Method for inverting marine primary productivity based on airborne dual-wavelength laser radar remote sensing data

Abstract

The invention discloses a method for inverting marine primary productivity based on airborne dual-wavelength laser radar remote sensing data, and the method comprises the steps: building a dual-wavelength high-precision water optical characteristic inversion model based on the airborne dual-wavelength laser radar remote sensing data, and obtaining a high-precision marine phytoplankton absorption coefficient vertical section; and inverting the marine primary productivity vertical section distribution coupled with the high-precision phytoplankton absorption coefficient. According to the invention, one laser wavelength is suitable for detecting an offshore sea area, the other laser wavelength is suitable for detecting an open sea area, and the dual-wavelength ocean laser radar improves the maximum detection depth of near and open seas and the inversion precision of the primary productivity vertical section distribution of a typical sea area. And the ocean carbon cycle space-time evolution precision and the observation capability in the aspect of ocean upper-layer energy conversion are further improved.

Description

Technical Field

[0001] The invention relates to the field of ocean optical detection, and in particular to a method for inverting ocean primary productivity based on airborne dual-wavelength laser radar remote sensing data. Background Art

[0002] The assessment of marine primary productivity is of great significance to global climate change and ocean carbon cycle. At present, the research on marine primary productivity at home and abroad is mainly carried out through observation platforms such as shipborne instrument field measurement, biogeochemical buoy (BGC-Argo) and satellite water color remote sensing. However, the shipborne instrument field measurement technology is relatively time-consuming, labor-intensive, and has a small observation range. The resolution of BGC-Argo is low. The current passive water color remote sensing satellite can only observe the surface information of the ocean water body, and the assessment accuracy of the marine primary productivity assessment model coupled with the seawater surface information is low. Although the current single-wavelength ocean lidar remote sensing can obtain the profile information of the ocean water body, it can only obtain the vertical profile of chlorophyll concentration through the backscatter signal of the single-wavelength lidar. The assessment accuracy of the marine primary productivity assessment model coupled with the vertical profile of chlorophyll concentration is also low. Therefore, the existing observation platform is still unable to conduct large-scale, long-time series, and high-precision assessment of marine primary productivity. Therefore, it is urgent to develop new marine observation technology to obtain high-precision vertical profile information of marine water bodies and construct a high-precision remote sensing inversion model of the vertical profile distribution of marine primary productivity. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention discloses a method for inverting marine primary productivity based on airborne dual-wavelength lidar remote sensing data. The lidar system uses lasers with emission wavelengths of λ1 and λ2 as emission light sources, and the receiving channels are parallel polarization channels and vertical polarization channels. The inversion method is based on the dual-wavelength high-precision vertical profile distribution of water body attenuation coefficient and phytoplankton absorption coefficient, and constructs an inversion model of marine primary productivity coupled with the vertical profile of phytoplankton absorption coefficient to obtain the vertical profile distribution of marine primary productivity along the lidar track.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A method for inverting ocean primary productivity based on airborne dual-wavelength lidar remote sensing data.

[0006] If the airborne dual-wavelength laser radar is an airborne dual-wavelength Mie scattering laser radar, the method comprises the following steps:

[0007] (1) The laser pulse passes through the surface of the ocean water body and is incident into the ocean water body. The backscattered signal generated in the ocean water body is received by the telescope and divided into a parallel polarized Mie scattering channel and a vertical polarized Mie scattering channel. The received lidar backscattered signal is preprocessed by water body signal extraction, averaging, denoising and distance correction.

[0008] (2) Assume that the volume scattering coefficient of the ocean water at π radians is β π (λ,z) ​​and the laser radar attenuation coefficient K lidar (λ,z) ​​satisfies β π (λ,z)=AK lidar (λ,z) R , where λ is the laser wavelength emitted by the laser radar, z is the detection depth, A is a related parameter, and R is the laser radar backscattering extinction logarithmic ratio; calculate the laser radar attenuation coefficient, diffuse attenuation coefficient, and vertical profile of the laser radar backscattering coefficient in the dual-wavelength λ1 and λ2 bands corresponding to the airborne dual-wavelength Mie scattering laser radar;

[0009] (3) Calculate the vertical profile of phytoplankton absorption coefficient;

[0010] (4) Calculate the vertical profile distribution of ocean primary productivity along the lidar track;

[0011] If the airborne dual-wavelength laser radar is an airborne dual-wavelength high spectral resolution laser radar, the method comprises the following steps:

[0012] (1) The laser pulse passes through the surface of the ocean water body and is incident into the ocean water body. The backscattered signal generated in the water body is received by the telescope and divided into a dual-wavelength water body Brillouin scattering channel and a dual-wavelength Mie scattering channel. The Brillouin scattering and Mie scattering channels are pre-processed by water body signal extraction, averaging, denoising and distance correction.

