A method and system for identifying cloud phase based on sounding

Abstract

The application provides a method and system for identifying cloud phase state based on sounding, and relates to the technical field of weather monitoring, comprising: collecting L-band sounding second data, identifying the cloud layer by using a relative humidity threshold method, determining the cloud bottom height and the cloud top height, and obtaining the temperature T and the relative humidity RH in the cloud layer; taking the cloud particle concentration data observed by an airplane as the true value of the cloud phase state, statistically processing the relative humidity probability cumulative distribution of the water cloud sample and the ice cloud sample matched in time and space, and obtaining the discrimination threshold value 93% through calibration; performing two-stage discrimination based on the temperature T and the relative humidity RH of the cloud layer: when the temperature T is greater than or equal to 0 DEG C, the water cloud is determined; when the temperature T is less than 0 DEG C, if the relative humidity RH is greater than or equal to 93%, the water cloud containing liquid water is determined, and if the relative humidity RH is less than 93%, the ice cloud is determined; and outputting the cloud phase state discrimination result, which is used for weather modification operation. The application calibrates the sounding threshold value through airplane observation, and realizes accurate, planar and operational discrimination of the cloud phase state.

Description

Technical Field

[0001] This invention relates to the field of weather monitoring technology, and in particular to a method and system for identifying cloud phases based on radiosonde. Background Technology

[0002] As a crucial component of Earth's climate system, the phase distribution of water within clouds—whether liquid, solid, or a mixture—has a critical impact on global radiation balance and precipitation processes. Ice clouds and water clouds differ significantly in their radiative forcing and precipitation formation mechanisms: ice clouds are typically closely associated with more complex cloud-climate feedback and multiple precipitation processes. Therefore, accurately identifying cloud phases is not only essential for understanding the role of clouds in weather systems and global climate, but also provides key observational data for cloud microphysical parameterization schemes in numerical weather prediction and climate models, particularly contributing to improved descriptions of key phase processes such as supercooled water.

[0003] At the application level, the accurate acquisition of cloud phase information is urgently needed in multiple fields. For example, in aviation safety, supercooled water is a major factor leading to aircraft icing, and accurate identification of its distribution is of great significance for route planning and flight safety early warning. In terms of weather modification, artificial rain (snow) enhancement operations require precise location of "seeding" areas rich in supercooled water, and the determination of cloud phase directly affects the effectiveness and scientific validity of the operation.

[0004] In conclusion, accurate identification of cloud phases is of great significance for understanding the role of clouds in the climate system and improving the effectiveness of weather forecasting and weather modification operations.

[0005] Currently, using radiosonde data to invert cloud vertical structure has become a relatively mature method. Studies have shown that by setting a reasonable relative humidity threshold, cloud layers can be effectively identified from L-band radiosonde data, and the height of cloud bases and tops can be determined with an accuracy of over 84%. However, existing research mainly focuses on cloud layer detection, and systematic identification of cloud phases (liquid, ice, or mixed states) is still lacking.

[0006] Temperature is a key thermodynamic parameter controlling cloud phases. It is generally believed that 0℃ to -40℃ is the range where supercooled water and a mixture of water and ice coexist. Studies comparing COSMIC occultation data and sounding data have shown that in the -40℃ to 0℃ range, simply treating clouds as pure water clouds can easily lead to the underestimation of high-level and multi-layered clouds, indicating that the presence of ice or mixed phases must be considered in this temperature range. Analysis of typical cases such as hail clouds also shows that high humidity zones often appear near the 0℃ layer, providing crucial microphysical conditions for hail growth.

[0007] In recent years, some studies have attempted to combine relative humidity and temperature thresholds to preliminarily determine cloud phases. For example, regions with temperatures below -40°C are classified as ice clouds, those above 0°C as water clouds, and those in between as mixed phases. Other studies, when retrieving cloud base height, compared the impact of different phase settings on the results based on the assumptions of pure water clouds and pure ice clouds, thus verifying the feasibility of using temperature and humidity parameters to determine cloud phases.

[0008] Currently, although radiosonde data is widely used in identifying cloud vertical structure, there is still a lack of accurate and reliable methods for phase discrimination. While aircraft observation can directly identify cloud phases with high accuracy through onboard cloud particle probes, it is costly, has limited spatiotemporal coverage, and is difficult to achieve large-scale long-term monitoring.

