Method for identifying mixed aerosol

Abstract

The invention discloses a mixed aerosol identification method, which comprises the following steps: acquiring aerosol optical parameters in a to-be-measured environment, and calculating to obtain a mixed aerosol depolarization ratio, a mixed aerosol radar ratio and mixed sol fluorescence capability based on the aerosol optical parameters; and based on the aerosol depolarization ratio, the aerosol radar ratio and the aerosol fluorescence capability, combining a preset threshold value to identify aerosol types contained in the mixed aerosol. According to the method, the aerosol types contained in the mixed aerosol can be recognized, the proportions of all types of aerosol can be recognized, then the back scattering coefficients and the extinction coefficients of the aerosol corresponding to the different aerosol types are determined, and therefore reliable data support is provided for atmospheric environment research.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent environmental monitoring, and in particular to a method for identifying a mixed aerosol. Background Art

[0002] Studying the physical and chemical properties and content of atmospheric aerosols is crucial to understanding their impact on the Earth's radiation balance and climate. In nature, aerosols exist in the atmosphere in the form of a mixture of multiple types, and the physical and chemical properties of different types of aerosols vary greatly. Therefore, in order to simplify the complexity of aerosol composition, it is necessary to classify aerosol types, that is, to identify and classify mixed aerosols. At present, common aerosol types in the atmospheric environment include urban haze, dust aerosols, sea salt aerosols, and biomass burning aerosols.

[0003] In order to understand the aerosols in the atmospheric environment, polarized Raman lidar can be used for observation to obtain the optical characteristic parameters of the aerosols. The observed optical characteristic parameters of the aerosols can be used as input for the aerosol classification scheme to facilitate analysis and determination of the corresponding aerosol type.

[0004] Aerosols in the atmosphere usually come from multiple sources, resulting in different types of aerosols usually mixed in the atmosphere to form mixed aerosols. In order to understand the impact of different aerosol types in mixed aerosols, it is necessary to quantify the content of each type of aerosol in the atmosphere.

[0005] However, there is currently no technical solution that can effectively identify different types of aerosols in the atmospheric environment, resulting in the inability to quantitatively analyze information such as the content of aerosols in the atmospheric environment.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a method for identifying a mixed aerosol, so as to effectively identify the type of aerosol in the atmospheric environment, thereby solving the above-mentioned problems existing in the prior art.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] A method for identifying a mixed aerosol, comprising:

[0010] Acquiring aerosol optical parameters in the environment to be measured, and calculating the mixed aerosol depolarization ratio, the mixed aerosol radar ratio and the mixed aerosol fluorescence capability based on the aerosol optical parameters;

[0011] Based on the mixed aerosol depolarization ratio, the mixed aerosol radar ratio and the mixed aerosol fluorescence capability, the aerosol type contained in the mixed aerosol is identified in combination with a predetermined threshold.

[0012] The aerosol optical parameters include aerosol optical parameters at wavelength λ, and include:

[0013] Aerosol backscattering coefficient β(λ), aerosol extinction coefficient α(λ), parallel channel aerosol backscattering coefficient β(λ) and vertical channel aerosol backscattering coefficient β obtained by polarized Raman lidar ⊥ (λ), and the aerosol fluorescence backscattering coefficient β obtained by fluorescence lidar F (λ).

[0014] The calculation formulas for the aerosol depolarization ratio, aerosol radar ratio and aerosol fluorescence capability include:

[0015] The calculation formula of the aerosol depolarization ratio DEP is:

[0016] The calculation formula of the aerosol radar ratio LR is:

[0017] The calculation formula of the aerosol fluorescence capacity FC is:

[0018] The process of identifying the aerosol type contained in the mixed aerosol includes:

[0019] identifying one or more aerosol types contained in the mixed aerosol;

[0020] Based on the included aerosol types and the correspondences between the various types of aerosol types, determining the proportion of each type of aerosol included;

[0021] Based on the proportions of each type of aerosol contained in the aerosol, the aerosol backscattering coefficient and the aerosol extinction coefficient corresponding to each of the different aerosol types are determined.

[0022] The process of identifying one or more aerosol types contained in the mixed aerosol includes:

[0023] S1. When the aerosol depolarization ratio is greater than a first depolarization ratio threshold, the aerosol type is determined to be dust aerosol; otherwise, execute S2;

[0024] S2. When the aerosol radar ratio is less than the first radar ratio threshold, the aerosol type is determined to be sea salt aerosol; otherwise, S3 is executed;

[0025] S3, when the aerosol fluorescence capacity is greater than the first fluorescence capacity threshold, determining that the aerosol type is an aerosol generated by biomass combustion, otherwise, executing S4;

[0026] S4. When the aerosol fluorescence capacity is less than the second fluorescence capacity threshold and the aerosol depolarization ratio is less than the second depolarization ratio threshold, the aerosol type is determined to be urban haze; otherwise, the aerosol is determined to be a mixed aerosol containing two or less aerosol types.

[0027] For the mixed aerosol containing two or less aerosol types, if the environment to be measured is a land surface, the process of identifying the aerosol type contained in the mixed aerosol includes:

[0028] S5. When the aerosol fluorescence capacity is less than the second fluorescence capacity threshold, and the aerosol type is a depolarization ratio that is less than the first depolarization ratio threshold and greater than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of sand and dust and urban haze. Otherwise, execute S6.

