A method for observing spatial distribution of pollutants at sea-air interface

Abstract

The application discloses a kind of marine interface pollutant spatial distribution observation methods, it is related to marine environmental optical remote sensing monitoring technical field.The present application is according to the characteristics of sunlight spectrum sea surface reflection, selects solar sea surface glint as light source, improves the signal-to-noise ratio of spectral signal when collecting, simultaneously, the sunlight of specular reflection is no longer refracted into seawater, and will not change the atmospheric absorption structure of solar spectrum;When solar sea surface glint occurs reflection on sea surface, incident light is direct sunlight, and direct sunlight has a certain angle of incidence, so using solar sea surface glint as light source has clear observation geometry mode, can accurately calculate the optical path length of solar spectrum after absorbing near-sea surface atmospheric pollution gas, to accurately retrieve the concentration of relevant sea area near-sea surface atmospheric pollution gas, by setting equidistant observation angle in turn along the direction of solar sea surface glint, the distance resolution measurement of sea surface pollution gas can be realized.

Description

Technical Field

[0001] This invention relates to the field of marine environmental optical remote sensing monitoring technology, and in particular to a method for observing the spatial distribution of pollutants at the air-sea interface. Background Technology

[0002] In recent years, with the rapid development of my country's social economy, my country's port throughput has ranked first in the world for many consecutive years, and my country accounts for seven of the world's top ten ports. Accompanying the shipping industry is severe environmental pollution. Pollutants such as sulfur dioxide and nitrogen oxides in ship exhaust are directly released into the atmosphere, increasingly impacting the marine atmospheric environment. To assess the atmospheric environmental quality at the port-sea interface and build a green shipping system, there is an urgent need for a remote sensing technology that can rapidly and comprehensively measure the spatial distribution of pollutants near the port's nearshore surface. This would allow for a comprehensive assessment and understanding of the impact of shipping activities in port areas on the marine atmospheric boundary layer environment, providing a rapid and comprehensive monitoring method for the prevention and control of boundary layer atmospheric pollution in densely populated shipping areas such as river channels, ports, and wharves.

[0003] Differential Optical Absorption Spectroscopy (DOAS) is a promising optical remote sensing technology for atmospheric environment monitoring. It can achieve non-contact, real-time, online, and multi-component measurement of the concentration of pollutants in the atmosphere. Traditional DOAS technology, when applied to monitoring pollutants at the air-sea interface, cannot accurately obtain the concentration and spatial distribution of pollutants. This is because the choice of light source type determines the observation adaptability and measurement accuracy. Active DOAS uses artificial light sources with definite optical path lengths, achieving high-precision measurements, but the instruments are expensive and have poor environmental adaptability. Once the observation path is selected, it cannot be easily changed, thus making it difficult to achieve spatially resolved measurements. Passive DOAS uses natural light sources, has good environmental adaptability, and can change the observation direction and position at any time to observe multiple areas, possessing a certain degree of spatially resolved observation capability. However, the length of the optical path is difficult to determine, and even with estimation methods, the accuracy is not high enough to accurately obtain the concentration of pollutants along the absorption path. If the sea surface light source is used directly, most of the incident light will be refracted into the seawater due to the low reflectivity of the sea surface, resulting in a weaker intensity of the scattered spectrum and a very low signal-to-noise ratio during spectral measurement. In addition, plankton and suspended matter in the seawater will absorb and scatter the light refracted into the seawater, changing the original atmospheric information in the spectrum. This will greatly interfere with the accurate inversion of the concentration of polluting gases on the sea surface using the sea surface light source.