[0009] Therefore, this invention uses aircraft observations as the "true value" to calibrate the temperature and relative humidity data obtained by the radiosonde, establishes a cloud phase discrimination model applicable to radiosonde data, and achieves accurate cloud phase discrimination, which has important scientific research and operational value. Summary of the Invention

[0010] To address the problems in the background technology, this invention provides a method and system for identifying cloud phases based on radiosonde data. Using water cloud and ice cloud regions observed by aircraft as the true values, the distribution of relative humidity in radiosonde data for corresponding time periods and regions is statistically analyzed, and a cloud phase discrimination method suitable for radiosonde data is established in conjunction with temperature.

[0011] To achieve the above objectives, the present invention provides a method for identifying cloud phases based on radiosonde, comprising: L-band radiosonde data were collected, and cloud layers were identified using the relative humidity threshold method to determine the cloud base height and cloud top height, and the temperature T and relative humidity RH inside the cloud layer were obtained. Using cloud particle concentration data observed by aircraft as the true value of cloud phase, the cumulative distribution of relative humidity probability of spatiotemporally matched water cloud samples and ice cloud samples was statistically analyzed, and a discrimination threshold of 93% was obtained. The cloud is classified into two levels based on its temperature T and relative humidity RH: when the temperature T ≥ 0℃, it is classified as a water cloud; when the temperature T < 0℃, if the relative humidity RH ≥ 93%, it is classified as a water cloud containing liquid water; if the relative humidity RH < 93%, it is classified as an ice cloud. Output cloud phase discrimination results for use in supercooled water area identification, artificial rain enhancement operation area planning, or flight icing early warning.

[0012] As a further improvement of the present invention, the sampling period of the L-band radiosonde data is 1.2s, the vertical resolution is about 8m, and the time period of aircraft observation entering the cloud is synchronized with the time period of radiosonde data acquisition and is in the same observation window.

[0013] As a further improvement of the present invention, the aircraft observation employs CDP, FCDP, CIP particle probes and the AIMMS-20 meteorological measurement system; the CIP particle probe only selects data with particle diameters greater than 100 μm for analysis; using N CDP / FCDP ≥10cm -3 As a criterion for determining the water cloud area, N CDP / FCDP <10cm -3 And N CIP ≥1L - ¹As a criterion for determining ice cloud zones.

[0014] As a further improvement of the present invention, the same observation window is a time interval in which the time period for aircraft cloud entry detection and the time period for acquiring L-band radiosonde data differ by no more than 2 hours.

[0015] As a further improvement of the present invention, the spatiotemporal matching includes synchronizing the latitude, longitude, and altitude of the aircraft and the sounding to ensure that the spatial positions of the probes are consistent.

[0016] As a further improvement of the present invention, within the temperature range T < 0℃, a relative humidity of 84% ≤ RH < 93% is determined to be an ice cloud, and a relative humidity of RH < 84% is also determined to be an ice cloud.

[0017] As a further improvement of the present invention, when the temperature T < -40℃, it is directly identified as an ice cloud, and the relative humidity discrimination is not performed.

[0018] As a further improvement of the present invention, the cloud phase discrimination is performed only within the identified cloud layer, and phase discrimination is not performed in non-cloud areas.

[0019] As a further improvement of the present invention, the discrimination threshold of 93% is the intersection threshold of the cumulative distribution curves of relative humidity probability of water cloud samples and ice cloud samples.

[0020] The present invention also provides a system for identifying cloud phase based on radiosonde, comprising: a radiosonde data acquisition module, a data calibration module, a cloud phase discrimination module, and a result output module; The radiosonde data acquisition module is used for: Acquire L-band radiosonde data, identify cloud layers, and extract temperature (T), relative humidity (RH), cloud base height, and cloud top height. The data calibration module is used for: Import the true values ​​of cloud phases observed from aircraft, and statistically calibrate the relative humidity discrimination threshold to 93%. The cloud phase discrimination module is used for: Configure the discrimination rules and perform joint discrimination based on temperature and relative humidity; The result output module is used for: Generate cloud phase vertical profile products and connect them to the weather modification operation command system.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses water cloud and ice cloud regions observed by aircraft as true values, statistically analyzes the distribution of relative humidity in radiosonde data for corresponding time periods and regions, and establishes a cloud phase discrimination method applicable to radiosonde data in combination with temperature. This fully leverages the calibration potential of aircraft observation data, promotes the expansion of cloud phase discrimination from "point detection" to "area monitoring," provides technical support for long-term and continuous monitoring of cloud phases within the radiosonde network, and further provides reliable scientific support for the precise implementation of weather warnings, climate assessments, and artificial weather modification operations.