[0029] S6. When the aerosol fluorescence capacity is greater than the second fluorescence capacity threshold and less than the first fluorescence capacity threshold, and the aerosol depolarization ratio is less than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of biomass burning and urban haze. Otherwise, execute S7.

[0030] S7. If the aerosol radar ratio is greater than the second radar ratio threshold, the aerosol type is determined to be a mixture of biomass burning and dust; otherwise, the aerosol type is determined to be a mixture of dust, biomass burning and urban haze.

[0031] For the mixed aerosol containing two or less aerosol types, if the environment to be measured is an ocean surface, the process of identifying the aerosol type contained in the mixed aerosol includes:

[0032] S8, when the aerosol fluorescence capacity is less than the second fluorescence capacity threshold, and the aerosol type is a depolarization ratio that is less than the first depolarization ratio threshold and greater than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of sand and sea salt, otherwise, execute S9;

[0033] S9, when the aerosol fluorescence capacity is greater than the second fluorescence capacity threshold and less than the first fluorescence capacity threshold, and the aerosol depolarization ratio is less than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of biomass burning and sea salt, otherwise, execute S10;

[0034] S10. If the aerosol radar ratio is greater than a third radar ratio threshold, the aerosol type is determined to be a mixture of biomass burning and sand and dust; otherwise, the aerosol type is determined to be a mixture of sand and dust, biomass burning, and sea salt.

[0035] The process of determining the proportion of each type of aerosol includes:

[0036] The identification process of the mixed aerosol composed of dust aerosol and another aerosol includes: based on the empirical values ​​of the aerosol depolarization ratios corresponding to the different aerosol types set in advance and the depolarization ratio of the mixed aerosol, the proportion of each type of aerosol is calculated;

[0037] The identification process of the mixed aerosol composed of biomass burning aerosol and another aerosol includes: based on the preset empirical values ​​of the aerosol fluorescence capabilities corresponding to the different aerosol types and the mixed aerosol fluorescence capabilities, calculating the proportion of each type of aerosol;

[0038] The identification process of mixed aerosols including three types of aerosols, namely biomass burning aerosols, dust aerosols and urban haze aerosols, includes: calculating the proportion of each type of aerosol based on the pre-set empirical values ​​of aerosol depolarization ratio and aerosol fluorescence capacity corresponding to different aerosol types, as well as the mixed aerosol depolarization ratio and mixed aerosol fluorescence capacity.

[0039] The identification process of mixed aerosols including biomass burning aerosol, dust aerosol and sea salt aerosol includes:

[0040] Based on the empirical value of the aerosol radar ratio corresponding to the sea salt aerosol, the proportion of sea salt aerosol P is calculated using the following formula: m for;

[0041]

[0042] In the formula, LR m is the radar ratio of sea salt aerosol, LR mix is the radar ratio corresponding to the biomass burning aerosol and the dust aerosol, and LR is the mixed aerosol radar ratio corresponding to the three types of aerosols;

[0043] The proportion of sea salt aerosol P m The ratio of the biomass burning aerosol and the dust aerosol is determined, and the ratio of the biomass burning aerosol and the dust aerosol is calculated by using the ratio of the biomass burning aerosol and the dust aerosol, combined with the preset empirical values ​​of the aerosol depolarization ratios corresponding to the different aerosol types, and the mixed aerosol depolarization ratios corresponding to the biomass burning aerosol and the dust aerosol.

[0044] The process of determining the aerosol backscattering coefficient and the aerosol extinction coefficient corresponding to different aerosol types includes:

[0045] Based on the proportion of each type of aerosol contained in the aerosol, the backscattering coefficient of each aerosol in the mixed aerosol is calculated;

[0046] The extinction coefficient of each aerosol is obtained by multiplying the backscatter coefficient of the corresponding aerosol by the radar ratio of the aerosol corresponding to the aerosol type.

[0047] Compared with the prior art, the present invention provides a method for identifying mixed aerosols, i.e., a separation algorithm for the extinction coefficient and backscattering coefficient of mixed aerosols, which can be combined with the aerosol optical parameters of the atmospheric environment monitored in the test environment to calculate the aerosol depolarization ratio, aerosol radar ratio and aerosol fluorescence capability, and then identify the aerosol type contained in the mixed aerosol in combination with a predetermined threshold. Specifically, it can not only identify the aerosol type contained in the mixed aerosol, but also identify the proportion of each type of aerosol, and then determine the backscattering coefficient and aerosol extinction coefficient of the aerosol corresponding to each type of aerosol, thereby providing reliable data support for atmospheric environment research. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0049] Figure 1 A schematic diagram of the implementation flow of a method is provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, which does not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0051] First, the terms that may be used in this article are explained as follows:

[0052] The term “and / or” means that either or both of them can be realized at the same time. For example, X and / or Y means both “X” or “Y” and “X and Y”.