[0004] Sea flare is a phenomenon related to the direct reflection of incident sunlight. When the undulating sea surface reflects direct sunlight reaching the sea surface and forms many shimmering points, the sea flare phenomenon occurs. As the roughness of the sea surface increases, the range of the shimmering band will expand accordingly. The solar sea flare is essentially a specular reflection of the sea surface reflecting at a certain angle. Currently, there is no research at home and abroad on using solar sea flare as a light source for differential absorption spectroscopy. Summary of the Invention

[0005] To overcome the aforementioned problems in the existing technology, this invention proposes a method for observing the spatial distribution of pollutants at the air-sea interface.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for observing the spatial distribution of pollutants at the air-sea interface, including methods for observing the concentration distribution of pollutants in the horizontal and vertical directions at the air-sea interface, specifically including the following steps:

[0007] Step 1: Set equidistant observation angles θ1 to θ2 along the direction of the solar flare from far to near. n The observation center collected data from θ1 to θ2 at different altitudes. n The sea surface blaze spectrum at each observation angle is used as the measurement spectrum, and the solar direct spectrum at the same moment is selected as the reference spectrum.

[0008] Step 2: Calculate the differential column concentration (DSCD) of pollutant gas at each observation angle based on the measurement spectrum and reference spectrum obtained in Step 1. n The specific calculation formula is as follows:

[0009] DSCD n =SCD Totn -SCD Ref

[0010] Among them, SCD Totn For the observation angle θ n Total pollutant gas concentration at the inclined column, SCD Ref The concentration of the oblique column in the direct sunlight reference spectrum;

[0011] Step 3: Based on the differential column concentration (DSCD) of pollutant gas obtained in Step 2. n Obtain the observation angle θ n The average concentration of pollutants at the air-sea interface, c n The specific calculation formula is as follows:

[0012]

[0013] Where L n Represents the observation angle θ n The optical absorption path length at the location, where δL represents the optical absorption path correction factor;

[0014] Step 4: Obtain the observation angles θ1 to θ2 at different heights sequentially through steps 1-3. n The average concentration of pollutants at the air-sea interface is obtained, thereby acquiring spatial distribution information of these pollutants.

[0015] In the above-mentioned method for observing the spatial distribution of pollutants at the air-sea interface, the formula for calculating δL in step 3 is as follows:

[0016] δL=h / cosθ sun

[0017] Where h is the height of the observation center above sea level, θ sun The solar zenith angle at the time of observation.

[0018] The above-mentioned method for observing the spatial distribution of pollutants at the air-sea interface, wherein the observation angle θ in step 2... n Total pollutant gas concentration (SCD) at the location Totn The calculation formula is:

[0019] SCD Totn =SCD Ref +SCD n +ΔSCD n

[0020] Among them, SCD n This indicates the pollutant gas at the air-sea interface along the optical path L. n The concentration integral, ΔSCD n For SCD Totn The portion of pollutant gases absorbed by sunlight incident on the sea surface below the observation altitude.

[0021] The above-mentioned method for observing the spatial distribution of pollutants at the air-sea interface, wherein the observation angle θ in step 2... n Total pollutant gas concentration (SCD) at the location Totn Calculated using the passive DOAS algorithm.

[0022] The above-mentioned method for observing the spatial distribution of pollutants at the air-sea interface, specifically the passive DOAS algorithm, involves the following calculation process:

[0023] The intensity of incident sunlight after absorption and scattering by the atmosphere can be given by Lambert-Beer's law.

[0024]

[0025] I0(λ) is the intensity of the incident sunlight, I(λ) is the spectral intensity of the solar spectrum reaching the detector after atmospheric absorption and scattering, σ(λ) is the absorption cross section of atmospheric molecules at wavelength λ, S is the optical path length of the incident sunlight as it passes through the atmosphere, and c(s) is the concentration of trace gases in the atmosphere.

