Method and device for measuring concentration of cloud condensation nucleus in atmospheric environment

Abstract

The invention discloses a method and a device for measuring the concentration of cloud condensation nuclei in an atmospheric environment. A drying tube, a first optical particle spectrometer and a second optical particle spectrometer are adopted to obtain the particle size distribution of the dried aerosol and the particle size distribution of the non-dried aerosol, and the moisture absorption growth factor is obtained through inversion by means of the measured particle size spectrum distribution of the whole aerosol; the second total scattering intensity is obtained by directly adopting the scattering intensity distribution spectrum obtained by calculation of the wet particle size aerosol, the first total scattering intensity is obtained by combining the dry particle size aerosol with the scattering intensity distribution spectrum obtained by calculation of the moisture absorption growth model, and the moisture absorption growth factor is obtained by inversion through a gradient descent method; calculating the concentration of the cloud condensation nucleus by combining the critical diameter of the aerosol and the concentration after drying; the instrument cost is remarkably reduced, a humidifying unit is not needed to control the humidity of instrument equipment, and the maintenance difficulty is remarkably reduced; according to the method, the moisture absorption growth factor is obtained through inversion by means of the measured particle size spectrum distribution of the whole aerosol, errors are smaller, and the cloud condensation nucleus concentration obtained through follow-up calculation is more accurate.

Description

Technical Field

[0001] This invention relates to cloud condensation nucleus measurement technology, specifically to a method and apparatus for measuring the concentration of cloud condensation nuclei in the atmospheric environment. Background Technology

[0002] Cloud condensation nuclei (CCNs) are a component of atmospheric aerosols, specifically referring to aerosols in the atmosphere that, under supersaturated conditions (relative humidity exceeding 100%), can cause water vapor to condense on their surfaces to form cloud droplets. CCN formation is closely related to aerosol particle size and chemical composition. CCNs not only influence cloud formation and precipitation processes but also indirectly affect the climate system by altering cloud radiation characteristics. Therefore, accurately measuring atmospheric CCN number concentration is of great significance for understanding weather processes, climate change, aerosol-cloud interactions, and weather modification. Currently, international methods for measuring CCN number concentration (N... CCN The primary method used is a cloud condensation nucleus counter manufactured by an American company. However, the difficulty in maintaining this equipment and its high cost severely limit the observation and research of cloud condensation nucleus characteristics. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention proposes a method and device for measuring the concentration of cloud condensation nuclei in the atmospheric environment. The method utilizes measurement data from two optical particle size spectrometers (OPS) to invert the concentration of cloud condensation nuclei, which has the advantages of high measurement time resolution, simple equipment, easy maintenance, and can meet the needs of aircraft observation and vertical observation.

[0004] One object of the present invention is to provide a method for measuring the concentration of cloud condensation nuclei in the atmospheric environment.

[0005] The method for measuring the concentration of cloud condensation nuclei in the atmospheric environment according to the present invention includes the following steps:

[0006] 1) Measuring device:

[0007] After sampling the environmental aerosols at the sampling port, they were divided into two paths. One path passed through a drying tube, and the particle size distribution PNSD1 of the dried aerosol was measured using the first optical particle spectrometer OPS1. The temperature T1 and relative humidity RH1 of the dried aerosol were measured using the first temperature and humidity probe. The other path was not dried, and the particle size distribution PNSD2 of the undried aerosol was directly measured using the second optical particle spectrometer OPS2. At the same time, the temperature T2 and relative humidity RH2 of the undried inlet of the gas path, as well as the temperature T3 and relative humidity RH3 of the undried outlet of the gas path, were measured using the second and third temperature and humidity probes before and after the second optical particle spectrometer OPS2, respectively.

