A device and method for vertical in-situ measurement of aerosol liquid water content

Abstract

This invention relates to a vertical in-situ measurement device and method for aerosol liquid water content. An airborne module on a UAV carries an onboard online measurement module and an onboard aerosol sampling module to different altitudes. The onboard online measurement module measures the relative humidity and aerosol particle size distribution at different altitudes. The onboard aerosol sampling module collects aerosol particles at different altitudes and maintains their aerosol state before bringing them back to the ground. The ground-based online measurement module measures the hygroscopicity of the aerosol samples to obtain the aerosol hygroscopic growth factor at different relative humidities. The aerosol liquid water content at different altitudes is calculated using the relative humidity, aerosol particle size distribution, and hygroscopic growth factor. This invention enables low-cost, high spatiotemporal resolution observation of the all-day vertical profile of aerosol liquid water content below 1 km, belonging to the field of atmospheric environmental monitoring technology.

Description

Technical Field

[0001] This invention relates to the field of atmospheric environmental monitoring technology, specifically to a vertical in-situ measurement device and method for measuring the liquid water content of aerosols. Background Technology

[0002] Aerosol particles in the atmosphere adsorb or absorb water vapor to form liquid water aerosols. Liquid water aerosols are an important component of atmospheric aerosols and a significant factor influencing aerosol physicochemical processes and environmental climate effects. On one hand, after absorbing water vapor from the atmosphere, particulate matter increases in size, leading to a larger light scattering cross-section and enhanced scattering ability of visible light, thus affecting atmospheric radiation balance and causing visibility reduction. On the other hand, liquid water in aerosols acts as a chemical reaction medium, providing a site for aerosol liquid-phase reactions and heterogeneous reactions on the aerosol surface, potentially playing a crucial role in secondary aerosol formation and haze outbreaks.

[0003] Current observational studies have investigated the vertical distribution characteristics of aerosol liquid water content. These studies directly or indirectly demonstrate significant differences in aerosol liquid water content at different vertical altitudes, affecting the accurate assessment of its environmental and climatic effects. However, the observation techniques relied upon in these studies are not in-situ observations and require numerous assumptions about various aerosol-related parameters. This inevitably introduces significant errors into the accurate acquisition of aerosol liquid water content, severely restricting our in-depth exploration of the vertical distribution characteristics of aerosol liquid water content and its impact on environmental climate. Therefore, to accurately obtain the profile of aerosol liquid water content under different environmental conditions, it is urgently necessary to design an in-situ observation method to directly characterize the real-time characteristics of aerosol liquid water content at different altitudes. This requires real-time online measurement of various parameters closely related to aerosol liquid water content at different vertical altitudes, namely, aerosol particle size distribution, hygroscopicity, and ambient relative humidity.

[0004] The most commonly used methods for detecting the hygroscopicity of environmental aerosols include: (1) humidified series differential electromobility analyzer; (2) humidified turbidimeter. However, the existing online observation instruments for the hygroscopicity of environmental aerosols are relatively large in size and mass, and currently can only rely on aircraft, large tethered airships and weather towers as vertical observation platforms, and the observation cost based on these platforms is extremely high. Moreover, the flight speed of aircraft is too fast, making it unsuitable for routine observations within a few hundred meters of the ground; and observations based on weather tower platforms can only be sampled and analyzed at a few specific heights of the weather tower, and for relatively small-scale changes, the vertical resolution of profile observations is insufficient, making it difficult to be used for observation studies with high vertical density. In addition, the effective payload of conventional UAVs is very limited, and they still cannot carry traditional online observation instruments for the hygroscopicity of aerosols. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the purpose of this invention is to provide a vertical in-situ measurement device and method for aerosol liquid water content. This device can measure the aerosol particle size distribution, aerosol hygroscopicity, and ambient relative humidity at multiple different altitudes during flight. The measurement results can provide high temporal and vertical resolution distribution characteristics of aerosol liquid water content. While ensuring real-time observation of the collected aerosol samples in an aerosol state, this invention provides online observation of aerosol physicochemical properties, overcoming the technical bottleneck that previous online aerosol physicochemical property (such as aerosol hygroscopicity and liquid water content) observation instruments weighed tens to hundreds of kilograms, making them unsuitable for real-time sampling on UAV platforms.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A vertical in-situ measurement device for aerosol liquid water content includes an UAV-borne module, an airborne online measurement module, an airborne aerosol sampling module, a ground-based online measurement module, and ground control equipment. The airborne online measurement module and the airborne aerosol sampling module are both mounted on the UAV-borne module. The UAV-borne module, the airborne online measurement module, and the airborne aerosol sampling module are all connected to the ground control equipment.