[0026] Considering Rayleigh scattering and Mie scattering of incident light as it passes through the atmosphere, equation (1) can be rewritten as:

[0027]

[0028] Where, ε R (λ) and ε M (λ) represents the absorption cross sections considering Rayleigh scattering and Mie scattering, respectively. and σ i '(λ) represents the broadband structural spectrum of trace gas i and the differential absorption spectrum after filtering, respectively;

[0029] After applying a high-pass filter to remove the effects of Rayleigh and Mie scattering from equation (2), equation (2) becomes:

[0030]

[0031] Where D(λ) is the differential optical thickness, SCD i For trace gas column concentration, SCD i =∫c(s)ds;

[0032] By performing least-squares fitting between the processed differential absorption spectrum and the differential absorption cross section, the column concentration (SCD) of each trace gas can be obtained. i .

[0033] The aforementioned method for observing the spatial distribution of pollutants at the air-sea interface also includes a method for observing the average concentration of pollutants at the air-sea interface, which specifically includes the following steps:

[0034] Step a: Delineate the area where the average concentration of pollutants needs to be observed, with the observation angles on both sides of the observation area being θ. a θ b θ were collected respectively a θ b The sea surface scintillation spectrum, where the observation angle closest to the observation position is θ. b The sea surface scintillation spectrum is used as the reference spectrum;

[0035] Step b: Calculate the differential column concentration (DSCD) of pollutant gases within the observation area based on the sea surface scintillation spectrum obtained in Step 1. The specific calculation formula is as follows:

[0036] DSCD = SCD a -SCDb

[0037] Among them, SCD a Air-sea interface pollutants along optical path L a Concentration integral, SCD b Air-sea interface pollutants along optical path L b The concentration integral;

[0038] Step c: Based on the differential slant column concentration (DSCD) of pollutants in the observation area obtained in step 2, the average concentration c of pollutants at the air-sea interface in the observation area is obtained. The specific calculation formula is as follows:

[0039]

[0040] The beneficial effects of the present invention are: (1) The present invention utilizes the solar sea surface blaze spectrum to conduct a refined observation and study of the spatial distribution of pollutants at the air-sea interface. Since the solar sea surface blaze spectrum is derived from the direct specular reflection of the incident sunlight on the wave surface of the sea, it has a high light intensity. At the same time, the reflected direct sunlight no longer refracts into the seawater and does not change the atmospheric absorption structure of the solar spectrum. Therefore, by setting an appropriate observation geometry mode, the accurate optical path length of the measured spectrum can be determined, and the accurate average concentration information of pollutant gases on the observation path can be obtained.

[0041] (2) The present invention utilizes the multi-angle scanning spectral acquisition method of telescope to achieve fine measurement of the concentration distribution of pollutant gas on the sea surface along the horizontal direction. By flexibly selecting multiple sets of observation angles, such as setting 10 or more sets of observation angles, a higher distance resolution observation of pollutant gas on the sea surface can be achieved, thus realizing the measurement of the horizontal distribution of pollutant gas at the sea-air interface.

[0042] (3) This invention utilizes observations from platforms at different heights to detect the concentration distribution of near-sea surface pollutants along the vertical direction based on solar flare. By selecting a single high-rise building with a good observation view by the sea and placing the air-sea interface pollutant observation system based on solar flare spectrum on different floors, it is possible to achieve distance-resolved measurement of air-sea interface pollutants in the vertical direction. Attached Figure Description

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0044] Figure 1 This is a schematic diagram illustrating the principle of detecting the average concentration of pollutants near the sea surface based on solar glare.

[0045] Figure 2 This is a schematic diagram illustrating the horizontal distance-resolved observation of near-sea surface pollutant gases based on solar flare of the sea surface, according to the present invention.