[0008] 2) Calculate the equivalent relative humidity:

[0009] Using the undried inlet temperature T2 and the undried inlet relative humidity RH2, the water vapor content e2 at the inlet of the second optical particle spectrometer OPS2 is calculated as follows:

[0010]

[0011] Using the undried outlet temperature T3 and the undried outlet relative humidity RH3, the outlet water vapor content e3 of the second optical particle spectrometer OPS2 is calculated as follows:

[0012]

[0013] The equivalent water content e0 in the second optical particle spectrometer OPS2 is obtained as follows:

[0014]

[0015] The equivalent temperature T0 in the second optical particle spectrometer OPS2 is:

[0016]

[0017] Using the equivalent temperature T0 and equivalent water content e0 in the second optical particle spectrometer OPS2, calculate the equivalent relative humidity RH0 of the aerosol in the second optical particle spectrometer OPS2:

[0018]

[0019] 3) The hygroscopic growth factor was obtained through inversion:

[0020] Based on the particle size distributions PNSD1 and PNSD2 of the dried aerosol, the equivalent relative humidity RH0 of the aerosol in the second optical particle spectrometer OPS2, and the commonly used complex refractive index RI0 of aerosol, the hygroscopic growth factor κ of the aerosol is calculated using the following method:

[0021] (1) The second total scattering intensity S2 is obtained by directly using the scattering intensity distribution spectrum calculated from wet particle size aerosol:

[0022] a. Particle size distribution of undried aerosols. PNSD2 represents different particle sizes Dp1, Dp2, ... Dp n The undried concentrations of the aerosols were N 21 N 22 …N 2n n is the number of different particle size types;

[0023] b. Using the Mie scattering model, the commonly used complex refractive index combinations for calculating particle size and aerosols are (Dp1,RI0), (Dp2,RI0)...(Dp... n The scattering intensities under RI0) are S 21 ,S 22 …S 2n The corresponding scattering intensity distribution spectrum S′ is obtained directly from wet particle size aerosol calculations. 2i for:

[0024] c. Based on the scattering intensity distribution spectrum obtained directly from wet particle size aerosols, the corresponding second total scattering intensity S2 is:

[0025]

[0026] (2) The first total scattering intensity S1 is obtained by calculating the scattering intensity distribution spectrum of dry particle size aerosol combined with the hygroscopic growth model:

[0027] a. An initial value for the hygroscopic growth factor is arbitrarily set. The particle size distribution after aerosol drying, PNSD1, represents different particle sizes Dp1, Dp2, ... Dp. n The concentrations of the dried aerosols were N 11 N 12 …N 1n ;

[0028] b. Using Capacola (κ- Theoretical formulas are used to calculate the aerosol particle sizes Dp1, Dp2, ... Dp under conditions of relative humidity RH1 to equivalent relative humidity RH0 and equivalent temperature T0 after drying. n Particle size Dp after hygroscopic growth at equivalent relative humidity 11 ,Dp 12 ,…Dp 1n ;

[0029] c. Calculate the particle size Dp of the corresponding aerosol after the i-th wet growth using the volume-weighted average method. 1i Complex refractive index RI of aerosols 1i :

[0030] Where i = 1, 2, ..., n

[0031] Among them, RI water is the complex refractive index of water;

[0032] d. Using the Mie scattering model, the particle size and complex refractive index combination of the aerosol after wet growth were calculated to be (Dp1, RI) 11 ), (Dp 12 ,RI12 ...(Dp) 1n ,RI 1n The scattering intensities under the following conditions are S 11 ,S 12 …S 1n The corresponding scattering intensity distribution spectrum S′ calculated using a dry particle size aerosol combined with a hygroscopic growth model. 1i for:

[0033] e. Based on the scattering intensity distribution spectrum calculated using the dry particle size aerosol combined with the hygroscopic growth model, the corresponding first total scattering intensity S1 is:

[0034]

[0035] (3) The first total scattering intensity S1 and the second total scattering intensity S2 are essentially the same, both being the total scattering intensity of wet particle size aerosols. The initial value of the hygroscopic growth factor is changed by using the gradient descent method until the first total scattering intensity S1 and the second total scattering intensity S2 are equal or the deviation between them is less than a set threshold. When this condition is met, the value of the hygroscopic growth factor κ0 is the aerosol hygroscopic growth factor obtained by the final inversion.