[0013] (2) The vertical profiles of the lidar attenuation coefficient and diffuse attenuation coefficient are calculated using the echo signal of the dual-wavelength Brillouin scattering channel, and the vertical profile of the lidar backscattering coefficient is further calculated using the echo signal of the dual-wavelength Mie scattering channel;

[0014] (3) The vertical profile of the phytoplankton absorption coefficient is calculated and finally the vertical profile distribution of the ocean primary productivity along the lidar track is inverted.

[0015] Furthermore, if the airborne dual-wavelength laser radar is an airborne dual-wavelength Mie scattering laser radar, the specific implementation process of steps (2) to (4) is as follows:

[0016] Take the depth of a certain boundary value detected by the laser radar as z B , then the laser radar attenuation coefficient at wavelength λ1 is expressed as:

[0017]

[0018] The laser radar attenuation coefficient at wavelength λ2 is expressed as:

[0019]

[0020] Where λ1 and λ2 are both laser wavelengths;

[0021] Based on the laser radar attenuation coefficients in the λ1 and λ2 bands, the diffuse attenuation coefficient K is further obtained. d (λ1,z) and K d (λ2,z);

[0022] Calculate the volume scattering coefficient β of dual-wavelength lidar π radians π (λ1,z) and β π (λ2,z):

[0023] Assuming that the volume scattering coefficient of ocean water at π radians is the sum of uniform water optical parameters that do not vary with depth and non-uniform water optical parameters that vary with depth, then:

[0024] The volume scattering coefficient of ocean water at λ1 wavelength π radians β π (λ1,z) is expressed as:

[0025]

[0026] Where S(λ1,z) is the total lidar echo signal generated by the λ1 laser, S h (λ1,z) is the lidar echo signal generated by the λ1 laser in the uniform water body, is the volume scattering coefficient of π radians generated by the λ1 laser in a uniform water body;

[0027] The volume scattering coefficient of ocean water at λ2 wavelength π radians β π (λ2,z) is expressed as:

[0028]

[0029] Where S(λ2,z) is the total lidar echo signal generated by the λ2 laser, S h (λ2,z) is the lidar echo signal generated by the λ2 laser in the uniform water body, is the volume scattering coefficient of π radians generated by λ2 laser in uniform water;

[0030] Calculate the backscattering coefficient of the lidar based on the volume scattering coefficient of the ocean water body of π radians in the λ1 and λ2 bands and

[0031]

[0032] Where χ is the conversion factor between the volume scattering coefficient of the ocean water body and the particle backscattering coefficient, b bw (λ1) is the backscattering coefficient of pure seawater at wavelength λ1, b bw (λ2) is the backscattering coefficient of pure seawater at wavelength λ2;

[0033] Calculate the vertical profile of the dual-wavelength total water absorption coefficient along the lidar track and

[0034]

[0035] Calculate vertical profiles of phytoplankton absorption coefficients along lidar tracks

[0036]

[0037] Among them, a w (λ1,z) is the absorption coefficient of pure seawater at wavelength λ1, a w (λ2,z) is the absorption coefficient of pure seawater at wavelength λ2, a dg (λ1,z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ1, a dg (λ2,z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ2, a0(λ1), a1(λ1), b0(λ2) and b1(λ2) are correlation coefficients;

[0038] Calculate the vertical profile of ocean primary productivity PP along the lidar track lidar (z):

[0039]

[0040] where φ is the quantum yield of phytoplankton photosynthesis and E(λ,z) ​​is the solar irradiance at wavelength λ and depth z.

[0041] Furthermore, if the airborne dual-wavelength laser radar is an airborne dual-wavelength high spectral resolution laser radar, the corresponding steps (2) to (3) are specifically implemented as follows:

[0042] Based on the seawater Brillouin scattering echo signal S b (λ,z), calculate the lidar attenuation coefficient The laser radar attenuation coefficient at wavelength λ1 is expressed as:

[0043]

[0044] The laser radar attenuation coefficient at wavelength λ2 is expressed as:

[0045]

[0046] in, is the Brillouin backscattering coefficient of seawater at λ1, is the Brillouin backscattering coefficient of seawater at λ2, n is the refractive index of seawater, and H is the flight altitude of the airborne laser radar;

[0047] Based on the lidar attenuation coefficients of the λ1 and λ2 bands, the diffuse attenuation coefficient is further obtained and

[0048] Based on the attenuation coefficient of dual-wavelength laser radar and The volume scattering coefficient of the dual-wavelength LiDAR at π radians is further obtained through the airborne dual-wavelength Mie scattering LiDAR echo signal. and

[0049] Volume scattering coefficient of dual-wavelength ocean water based on π radians and Calculating the Backscatter Coefficient of Dual-Wavelength LiDAR and

[0050]