[0046] Figure 3 This is a schematic diagram illustrating the principle of introducing the correction term ΔSCD n in the distance-resolved observation of the coastal glare direction in this invention;

[0047] Figure 4 This is a schematic diagram of the vertical distance-resolved observation of near-sea surface pollutant gases based on solar flare, according to the present invention. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] To address the shortcomings of existing technologies, this invention, based on the characteristics of solar spectrum reflection from the sea surface, considers that solar flares originate from the specular reflection of direct sunlight by the undulating sea surface. By selecting solar flares as the light source, it achieves high intensity and sufficient range, improving the signal-to-noise ratio of the spectral signal during acquisition. Furthermore, the specularly reflected sunlight does not refract into the seawater, thus preserving the atmospheric absorption structure of the solar spectrum. More importantly, the incident light when solar flares are reflected from the sea surface is direct sunlight, which has a definite incident angle (solar zenith angle). Therefore, using solar flares as the light source provides a clear observation geometry, allowing for accurate calculation of the optical path length of the solar spectrum after absorption by near-sea surface atmospheric pollutants (NO2, SO2). This enables precise inference of the near-sea surface atmospheric pollutant concentration in the relevant sea area. By sequentially setting equidistant observation angles along the direction of the solar flares, distance-resolved measurements of sea surface pollutants can be achieved.

[0050] The purpose of this embodiment is to provide a method for detecting the spatial distribution of pollutants at the air-sea interface based on the solar sea surface blaze spectrum, which meets the requirement of continuously detecting the spatial distribution of pollutants at the air-sea interface using optical remote sensing methods.

[0051] This embodiment discloses a method for detecting the spatial distribution of pollutants at the air-sea interface based on the solar sea surface flare spectrum, including a method for detecting the average concentration of pollutants near the sea surface based on the solar sea surface flare, a method for detecting the concentration distribution of pollutants near the sea surface along the horizontal direction based on the solar sea surface flare, and a method for detecting the concentration distribution of pollutants near the sea surface along the vertical direction based on the solar sea surface flare.

[0052] The principle of the near-shore average concentration detection method based on solar flare is as follows: Figure 1As shown, sunlight shining directly onto the sea surface produces solar flares. A telescope mounted on a tripod on the shore, equipped with a noise-reducing light-collecting lens, captures the spectrum of these solar flares. In the diagram, L1 represents the optical path length of the solar flares from the sea surface along optical path L1 into the telescope, and L2 represents the optical path length of the solar flares from the sea surface along optical path L2 into the telescope. θ1 is the observation angle when observing along optical path L1, and θ2 is the observation angle when observing along optical path L2. Both L1 and L2 can be precisely calculated from the telescope's height h and the observation angles θ1 and θ2. Atm SCD1 represents the concentration of the oblique column of sunlight after passing through the atmosphere to the sea surface, SCD2 represents the concentration integral of the pollutant gas at the air-sea interface along the optical path L1, and SCD3 represents the concentration integral of the pollutant gas at the air-sea interface along the optical path L2.

[0053] During the measurement, the photons received by the telescope travel through two optical paths: from the top of the atmosphere to the sea surface and from the sea surface to the telescope. Therefore, the SCD along the entire optical path at the observation angle θ1 is... Tot1 It can be represented as:

[0054] SCD Tot1 =SCD Atm +SCD1

[0055] SCD along the entire optical path at an observation angle of θ2 Tot2 It can be represented as:

[0056] SCD Tot2 =SCD Atm +SCD2

[0057] The measured spectrum at an observation angle θ2, which is closer to the telescope, is selected as the reference spectrum. Under clear weather conditions and a small solar zenith angle, assuming that the absorption of sunlight at the sea surface at both θ1 and θ2 is consistent after passing through the atmosphere, the SCD can be calculated. Atm Subtraction yields the differential concentration of pollutant gas in the oblique column between observation angles θ1 and θ2.

[0058] DSCD = SCD Tot1 -SCD Tot2 =(SCD) Atm +SCD1)-(SCD Atm +SCD2)=SCD1-SCD2

[0059] Dividing the differential oblique column concentration by the difference in optical path length ΔL between the two angles yields the average concentration c of pollutants at the air-sea interface between the two observed angles.