[0036] 4) Calculate the critical diameter of the aerosol:

[0037] Using the aerosol hygroscopic growth factor obtained from step 3), calculate the critical diameter Dc of the aerosol at a given supersaturation ratio ss:

[0038] Dc=exp(-0.33log(κ)-3.73-0.667log(ss))

[0039] 5) Calculate the concentration of cloud condensation nuclei:

[0040] Calculate the cloud condensation nucleus concentration N by combining the critical diameter of the aerosol and the concentration of the aerosol after drying. CCN :

[0041]

[0042] Where i = 1, ..., n.

[0043] In step 3), (2) the initial value of any hygroscopic growth factor is 0.01 to 1. n is 32 or 64, which is the number of particle size types measured in the aerosol particle size distribution. The number of particle size types n is different for different optical particle spectrometer OPS models.

[0044] Capakola The theoretical formula is:

[0045]

[0046] Among them, Dp 1i Let Dp be the particle size after hygroscopic growth at the i-th equivalent relative humidity. i Let σ represent the i-th particle size, κ be the hygroscopic growth factor of the aerosol, reflecting the hygroscopic growth capacity of the aerosol itself, and σ be the hygroscopic growth factor. s / a R is the surface tension of the aerosol. Under high relative humidity, this value is usually taken to be equal to the surface tension of water. R is Avogadro's constant, and M is... water Let ρ be the molar mass of water, T0 be the equivalent temperature, and ρ be the molar mass of water. w This is the density of water.

[0047] In step 3), (6) the threshold is set to 10. -6 ~10 -5 .

[0048] Another objective of this invention is to provide a device for measuring the concentration of cloud condensation nuclei in the atmospheric environment.

[0049] The atmospheric cloud condensation nucleus concentration measuring device of the present invention includes: a drying tube, first and second optical particle spectrometers, and first and third temperature and humidity probes; wherein, the inlet of the environmental aerosol is connected via pipes to the inlet of the drying tube and the air inlet of the second optical particle spectrometer; the outlet of the drying tube is connected to the air inlet of the first optical particle spectrometer; a first temperature and humidity probe is installed at the inlet of the first optical particle spectrometer; a second and a third temperature and humidity probe are installed at the air inlet and outlet of the second optical particle spectrometer, respectively; after sampling, the environmental aerosol is divided into two paths, one of which passes through the drying tube and is then measured by the first optical particle spectrometer. The particle size distribution of the aerosol after drying was measured using a first temperature and humidity probe, which measured the temperature and relative humidity of the dried aerosol. In another path, the aerosol was not dried; the particle size distribution of the undried aerosol was directly measured using a second optical particle spectrometer. Simultaneously, before and after the second optical particle spectrometer, the temperature and relative humidity of the undried inlet and outlet of the undried aerosol were measured using second and third temperature and humidity probes, respectively. The equivalent relative humidity was calculated based on the inlet and outlet temperatures and humidity readings from the second optical particle spectrometer. The particle size distribution was then measured using a Capacitor (κ-) probe. The theoretical formula calculates the particle size of aerosols after hygroscopic growth under equivalent relative humidity for each particle size. The first total scattering intensity is obtained by calculating the scattering intensity distribution spectrum of dry particle size aerosols combined with the hygroscopic growth model. The second total scattering intensity is obtained by directly calculating wet particle size aerosols. The initial value of the hygroscopic growth factor is changed using the gradient descent method until the first and second total scattering intensities are equal or their deviation is less than a set threshold. The value of the hygroscopic growth factor when this condition is met is the hygroscopic growth factor of the aerosol obtained by inversion. Based on the hygroscopic growth factor of the aerosol, the critical diameter of the aerosol at a given supersaturation ratio is calculated. Combining the critical diameter of the aerosol and the concentration of the aerosol after drying, the concentration of cloud condensation nuclei is calculated.

