a computer readable storage medium, which stores computer program instructions, which, when executed by a processor, cause the processor to perform the steps of the tropical cyclone precipitation analysis method based on dynamic mapping of the solar morning / evening line according to various embodiments of the present application described in the above "Exemplary Method" section of the present specification.

[0157] The computer readable storage medium can be any combination of one or more non-transitory media. The non-transitory medium can be a non-transitory signal medium or a non-transitory storage medium. The non-transitory storage medium can include, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the above. More specific examples (a non-exhaustive list) of the non-transitory storage medium include an electrical connection having one or more wires, a portable disc, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0158] The foregoing description has been presented for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the application to the forms disclosed herein. Although various example aspects and embodiments have been discussed above, those of ordinary skill in the art will appreciate a variety of modifications, alternatives, permutations, additions, and sub-combinations, which fall within the scope of the application.

Claims

1. A tropical cyclone precipitation analysis method based on dynamic mapping of solar morning and evening lines, characterized by, The method comprises the following steps: acquiring high-resolution tropical cyclone path and precipitation data; wherein the tropical cyclone path comprises position and Z time information of the tropical cyclone; the precipitation data comprises satellite precipitation product data; converting Z time information of each path point in the tropical cyclone path into Sun-tracking time information; specifically comprising: calculating the solar declination angle and the subsolar point based on the Z time information, and determining the Sun-tracking time information of each path point based on the relative relationship among the position information of the path point, the solar declination angle and the subsolar point; determining a mask area composed of a circle with the tropical cyclone track point as the center and a first preset value as the radius based on the tropical cyclone path; extracting effective precipitation grids in the mask area based on the precipitation data, and determining the corresponding precipitation information and Sun-tracking time information of the effective precipitation grids as the data to be analyzed; analyzing the data to be analyzed by taking the Sun-tracking time information as the label to obtain tropical cyclone precipitation diurnal variation information; the tropical cyclone precipitation diurnal variation information specifically comprises: an hourly precipitation statistical table, radial profile time series data, cumulative precipitation spatial distribution map, solar time precipitation thermal map and path superposition map; wherein the hourly precipitation statistical table is in CSV format, and the radial profile time series data is in nested array format.

2. The tropical cyclone precipitation analysis method based on dynamic mapping of solar morning / evening line according to claim 1, characterized in that, The satellite precipitation product data is specifically: satellite precipitation product data with a resolution of half an hour / 0.1°.

3. The tropical cyclone precipitation analysis method based on dynamic mapping of solar morning / evening line according to claim 1, characterized in that, The first preset value ranges from 0km to 500km.

4. A tropical cyclone precipitation analysis device based on dynamic mapping of solar morning and evening lines, characterized by, The method comprises the following steps: an acquisition module is configured to acquire high-resolution tropical cyclone path and precipitation data; wherein the tropical cyclone path comprises position and Z time information of the tropical cyclone; the precipitation data comprises satellite precipitation product data; a conversion module is configured to convert Z time information of each path point in the tropical cyclone path into Sun-tracking time information; specifically comprising: calculating the solar declination angle and the subsolar point based on the Z time information, and determining the Sun-tracking time information of each path point based on the relative relationship among the position information of the path point, the solar declination angle and the subsolar point; a determination module is configured to determine a mask area composed of a circle with the tropical cyclone track point as the center and a first preset value as the radius based on the tropical cyclone path; an extraction module is configured to extract effective precipitation grids in the mask area based on the precipitation data, and determine the corresponding precipitation information and Sun-tracking time information of the effective precipitation grids as the data to be analyzed; an analysis module is configured to analyze the data to be analyzed by taking the Sun-tracking time information as the label to obtain tropical cyclone precipitation diurnal variation information; the tropical cyclone precipitation diurnal variation information specifically comprises: an hourly precipitation statistical table, radial profile time series data, cumulative precipitation spatial distribution map, solar time precipitation thermal map and path superposition map; wherein the hourly precipitation statistical table is in CSV format, and the radial profile time series data is in nested array format.

5. The tropical cyclone precipitation analysis apparatus based on dynamic mapping of solar morning and evening lines according to claim 4, characterized in that, The satellite precipitation product data is: satellite precipitation product data with a resolution of half an hour / 0.1°.

6. The tropical cyclone precipitation analysis apparatus based on dynamic mapping of solar morning and evening lines according to claim 4, wherein, The first preset value ranges from 0 km to 500 km.

7. An electronic device, comprising: The method comprises the following steps: A processor and a memory for storing programs executable by the processor; The processor is configured to implement the method for analyzing tropical cyclone precipitation based on dynamic mapping of the solar morning and evening twilight lines according to any one of claims 1 to 3 by running the programs in the memory.

8. A computer-readable storage medium, characterized in that, The computer program stored on the computer readable storage medium causes the processor to execute the method for analyzing tropical cyclone precipitation based on dynamic mapping of the solar morning and evening twilight lines according to any one of claims 1 to 3 when the computer program is run by the processor.

9. A computer program product, characterised in that, The computer program causes the processor to implement the method for analyzing tropical cyclone precipitation based on dynamic mapping of the solar morning and evening twilight lines according to any one of claims 1 to 3 when the computer program is executed by the processor.

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