Method and system for converting cumulative precipitation of rain gauge to instantaneous precipitation rate

Abstract

The invention discloses a method and a system for converting cumulative precipitation of a rain gauge to an instantaneous precipitation rate. According to the conversion method, precipitation events are divided through time intervals, cubic spline interpolation processing is carried out on the accumulated precipitation amount of each event, so that negative numbers are eliminated, and the instantaneous precipitation rate is accurately calculated. According to the invention, the precision of conversion from the cumulative precipitation of the rain gauge to the instantaneous precipitation rate is improved, and particularly, the method has excellent performance in the aspect of capturing weak precipitation events. By utilizing the method, accurate instantaneous precipitation rate estimation can be provided under various precipitation conditions, an instantaneous precipitation rate data set with a long time sequence can be generated, powerful support is provided for precision inspection of satellite remote sensing precipitation products, and the accuracy and reliability of satellite remote sensing precipitation data are remarkably improved.

Description

Technical Field

[0001] The invention relates to a method for converting the accumulated precipitation of a rain gauge into an instantaneous precipitation rate, and also relates to a corresponding conversion system, belonging to the technical field of satellite remote sensing precipitation. Background Art

[0002] Precipitation is an important meteorological factor that affects key areas such as agricultural production, water resources management, and flood prevention and disaster reduction. In order to accurately monitor precipitation, the meteorological community has adopted a variety of observation technologies, including rain gauges, raindrop spectrometers, ground-based radars, and meteorological satellites. As a traditional precipitation observation tool, rain gauges provide direct and highly accurate precipitation data by measuring the cumulative precipitation over a period of time, providing important support for weather forecasts. The raindrop spectrometer measures microphysical parameters such as the diameter, number, and falling speed of raindrops, and obtains precipitation through theoretical calculations based on a specific raindrop spectrum model and observation data, thereby revealing the development and evolution of precipitation.

[0003] Compared with the point-scale observations of rain gauges and raindrop spectrometers, ground-based radar and satellite remote sensing technologies can achieve surface-scale precipitation observations over a wider range. Ground-based radars monitor the movement direction and intensity of rain clusters by analyzing the intensity of backscattered echoes from precipitation particles, which plays an important role in the monitoring and early warning of severe convective weather. Satellite remote sensing technology, especially the Fengyun-3G satellite launched in 2023, uses the collaborative observation technology of dual-frequency precipitation measurement radar, passive microwave and optical remote sensing to significantly improve the comprehensive capability of precipitation observation, and realize precipitation detection on a global scale, especially in remote areas such as oceans and deserts, as well as in complex terrain areas, effectively making up for the shortcomings of ground observation equipment.

[0004] However, satellite remote sensing technology obtains instantaneous precipitation rate, that is, the instantaneous precipitation rate at the moment of satellite observation, while ground-based minute rain gauges measure the cumulative precipitation within a certain time interval (such as one minute). The physical quantities represented by these two measurement methods are essentially different. Therefore, in order to use the observation data of ground-based minute rain gauges to verify the accuracy of satellite remote sensing precipitation products, the cumulative precipitation of the rain gauge must be converted into instantaneous precipitation rate. This conversion is a necessary prerequisite for the accuracy verification of satellite precipitation products and is of great significance for improving the accuracy and reliability of satellite remote sensing precipitation data. Summary of the invention

[0005] The primary technical problem to be solved by the present invention is to provide a method for converting the accumulated precipitation of a rain gauge into the instantaneous precipitation rate.

[0006] Another technical problem to be solved by the present invention is to provide a conversion system from the rain gauge accumulated precipitation to the instantaneous precipitation rate.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] According to a first aspect of an embodiment of the present invention, there is provided a method for converting a rain gauge accumulated precipitation to an instantaneous precipitation rate, comprising the following steps:

[0009] S1: Divide precipitation events according to time intervals;

[0010] S2: For each precipitation event, sum the precipitation at all times in the precipitation event to obtain a sequence of cumulative precipitation changing over time;

[0011] S3: interpolating the time-varying sequence of the accumulated precipitation within a certain period before the start of the precipitation event and within a certain period after the end of the precipitation event;

[0012] S4: Eliminate negative numbers in the interpolation result;

[0013] S5: comparing the difference between the total accumulated precipitation obtained after interpolation and the original total accumulated precipitation; wherein, if the total accumulated precipitation obtained after interpolation is less than half of the original total accumulated precipitation, or the total accumulated precipitation obtained after interpolation is greater than half of the original total accumulated precipitation, then re-interpolating the sequence of the cumulative precipitation changing with time using an interpolation method different from that in step S3; after the interpolation is completed, entering step S6;

[0014] S6: Calculate the difference between the current precipitation and the previous precipitation to obtain minute precipitation, and multiply the obtained minute precipitation by 60 to obtain the instantaneous precipitation rate.