[0051] Where χ is the conversion factor between the volume scattering coefficient of the ocean water body and the particle backscattering coefficient, b bw (λ1) is the backscattering coefficient of pure seawater at wavelength λ1, b bw (λ2) is the backscattering coefficient of pure seawater at wavelength λ2;

[0052] Calculate the vertical profile of the dual-wavelength total water absorption coefficient along the lidar track and

[0053]

[0054] Calculate vertical profiles of phytoplankton absorption coefficients along lidar tracks

[0055]

[0056] Among them, a w (λ1,z) is the absorption coefficient of pure seawater at wavelength λ1, a w (λ2,z) is the absorption coefficient of pure seawater at wavelength λ2, a dg(λ1,z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ1, a dg (λ2,z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ2, a0(λ1), a1(λ1), b0(λ2) and b1(λ2) are correlation coefficients;

[0057] Calculate the vertical profile of ocean primary productivity PP along the lidar track HSRL (z):

[0058]

[0059] where φ is the quantum yield of phytoplankton photosynthesis and E(λ,z) ​​is the solar irradiance at wavelength λ and depth z.

[0060] Furthermore, the two laser wavelengths of the airborne dual-wavelength laser radar are 532nm and 486nm respectively.

[0061] Furthermore, the value of λ3 is 440 nm.

[0062] The method for inverting ocean primary productivity based on airborne dual-wavelength lidar remote sensing data of the present invention uses airborne dual-wavelength lidar remote sensing data to obtain dual-wavelength high-precision water body optical vertical profiles, and inverts the vertical profile distribution of ocean primary productivity coupled with high-precision phytoplankton absorption coefficient vertical profiles. Compared with passive satellite remote sensing data and single-wavelength lidar remote sensing data, the beneficial effects are as follows:

[0063] (1) The method of inverting ocean primary productivity based on dual-wavelength ocean lidar remote sensing data of the present invention can obtain a high-precision vertical profile of phytoplankton absorption coefficient, and then obtain a high-precision vertical profile distribution of ocean primary productivity;

[0064] (2) The present invention is a dual-wavelength detection, in which one laser wavelength is suitable for detecting nearshore waters, and the other laser wavelength is suitable for detecting offshore waters. The dual-wavelength ocean lidar improves the inversion accuracy of the maximum detection depth of near and far seas and the vertical profile distribution of primary productivity in typical sea areas, and further improves the accuracy of the spatiotemporal evolution of the ocean carbon cycle and the observation capability of energy conversion in the upper ocean. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 The figure is a flow chart of the inversion method of the present invention.

[0066] Figure 2 This is the vertical profile result of the inverted dual-wavelength diffuse attenuation coefficient.

[0067] Figure 3 This is the vertical profile result of the inverted phytoplankton absorption coefficient. DETAILED DESCRIPTION

[0068] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0069] Based on dual-wavelength ocean lidar remote sensing data, the present invention can obtain dual-wavelength seawater optical property vertical profile information, further obtain the vertical profile of phytoplankton plant absorption coefficient, and construct an ocean primary productivity assessment model coupled with the vertical profile of phytoplankton absorption coefficient to improve the assessment accuracy of ocean primary productivity.

[0070] like Figure 1 As shown, the method for inverting ocean primary productivity based on airborne dual-wavelength lidar remote sensing data of the present invention specifically includes the following steps:

[0071] If the airborne dual-wavelength laser radar is an airborne dual-wavelength Mie scattering laser radar, and the emitted laser wavelengths are λ1 and λ2 respectively, then the method for inverting the ocean primary productivity includes the following steps:

[0072] (1) The laser pulse passes through the surface of the ocean water and is incident into the ocean water. The backscattered signal generated in the ocean water is received by the telescope and divided into a parallel polarized Mie scattering channel and a vertical polarized Mie scattering channel. The received airborne dual-wavelength Mie scattering lidar backscattered signal is subjected to water signal extraction, averaging, denoising and distance correction preprocessing.

[0073] (2) Calculation of the attenuation coefficient K of the dual-wavelength laser radar lidar (λ1,z) and K lidar (λ2,z):

[0074] Assume that the volume scattering coefficient of ocean water at π radians is β π (λ,z) ​​and the laser radar attenuation coefficient K lidar (λ,z) ​​satisfies:

[0075] β π (λ,z)=AK lidar (λ,z) R

[0076] Among them, S(λ,z) ​​is the laser radar echo signal, z is the detection depth, A is the relevant parameter, R is the laser radar backscattering extinction logarithmic ratio; λ is the laser wavelength emitted by the laser radar;

[0077] Take the depth of a certain boundary value detected by the laser radar as z B , then the laser radar attenuation coefficient at wavelength λ1 is expressed as:

[0078]

[0079] The laser radar attenuation coefficient at wavelength λ2 is expressed as:

[0080]

[0081] Wherein, λ1 and λ2 are both laser wavelengths; preferably, λ1 is 532nm and λ2 is 486nm.