[0022] This invention uses aircraft observations to statistically calibrate radiosonde temperature and humidity data, establishes joint discrimination rules for temperature and relative humidity, and achieves accurate cloud phase discrimination based on radiosonde data. This solves the technical problem that traditional radiosondes can only identify cloud layers but cannot accurately distinguish between water clouds and ice clouds, and significantly improves the accuracy and reliability of cloud phase identification.

[0023] This invention limits cloud phase discrimination to the area within identified cloud layers, eliminating interference from non-cloud regions, reducing invalid calculations and misjudgments, and improving the efficiency and rationality of cloud phase discrimination.

[0024] This invention uses the intersection of the cumulative distribution curves of relative humidity probability of water cloud samples and ice cloud samples to determine a 93% objective discrimination threshold, rather than an empirical threshold, which greatly reduces the error of human setting and makes the discrimination results more statistically objective.

[0025] This invention enables cloud phase monitoring based on operational L-band radiosonde data, expanding cloud phase monitoring from point detection by aircraft to continuous regional area monitoring. It overcomes the limitations of high cost and limited spatiotemporal coverage of aircraft observation and has the capability for long-term operational use.

[0026] This invention can accurately identify supercooled water areas in clouds, providing a reliable target area basis for weather modification operations. It can also provide data support for early warning of aviation icing risks, and has significant practical application value.

[0027] The discrimination rules of this invention are simple and can be executed automatically. They can be directly connected to meteorological operational systems without the need for additional detection equipment, and are easy to promote and apply in the existing radiosonde station network. Attached Figure Description

[0028] Figure 1 This is a flowchart of a method for identifying cloud phases based on radiosonde, as disclosed in one embodiment of the present invention; Figure 2 This is a schematic diagram of the relative humidity distribution in a water cloud area according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the relative humidity distribution in an ice cloud region according to an embodiment of the present invention; Figure 4 This is a detailed flowchart of cloud phase state discrimination according to one embodiment of the present invention; Figure 5 This is a schematic diagram of a Hebei provincial artificial weathering operation analysis, decision-making, and command system disclosed in one embodiment of the present invention; Figure 6 This invention discloses a 08 o'clock radiosonde cloud analysis product for Xingtai, as shown in one embodiment of the present invention. Figure 7 This is a cross-sectional view of the flight trajectory and superimposed radar reflectivity of aircraft 3765 on November 6, 2023, as disclosed in an embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings: like Figure 1 As shown, this invention provides a method for identifying cloud phases based on radiosonde data. Utilizing aircraft observation data and L-band radiosonde data from Hebei Province between 2017 and 2022, six spatiotemporally matched cases were selected. The detection locations of these six cases covered areas such as Xingtai, Huangsi, and Neiqiu. Cloud particle data were acquired using airborne probes such as CDP and CIP. The temperature range for water cloud samples was -12.65℃ to -0.7℃, and for ice cloud samples it was -28.6℃ to -0.1℃. A total of 384 water cloud samples (pure water clouds or mixed clouds) and 1246 ice cloud samples were collected. Using the water cloud and ice cloud areas observed by the aircraft as the true values, the relative humidity distribution of radiosonde data for the corresponding time periods and regions was statistically analyzed. Combined with temperature data, a cloud phase discrimination method suitable for radiosonde data was established. This invention ensures the reliability and regional applicability of the discrimination method through a large number of measured samples, including the following steps: S1. Collect L-band radiosonde data, use the relative humidity threshold method to identify cloud layers, determine the cloud base height and cloud top height, and obtain the temperature T and relative humidity RH inside the cloud layer; The sampling period for L-band radiosonde data is 1.2s, with a vertical resolution of approximately 8m. Furthermore, the time period for aircraft observations entering the clouds is synchronized with the time period for acquiring radiosonde data, and both are within the same observation window.