[0008] The UAV-borne module is used to propel the onboard online measurement module and the onboard aerosol sampling module to different altitudes.

[0009] The airborne online measurement module is used for online measurement of atmospheric relative humidity and aerosol particle size distribution at different altitudes;

[0010] The airborne aerosol sampling module is used to collect aerosol particles at different altitudes and maintain their aerosol state to bring them back to the ground. The hygroscopicity of the aerosol samples is measured using the ground-based online measurement module to obtain the aerosol hygroscopic growth factor under different relative humidities.

[0011] The liquid water content of aerosols at different altitudes was calculated using atmospheric relative humidity, aerosol particle size distribution, and hygroscopic growth factor of aerosols at different altitudes.

[0012] As a preferred embodiment, the airborne online measurement module includes a first air intake sampling port, an air intake pipe, a temperature sensor, a humidity sensor, a pressure sensor, a first drying tube, and an aerosol optical particle size spectrometer. The first air intake sampling port is located 0.5 meters above the two propellers in the nose direction of the UAV's onboard module. The air intake pipe is fixed to the UAV's onboard module, and the first air intake sampling port is connected to the air intake pipe. The temperature sensor, humidity sensor, and pressure sensor are fixed to the outer wall of the air intake pipe and are all electrically connected to the airborne aerosol sampling module, respectively used for online measurement of atmospheric pressure, temperature, and relative humidity of the UAV at different altitudes. One end of the first drying tube is connected to the air intake pipe, and the other end of the first drying tube is connected to the aerosol optical particle size spectrometer.

[0013] As a preferred embodiment, the airborne aerosol sampling module includes a circuit control system, a sampling frame, and a sampling container. The sampling frame is connected to the UAV's onboard module. The circuit control system is located between the airborne online measurement module and the sampling frame. The circuit control system includes a second sampling air inlet, a third black rubber tube, a second drying tube, a solenoid valve, and a circuit integration system. The circuit integration system includes a battery, a power distribution system, a microcontroller module, a remote communication module, and a data storage module. The battery is electrically connected to the power distribution system, which provides power to the microcontroller module, the remote communication module, and the data storage module. The microcontroller module is electrically connected to the remote communication module, which can communicate with ground control equipment. The data storage module is electrically connected to a temperature sensor via a data cable. A humidity sensor and a barometric pressure sensor are used to store atmospheric pressure, temperature, and relative humidity data collected by the temperature sensor, humidity sensor, and barometric pressure sensor at different altitudes. A sampling container is installed on a sampling frame, and the sampling container has a first sampling port and a second sampling port. The first sampling port is connected in sequence to a first manual valve and a first black rubber tube, and the second sampling port is connected in sequence to a second manual valve and a second black rubber tube. The first black rubber tube and the second black rubber tube are connected by a Y-shaped tee. The third port of the Y-shaped tee is connected in sequence to a third black rubber tube, a solenoid valve, and a second drying tube. The second drying tube is connected to a second sampling air inlet, which is open to the atmosphere. The solenoid valve is connected to a microcontroller module via a wire. The microcontroller module receives instructions from a remote communication module to control the opening and closing of the solenoid valve.

[0014] As a preferred embodiment, the inner wall of the sampling container is made of conductive copper foil material, the outer wall of the sampling container is made of PE film, and there are connecting plates on both sides of the PE film. The connecting plates are connected to the sampling frame through hooks.

[0015] As a preferred embodiment, the sampling frame has a hexagonal star-shaped structure. Each corner of the sampling frame has a groove on its edge, and a spring is installed in the groove. The springs of two adjacent corners of the sampling frame are connected by a steel wire, and a ring is attached to the steel wire. The sampling container is connected to the ring by a hook, and the steel wire is in a stretched state due to the spring tension.

[0016] A vertical in-situ measurement method for the liquid water content of aerosols, employing a vertical in-situ measurement device, includes the following steps:

[0017] The drone was equipped with an airborne online measurement module and an airborne aerosol sampling module and flew to different altitudes.

[0018] An airborne online measurement module measures atmospheric relative humidity and aerosol particle size distribution at different altitudes.

[0019] The airborne aerosol sampling module collects aerosol particles at different altitudes and maintains their aerosol state before bringing them back to the ground.