[0060]

[0061] The principle of the method for detecting the horizontal concentration distribution of near-shore pollutant gases based on solar flare is as follows: Figure 2 As shown, equidistant observation angles θ1 to θ6 are set sequentially from far to near along the direction of the solar flare on the sea surface. The telescope is controlled by a gimbal to collect the sea surface flare spectrum at each observation angle in the order of θ1 to θ6 as the measurement spectrum. The direct solar spectrum at this moment is also collected as the reference spectrum. Assuming that the atmosphere above the air-sea interface is uniformly distributed, the SCD (Spectral Density Diffusion) can be obtained by subtracting the atmospheric common absorption portion from the reference spectrum. Ref To obtain the DSCD at each observation angle n :

[0062] DSCD n =SCD Totn -SCD Ref

[0063] SCD Totn For the observation angle θ n Total pollutant gas concentration at the inclined column, SCD Ref The average concentration of pollutants at the air-sea interface at each observation angle is obtained by dividing the oblique column concentration in the direct sunlight reference spectrum by the optical absorption path length at each observation angle.

[0064]

[0065] In actual observations, telescopes generally need to be mounted on a tripod and the observation angle controlled by a high-precision gimbal. Therefore, the telescope is at a certain height h above the sea surface. When observing at a large solar zenith angle, the observation angle θ needs to be considered. n Total pollutant gas concentration (SCD) at the location Totn The optical path length L contained in n SCD concentration on the inclined column n SCD concentration of oblique column in direct sunlight reference spectrum Ref Other than ΔSCD n Parts, such as Figure 3 As shown, ΔSCD n For SCD Totn The portion of sunlight incident on the sea surface that is absorbed by polluting gases below the telescope's height. At this point, the SCD... Totn for:

[0066] SCD Totn =SCD Ref +SCD n +ΔSCD n .

[0067] Meanwhile, the atmospheric common absorption portion (SCD) in the measured spectrum is subtracted from the direct sunlight reference spectrum. RefIn the subsequent calculation of the optical path length, it is necessary to introduce the optical absorption path δL of the sunlight incident on the sea surface below the telescope height for correction, such as... Figure 3 As shown, δL=h / cosθ sun Where h is the height of the telescope center above sea level, and θ sun Let be the solar zenith angle at that moment. The average concentration of pollutants at the air-sea interface at each observation angle can be expressed as:

[0068]

[0069] Using the passive DOAS algorithm to measure the observation angle θ n The SCD can be obtained by subtracting the portion of atmospheric common absorption in the direct solar reference spectrum from the measured spectrum at that location. n +ΔSCD n The formula includes several terms, such as h and θ, which can be accurately measured. By sequentially reversing the average concentration at each observation angle according to the observation order from θ1 to θ6, the spatial distribution information of pollutants at the air-sea interface can be obtained. In the actual observation process, multiple sets of observation angles can be flexibly selected according to the actual situation. For example, when the solar flare light from the sea surface has a large viewing angle for the telescope, 10 or more sets of observation angles can be set to achieve higher distance resolution, enabling real-time online, multi-component (NO2 and SO2) distance-resolved measurement of pollutants at the air-sea interface.

[0070] Passive DOAS algorithm SCD n +ΔSCD n The specific process is as follows:

[0071] The intensity of incident sunlight after absorption and scattering by the atmosphere can be given by Lambert-Beer's law.

[0072]

[0073] I0(λ) is the intensity of the incident sunlight (i.e., the intensity of the reference spectrum), I(λ) is the spectral intensity of the solar spectrum reaching the detector after atmospheric absorption and scattering, σ(λ) is the absorption cross section of atmospheric molecules at wavelength λ, S is the optical path length of the incident sunlight as it passes through the atmosphere, and c(s) is the concentration of trace gases in the atmosphere. Considering Rayleigh scattering and Mie scattering when the incident light passes through the atmosphere, equation (1) can be rewritten as follows:

[0074]