[0053] The terms "include", "comprises", "contains", "has" or other descriptions with similar semantics should be interpreted as non-exclusive inclusion. For example, including certain technical feature elements (such as raw materials, components, ingredients, carriers, dosage forms, materials, dimensions, parts, components, mechanisms, devices, steps, procedures, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or products, etc.) should be interpreted as including not only certain technical feature elements explicitly listed, but also other technical feature elements known in the art that are not explicitly listed.

[0054] The term "consisting of..." means excluding any technical feature elements not explicitly listed. If this term is used in a claim, it will make the claim closed, so that it does not contain technical feature elements other than the technical feature elements explicitly listed, except for the conventional impurities related to them. If this term only appears in a clause of a claim, it only limits the elements explicitly listed in the clause, and the elements recorded in other clauses are not excluded from the overall claim.

[0055] The term "parts by mass" refers to the mass ratio relationship between multiple components. For example, if it is described that component X is x parts by mass and component Y is y parts by mass, then the mass ratio of component X to component Y is x:y. 1 part by mass can represent any mass, for example, 1 part by mass can be represented as 1 kg or 3.1415926 kg. The sum of the parts by mass of all components is not necessarily 100 parts, but can be greater than 100 parts, less than 100 parts or equal to 100 parts. Unless otherwise specified, the parts, proportions and percentages described herein are all measured by mass.

[0056] Unless otherwise specified or limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this article can be understood according to specific circumstances.

[0057] When concentration, temperature, pressure, size or other parameters are expressed in the form of a numerical range, the numerical range should be understood to specifically disclose all ranges formed by the pairing of any upper limit, lower limit, and preferred value in the numerical range, regardless of whether the range is explicitly stated; for example, if a numerical range of "2 to 8" is stated, the numerical range should be interpreted as including ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise specified, the numerical ranges stated herein include both their end values ​​and all integers and fractions within the numerical range.

[0058] The orientation or position relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or position relationship shown in the drawings and are only for the convenience and simplification of description, and do not explicitly or implicitly indicate that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation of this document.

[0059] The following is a detailed description of a mixed aerosol identification method provided by the present invention. The contents not described in detail in the embodiments of the present invention belong to the prior art known to professional and technical personnel in the field. If no specific conditions are specified in the embodiments of the present invention, the conventional conditions in the field or the conditions recommended by the manufacturer are followed. The reagents or instruments used in the embodiments of the present invention, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0060] In the specific implementation process of the present invention, it is found that the separation of aerosol backscattering coefficients is very simple for the case of a mixture of two aerosol types with significantly different depolarization ratios. However, when it is necessary to process different types of particles with similar depolarization ratios, the corresponding identification and separation process becomes very challenging.

[0061] To this end, in the implementation process of the present invention, additional independent information is specifically used to enhance the characterization of aerosol parameters, including the fluorescence capability (FC) of aerosol characteristics that can be obtained through fluorescence lidar measurement, so that biomass burning aerosols can be effectively identified. Specifically, the optical parameters of aerosols measured by polarized Raman lidar and fluorescence lidar can be applied to identify a mixture of multiple aerosols, and to identify and separate the content of each type of aerosol in the mixed aerosol.

[0062] In other words, the purpose of the embodiments of the present invention is to develop a method for identifying a mixed aerosol, including evaluating the contribution of each aerosol type in the mixed aerosol to the backscattering coefficient and the extinction coefficient, so as to achieve the identification of the corresponding mixed aerosol.

[0063] To facilitate understanding of the embodiments of the present invention, Figure 1 The specific implementation process of the present invention is described in detail.

[0064] Reference Figure 1 As shown, the processing process of a mixed aerosol identification method provided by an embodiment of the present invention may include the following steps:

[0065] (i) Obtain the aerosol optical parameters of the environment to be measured, and calculate the mixed aerosol depolarization ratio DEP, mixed aerosol radar ratio LR and mixed aerosol fluorescence capability FC based on the corresponding aerosol optical parameters;

[0066] Specifically, the process of obtaining the corresponding aerosol optical parameters includes:

[0067] Polarized Raman lidar can be used to observe the aerosol backscattering coefficient β(λ) at wavelength λ), the aerosol extinction coefficient α(λ), the parallel channel aerosol backscattering coefficient β(λ)), and the vertical channel aerosol backscattering coefficient β ⊥ (λ), the aerosol fluorescence backscattering coefficient β can be observed by fluorescence lidar F (λ);

[0068] Based on the information of aerosol optical parameters obtained above, the following can be calculated:

[0069] The aerosol depolarization ratio DEP is defined as: It is called the mixed aerosol depolarization ratio;

[0070] The aerosol radar ratio LR is defined as: It is called the mixed aerosol radar ratio;

[0071] The aerosol fluorescence capacity FC is defined as: It is called mixed aerosol fluorescence capability;

[0072] This step also includes performing spatiotemporal resolution matching on the calculated three mixed aerosol optical parameters DEP, LR, and FC, that is, resampling the time resolution to a predetermined time period, and resampling the vertical resolution to a predetermined height; for example, the corresponding spatiotemporal resolution matching may include: resampling the time resolution to ten minutes, and resampling the vertical resolution to 30 meters.