[0020] Aerosol particulate matter at different altitudes was measured using a ground-based online measurement module to obtain the aerosol hygroscopic growth factor under different relative humidity levels.

[0021] The liquid water content of aerosols at different altitudes was calculated using atmospheric relative humidity, aerosol particle size distribution, and hygroscopic growth factor of aerosols at different altitudes.

[0022] As a preferred embodiment, the airborne online measurement module includes two aerosol optical particle size spectrometers, namely a first aerosol optical particle size spectrometer and a second aerosol optical particle size spectrometer, which are used to detect the aerosol particle size distribution in the range of 0.13-3 micrometers and 0.25-32 micrometers, respectively.

[0023] As a preferred option, the sampling container of the airborne aerosol sampling module is rinsed clean and evacuated to a vacuum before installation.

[0024] As a preferred option, before sampling, the sampling bag of the airborne aerosol sampling module is placed under negative pressure. When the UAV airborne module reaches the corresponding altitude, the solenoid valve corresponding to the sampling container is opened to automatically inflate the sampling container and collect aerosol samples, thereby realizing automatic sampling of aerosol samples at different altitudes.

[0025] As a preferred method, the calculation of liquid water content in aerosols at different altitudes is as follows: The liquid water content in aerosols at different altitudes is calculated using atmospheric relative humidity and aerosol particle size distribution data collected by an airborne online measurement module, as well as the hygroscopic growth factor of aerosols at different altitudes measured by a ground-based online measurement module. The formula for calculating the liquid water content in aerosols at different altitudes is as follows:

[0026] ,

[0027] N i To collect the number concentration of dry particulate matter at a certain particle size at different heights using an airborne online measurement module, D i ρ is the diameter of the particle, GF is the hygroscopic growth factor of the particle at this diameter obtained by the ground-based online measurement module, RH is the atmospheric relative humidity at different altitudes collected by the airborne online measurement module, and ρ is the particle diameter. w The density of water is 1.0 g / cm³.

[0028] In summary, the present invention has the following advantages:

[0029] 1. The vertical in-situ measurement device and method of this invention utilizes an airborne online measurement module mounted on an UAV to measure atmospheric relative humidity and aerosol particle size distribution at different altitudes in real time. Simultaneously, an airborne aerosol sampling module mounted on the UAV collects aerosol samples from the air and maintains their aerosol state. This is combined with traditional ground-based aerosol hygroscopicity observation techniques to measure the hygroscopicity of aerosol samples at different altitudes in a near-online manner. Finally, theoretical calculations are performed based on the measurement results to achieve low-cost and high spatiotemporal resolution observation of the all-day vertical profile of aerosol liquid water content below 1 km. Compared with traditional aerosol observation methods, UAVs can accurately cover multiple altitude layers of the atmospheric boundary layer, providing more comprehensive and detailed data support for the study of aerosol liquid water content. This data not only reveals the vertical distribution of aerosol liquid water content but also captures the dynamic influence of environmental factors on its changes, helping to understand the behavior of aerosols in the atmosphere and its relationship with climate change.

[0030] 2. This invention offers low-cost and high-efficiency all-weather observation. Traditional aerosol observation techniques are often limited by expensive equipment and high maintenance costs, while the device of this invention integrates multiple observation devices, resulting in lower operating costs. The drone can efficiently and flexibly conduct all-weather vertical observations under various weather and pollution conditions, reducing the possibility of human intervention and equipment failure. Through the automation and efficient operation of the drone, the aerosol sample collection and analysis process is optimized, significantly improving the frequency and quality of data acquisition.

[0031] 3. This invention employs an innovative observation scheme combining "online" and "quasi-online" methods. By integrating an "online" observation module mounted on a UAV with ground-based "quasi-online" measurement technology, two complementary observation methods are used to make the measurement of aerosol liquid water content more accurate and comprehensive. The UAV measures the particle size distribution and atmospheric relative humidity of aerosols at different altitudes in real time, ensuring the immediacy and efficiency of the data. Meanwhile, the ground station performs hygroscopic analysis on the collected aerosol samples, overcoming the obstacle of large and heavy ground instruments that cannot be mounted on UAVs or other flight platforms. This enables vertical measurement of the complex physicochemical properties of aerosols, further enhancing the depth and accuracy of the observation data. This innovative combined observation method, while ensuring efficient real-time data acquisition, also provides rich physicochemical analysis information, demonstrating strong practicality and forward-looking potential. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a vertical in-situ measurement device.