[0031] Furthermore, the same observation window is a time interval within which the aircraft cloud entry detection period and the L-band radiosonde data acquisition period differ by no more than 2 hours.

[0032] Specifically, the L-band radiosonde data comes from the Xingtai and Zhangjiakou National Observatory, and is collected using the GFE(L)1 secondary wind-measuring radar and the GTS1 digital radiosonde. It can continuously and automatically acquire upper-air temperature, air pressure, humidity, and wind field elements, and has the ability to acquire data in real time with high resolution. The acquisition time is 07:15 and 19:15 (Beijing time, the same below). The relative humidity threshold method is used to identify clouds, referring to existing mature technologies, which can accurately locate the height of the cloud base and cloud top. Temperature and humidity data are extracted only inside the cloud layer, effectively eliminating interference from clear sky non-cloud areas and improving the validity of the data.

[0033] S2. Using cloud particle concentration data observed by aircraft as the true value of cloud phase, the cumulative distribution of relative humidity probability of spatiotemporally matched water cloud samples and ice cloud samples was statistically analyzed, and the discrimination threshold of 93% was determined. The aircraft observation employed CDP, FCDP, and CIP particle probes in conjunction with the AIMMS-20 meteorological measurement system (Aircraft Integrated Meteorological Measurement System). The CIP particle probe only analyzed data with particle diameters greater than 100 μm. (The last part, "N," appears to be an incomplete sentence or fragment and doesn't translate directly.) CDP / FCDP ≥10cm -3 As a criterion for determining the water cloud area, N CDP / FCDP <10cm -3 And N CIP ≥1L -1 As a criterion for determining ice cloud areas.

[0034] To match the 07:15 and 19:15 L-band radiosonde data, observational data of aircraft entering clouds in Xingtai and Zhangjiakou areas of Hebei Province from 07:00-09:00 and 19:00-21:00 were selected. Spatiotemporal matching also included aligning the latitude, longitude, and altitude of the aircraft and the radiosonde to ensure consistent spatial location. Using temporal and spatial (latitude, longitude, and altitude) matching criteria, the aircraft cloud-penetrating data and the radiosonde data were paired to establish a statistical relationship between "water cloud / ice cloud area" and "radiosonde relative humidity," and the cumulative distribution function of relative humidity probability for the "water cloud area" and "ice cloud area" samples was plotted. The intersection of the two distribution curves was defined as the discrimination threshold.

[0035] The discrimination threshold of 93% is the intersection threshold of the cumulative distribution curves of relative humidity probability of water cloud samples and ice cloud samples.

[0036] Specifically, the aircraft observation used a King-air 350HW model. The CDP (Cloud Droplet Probe) and FCDP (Fast Cloud Droplet Probe) were used to measure cloud droplet particles of 2-50 μm, while the CIP probe measured ice and snow crystal particles of 25-1550 μm. Due to the depth of field limitation of the CIP probe, the data of particles smaller than 100 μm had low accuracy, so only data with a diameter greater than 100 μm were selected for concentration calculation. The AIMMS 20 system simultaneously acquired meteorological parameters such as latitude, longitude, altitude, temperature, and humidity. The instrument parameters are shown in Table 1. The intersection of the cumulative distribution curves of relative humidity probability in water cloud areas and ice cloud areas was used as the statistical threshold to objectively distinguish phase states and avoid the bias of empirical thresholds.

[0037] Table 1 Parameters of Airborne Detection Instruments

[0038] S3. Two-level discrimination is made based on cloud temperature T and relative humidity RH: when temperature T≥0℃, it is judged as water cloud; when temperature T<0℃, if relative humidity RH≥93%, it is judged as water cloud containing liquid water; if relative humidity RH<93%, it is judged as ice cloud. in, Within the temperature range T < 0℃, a relative humidity of 84% ≤ RH < 93% is considered an ice cloud, and a relative humidity of RH < 84% is also considered an ice cloud. When the temperature T < -40℃, it is directly identified as an ice cloud, and relative humidity is not considered.