[0073] (ii) performing mixed aerosol type identification processing, that is, identifying one or more aerosol types contained in the mixed aerosol;

[0074] The corresponding identification process for the mixed aerosol type may include: the identification of the aerosol type mainly depends on the three preset aerosol optical parameter thresholds. The specific implementation process is referred to Figure 1 As shown, Figure 1 The thresholds used in the above are only examples of empirical values. For different regions, the thresholds may vary to a certain extent. The specific values ​​can be accurately determined through long-term radar observation statistics.

[0075] In this step, the aerosol optical parameters obtained by the above calculation, namely, DEP, FC and LR of the mixed aerosol, are the most powerful optical parameters for identifying the mixed aerosol. The process of determining the aerosol type based on the aerosol optical parameters DEP, FC and LR obtained by the respective calculations may include:

[0076] S1. When the aerosol depolarization ratio is greater than a first depolarization ratio threshold, the aerosol type is determined to be dust aerosol; otherwise, execute S2;

[0077] S2. When the aerosol radar ratio is less than the first radar ratio threshold, the aerosol type is determined to be sea salt aerosol; otherwise, S3 is executed;

[0078] S3, when the aerosol fluorescence capacity is greater than the first fluorescence capacity threshold, determining that the aerosol type is an aerosol generated by biomass combustion, otherwise, executing S4;

[0079] S4. When the aerosol fluorescence capacity is less than the second fluorescence capacity threshold and the aerosol depolarization ratio is less than the second depolarization ratio threshold, the aerosol type is determined to be urban haze; otherwise, the aerosol is determined to be a mixed aerosol containing two or less aerosol types.

[0080] For the mixed aerosol containing two or less aerosol types, if the environment to be measured is a land surface, the process of identifying the aerosol type contained in the mixed aerosol includes:

[0081] S5. When the aerosol fluorescence capacity is less than the second fluorescence capacity threshold, and the aerosol type is a depolarization ratio that is less than the first depolarization ratio threshold and greater than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of sand and dust and urban haze. Otherwise, execute S6.

[0082] S6. When the aerosol fluorescence capacity is greater than the second fluorescence capacity threshold and less than the first fluorescence capacity threshold, and the aerosol depolarization ratio is less than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of biomass burning and urban haze. Otherwise, execute S7.

[0083] S7. If the aerosol radar ratio is greater than the second radar ratio threshold, the aerosol type is determined to be a mixture of biomass burning and dust; otherwise, the aerosol type is determined to be a mixture of dust, biomass burning and urban haze.

[0084] For the mixed aerosol containing two or less aerosol types, if the environment to be measured is an ocean surface, the process of identifying the aerosol type contained in the mixed aerosol includes:

[0085] S8, when the aerosol fluorescence capacity is less than the second fluorescence capacity threshold, and the aerosol type is a depolarization ratio that is less than the first depolarization ratio threshold and greater than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of sand and sea salt, otherwise, execute S0;

[0086] S9, when the aerosol fluorescence capacity is greater than the second fluorescence capacity threshold and less than the first fluorescence capacity threshold, and the aerosol depolarization ratio is less than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of biomass burning and sea salt, otherwise, execute S10;

[0087] S10. If the aerosol radar ratio is greater than a third radar ratio threshold, the aerosol type is determined to be a mixture of biomass burning and sand and dust; otherwise, the aerosol type is determined to be a mixture of sand and dust, biomass burning, and sea salt.

[0088] Through the above processing, one or more aerosol types contained in the mixed aerosol in the environment to be tested can be accurately identified.

[0089] In an embodiment of the present invention, based on the identified multiple aerosol types, the respective proportion contents of the multiple aerosols contained in the mixed aerosol can be further identified, and then the extinction coefficient and backscattering coefficient of the mixed aerosol are separately calculated based on the corresponding proportion contents, that is, the extinction coefficient and backscattering coefficient of each type of aerosol contained therein are respectively determined.

[0090] The corresponding processing of separately calculating the extinction coefficient and the backscattering coefficient of the mixed aerosol may include the following processing steps:

[0091] First, based on the types of aerosols contained and the correspondences between the types of aerosols, the proportion of each type of aerosol contained is determined;

[0092] Afterwards, based on the proportions of the various types of aerosols, the aerosol backscattering coefficients and aerosol extinction coefficients corresponding to the different aerosol types are determined.

[0093] The implementation of the above separation calculation process is described in detail below, wherein:

[0094] (A1) The process of determining the proportion of each type of aerosol includes:

[0095] (A11) The identification process of a mixed aerosol composed of dust aerosol and another aerosol includes: calculating the proportion of each type of aerosol based on the preset empirical values ​​of the aerosol depolarization ratios corresponding to the different aerosol types and the depolarization ratio of the mixed aerosol;

[0096] (A12) The identification process of the mixed aerosol composed of biomass burning aerosol and another aerosol includes: calculating the proportion of each type of aerosol based on the preset empirical values ​​of the aerosol fluorescence capabilities corresponding to each of the different aerosol types and the fluorescence capabilities of the mixed aerosol;