[0033] Figure 2 This is a schematic diagram showing the connection of the UAV onboard module, onboard online measurement module, and onboard aerosol sampling module.

[0034] Figure 3 This is a schematic diagram of the circuit control system in the airborne aerosol sampling module.

[0035] Figure 4 This is a schematic diagram of an airborne online measurement module.

[0036] Figure 5 This is a side view showing the connection between the UAV onboard module, the onboard online measurement module, and the onboard aerosol sampling module.

[0037] Figure 6 A 3D diagram showing the connection of the UAV onboard module, onboard online measurement module, and onboard aerosol sampling module.

[0038] Figure 7 This is a side view showing the connection between the sampling rack and the sampling container.

[0039] Figure 8 This is a three-dimensional view of the sampling rack and sampling container.

[0040] Figure 9 This is a top view of the sampling rack and sampling container.

[0041] Among them, 1 is the first air intake sampling port, 2 is the sensor integrated module, 3 is the first drying tube, 4 is the second aerosol optical particle size spectrometer, 5 is the first aerosol optical particle size spectrometer, 6 is the second drying tube, 7 is the circuit integrated system, 8 is the solenoid valve, 9 is the sampling frame, 10 is the sampling container, 11 is the hook, 12 is the steel wire, 13 is the spring, 14 is the ring, 15 is the UAV airborne module, 16 is the ground control equipment, 17 is the ground online measurement module, 18 is the black load box, 19 is the airborne online measurement module, 20 is the circuit control system, and 21 is the second sampling air intake. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to specific embodiments.

[0043] Example 1

[0044] like Figure 1-9 As shown in the figure, this embodiment provides a vertical in-situ measurement device for aerosol liquid water content, including an UAV-borne module 15, an airborne online measurement module 19, an airborne aerosol sampling module, a ground-based online measurement module 17, and a ground control device 16. The airborne online measurement module 19 and the airborne aerosol sampling module are both mounted below the UAV-borne module 15. The UAV-borne module 15, airborne online measurement module 19, and airborne aerosol sampling module are all connected to the ground control device 16. The UAV-borne module 15 is an existing UAV, which will not be described in detail here. The ground-based online measurement module 17 is a particulate matter hygroscopicity and volatile matter analyzer (HTDMA, Bmet3000) manufactured by Sekma, which can be directly used to measure the hygroscopicity of particulate matter at different particle sizes to obtain the aerosol hygroscopic growth factor under different relative humidities. The ground control device 16 is a computer equipped with an antenna. This antenna can communicate remotely with the microcontroller module in the airborne aerosol sampling module through the remote communication module in the circuit control system to control the opening and closing of the solenoid valve 8. A schematic diagram of the entire device is shown below. Figure 1 As shown.

[0045] The UAV onboard module 15 is used to drive the onboard online measurement module 19 and the onboard aerosol sampling module to different altitudes;

[0046] The airborne online measurement module 19 is used for online measurement of atmospheric relative humidity and aerosol particle size distribution at different altitudes;

[0047] The airborne aerosol sampling module is used to collect aerosol particles at different altitudes and maintain their aerosol state to bring them back to the ground. The hygroscopicity of the aerosol samples is measured using the ground online measurement module 17 to obtain the aerosol hygroscopic growth factor under different relative humidity.

[0048] The liquid water content of aerosols at different heights was calculated using the aerosol particle size distribution at different heights and the hygroscopic growth factor of aerosols at different heights.

[0049] The airborne online measurement module 19 includes a first air intake sampling port 1, an air intake pipe, a temperature sensor, a humidity sensor, a pressure sensor, a first drying tube 3, and an aerosol optical particle size spectrometer. The first air intake sampling port 1 is positioned 0.5 meters above the two propellers in the nose direction of the UAV airborne module 15 to minimize the impact of airflow disturbance during propeller rotation on sampling. The air intake pipe is fixed to the UAV airborne module 15. Specifically, the air intake pipe is a stainless steel pipe fixed to a mounting bracket at the front of the UAV nose, and the first air intake sampling port 1 is connected to the air intake pipe. The temperature sensor, humidity sensor, and pressure sensor are fixed to the outer wall of the air intake pipe through a sensor integration module 2. The temperature sensor, humidity sensor, and pressure sensor are all electrically connected to the airborne aerosol sampling module and are used to measure the atmospheric pressure, temperature, and relative humidity of the UAV at different altitudes online. One end of the first drying tube 3 is connected to the air intake pipe, and the other end of the first drying tube 3 is connected to the aerosol optical particle size spectrometer. The first drying tube 3 is a diffusion-type drying tube, and its drying efficiency can be controlled below 40% relative humidity. The first air intake sampling port 1 extends downward through the air intake pipe and into the black load box 18 located below the UAV onboard module through a small hole. The black load box 18 is used to load the onboard online measurement module 19 and the onboard aerosol sampling module. It continues to be connected to the first drying tube 3 through the air intake pipe for drying. The dried aerosol sample is then connected to an aerosol optical particle size spectrometer to measure the aerosol particle size distribution at different heights. The three-dimensional dissection diagram of the onboard online measurement module 19 is shown below. Figure 4 As shown, the entire airborne online measurement module 19 weighs only about 2 kilograms, effectively overcoming the problem that traditional online observation instruments, which weigh tens to hundreds of kilograms, cannot be mounted on UAV platforms.