[0039] Specifically, when the temperature is ≥0℃, there are no frozen particles in the cloud layer, and it is all liquid water cloud; when the temperature is <0℃, it is the range where supercooled water and ice phase coexist, and it needs to be judged in conjunction with relative humidity; statistics show that 77.85% of ice cloud areas have a relative humidity of 84%~90%, 16.53% have a relative humidity of less than 84%, and only 5.62% have a relative humidity of more than 90%. Subdividing the range can improve the accuracy of ice cloud identification; -40℃ is the critical temperature for spontaneous freezing of water droplets in the natural environment. Below this temperature, there is no liquid water and it can be directly identified as an ice cloud.

[0040] S4. Output cloud phase discrimination results, which can be used for supercooled water area identification, artificial rain enhancement operation area planning, or flight icing early warning.

[0041] The cloud phase discrimination is performed only within the identified cloud layers; phase discrimination is not performed in non-cloud areas.

[0042] Specifically, identifying cloud layers before conducting phase discrimination can reduce invalid calculations and lower the misjudgment rate. The discrimination results can extend cloud phase detection from point detection by aircraft to continuous surface monitoring via sounding, and can accurately identify the distribution of supercooled water, providing reliable technical support for the selection of target areas for artificial rain enhancement operations and early warning of aviation icing risks.

[0043] In one embodiment of the present invention, the specific process of determining the relative humidity threshold and realizing cloud phase discrimination includes: Using aircraft observation and radiosonde data from Hebei Province from 2017 to 2022, six spatiotemporal matching cases were selected, as shown in Table 2, which introduces the selected spatiotemporal matching cases.

[0044] Table 2 shows the spatiotemporal matching data of the six aircraft and radiosonde observations obtained through screening.

[0045] A total of 384 water cloud area samples and 1246 ice cloud area samples were collected using this standard. Figure 2 This shows the relative humidity distribution in the water cloud region. Figure 3 The relative humidity distribution in the ice cloud region can be seen as follows: (1) The temperature corresponding to the water cloud region is -12.65℃ to -0.7℃, which is a supercooled water region, and the corresponding relative humidity of the sounding is 90% to 100%; (2) The temperature corresponding to the ice cloud area is -28.6~-0.1℃, and the corresponding relative humidity for radiosonde is 58%~96%; The frequency distribution of relative humidity in water cloud and ice cloud regions shows that in the water cloud region, values ​​with relative humidity less than 93% account for 9.89% of the sample, while values ​​with relative humidity greater than or equal to 93% account for 90.1%. In the ice cloud region, values ​​with relative humidity less than 84% account for 16.53% of the sample, values ​​with relative humidity greater than 90% account for 5.62%, and values ​​with relative humidity between 84% and 90% account for 77.85%.

[0046] Considering the influence of factors such as spatiotemporal matching, sounding component errors, and ambient temperature, when the relative humidity is close to saturation (e.g., >95%), the sensor components may be wetted by tiny water droplets or ice crystals, causing the measured values ​​to be abnormally high. Under medium to low humidity conditions, a systematic negative bias (the measured value is lower than the actual value) may occur.

[0047] To improve the accuracy of supercooled water identification, it was initially set that a relative humidity value of 93% or higher in the sounding was a liquid water cloud, and a relative humidity value between 84% and 93% was further set as an ice cloud, and a relative humidity RH < 84% was also identified as an ice cloud.

[0048] Based on this, the cloud phase determination process includes: if the temperature observed by radiosonde is T and the relative humidity is RH, based on the cloud layer identification by radiosonde, (1) When T>=0, all clouds are identified as water clouds, and the RH value of radiosonde observation is not considered; (2) When T < 0, if the RH observed by radiosonde is < 93%, it indicates an ice cloud; if the RH observed by radiosonde is >= 93%, it indicates a water cloud (a cloud region containing liquid water). The detailed procedure for cloud phase determination is as follows: Figure 4 As shown.

[0049] In another embodiment, the cloud phase discrimination method of the present invention is verified, specifically including: On November 5, 2023, precipitation occurred due to the influence of a large-scale stratiform cloud system, with the cloud system developing deeply. This precipitation was recorded using the Hebei Provincial Artificial Weather Modification Operation Analysis and Decision-Making Command System (CPAS) (such as...). Figure 5 The Xingtai 08 o'clock radiosonde cloud analysis product (as shown) Figure 6 As shown in the image, the cloud base is about 0.3 km high, the cloud top is about 1.1 km high, the 0-degree layer is about 2.6 km high, and liquid water exists below 6.5 km, making it suitable for cloud seeding operations.