[0015] Preferably, in step S1, the time interval is 15 minutes.

[0016] Preferably, in step S1, the precipitation event refers to a time interval between two consecutive precipitation observations not exceeding 15 minutes.

[0017] Preferably, in step S3, the certain time before the precipitation event starts is within 7 minutes before the precipitation event starts, and the certain time after the precipitation event ends is within 7 minutes after the precipitation event ends.

[0018] Preferably, in step S3, cubic spline interpolation is used to interpolate the sequence of the cumulative precipitation varying with time.

[0019] Preferably, in step S4, the negative number refers to a value of the accumulated precipitation obtained after interpolation that is less than 0.

[0020] Preferably, in step S5, the interpolation method different from that in step S3 is any one of linear interpolation, nearest neighbor interpolation, and polynomial interpolation.

[0021] According to a second aspect of an embodiment of the present invention, there is provided a system for converting accumulated precipitation in a rain gauge to instantaneous precipitation rate, comprising a processor and a memory; wherein the memory is coupled to the processor and is used to store a computer program, and when the computer program is executed by the processor, the processor implements the above-mentioned conversion method.

[0022] Compared with the prior art, the present invention improves the accuracy of conversion from rain gauge cumulative precipitation to instantaneous precipitation rate by using cubic spline interpolation method to interpolate cumulative precipitation, especially in capturing weak precipitation events. The present invention not only enhances data consistency, but also significantly improves the correlation coefficient of weak precipitation, while greatly reducing the deviation and mean absolute error. In addition, the present invention is not only applicable to weak precipitation events, but also can provide accurate instantaneous precipitation rate estimation under various precipitation conditions, which helps to generate long-term series of instantaneous precipitation rate data sets, provides strong support for the accuracy verification of satellite remote sensing precipitation products, and significantly improves the accuracy and reliability of satellite remote sensing precipitation data. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a method for converting the accumulated precipitation of a rain gauge to the instantaneous precipitation rate provided by an embodiment of the present invention;

[0024] Figure 2 A comparison diagram of the instantaneous precipitation rate (blue line) converted using the method provided in an embodiment of the present invention and the instantaneous precipitation rate of the raindrop spectrum (red line);

[0025] Figure 3 A schematic diagram of a system for converting rain gauge accumulated precipitation to instantaneous precipitation rate provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The technical content of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] The traditional method of converting the accumulated precipitation of a rain gauge into the instantaneous precipitation rate (referred to as the traditional method) is based on a simple assumption: the rainfall measured per minute multiplied by 60 can be used to obtain the hourly precipitation. This method is easy to implement, but it ignores the dynamic changes of the precipitation process, especially in weak precipitation events. For example, as shown in the observation data of a certain place, the correlation between the instantaneous precipitation rate obtained by the traditional method and the raindrop spectrum measurement value is poor, with a correlation coefficient of only 0.3183 and a deviation of -3.45 mm / h. This shows that the traditional method has obvious limitations when dealing with weak precipitation and cannot accurately reflect the true situation of precipitation.

[0028] First embodiment

[0029] like Figure 1As shown, the first embodiment of the present invention provides a method for converting the accumulated precipitation of a rain gauge to the instantaneous precipitation rate, which at least includes the following steps:

[0030] Step S1: Divide precipitation events according to time intervals.

[0031] First, precipitation events are divided according to time intervals. In one embodiment of the present invention, a precipitation event is defined as a situation where the time interval between two adjacent precipitation observations does not exceed 15 minutes. This definition helps to divide continuous precipitation processes into independent events for subsequent processing.

[0032] Step S2: For each precipitation event, sum the precipitation at all moments in the precipitation event to obtain a sequence of cumulative precipitation changing over time.

[0033] Next, the precipitation in each precipitation event is accumulated to obtain the cumulative precipitation series over time. This step is to obtain the total precipitation at each moment and provide basic data for subsequent interpolation and conversion.

[0034] Step S3: interpolating the time-varying sequence of the accumulated precipitation within a certain period before the precipitation event begins and within a certain period after the precipitation event ends.

[0035] The cumulative precipitation sequence is interpolated within 7 minutes before the precipitation event begins and within 7 minutes after the end. In one embodiment of the present invention, the cubic spline interpolation method is preferably used because after a large number of experimental tests, it is found that the total precipitation obtained by this method is closest to the actual observed value. However, the interpolation method that can be used in the embodiment of the present invention is not limited to the cubic spline interpolation method, and can also include linear interpolation, nearest neighbor interpolation, polynomial interpolation, etc. The most appropriate interpolation method is selected to estimate the precipitation more accurately, especially near the boundary of the precipitation event.