[0050] The airborne aerosol sampling module includes a circuit control system 20, a sampling frame 9, and a sampling container 10. The sampling frame 9 is connected to the UAV airborne module 15. The circuit control system 20 is located between the airborne online measurement module and the sampling frame 9. The circuit control system 20 includes a second sampling air inlet, a third black rubber tube, a second drying tube 6, a solenoid valve 8, and a circuit integration system 7. The circuit integration system 7 includes a battery, a power distribution system, a microcontroller module, a remote communication module, and a data storage module. The battery is electrically connected to the power distribution system, which provides power to the microcontroller module, the remote communication module, and the data storage module. The data storage module is electrically connected to a temperature sensor, a humidity sensor, and a barometric pressure sensor via data lines to store atmospheric pressure, temperature, and relative humidity data collected by the temperature sensor, humidity sensor, and barometric pressure sensor at different altitudes. The microcontroller module is electrically connected to the remote communication module, which can communicate with the ground control equipment 16. The microcontroller module receives commands from the remote communication module to control the opening and closing of the solenoid valve 8.

[0051] Sampling container 10 is installed on sampling rack 9, such as Figure 5 As shown, the sampling container 10 is connected to two black rubber tubes, namely the first black rubber tube and the second black rubber tube. The sampling container 10 has two sampling ports, namely the first sampling port and the second sampling port. The first sampling port is connected to the first manual valve and the first black rubber tube in sequence, and the second sampling port is connected to the second manual valve and the second black rubber tube in sequence. The first and second black rubber tubes are connected by a Y-shaped tee. The third port of the Y-shaped tee is connected to the third black rubber tube, the solenoid valve 8, and the second drying tube 6 in sequence. The second drying tube 6 is connected to the second sampling air inlet 21, which is open to the atmosphere. The solenoid valve 8 is connected to the microcontroller module via a wire. The airborne aerosol sampling module is as follows... Figure 3 As shown in the figure. The sampling rack 9 and sampling container 10 are not included in this figure; key details of the sampling rack 9 and sampling container 10 are as follows: Figure 7-9 As shown.

[0052] The inner wall of the sampling container 10 is made of conductive copper foil, and the outer wall is made of PE film. The conductive copper foil and PE film together form a sampling bag (i.e., the sampling container, hereinafter referred to as the sampling bag). Connecting plates are provided on both sides of the PE film, and these connecting plates are connected to the sampling frame 9 via hooks 11. Specifically, the connecting plates are transparent PET plastic sheets, which serve to fix and support the bag. Two small holes are opened in the center of the plastic sheet, through which two hooks 11 are installed. Industrial tape is applied to the outside of the transparent PET plastic sheet to increase the strength of the bag.

[0053] The sampling frame 9 has a hexagonal star-shaped structure. Each corner of the sampling frame 9 has a groove along its edge, and a spring 13 is installed within each groove. The springs 13 at adjacent corners of the sampling frame 9 are connected by a steel wire 12. A ring 14 is attached to the steel wire 12. The sampling container 10 is connected to the ring 14 via a hook 11. The steel wire 12 is stretched by the spring 13. The sampling frame 9 and the sampling bag are as follows... Figure 7-9 As shown.