[0097] (A13) The identification process of the mixed aerosol including the three types of aerosols, namely, biomass burning aerosol, dust aerosol and urban haze aerosol, comprises: calculating the proportion of each type of aerosol contained in the mixed aerosol based on the pre-set empirical values ​​of the aerosol depolarization ratio and the aerosol fluorescence capability corresponding to each type of aerosol, as well as the mixed aerosol depolarization ratio and the mixed aerosol fluorescence capability;

[0098] (A14) The identification process of mixed aerosols including biomass burning aerosol, dust aerosol and sea salt aerosol includes:

[0099] Based on the empirical value of the aerosol radar ratio corresponding to the sea salt aerosol, the proportion of sea salt aerosol P is calculated using the following formula: m for;

[0100]

[0101] In the formula, LR m is the radar ratio of sea salt aerosol, LR mix is the radar ratio corresponding to the biomass burning aerosol and the dust aerosol, and LR is the mixed aerosol radar ratio corresponding to the three types of aerosols;

[0102] The proportion of sea salt aerosol P m The ratio of the biomass burning aerosol and the dust aerosol is determined, and the ratio of the biomass burning aerosol and the dust aerosol is calculated by using the ratio of the biomass burning aerosol and the dust aerosol, combined with the preset empirical values ​​of the aerosol depolarization ratios corresponding to the different aerosol types, and the mixed aerosol depolarization ratios corresponding to the biomass burning aerosol and the dust aerosol.

[0103] (A2) The process of determining the aerosol backscattering coefficient and the aerosol extinction coefficient corresponding to each of the different aerosol types may include:

[0104] First, based on the proportion of each type of aerosol contained in the mixed aerosol, the backscattering coefficient of each aerosol in the mixed aerosol is calculated; then, the extinction coefficient of each aerosol is obtained by multiplying the backscattering coefficient of the corresponding aerosol by the radar ratio of the aerosol of the corresponding aerosol type, thereby realizing the separate calculation of the backscattering coefficient of the corresponding aerosol and the extinction coefficient of the aerosol.

[0105] To facilitate understanding of the present invention, the application process of the present invention will be described in detail below in conjunction with specific application embodiments.

[0106] In the following application embodiments, it can be assumed that the corresponding first depolarization ratio threshold is 0.28, the first radar ratio threshold is 25, the first fluorescence capability threshold is 0.0002, the corresponding second depolarization ratio threshold is 0.1, the second radar ratio threshold is 50, the second fluorescence capability threshold is 0.0001, and the corresponding third radar ratio threshold is 40. Then the corresponding process of identifying and determining the aerosol type may include:

[0107] When the DEP value is between 0.1 and 0.28, the aerosol is usually mixed with dust aerosol;

[0108] When the FC value is between 0.0001 and 0.0002, biomass burning aerosol is usually mixed in it;

[0109] When sea salt aerosol is mixed in, the LR value will drop rapidly.

[0110] According to the differences of the above thresholds pre-set based on the three aerosol optical parameters, seven mixed aerosols can be identified. The corresponding seven mixed aerosols can be shown in Table 1:

[0111] Table 1

[0112] serial number Mixed aerosol types 1 Dust aerosol and urban haze aerosol mixed 2 Biomass burning, urban haze aerosols 3 Dust aerosol and biomass burning mixed 4 A mixture of three types of aerosols: biomass burning aerosol, dust aerosol, and urban haze aerosol 5 Dust aerosol and sea salt aerosol mixed 6 Mixture of biomass burning aerosol and sea salt aerosol 7 A mixture of three types of aerosols: biomass burning aerosol, dust aerosol, and sea salt aerosol

[0113] Based on the above Table 1 and the various threshold values ​​set, the following will describe in detail how to identify seven types of mixed aerosols according to the various threshold values ​​of the three preset aerosol optical parameters.

[0114] Specifically, the process of identifying seven types of mixed aerosols according to the respective thresholds of the three pre-set aerosol optical parameters is as follows: Figure 1 As shown, the following steps may be included:

[0115] S11. When the aerosol depolarization ratio is greater than 0.28, the aerosol type is determined to be dust aerosol; otherwise, S12 is executed;

[0116] S12. When the aerosol radar ratio is less than 25, the aerosol type is determined to be sea salt aerosol, otherwise, executing S13;

[0117] S13, when the aerosol fluorescence capacity is greater than 0.0002, the aerosol type is determined to be an aerosol generated by biomass combustion, otherwise, execute S14;

[0118] S14. When the aerosol fluorescence capability is less than 0.0001 and the aerosol depolarization ratio is less than 0.1, the aerosol type is determined to be urban haze, otherwise, the aerosol is determined to be a mixed aerosol containing two or less aerosol types. In this case, different processing methods need to be used according to different observation scenes for subsequent aerosol type identification processing.

[0119] (1) Processing process in land surface observation scenario

[0120] For the mixed aerosol containing two or less aerosol types, if the environment to be measured is a land surface, that is, the corresponding observation result is a land surface observation result, the processing process for identifying the aerosol type contained in the mixed aerosol includes:

[0121] S15, when the aerosol fluorescence ability is less than 0.0001, and the aerosol type is a depolarization ratio less than 0.28 and greater than 0.1, it is determined that the aerosol type is a mixture of dust and urban haze, otherwise, execute S16;

[0122] S16. When the aerosol fluorescence capability is greater than 0.0001 and less than 0.0002, and the aerosol depolarization ratio is less than 0.1, it is determined that the aerosol type is a mixture of biomass burning and urban haze. Otherwise, execute S17.