[0036] Step S4: Eliminate negative numbers in the interpolation result.

[0037] During the interpolation process, negative results may appear, which is meaningless in actual situations. Therefore, these negative numbers need to be removed to ensure the rationality of the data.

[0038] Step S5: Compare the difference between the total accumulated precipitation obtained after interpolation and the original total accumulated precipitation, and perform corresponding processing according to the difference.

[0039] Compare the interpolated cumulative precipitation with the original cumulative precipitation. If the interpolated result is less than half of the original value, or greater than half of the original value, it indicates that there is a large deviation between the interpolated result and the actual observed value. In this case, a different interpolation method needs to be used to re-interpolate.

[0040] Step S6: Calculate the difference between the current precipitation and the previous precipitation to obtain the minute precipitation, and multiply the minute precipitation by 60 to obtain the instantaneous precipitation rate.

[0041] Finally, the minute precipitation is obtained by calculating the difference between the current moment and the previous moment. Then the minute precipitation is multiplied by 60 to convert it into the instantaneous precipitation rate. This step is to convert the cumulative precipitation into the instantaneous precipitation rate corresponding to the satellite remote sensing observation data, so that it can be used for accuracy verification and comparison.

[0042] Figure 2 The figure shows the comparison between the instantaneous precipitation rate (blue line) converted by the method provided by the embodiment of the present invention and the instantaneous precipitation rate of the raindrop spectrum (red line). By visually observing the two curves, it can be found that in the weak precipitation part, that is, the area where the precipitation rate is less than 10 mm / h, the consistency between the two is significantly improved. This improvement in consistency shows that the method provided by the embodiment of the present invention can more accurately reflect the actual precipitation situation, especially when the precipitation rate is low.

[0043] Table 1 Comparison of instantaneous precipitation rates between rain gauge and raindrop spectrum

[0044]

[0045] Furthermore, the performance difference between the method provided by the embodiment of the present invention and the traditional method is quantitatively compared by the statistical indicators shown in Table 1. Specifically, after using the method provided by the embodiment of the present invention, the correlation coefficient of weak precipitation is increased from 0.3183 to 0.7529, which indicates that the linear correlation between the two measurement methods is significantly enhanced. At the same time, the deviation is reduced from -3.4545 mm / h to -0.9413 mm / h, which means that the instantaneous precipitation rate predicted by the method provided by the embodiment of the present invention is closer to the actual observed value of the raindrop spectrum. In addition, the mean absolute error (MAE) is also reduced from 3.9976 mm / h to 1.7733 mm / h, which further confirms the improvement in prediction accuracy of the method provided by the embodiment of the present invention.

[0046] The method provided by the embodiment of the present invention shows better performance than the traditional method not only in the weak precipitation part, but also in the entire sample range. This shows that the method provided by the embodiment of the present invention can provide more accurate instantaneous precipitation rate estimation under various precipitation conditions. This comprehensive performance improvement is crucial for generating long-term series of instantaneous precipitation rate datasets, because these datasets will be used to support the accuracy verification of satellite precipitation products.

[0047] Compared with the above-mentioned prior art, the present invention first accurately divides precipitation events, and divides the continuous precipitation process into independent events at a time interval of 15 minutes. This division method takes into account the continuity and dynamic changes of precipitation, and provides a more accurate basis for subsequent data processing. In contrast, the traditional method fails to distinguish different precipitation events, but simply accumulates all observation data to calculate the instantaneous precipitation rate, which may lead to inaccurate data when the precipitation intensity changes greatly.

[0048] When processing the accumulated precipitation, the present invention adopts an advanced interpolation strategy, especially in the boundary area of ​​the precipitation event, preferably using the cubic spline interpolation method for processing. This interpolation method can better reflect the dynamic changes of precipitation and improve the accuracy of the data. In addition, the present invention also introduces a negative number elimination and difference comparison mechanism to ensure the rationality and accuracy of the interpolation results. This strategy is significantly better than the traditional method, which fails to effectively process the dynamic changes of precipitation.

[0049] Finally, the present invention calculates the difference between the current moment and the previous moment to obtain the minute precipitation, and converts it into the instantaneous precipitation rate. This method avoids the oversimplification problem that may occur in the traditional method and provides a more accurate estimation of the instantaneous precipitation rate. Through this precise calculation method, the present invention can more accurately reflect the actual situation of precipitation, especially in weak precipitation events. Compared with the traditional method, the present invention can significantly improve the estimation accuracy of the instantaneous precipitation rate.