[0050] Based on the aforementioned monitoring and identification results, the 3765 rain enhancement aircraft took off from Zhengding Airport at 9:22 AM and conducted vertical detection at 2100-3600m in Luancheng. The aircraft's observations showed liquid water at this altitude. At 10:48 AM, the aircraft flew at 3600m to the area encompassing Lincheng, Xingtai, Zhaoxian, and Baixiang to conduct rain enhancement operations, seeding a total of 23 silver iodide smoke sticks (e.g., ...). Figure 7 As shown in the figure, the work results were significant.

[0051] The present invention also provides a system for identifying cloud phase based on radiosonde, comprising: a radiosonde data acquisition module, a data calibration module, a cloud phase discrimination module, and a result output module; The sounding data acquisition module is used for: Acquire L-band radiosonde data, identify cloud layers, and extract temperature (T), relative humidity (RH), cloud base height, and cloud top height. The data calibration module is used for: Import the true values ​​of cloud phases observed from aircraft, and statistically calibrate the relative humidity discrimination threshold to 93%. The cloud phase discrimination module is used for: Configure the discrimination rules and perform joint discrimination based on temperature and relative humidity; The results output module is used for: Generate cloud phase vertical profile products and connect them to the weather modification operation command system.

[0052] Example: Cloud phase state discrimination using the method of the present invention includes: Step 1: Collect radiosonde data and identify cloud layers L-band radiosonde data from Xingtai and Zhangjiakou stations were used, with a sampling period of 1.2s and a vertical resolution of approximately 8m. The relative humidity threshold method was used to identify cloud layers and determine the height of the cloud base and cloud top. Temperature T and relative humidity RH were extracted only within the cloud layer to exclude interference from non-cloud areas.

[0053] Step 2: Two-level discrimination T≥0℃: Determined to be water cloud; T < -40℃: Directly identified as ice cloud; 0℃>T≥-40℃: RH≥93%→Water cloud (including supercooled water); 84%≤RH<93%→Ice Cloud; RH < 84% → Ice Cloud.

[0054] Step 3: Output the results and apply them It only performs discrimination within identified cloud layers and outputs phase state results, which can be used for supercooled water identification, artificial rain enhancement operation planning, and flight icing early warning.

[0055] Step 4: Verification of actual weather events (November 5, 2023) Weather background: Widespread stratiform clouds in Hebei Province, with thick cloud systems and precipitation; Radiosonde identification: At 08:00, the cloud base height at Xingtai station was approximately 0.3 km, the cloud top height was approximately 1.1 km, the 0°C layer height was approximately 2.6 km, and liquid water was found below 6.5 km. Aircraft operation: Aircraft 3765 took off at 9:22 and detected liquid water at 2100–3600m. At 10:48, it carried out operations at an altitude of 3600m in the Lincheng, Xingtai, Zhaoxian and Baixiang areas, spreading 23 silver iodide smoke sticks. The operation was very effective. System support: The judgment results are connected to the Hebei Provincial Artificial Weather Modification Operation Analysis and Decision-Making Command System (CPAS) to generate cloud phase vertical profile products, supporting the entire command process.

[0056] Advantages of this invention: This invention uses true values ​​from aircraft observations to calibrate the relative humidity threshold for sounding. The threshold is objectively determined by the intersection of statistical distributions. Compared with the traditional empirical threshold method, cloud phase identification is more accurate and precise, and the reliability of supercooled water area identification is significantly improved.

[0057] This invention enables continuous monitoring of cloud phases and surface features based on operational L-band radiosonde data, overcoming the limitations of high cost and limited spatiotemporal coverage of aircraft observations. It provides a wider monitoring range and enables long-term stable regional observations.

[0058] This invention employs a two-step process of "first identifying cloud layers and then determining the phase state," and combines temperature and relative humidity as dual constraints to eliminate interference from non-cloudy areas and reduce the false judgment rate.