[0123] S17. If the aerosol radar ratio is greater than 50, the aerosol type is determined to be a mixture of biomass burning and dust; otherwise, the aerosol type is determined to be a mixture of dust, biomass burning and urban haze.

[0124] (2) Processing process in ocean surface observation scenario

[0125] For the mixed aerosol containing two or less aerosol types, if the environment to be measured is the ocean surface, that is, the corresponding observation result is an ocean surface observation result, the processing process for identifying the aerosol type contained in the mixed aerosol includes:

[0126] S18, when the aerosol fluorescence capability is less than 0.0001, and the aerosol type is a depolarization ratio less than 0.28 and greater than 0.1, it is determined that the aerosol type is a mixture of sand and sea salt, otherwise, execute S19;

[0127] S19, when the aerosol fluorescence capability is greater than 0.0001 and less than 0.0002, and the aerosol depolarization ratio is less than 0.1, it is determined that the aerosol type is a mixture of biomass burning and sea salt, otherwise, execute S110;

[0128] S110: If the aerosol radar ratio is less than 40, the aerosol type is determined to be a mixture of biomass burning and sand and dust; otherwise, the aerosol type is determined to be a mixture of sand and dust, biomass burning, and sea salt.

[0129] Through the above processing, one or more aerosol types contained in the mixed aerosol in the test environment can be accurately identified. The following will describe the process of separately calculating the extinction coefficient and the backscattering coefficient of the aerosol based on the identification result.

[0130] In order to separate and calculate the extinction coefficient and backscattering coefficient of the mixed aerosol in the test environment, it is first necessary to understand the composition of the corresponding backscattering coefficient, that is, its calculation method, where:

[0131] The backscattering coefficient of mixed aerosols observed by polarized Raman lidar is contributed by multiple aerosols, and its specific calculation formula is:

[0132]

[0133] Wherein, subscript i represents any one of biomass burning aerosol, dust aerosol, sea salt aerosol or urban haze, n = 2 or 3, n = 2 represents a mixture of two aerosols, and n = 3 represents a mixture of three aerosols;

[0134] Similarly, the aerosol fluorescence backscattering coefficient observed by fluorescence lidar can also be expressed as:

[0135]

[0136] The meanings of the parameters in the formula are the same as those in the above formula (1).

[0137] Furthermore, it is also necessary to understand the corresponding aerosol depolarization ratio and the fluorescence capacity composition of the aerosol.

[0138] Assume that the mixed proportions of biomass burning aerosol, dust aerosol, sea salt aerosol and urban haze are p b 、p d 、p m 、p u, where the subscripts b, d, m, and u represent combustion aerosol, dust aerosol, sea salt aerosol, and urban haze, respectively.

[0139] The corresponding aerosol depolarization ratio and aerosol fluorescence ability can be expressed as:

[0140]

[0141]

[0142] The subscript i represents any one of biomass burning aerosol, dust aerosol, sea salt aerosol or urban haze, and n = 2 or 3. When n = 2, it means a mixture of two aerosols, and when n = 3, it means a mixture of three aerosols.

[0143] In addition, in the specific application process of the embodiment of the present invention, it is also necessary to predetermine the empirical values ​​of DEP, LR and FC corresponding to various types of aerosols. For the three aerosol optical parameters DEP, LR and FC corresponding to different types of aerosols, their empirical values ​​can be shown in Table 2; the empirical values ​​in Table 2 can also be obtained by long-term observation statistics of laser radar, and the empirical values ​​based on long-term field observations have smaller errors in separation of mixed aerosol backscattering coefficients.

[0144] Table 2

[0145]

[0146]

[0147] Based on the identified types of various mixed aerosols shown in Table 1, as well as the composition of the above-mentioned backscattering coefficient, aerosol depolarization ratio and aerosol fluorescence ability, and the empirical values ​​of DEP, LR and FC corresponding to various types of aerosols shown in Table 2, the corresponding aerosol backscattering coefficient and aerosol extinction coefficient can be calculated separately; that is, the subsequent backscattering coefficients of each aerosol are first calculated separately, and then the corresponding aerosol extinction coefficient is calculated based on the backscattering coefficient of the aerosol.

[0148] The following will explain the separate calculation process of the corresponding aerosol backscattering coefficient and the aerosol extinction coefficient in conjunction with a specific application example.

[0149] Based on the empirical values ​​shown in Table 2 above, after identifying the mixing ratios of the mixed aerosols in Table 1, the corresponding aerosol backscattering coefficient and aerosol extinction coefficient are calculated separately as follows:

[0150] 1) Identification of mixed aerosols composed of dust aerosol and another type of aerosol, that is, identification of the three mixed aerosols numbered 1, 3, and 5 in Table 1;

[0151] The identification process mainly uses DEP for separation. Taking the mixture of dust and biomass burning aerosol as an example, the mixing ratio of the two aerosols can be solved by the following formulas (5) and (6);

[0152] p d +p b =1(5)

[0153] p d DEP d +p b DEP b =DEP(6)

[0154] Based on the above formulas (5) and (6), and the empirical values ​​shown in Table 2, the backscattering coefficient of each aerosol in the mixed aerosol can be calculated. Then, the extinction coefficient of each aerosol can be obtained by multiplying the backscattering coefficient of the corresponding aerosol by the radar ratio of the aerosol of the corresponding aerosol type, thereby realizing the separate calculation of the backscattering coefficient of the aerosol and the extinction coefficient of the aerosol for the mixed aerosol.