[0075] Where, ε R (λ) and ε M (λ) represents the absorption cross sections considering Rayleigh scattering and Mie scattering, respectively. and σ i'(λ) represents the broadband structural spectrum ("slowly changing" part) of trace gas i and the differential absorption spectrum ("fastly changing" part) after filtering, respectively. Since the absorption cross-sections of Rayleigh scattering and Mie scattering both change "slowly" with wavelength, high-pass filtering can be performed on equation (2) to remove the influence of Rayleigh scattering and Mie scattering, and then equation (2) becomes

[0076]

[0077] Here, D(λ) is the differential optical thickness, SCD i For trace gas column concentration, SCD i =∫c(s)ds. Then, by performing least-squares fitting between the processed differential absorption spectrum and the differential absorption cross section, the column concentration SCD of each trace gas can be obtained. i .

[0078] The main difference between the method for detecting the horizontal concentration distribution of near-shore pollutants based on solar flares and the method for detecting the average concentration of near-shore pollutants based on solar flares lies in the choice of reference spectrum. The method for detecting the average concentration of near-shore pollutants based on solar flares uses a blaze spectrum, also derived from sea surface reflection, as the reference spectrum, while this method uses the direct solar spectrum. After reflection from the sea surface, the spectral structure of incident sunlight undergoes some changes. Therefore, using the blaze spectrum after sea surface reflection as the reference spectrum in the method for detecting the average concentration of near-shore pollutants based on solar flares helps to offset the influence of spectral structure changes during the inversion process. However, using the direct sunlight spectrum as the reference spectrum during spectral fitting results in a larger fitting residual, leading to a greater inversion error than the method based on solar flares which uses the solar spectrum derived from sea surface reflection as the reference spectrum. In summary, when the telescope has a large viewing angle, the inversion method in the near-sea surface pollutant gas average concentration detection method based on solar sea surface flare can be used to reduce the inversion error when observing the spectral direction of the sea surface flare. This reduces the inversion error caused by the selection of the reference spectrum without affecting the range resolution.

[0079] The principle of the method for detecting the vertical concentration distribution of near-shore pollutant gases based on solar flare is as follows: Figure 4 As shown, by selecting a single building with a good observation view by the sea, and placing the air-sea interface pollutant gas observation system based on the solar sea surface blaze spectrum on different floors for observation, it is possible to achieve distance-resolved measurement of air-sea interface pollutants in the vertical direction.

[0080] On multi-story buildings by the sea, a pollutant gas measurement system is placed at intervals between buildings to collect solar flare spectra from different observation angles on each floor. By using a detection method based on the horizontal concentration distribution of near-sea surface pollutants based on solar flare, the distance resolution information of pollutants along the solar flare direction at each observation floor is obtained. This yields the concentration distribution information of pollutants at the air-sea interface at different heights along the solar flare direction.

[0081] Furthermore, selecting high-rise buildings with more floors for observation can obtain more information on the concentration distribution in the vertical direction, enabling distance-resolved observation of pollutant gases in the vertical direction.

[0082] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A method for observing the spatial distribution of pollutants at the air-sea interface, characterized in that, Methods for observing the concentration distribution of pollutants at the air-sea interface in both horizontal and vertical directions include the following steps: Step 1: Set equidistant observation angles θ1 to θ2 along the direction of the solar flare from far to near. n Collect θ1 to θ2 at different heights sequentially n The sea surface blaze spectrum at each observation angle is used as the measurement spectrum, and the solar direct spectrum at the same moment is selected as the reference spectrum. Step 2: Calculate the differential column concentration (DSCD) of pollutant gas at each observation angle based on the measurement spectrum and reference spectrum obtained in Step 1. n The specific calculation formula is as follows: DSCD n =SCD Totn -SCD Ref Among them, SCD Totn For the observation angle θ n Total pollutant gas concentration at the slant column, SCD Ref The concentration of the oblique column in the direct sunlight reference spectrum; Step 3: Based on the differential column concentration (DSCD) of pollutant gas obtained in Step 2. n Obtain the observation angle θ n The average concentration of pollutants at the air-sea interface, c n The specific calculation formula is as follows: Where L n Represents the observation angle θ n The optical absorption path length at the location, where δL represents the optical absorption path correction factor; Step 4: Obtain the observation angles θ1 to θ2 at different heights sequentially through steps 1-3. n The average concentration of pollutants at the air-sea interface is obtained, thereby acquiring spatial distribution information of these pollutants.