[0059] This invention can be directly operated based on the existing radiosonde network without the need for additional detection equipment. The judgment results can be directly used for artificial rain enhancement operations and flight icing early warning, and the threshold for engineering application is low.

[0060] This invention is based on extensive field training and validation of stratiform cloud systems in Hebei Province. The method has good regional adaptability and can meet the actual operational needs of artificial weather modification operations and weather forecasting.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for identifying cloud phases based on radiosonde, characterized in that, include: L-band radiosonde data were collected, and cloud layers were identified using the relative humidity threshold method to determine the cloud base height and cloud top height, and the temperature T and relative humidity RH inside the cloud layer were obtained. Using cloud particle concentration data observed by aircraft as the true value of cloud phase, the cumulative distribution of relative humidity probability of spatiotemporally matched water cloud samples and ice cloud samples was statistically analyzed, and a discrimination threshold of 93% was obtained. The cloud is classified into two levels based on its temperature T and relative humidity RH: when the temperature T ≥ 0℃, it is classified as a water cloud; when the temperature T < 0℃, if the relative humidity RH ≥ 93%, it is classified as a water cloud containing liquid water; if the relative humidity RH < 93%, it is classified as an ice cloud. Output cloud phase discrimination results for use in supercooled water area identification, artificial rain enhancement operation area planning, or flight icing early warning.

2. The method for identifying cloud phases based on radiosonde according to claim 1, characterized in that: The sampling period for the L-band radiosonde data is 1.2s, with a vertical resolution of approximately 8m. Furthermore, the time period for aircraft observations entering the clouds is synchronized with the time period for acquiring radiosonde data, and both are within the same observation window.

3. The method for identifying cloud phases based on radiosonde according to claim 1, characterized in that: The aircraft observations employed CDP, FCDP, and CIP particle probes along with the AIMMS-20 meteorological measurement system; the CIP particle probe only analyzed data with particle diameters greater than 100 μm; using N... CDP / FCDP ≥10cm - ³ is used as the criterion for determining the water cloud area, with N CDP / FCDP <10cm -3 And N CIP ≥1L -1 As a criterion for determining ice cloud areas.

4. The method for identifying cloud phases based on radiosonde according to claim 2, characterized in that: The same observation window refers to a time interval within which the aircraft cloud entry detection period and the L-band radiosonde data acquisition period differ by no more than 2 hours.

5. The method for identifying cloud phases based on radiosonde according to claim 1, characterized in that: The spatiotemporal matching includes synchronizing the latitude, longitude, and altitude of the aircraft and the sounding to ensure that the spatial location of the probe is consistent.

6. The method for identifying cloud phases based on radiosonde according to claim 1, characterized in that: Within the temperature range T < 0℃, a relative humidity of 84% ≤ RH < 93% is considered an ice cloud, and a relative humidity of RH < 84% is also considered an ice cloud.

7. The method for identifying cloud phases based on radiosonde according to claim 1, characterized in that: When the temperature T < -40℃, it is directly identified as an ice cloud, and relative humidity is not considered.

8. The method for identifying cloud phases based on radiosonde according to claim 1, characterized in that: The cloud phase discrimination is performed only within the identified cloud layers; phase discrimination is not performed in non-cloud areas.

9. The method for identifying cloud phases based on radiosonde according to claim 1, characterized in that: The discrimination threshold of 93% is the threshold of the intersection of the cumulative distribution curves of relative humidity probability of water cloud samples and ice cloud samples.

10. A system for identifying cloud phases based on radiosonde, implementing the method for identifying cloud phases based on radiosonde as described in any one of claims 1-9, characterized in that, include: The system includes a sounding data acquisition module, a data calibration module, a cloud phase discrimination module, and a result output module. The radiosonde data acquisition module is used for: Acquire L-band radiosonde data, identify cloud layers, and extract temperature (T), relative humidity (RH), cloud base height, and cloud top height. The data calibration module is used for: Import the true values ​​of cloud phases observed from aircraft, and statistically calibrate the relative humidity discrimination threshold to 93%. The cloud phase discrimination module is used for: Configure the discrimination rules and perform joint discrimination based on temperature and relative humidity; The result output module is used for: Generate cloud phase vertical profile products and connect them to the weather modification operation command system.

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