[0054] Before sampling, the manual valve is opened, and the solenoid valve 8 is closed, placing the sampling bag under negative pressure. Once the UAV reaches the designated altitude, the ground control device 16 communicates with the circuit control system 20, opening the solenoid valve 8 corresponding to the designated sampling bag in the circuit control system 20. This allows the sampling bag to automatically inflate and collect aerosol samples, achieving automatic sampling of aerosol samples at different altitudes. Both the airborne online measurement module 19 and the airborne aerosol sampling module are mounted on the UAV's airborne module 15. The airborne online measurement module 19 is on the upper layer, and the airborne aerosol sampling module is located below it. The airborne online measurement module 19 samples through the first sampling inlet, while the airborne aerosol sampling module samples through the second sampling inlet 21. A schematic diagram of the UAV's airborne module 15, airborne online measurement module 19, and airborne aerosol sampling module is shown below. Figure 2 , 5 As shown in Figure 6.

[0055] The ground-based online measurement module 17 is a particulate matter hygroscopicity and volatile matter analyzer (HTDMA, Bmet3000) manufactured by Secma Corporation. It is used to measure the hygroscopicity of aerosol samples brought back by the automatic aerosol sampling module, obtain the aerosol hygroscopic growth factor (GF) under different relative humidities, and provide basic data for the calculation of aerosol liquid water content.

[0056] Example 2

[0057] This embodiment provides a vertical in-situ measurement method for the liquid water content of aerosols, which employs a vertical in-situ measurement device and includes the following steps:

[0058] The UAV can fly to different altitudes by carrying an airborne online measurement module 19 and an airborne aerosol sampling module on its airborne module 15.

[0059] Airborne online measurement module 19 measures the aerosol particle size distribution at different altitudes;

[0060] The airborne aerosol sampling module collects aerosol particles at different altitudes and maintains their aerosol state before bringing them back to the ground.

[0061] The aerosol hygroscopic growth factor under different relative humidity conditions was obtained by measuring aerosol particles at different altitudes using the ground-based online measurement module 17.

[0062] The liquid water content of aerosols at different altitudes was calculated using the aerosol particle size distribution at different altitudes and the hygroscopic growth factor of aerosols at different altitudes.

[0063] The airborne online measurement module 19 includes two aerosol optical particle size spectrometers: a first aerosol optical particle size spectrometer 5 (Handix Scientific, POPS-1010) and a second aerosol optical particle size spectrometer 4 (GRIMM, GRIMM OPC 11-C, Germany). The first aerosol optical particle size spectrometer 5 and the second aerosol optical particle size spectrometer 4 are used to detect the aerosol particle size distribution in the range of 0.13-3 micrometers and 0.25-32 micrometers, respectively. By using the two aerosol optical particle size spectrometers in conjunction, the aerosol particle size distribution within the range of 0.13-32 micrometers at different heights can be directly measured online.

[0064] The sampling container 10 of the airborne aerosol sampling module is rinsed clean and evacuated before installation.

[0065] Before sampling, the sampling container 10 of the airborne aerosol sampling module is made to be under negative pressure. When the UAV airborne module 15 reaches the corresponding altitude, it flushes the sampling air inlet pipe of the online measurement module. After flushing, the channel solenoid valve 8 of the designated sampling container 10 is opened, so that the sampling container 10 is automatically inflated to collect aerosol samples, thereby realizing automatic sampling of aerosol samples at different altitudes.

[0066] The calculation method for the liquid water content of aerosols at different altitudes is as follows: The liquid water content of aerosols at different altitudes is calculated using the atmospheric relative humidity and aerosol particle size distribution collected by the airborne online measurement module 19, and the hygroscopicity of aerosols at different altitudes measured by the ground-based online measurement module 17. The calculation formula for the liquid water content of aerosols at different altitudes is as follows:

[0067] ,

[0068] N i The airborne online measurement module 19 collects the particle number concentration of dry particulate matter at different heights and with a certain particle size, D. i ρ is the diameter of the particle, GF is the hygroscopic growth factor of the particle at this diameter obtained by the ground-based online measurement module 17, RH is the atmospheric relative humidity at different altitudes collected by the airborne online measurement module, and ρ is the particle diameter of the particle. w The density of water is 1.0 g / cm³.

[0069] The parts not mentioned in this embodiment are the same as in Embodiment 1.

[0070] Specific application example 1

[0071] The airborne aerosol sampling module is located in a bracket directly below the UAV's onboard module 15. Depending on the observation requirements, it can carry 1-6 sampling bags for sampling through different channels. Each sampling bag has a volume of approximately 2 liters and is made with conductive copper foil nested within a composite membrane to reduce electrostatic adsorption loss of particles. Before takeoff, the sampling bags are repeatedly flushed with nitrogen and then emptied and compressed using a vacuum pump. Once the UAV's onboard module 15 reaches the designated altitude, the ground control equipment 16 communicates with the circuit control system to open the solenoid valve 8 corresponding to the designated sampling bag, automatically inflating the bag to collect aerosol samples. Aerosol particles experience diffusion and sedimentation losses within the sampling bags; the particle size loss rate has been calibrated and corrected at the laboratory level. Simultaneously, the online aerosol module's measurement of the particle size distribution during sampling can also be used to estimate the particle loss rate within the sampling bags.