2. The method for observing the spatial distribution of pollutants at the air-sea interface according to claim 1, characterized in that, The formula for calculating δL in step 3 is: δL=h / cosθ sun Where h is the height of the observation center above sea level, θ sun The solar zenith angle at the time of observation.

3. The method for observing the spatial distribution of pollutants at the air-sea interface according to claim 1, characterized in that, In step 2, the observation angle θ n Total pollutant gas concentration (SCD) at the location Totn The calculation formula is: SCD Totn =SCD Ref +SCD n +ΔSCD n Among them, SCD n This indicates the pollutant gas at the air-sea interface along the optical path L. n The concentration integral, ΔSCD n For SCD Totn The portion of pollutant gases absorbed by sunlight incident on the sea surface below the observation altitude.

4. The method for observing the spatial distribution of pollutants at the air-sea interface according to claim 1, characterized in that, In step 2, the observation angle θ n Total pollutant gas concentration (SCD) at the location Totn Calculated using the passive DOAS algorithm.

5. The method for observing the spatial distribution of pollutants at the air-sea interface according to claim 4, characterized in that, The specific calculation process of the passive DOAS algorithm is as follows: The intensity of incident sunlight after absorption and scattering by the atmosphere can be given by Lambert-Beer's law. I0(λ) is the intensity of the incident sunlight, I(λ) is the spectral intensity of the solar spectrum reaching the detector after atmospheric absorption and scattering, σ(λ) is the absorption cross section of atmospheric molecules at wavelength λ, S is the optical path length of the incident sunlight as it passes through the atmosphere, and c(s) is the concentration of trace gases in the atmosphere. Considering Rayleigh scattering and Mie scattering of incident light as it passes through the atmosphere, equation (1) can be rewritten as: Where, ε R (λ) and ε M (λ) represents the absorption cross sections considering Rayleigh scattering and Mie scattering, respectively. and σ′ i (λ) represents the broadband structural spectrum of trace gas i and the differential absorption spectrum after filtering, respectively; After applying a high-pass filter to remove the effects of Rayleigh and Mie scattering from equation (2), equation (2) becomes: Where D(λ) is the differential optical thickness, SCD i For trace gas column concentration, SCD i =∫c(s)ds; By performing least-squares fitting between the processed differential absorption spectrum and the differential absorption cross section, the column concentration (SCD) of each trace gas can be obtained. i .

6. The method for observing the spatial distribution of pollutants at the air-sea interface according to claim 1, characterized in that, It also includes methods for observing the average concentration of pollutants at the air-sea interface, specifically comprising the following steps: Step a: Delineate the area where the average concentration of pollutants needs to be observed, with the observation angles on both sides of the observation area being θ. a θ b θ were collected respectively a θ b The sea surface scintillation spectrum, where the observation angle closest to the observation position is θ. b The sea surface scintillation spectrum is used as a reference spectrum; Step b: Calculate the differential column concentration (DSCD) of pollutant gases within the observation area based on the sea surface scintillation spectrum obtained in Step 1. The specific calculation formula is as follows: DSCD=SCD a -SCD b Among them, SCD a Air-sea interface pollutants along optical path L a Concentration integral, SCD b Air-sea interface pollutants along optical path L b The concentration integral; Step c: Based on the differential slant column concentration (DSCD) of pollutants in the observation area obtained in step 2, the average concentration c of pollutants at the air-sea interface in the observation area is obtained. The specific calculation formula is as follows:

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