[0155] 2) Identification of mixed aerosols composed of biomass burning aerosol and another aerosol, and identification of the two mixed aerosols marked with 2 and 6 in Table 1;

[0156] The identification process mainly uses FC for separation. Taking the mixture of biomass burning and urban haze aerosols as an example, the mixing ratio of the two aerosols can be solved by the following formulas (7) and (8).

[0157] p b +p u =1(7)

[0158] p b FC b +p u FC u =FC(8)

[0159] Based on the above formulas (7) and (8), and the empirical values ​​shown in Table 2, the aerosol backscattering coefficient and the aerosol extinction coefficient can be separated for the mixed aerosol by using the method in the above process 1).

[0160] 3) Identification of the three mixed aerosols of biomass burning aerosol, dust aerosol, and urban haze aerosol indicated by 4 in Table 1;

[0161] The identification process requires the use of FC and DEP. The three aerosol mixing ratios can be solved through the following formulas (9)-(11).

[0162] p b +p d +p u =1(9)

[0163] p b DEP b +p d DEP d +p u DEP u =DEP(10)

[0164] p b FC b +p d FC d +p u FC u =FC(11)

[0165] Based on the above formulas (9), (10) and (11), and the empirical values ​​shown in Table 2, the method in the above process 1) can be used to achieve the separate calculation of the aerosol backscattering coefficient and the aerosol extinction coefficient for the mixed aerosol;

[0166] 4) Identification of the three mixed aerosols of biomass burning aerosol, dust aerosol, and sea salt aerosol indicated by 7 in Table 1;

[0167] Since the LR of sea salt aerosol is very different from the other two aerosols, the identification process first needs to use LR to calculate the proportion of sea salt aerosol based on the following formula:

[0168]

[0169] Wherein, the subscript mix indicates a mixture of biomass burning aerosol and dust aerosol. The empirical value of LR can be obtained through long-term radar observation statistics. Then, the above formulas (5) and (6) are used to calculate the mixing ratio of dust and biomass burning aerosol. Then, combined with the empirical value shown in 2, the method in the above process 1) can be used to realize the separate calculation of the aerosol backscattering coefficient and the aerosol extinction coefficient for the mixed aerosol.

[0170] In summary, in the process of implementing the above technical solution provided by the present invention, the aerosol depolarization ratio, aerosol radar ratio and aerosol fluorescence capability can be calculated in combination with the aerosol optical parameters of the atmospheric environment monitored in the test environment, and then the aerosol type contained in the mixed aerosol can be identified in combination with the predetermined threshold. Through the above-mentioned embodiment of the present invention, not only the aerosol type contained in the mixed aerosol can be identified, but also the proportion of each type of aerosol can be identified, and then the backscattering coefficient and aerosol extinction coefficient of the aerosol corresponding to each type of aerosol can be determined, thereby providing reliable data support for atmospheric environment research.

[0171] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. The information disclosed in the background technology section of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A method for identifying a mixed aerosol, characterized in that: include: Acquiring aerosol optical parameters in the environment to be measured, and calculating the mixed aerosol depolarization ratio, the mixed aerosol radar ratio and the mixed aerosol fluorescence capability based on the aerosol optical parameters; Based on the mixed aerosol depolarization ratio, the mixed aerosol radar ratio and the mixed aerosol fluorescence capability, the aerosol type contained in the mixed aerosol is identified in combination with a predetermined threshold.

2. The method according to claim 1, characterized in that The aerosol optical parameters include aerosol optical parameters at wavelength λ, and include: Aerosol backscattering coefficient β(λ), aerosol extinction coefficient α(λ), parallel channel aerosol backscattering coefficient β(λ) and vertical channel aerosol backscattering coefficient β obtained by polarized Raman lidar ⊥ (λ), and the aerosol fluorescence backscattering coefficient β obtained by fluorescence lidar F (λ).

3. The method according to claim 2, characterized in that The calculation formulas for the aerosol depolarization ratio, aerosol radar ratio and aerosol fluorescence capability include: The calculation formula of the aerosol depolarization ratio DEP is: The calculation formula of the aerosol radar ratio LR is: The calculation formula of the aerosol fluorescence capacity FC is:

4. The method according to claim 1, 2 or 3, characterized in that: The process of identifying the aerosol type contained in the mixed aerosol includes: identifying one or more aerosol types contained in the mixed aerosol; Based on the included aerosol types and the correspondences between the various types of aerosol types, determining the proportion of each type of aerosol included; Based on the proportions of each type of aerosol contained in the aerosol, the aerosol backscattering coefficient and the aerosol extinction coefficient corresponding to each of the different aerosol types are determined.