[0072] Specific application example 2

[0073] The UAV's onboard module 15 first ascends to 1 kilometer and then descends to conduct sampling measurements. During the descent, it pauses for 120 seconds at each of six altitudes, including the ground, to automatically collect samples from the sampling bags, while other equipment performs real-time measurements according to their respective time resolutions. Vertical observations of all parameters on the UAV's onboard module 15 are completed within 20 minutes. During the vertical observations, the ground-based online measurement module 17 simultaneously and continuously observes the hygroscopicity of surface particulate matter. After the UAV completes the vertical observations and lands back on the ground, the sampling bags are removed and immediately connected to ground instruments. The hygroscopicity parameters of different particle sizes in aerosol samples at different vertical altitudes are measured sequentially from top to bottom at 85% relative humidity.

[0074] Specific application example 3

[0075] The core observations at the ground station focused on measuring the hygroscopicity of particulate matter. Based on the observed data on aerosol particle size distribution, hygroscopicity, and the vertical distribution of ambient relative humidity, the difference in mass of aerosols before and after hygroscopic absorption was calculated. The liquid water content of aerosols was calculated by particle size integration, ultimately obtaining the vertical distribution data of aerosol liquid water content. Simultaneously, the vertical distribution characteristics and temporal variation patterns of aerosol liquid water content under different pollution and meteorological conditions were analyzed, and key influencing factors were explored.

[0076] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A vertical in-situ measurement device for the liquid water content of aerosols, characterized in that: It includes an UAV onboard module, an onboard online measurement module, an onboard aerosol sampling module, a ground-based online measurement module, and ground control equipment. The onboard online measurement module and the onboard aerosol sampling module are both mounted on the UAV onboard module; the UAV onboard module, the onboard online measurement module, and the onboard aerosol sampling module are all connected to the ground control equipment. The UAV-borne module is used to propel the onboard online measurement module and the onboard aerosol sampling module to different altitudes. The airborne online measurement module is used to measure ambient temperature, relative humidity, air pressure, and aerosol particle size distribution at different altitudes. The airborne aerosol sampling module is used to collect aerosol particles at different altitudes and maintain their aerosol state to bring them back to the ground. The hygroscopicity of the aerosol samples is measured using the ground-based online measurement module to obtain the aerosol hygroscopic growth factor under different relative humidities. The liquid water content of aerosols at different altitudes was calculated using the relative humidity of the environment at different altitudes, the aerosol particle size distribution, and the hygroscopic growth factor of aerosols at different altitudes.

2. The vertical in-situ measurement device for aerosol liquid water content according to claim 1, characterized in that: The airborne online measurement module includes a first air intake sampling port, an air intake pipe, a temperature sensor, a humidity sensor, a pressure sensor, a first drying tube, and an aerosol optical particle size spectrometer. The first air intake sampling port is located 0.5 meters above the two propellers in the nose direction of the UAV's onboard module. The air intake pipe is fixed to the UAV's onboard module, and the first air intake sampling port is connected to the air intake pipe. The temperature sensor, humidity sensor, and pressure sensor are fixed to the outer wall of the air intake pipe and are all electrically connected to the airborne aerosol sampling module. They are used to measure the atmospheric pressure, temperature, and relative humidity of the UAV at different altitudes online. One end of the first drying tube is connected to the air intake pipe, and the other end of the first drying tube is connected to the aerosol optical particle size spectrometer.