[0050] In summary, the present invention significantly improves the accuracy and reliability of the conversion from rain gauge accumulated precipitation to instantaneous precipitation rate through precise precipitation event division, advanced interpolation strategy and precise instantaneous precipitation rate calculation. Especially when dealing with weak precipitation events, the present invention shows obvious advantages compared with traditional methods.

[0051] Second embodiment

[0052] Based on the above conversion method, the second embodiment of the present invention provides a system for converting the rain gauge accumulated precipitation to the instantaneous precipitation rate.

[0053] like Figure 3 As shown, the system includes one or more processors 41 and a memory 42. The memory 42 is used to store one or more programs, and when the one or more programs are executed by the one or more processors 41, the method in the above embodiment is implemented.

[0054] Wherein, the processor is used to control the overall operation of the system to complete all or part of the steps of the above method. The processor can be a central processing unit (CPU), a graphics processing unit (GPU), a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a digital signal processing (DSP) chip, etc. The memory is used to store various types of data to support operations in the system, and these data may include, for example, instructions for any application or method for operating on the system, and application-related data. The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic memory, a flash memory, etc.

[0055] In an exemplary embodiment, the system can be implemented by a microprocessor or a computer, or by a product with a certain function, for executing the above method and achieving the same technical effect as the above method. Specifically, the computer can be, for example, a personal computer, a laptop computer, a vehicle-mounted human-computer interaction device, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0056] In another exemplary embodiment, the present invention further provides a computer-readable storage medium including program instructions, which, when executed by a processor, implements the steps of the method in any of the above embodiments. For example, the computer-readable storage medium may be the above-mentioned memory including program instructions, which may be executed by a processor to complete the above-mentioned method and achieve the same technical effect as the above-mentioned method.

[0057] It should be noted that the above embodiments are only examples, and the technical solutions of the various embodiments can be combined, all within the protection scope of the present invention.

[0058] The above is a detailed description of the method and system for converting the accumulated precipitation of a rain gauge to the instantaneous precipitation rate provided by the present invention. For a person skilled in the art, any obvious changes made to it without departing from the essence of the present invention will constitute an infringement of the patent right of the present invention and will bear the corresponding legal liability.

Claims

1. A method for converting the accumulated precipitation of a rain gauge into the instantaneous precipitation rate, characterized in that The steps include: S1: Divide precipitation events according to time intervals; S2: For each precipitation event, sum the precipitation at all times in the precipitation event to obtain a sequence of cumulative precipitation changing over time; S3: interpolating the time-varying sequence of the accumulated precipitation within a certain period before the start of the precipitation event and within a certain period after the end of the precipitation event; S4: Eliminate negative numbers in the interpolation result; S5: comparing the difference between the total accumulated precipitation obtained after interpolation and the original total accumulated precipitation; wherein, if the total accumulated precipitation obtained after interpolation is less than half of the original total accumulated precipitation, or the total accumulated precipitation obtained after interpolation is greater than half of the original total accumulated precipitation, then re-interpolating the sequence of the cumulative precipitation changing with time using an interpolation method different from that in step S3; after the interpolation is completed, entering step S6; S6: Calculate the difference between the current precipitation and the previous precipitation to obtain minute precipitation, and multiply the obtained minute precipitation by 60 to obtain the instantaneous precipitation rate.

2. The conversion method according to claim 1, characterized in that: In step S1, the time interval is 15 minutes.

3. The conversion method according to claim 2, characterized in that: In step S1, the precipitation event refers to a time interval between two consecutive precipitation observations not exceeding 15 minutes.

4. The conversion method according to claim 1, characterized in that: In step S3, the certain time before the precipitation event starts is within 7 minutes before the precipitation event starts, and the certain time after the precipitation event ends is within 7 minutes after the precipitation event ends.

5. The conversion method according to claim 1, characterized in that: In step S3, the cubic spline interpolation method is used to interpolate the sequence of the cumulative precipitation changing with time.

6. The conversion method according to claim 1, characterized in that: In step S4, the negative number refers to a value of the accumulated precipitation obtained after interpolation that is less than 0.

7. The conversion method according to claim 1, characterized in that: In step S5, the interpolation method different from that in step S3 is any one of linear interpolation, nearest neighbor interpolation, and polynomial interpolation.

8. A system for converting the accumulated precipitation of a rain gauge into the instantaneous precipitation rate, characterized in that It comprises a processor and a memory; wherein the memory is coupled to the processor and is used to store a computer program, and when the computer program is executed by the processor, the processor implements the conversion method described in any one of claims 1 to 7.

Images