5. The method according to claim 4, characterized in that The process of identifying one or more aerosol types contained in the mixed aerosol includes: S1. When the aerosol depolarization ratio is greater than a first depolarization ratio threshold, the aerosol type is determined to be dust aerosol; otherwise, execute S2; S2. When the aerosol radar ratio is less than the first radar ratio threshold, the aerosol type is determined to be sea salt aerosol; otherwise, S3 is executed; S3, when the aerosol fluorescence capacity is greater than the first fluorescence capacity threshold, determining that the aerosol type is an aerosol generated by biomass combustion, otherwise, executing S4; S4. When the aerosol fluorescence capacity is less than the second fluorescence capacity threshold and the aerosol depolarization ratio is less than the second depolarization ratio threshold, the aerosol type is determined to be urban haze; otherwise, the aerosol is determined to be a mixed aerosol containing two or less aerosol types.

6. The method according to claim 5, characterized in that For the mixed aerosol containing two or less aerosol types, if the environment to be measured is a land surface, the process of identifying the aerosol type contained in the mixed aerosol includes: S5. When the aerosol fluorescence capacity is less than the second fluorescence capacity threshold, and the aerosol type is a depolarization ratio that is less than the first depolarization ratio threshold and greater than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of sand and dust and urban haze. Otherwise, execute S6. S6. When the aerosol fluorescence capacity is greater than the second fluorescence capacity threshold and less than the first fluorescence capacity threshold, and the aerosol depolarization ratio is less than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of biomass burning and urban haze. Otherwise, execute S7. S7. If the aerosol radar ratio is greater than the second radar ratio threshold, the aerosol type is determined to be a mixture of biomass burning and dust; otherwise, the aerosol type is determined to be a mixture of dust, biomass burning and urban haze.

7. The method according to claim 5, characterized in that For the mixed aerosol containing two or less aerosol types, if the environment to be measured is an ocean surface, the process of identifying the aerosol type contained in the mixed aerosol includes: S8, when the aerosol fluorescence capacity is less than the second fluorescence capacity threshold, and the aerosol type is a depolarization ratio that is less than the first depolarization ratio threshold and greater than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of sand and sea salt, otherwise, execute S9; S9, when the aerosol fluorescence capacity is greater than the second fluorescence capacity threshold and less than the first fluorescence capacity threshold, and the aerosol depolarization ratio is less than the second depolarization ratio threshold, it is determined that the aerosol type is a mixture of biomass burning and sea salt, otherwise, execute S10; S10. If the aerosol radar ratio is greater than a third radar ratio threshold, the aerosol type is determined to be a mixture of biomass burning and sand and dust; otherwise, the aerosol type is determined to be a mixture of sand and dust, biomass burning, and sea salt.

8. The method according to claim 4, characterized in that The process of determining the proportion of each type of aerosol includes: The identification process of the mixed aerosol composed of dust aerosol and another aerosol includes: based on the empirical values ​​of the aerosol depolarization ratios corresponding to the different aerosol types set in advance and the depolarization ratio of the mixed aerosol, the proportion of each type of aerosol is calculated; The identification process of the mixed aerosol composed of biomass burning aerosol and another aerosol includes: based on the preset empirical values ​​of the aerosol fluorescence capabilities corresponding to the different aerosol types and the mixed aerosol fluorescence capabilities, calculating the proportion of each type of aerosol; The identification process of mixed aerosols including three types of aerosols, namely biomass burning aerosols, dust aerosols and urban haze aerosols, includes: calculating the proportion of each type of aerosol based on the pre-set empirical values ​​of aerosol depolarization ratio and aerosol fluorescence capacity corresponding to different aerosol types, as well as the mixed aerosol depolarization ratio and mixed aerosol fluorescence capacity.

9. The method according to claim 8, characterized in that The identification process of mixed aerosols including biomass burning aerosol, dust aerosol and sea salt aerosol includes: Based on the empirical value of the aerosol radar ratio corresponding to the sea salt aerosol, the proportion of sea salt aerosol P is calculated using the following formula: m for; In the formula, LR m is the radar ratio of sea salt aerosol, LR mix is the radar ratio corresponding to the biomass burning aerosol and dust aerosol, LR is the mixed aerosol radar ratio corresponding to the three types of aerosols; The proportion of sea salt aerosol P m The ratio of the biomass burning aerosol and the dust aerosol is determined, and the ratio of the biomass burning aerosol and the dust aerosol is calculated by using the ratio of the biomass burning aerosol and the dust aerosol, combined with the preset empirical values ​​of the aerosol depolarization ratios corresponding to the different aerosol types, and the mixed aerosol depolarization ratios corresponding to the biomass burning aerosol and the dust aerosol.

10. The method according to claim 4, characterized in that The process of determining the aerosol backscattering coefficient and the aerosol extinction coefficient corresponding to different aerosol types includes: Based on the proportion of each type of aerosol contained in the aerosol, the backscattering coefficient of each aerosol in the mixed aerosol is calculated; The extinction coefficient of each aerosol is obtained by multiplying the backscatter coefficient of the corresponding aerosol by the radar ratio of the aerosol corresponding to the aerosol type.

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