3. The vertical in-situ measurement device for aerosol liquid water content according to claim 2, characterized in that: The airborne aerosol sampling module includes a circuit control system, a sampling frame, and a sampling container. The sampling frame is connected to the UAV's onboard module. The circuit control system is located between the airborne online measurement module and the sampling frame. The circuit control system includes a second sampling air inlet, a third black rubber tube, a second drying tube, a solenoid valve, and a circuit integration system. The circuit integration system includes a battery, a power distribution system, a microcontroller module, a remote communication module, and a data storage module. The battery is electrically connected to the power distribution system, which provides power to the microcontroller module, remote communication module, and data storage module. The microcontroller module is electrically connected to the remote communication module, which can communicate with ground control equipment. The data storage module... The storage module is electrically connected to the temperature sensor, humidity sensor, and barometric pressure sensor via data cables to store atmospheric pressure, temperature, and relative humidity data collected by the temperature sensor, humidity sensor, and barometric pressure sensor at different altitudes. The sampling container is installed on the sampling frame and has a first sampling port and a second sampling port. The first sampling port is connected to a first manual valve and a first black rubber tube in sequence, and the second sampling port is connected to a second manual valve and a second black rubber tube in sequence. The first black rubber tube and the second black rubber tube are connected by a Y-shaped tee. The third port of the Y-shaped tee is connected to a third black rubber tube, a solenoid valve, and a second drying tube in sequence. The second drying tube is connected to a second sampling air inlet, which is open to the atmosphere. The solenoid valve is connected to the microcontroller module via wires. The microcontroller module receives instructions from the remote communication module to control the opening and closing of the solenoid valve.

4. The vertical in-situ measurement device for aerosol liquid water content according to claim 3, characterized in that: The inner wall of the sampling container is made of conductive copper foil, and the outer wall of the sampling container is made of PE film. There are connecting plates on both sides of the PE film, and the connecting plates are connected to the sampling frame through hooks.

5. The vertical in-situ measurement device for aerosol liquid water content according to claim 3, characterized in that: The sampling frame has a hexagonal star-shaped structure. Each corner of the sampling frame has a groove on its edge, and a spring is installed in the groove. The springs of two adjacent corners of the sampling frame are connected by a steel wire, and a ring is attached to the steel wire. The sampling container is connected to the ring by a hook, and the steel wire is stretched by the spring force.

6. A vertical in-situ measurement method for the liquid water content of aerosols, characterized in that, The method using the vertical in-situ measuring device according to any one of claims 1-5 includes the following steps: The drone was equipped with an airborne online measurement module and an airborne aerosol sampling module and flew to different altitudes. The airborne online measurement module measures the atmospheric relative humidity and aerosol particle size distribution at different altitudes; The airborne aerosol sampling module collects aerosol particles at different altitudes and maintains their aerosol state before bringing them back to the ground. Aerosol particulate matter at different altitudes was measured using a ground-based online measurement module to obtain the aerosol hygroscopic growth factor under different relative humidity levels. The liquid water content of aerosols at different altitudes was calculated using atmospheric relative humidity, aerosol particle size distribution, and hygroscopic growth factor of aerosols at different altitudes.

7. The vertical in-situ measurement method for the liquid water content of aerosols according to claim 6, characterized in that: The airborne online measurement module includes two aerosol optical particle size spectrometers, namely the first aerosol optical particle size spectrometer and the second aerosol optical particle size spectrometer. The first aerosol optical particle size spectrometer and the second aerosol optical particle size spectrometer are used to detect the aerosol particle size distribution in the range of 0.13-3 micrometers and 0.25-32 micrometers, respectively.

8. The vertical in-situ measurement method for the liquid water content of aerosols according to claim 6, characterized in that: The sampling container of the airborne aerosol sampling module is rinsed clean and evacuated before installation.

9. A vertical in-situ measurement method for the liquid water content of aerosols according to claim 6, characterized in that: Before sampling, the sampling container of the airborne aerosol sampling module is placed under negative pressure. When the UAV airborne module reaches the corresponding altitude, the solenoid valve corresponding to the sampling container is opened to automatically inflate the sampling container and collect aerosol samples, thus realizing automatic sampling of aerosol samples at different altitudes.

10. A vertical in-situ measurement method for the liquid water content of aerosols according to claim 6, characterized in that, The calculation method for the liquid water content of aerosols at different altitudes is as follows: The liquid water content of aerosols at different altitudes is calculated using the atmospheric relative humidity and aerosol particle size distribution collected by the airborne online measurement module, and the hygroscopic growth factor of aerosols at different altitudes measured by the ground-based online measurement module. The calculation formula for the liquid water content of aerosols at different altitudes is as follows: ， N i The airborne online measurement module collects the particle number concentration of dry particulate matter at a certain particle size at different altitudes, D i is the particle diameter, GF is the hygroscopic growth factor of the particulate matter at the particle size obtained by the ground online measurement module, RH is the relative humidity of the atmosphere at different altitudes measured by the airborne online measurement module, and ρ w The water density is 1.0 g / cm³.

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