[0050] Advantages of this invention:

[0051] This invention employs a drying tube and first and second optical particle spectrometers to obtain the particle size distribution of aerosols after drying and before drying. The hygroscopic growth factor is obtained by inverting the measured particle size distribution of the entire aerosol. This invention does not use a differential electromigration analyzer, significantly reducing instrument costs. Furthermore, it eliminates the need for a humidification unit to control the humidity of the instrument, significantly reducing maintenance difficulty. The inversion method of this invention uses the measured particle size distribution of the entire aerosol to obtain the hygroscopic growth factor, resulting in smaller errors and more accurate calculations of cloud condensation nucleus concentration. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the atmospheric cloud condensation nucleus concentration measuring device of the present invention;

[0053] Figure 2 This is a flowchart of the atmospheric environment cloud condensation nucleus concentration measurement method of the present invention. Detailed Implementation

[0054] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0055] The method for measuring the concentration of atmospheric cloud condensation nuclei in this embodiment, such as... Figure 2 As shown, it includes the following steps:

[0056] 1) Measuring device:

[0057] like Figure 1As shown, after sampling the environmental aerosol from the sampling port, it is divided into two paths. One path passes through a drying tube, and the particle size distribution PNSD1 of the dried aerosol is measured using the first optical particle spectrometer OPS1. The temperature T1 and relative humidity RH1 of the dried aerosol are measured using the first temperature and humidity probe. The other path is not dried, and the particle size distribution PNSD2 of the undried aerosol is directly measured using the second optical particle spectrometer OPS2. At the same time, the temperature T2 and relative humidity RH2 of the undried inlet of the gas path, and the temperature T3 and relative humidity RH3 of the undried outlet of the gas path are measured using the second and third temperature and humidity probes before and after the second optical particle spectrometer OPS2, respectively.

[0058] 2) Calculate the equivalent relative humidity:

[0059] The second optical particle spectrum was calculated using the undried inlet temperature T2 and the undried inlet relative humidity RH2.

[0060] The water vapor content e2 at the inlet of instrument OPS2 is:

[0061]

[0062] The second optical particle spectrum was calculated using the undried outlet temperature T3 and the undried outlet relative humidity RH3.

[0063] The water vapor content e3 at the outlet of instrument OPS2 is:

[0064]

[0065] The equivalent water content e0 in the second optical particle spectrometer OPS2 is obtained as follows:

[0066]

[0067] The equivalent temperature T0 in the second optical particle spectrometer OPS2 is:

[0068]

[0069] Using the equivalent temperature T0 and equivalent water content e0 in the second optical particle spectrometer OPS2, calculate the equivalent relative humidity RH0 of the aerosol in the second optical particle spectrometer OPS2.

[0070]

[0071] 3) Hygroscopic growth factor κ:

[0072] (1) The second total scattering intensity S2 is obtained by directly using the scattering intensity distribution spectrum of wet particle size aerosol:

[0073] a. Particle size distribution of undried aerosols. PNSD2 represents different particle sizes Dp1, Dp2, ... Dp n The undried concentrations of the aerosols were N 21 N 22 …N 2n n is the number of different particle size types;

[0074] b. Using the Mie scattering model, the commonly used complex refractive index combinations for calculating particle size and aerosols are (Dp1,RI0), (Dp2,RI0)...(Dp... n The scattering intensities under RI0) are S 21 ,S 22 …S 2n RI0 = 1.46; the corresponding scattering intensity distribution spectrum S′ is obtained directly from wet particle size aerosol calculation. 2i for:

[0075] c. Based on the scattering intensity distribution spectrum obtained directly from wet particle size aerosols, the corresponding second total scattering intensity S2 is:

[0076]

[0077] (2) The first total scattering intensity S1 is obtained by calculating the scattering intensity distribution spectrum of dry particle size aerosol combined with the hygroscopic growth model:

[0078] a. An initial value for the hygroscopic growth factor is arbitrarily set. The particle size distribution after aerosol drying, PNSD1, represents different particle sizes Dp1, Dp2, ... Dp. n The concentrations of the dried aerosols were N 11 N 12 …N 1n ;

[0079] b. Using Capacola The theoretical formula calculates the aerosol particle sizes Dp1, Dp2, ... Dp under the conditions of relative humidity RH1 to equivalent relative humidity RH0 and equivalent temperature T0 after drying. n Particle size Dp after hygroscopic growth at equivalent relative humidity 11 ,Dp 12 ,…Dp 1n :

[0080]

[0081] Among them, Dp 1i Let Dp be the particle size after hygroscopic growth at the i-th equivalent relative humidity. i Let σ represent the i-th particle size, κ be the hygroscopic growth factor of the aerosol, reflecting the hygroscopic growth capacity of the aerosol itself, and σ be the hygroscopic growth factor.s / a R is the surface tension of the aerosol. Under high relative humidity, this value is usually taken to be equal to the surface tension of water. R is Avogadro's constant, and M is... water Let ρ be the molar mass of water, T0 be the equivalent temperature, and ρ be the molar mass of water. w The density of water;

[0082] c. Calculate the particle size Dp of the corresponding aerosol after the i-th wet growth using the volume-weighted average method. 1i Complex refractive index RI of aerosols 1i :

[0083] Where i = 1, 2, ..., n

[0084] Among them, RI water is the complex refractive index of water;

[0085] d. Using the Mie scattering model, the particle size and complex refractive index combination of the aerosol after wet growth were calculated to be (Dp1, RI) 11 ), (Dp 12 ,RI 12 ...(Dp) 1n ,RI 1n The scattering intensities under the following conditions are S 11 ,S 12 …S 1n The corresponding scattering intensity distribution spectrum S′ calculated using a dry particle size aerosol combined with a hygroscopic growth model. 1i for:

[0086] e. Based on the scattering intensity distribution spectrum calculated using the dry particle size aerosol combined with the hygroscopic growth model, the corresponding first total scattering intensity S1 is:

[0087]

[0088] (3) The first total scattering intensity S1 and the second total scattering intensity S2 are essentially the same, both being the total scattering intensity of wet particle aerosols. The initial value of the hygroscopic growth factor is changed using the gradient descent method until the first total scattering intensity S1 and the second total scattering intensity S2 are equal or their deviation is less than 10. -5 The value of the hygroscopic growth factor κ0 when this condition is met is the aerosol hygroscopic growth factor obtained by the final inversion.

[0089] 4) Calculate the critical diameter of the aerosol:

[0090] Using the aerosol hygroscopic growth factor obtained from the final inversion in step 3), calculate the critical diameter Dc of the aerosol at given supersaturation ratios ss = 0.4%, 0.1%, and 0.2%, respectively:

[0091] Dc=exp(-0.33log(κ)-3.73-0.667log(ss))

[0092] 5) Calculate the concentration of cloud condensation nuclei:

[0093] Calculate the cloud condensation nucleus concentration by combining the critical diameter of the aerosol and the concentration of the aerosol after drying:

[0094]

[0095] Where i = 1, ..., n, n = 32.

[0096] Finally, it should be noted that the purpose of disclosing the embodiments is to help further understand the present invention. However, those skilled in the art will understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the scope of protection of the present invention is defined by the claims.

Claims

1. A method for measuring the concentration of cloud condensation nuclei in the atmospheric environment, characterized in that, The measurement method includes the following steps: 1) Measuring device: After sampling the environmental aerosols at the inlet, they were divided into two paths. One path passed through a drying tube, and the particle size distribution PNSD1 of the dried aerosol was measured using a first optical particle spectrometer. The temperature T1 and relative humidity RH1 of the dried aerosol were also measured. The other path was not dried, and the particle size distribution PNSD2 of the undried aerosol was measured directly using a second optical particle spectrometer. At the same time, the temperature T2 and relative humidity RH2 of the undried inlet, as well as the temperature T3 and relative humidity RH3 of the undried outlet, were measured before and after the second optical particle spectrometer, respectively. 2) Calculate the equivalent relative humidity: Using the temperature and relative humidity of the undried inlet and outlet, the water vapor content of the inlet and outlet is calculated to obtain the equivalent water content and equivalent temperature in the second optical particle spectrometer, and then the equivalent relative humidity of the aerosol in the second optical particle spectrometer is calculated. 3) Hygroscopic growth factor κ: (1) The second total scattering intensity S2 is obtained by directly using the scattering intensity distribution spectrum calculated from wet particle size aerosol; (2) Obtain the particle size after hygroscopic growth under equivalent relative humidity, and obtain the first total scattering intensity S1 by calculating the scattering intensity distribution spectrum of dry particle size aerosol combined with hygroscopic growth model. (3) Use the gradient descent method to change the initial value of the hygroscopic growth factor until the first total scattering intensity S1 and the second total scattering intensity S2 are equal or the deviation between them is less than the set threshold. When this condition is met, the value of the hygroscopic growth factor is the aerosol hygroscopic growth factor obtained by the final inversion. 4) Calculate the critical diameter of the aerosol: Using the aerosol hygroscopic growth factor obtained from step 3), calculate the critical diameter Dc of the aerosol at a given supersaturation ratio ss. 5) Calculate the concentration of cloud condensation nuclei: Calculate the cloud condensation nucleus concentration N by combining the critical diameter of the aerosol and the concentration of the aerosol after drying. CCN .

2. The measurement method as described in claim 1, characterized in that, In step 2), the equivalent relative humidity is calculated, including the following steps: a) Using the undried inlet temperature T2 and the undried inlet relative humidity RH2, calculate the water vapor content e2 at the inlet of the second optical particle spectrometer as follows: b) Using the undried outlet temperature T3 and the undried outlet relative humidity RH3, calculate the outlet water vapor content e3 of the second optical particle spectrometer as follows: c) The equivalent water content e0 in the second optical particle spectrometer is obtained as follows: d) The equivalent temperature T0 in the second optical particle spectrometer is: e) Using the equivalent temperature T0 and equivalent water content e0 in the second optical particle spectrometer, calculate the equivalent relative humidity RH0 of the aerosol in the second optical particle spectrometer OPS2:

3. The measurement method as described in claim 1, characterized in that, In step 3), (1) the second total scattering intensity S2 is obtained directly from the scattering intensity distribution spectrum calculated using wet particle size aerosol, including the following steps: a. Particle size distribution of undried aerosols. PNSD2 represents different particle sizes Dp1, Dp2, ... Dp n The undried concentrations of the aerosols were N 21 N 22 …N 2n n represents the number of different particle sizes; b. Using the Mie scattering model, the commonly used complex refractive index combinations for particle size and aerosols are (Dp1,RI0), (Dp2,RI0)...(Dp... n The scattering intensities under RI0) are S 21 ,S 22 …S 2n The corresponding scattering intensity distribution spectrum S′ is obtained directly from wet particle size aerosol calculations. 2i for: c. Based on the scattering intensity distribution spectrum obtained directly from wet particle size aerosols, the corresponding second total scattering intensity S2 is:

4. The measurement method as described in claim 1, characterized in that, In step 3), (2) the first total scattering intensity S1 is obtained by calculating the scattering intensity distribution spectrum of dry particle size aerosol combined with the hygroscopic growth model, including the following steps: a. An initial value for the hygroscopic growth factor is arbitrarily set. The particle size distribution after aerosol drying, PNSD1, represents different particle sizes Dp1, Dp2, ... Dp. n The concentrations of the dried aerosols were N 11 N 12 …N 1n ; b. Using the Capacola theory, calculate the aerosol particle sizes Dp1, Dp2, ... Dp under conditions of relative humidity RH1 to equivalent relative humidity RH0 and equivalent temperature T0 after drying. n Particle size Dp after hygroscopic growth at equivalent relative humidity 11 ,Dp 12 ,…Dp 1n ; c. Calculate the particle size Dp of the corresponding aerosol after the i-th wet growth using the volume-weighted average method. 1i Complex refractive index RI of aerosols 1i : Where i = 1, 2, ..., n Among them, RI water is the complex refractive index of water; d. Using the Mie scattering model, the particle size and complex refractive index combination of the aerosol after wet growth are calculated to be (Dp1, RI). 11 ), (Dp 12 ,RI 12 ...(Dp) 1n ,RI 1n The scattering intensities under the following conditions are S 11 ,S 12 …S 1n The corresponding scattering intensity distribution spectrum S′ calculated using a dry particle size aerosol combined with a hygroscopic growth model. 1i for: e. Based on the scattering intensity distribution spectrum calculated using the dry particle size aerosol combined with the hygroscopic growth model, the corresponding first total scattering intensity S1 is:

5. The measurement method as described in claim 1, characterized in that, In step 3), (2) the initial value of the hygroscopic growth factor is 0.01 to 1.

6. The measurement method as described in claim 1, characterized in that, In step 3), (3) the threshold is set to 10. -6 ~10 -5 .

7. The measurement method as described in claim 1, characterized in that, In step 4), the critical diameter Dc of the aerosol at a given supersaturation ratio ss is calculated to satisfy: Dc=exp(-0.33log(κ)-3.73-0.667log(ss)).

8. The measurement method as described in claim 1, characterized in that, In step 5), the concentration of the dried aerosol is N 11 N 12 …N 1n Calculate the concentration of cloud condensation nuclei N CCN satisfy: Where i = 1,...,n, Dp i Let be the particle size of the i-th particle.

9. A measuring device for the concentration of atmospheric cloud condensation nuclei, characterized in that, The measuring device includes: a drying tube, first and second optical particle spectrometers, and first to third temperature and humidity probes; wherein, the inlet of the environmental aerosol is connected to the inlet of the drying tube and the air inlet of the second optical particle spectrometer via pipes; the outlet of the drying tube is connected to the air inlet of the first optical particle spectrometer; the first temperature and humidity probe is installed at the inlet of the first optical particle spectrometer; the second and third temperature and humidity probes are installed at the air inlet and outlet of the second optical particle spectrometer, respectively; after sampling, the environmental aerosol is divided into two paths, one path passes through the drying tube, and the particle size distribution of the dried aerosol is measured using the first optical particle spectrometer, and the temperature and relative humidity of the dried aerosol are measured using the first temperature and humidity probes; The other path is not dried. The particle size distribution of the undried aerosol is directly measured using a second optical particle spectrometer. Simultaneously, before and after the second optical particle spectrometer, the temperature and relative humidity of the undried inlet and outlet are measured using second and third temperature and humidity probes, respectively. The equivalent relative humidity is calculated based on the inlet and outlet temperatures and humidity from the second optical particle spectrometer. The particle size after moisture absorption and growth at the equivalent relative humidity is calculated using the Capacitor theory formula. The first total scattering intensity is obtained by calculating the scattering intensity distribution spectrum of the dry particle size aerosol combined with the moisture absorption and growth model. The second total scattering intensity is directly calculated using wet particle size aerosols. The initial value of the hygroscopic growth factor is changed using the gradient descent method until the first and second total scattering intensities are equal or their deviation is less than a set threshold. The value of the hygroscopic growth factor when this condition is met is the final inversion value of the aerosol hygroscopic growth factor. Based on the aerosol hygroscopic growth factor, the critical diameter of the aerosol at a given supersaturation ratio is calculated. Combining the critical diameter of the aerosol and the concentration of the aerosol after drying, the cloud condensation nucleus concentration is calculated.

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