[0082] (3) Based on the lidar attenuation coefficients in the λ1 and λ2 bands, the diffuse attenuation coefficient K can be further obtained. d (λ1,z) and K d (λ2,z).

[0083] (4) Calculate the volume scattering coefficient β of the dual-wavelength lidar π radians π (λ1,z) and β π (λ2,z):

[0084] Assuming that the volume scattering coefficient of ocean water at π radians is the sum of uniform water optical parameters that do not vary with depth and non-uniform water optical parameters that vary with depth, then:

[0085] The volume scattering coefficient of ocean water at λ1 wavelength π radians β π (λ1,z) is expressed as:

[0086]

[0087] Where S(λ1,z) is the total lidar echo signal generated by the λ1 laser, S h (λ1,z) is the lidar echo signal generated by the λ1 laser in the uniform water body, is the volume scattering coefficient of π radians generated by the λ1 laser in a uniform water body;

[0088] The volume scattering coefficient of ocean water at λ2 wavelength π radians β π (λ2,z) is expressed as:

[0089]

[0090] Where S(λ2,z) is the total lidar echo signal generated by the λ2 laser, S h (λ2,z) is the lidar echo signal generated by the λ2 laser in the uniform water body, is the volume scattering coefficient of π radians generated by λ2 laser in uniform water.

[0091] (5) Calculate the backscattering coefficient of the lidar based on the volume scattering coefficient of the ocean water body of π radians in the λ1 and λ2 bands and

[0092]

[0093] Where χ is the conversion factor between the volume scattering coefficient of the ocean water body and the particle backscattering coefficient, b bw (λ1) is the backscattering coefficient of pure seawater at wavelength λ1, b bw (λ2) is the backscattering coefficient of pure seawater at wavelength λ2.

[0094] (6) Calculate the vertical profile of the dual-wavelength water total absorption coefficient along the lidar trajectory and

[0095]

[0096] (7) Calculate the vertical profile of phytoplankton absorption coefficient along the lidar track

[0097]

[0098] Among them, a w (λ1,z) is the absorption coefficient of pure seawater at wavelength λ1, a w (λ2,z) is the absorption coefficient of pure seawater at wavelength λ2, a dg (λ1,z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ1, a dg (λ2,z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ2, and a0(λ1), a1(λ1), b0(λ2) and b1(λ2) are correlation coefficients.

[0099] (8) Calculate the vertical profile of ocean primary productivity PP along the lidar track lidar (z):

[0100]

[0101] Wherein, φ is the quantum yield of phytoplankton photosynthesis, and E(λ,z) ​​is the solar irradiance at wavelength λ and depth z. Preferably, λ3 is 440nm.

[0102] If the airborne dual-wavelength laser radar is an airborne dual-wavelength high spectral resolution laser radar, and the emitted laser wavelengths are λ1 and λ2 respectively, then the method for inverting the ocean primary productivity includes the following steps:

[0103] (1) The laser pulse passes through the surface of the ocean water body and is incident into the ocean water body. The backscattered signal generated in the water body is received by the telescope and divided into a dual-wavelength water body Brillouin scattering channel and a dual-wavelength Mie scattering channel. The Brillouin scattering and Mie scattering channels are pre-processed by water body signal extraction, averaging, denoising and distance correction.

[0104] (2) Calculation of dual-wavelength lidar attenuation coefficient and

[0105] Based on the seawater Brillouin scattering echo signal S b (λ,z), calculate the lidar attenuation coefficient The laser radar attenuation coefficient at wavelength λ1 is expressed as:

[0106]

[0107] The laser radar attenuation coefficient at wavelength λ2 is expressed as:

[0108]

[0109] in, is the Brillouin backscattering coefficient of seawater at λ1, is the Brillouin backscattering coefficient of seawater at λ2, n is the refractive index of seawater, and H is the flight altitude of the airborne laser radar. Wherein, λ1 and λ2 are both laser wavelengths; as a preferred embodiment, λ1 is 532nm and λ2 is 486nm.

[0110] (3) Based on the lidar attenuation coefficients of the λ1 and λ2 bands, the diffuse attenuation coefficient can be further obtained: and

[0111] (4) Based on the attenuation coefficient of dual-wavelength laser radar and The volume scattering coefficient of the dual-wavelength LiDAR at π radians can be further obtained through the airborne dual-wavelength Mie scattering LiDAR echo signal. and

[0112] (5) Volume scattering coefficient based on dual-wavelength ocean water π radians and Calculating the Backscatter Coefficient of Dual-Wavelength LiDAR and

[0113]

[0114] Where χ is the conversion factor between the volume scattering coefficient of the ocean water body and the particle backscattering coefficient, bbw (λ1) is the backscattering coefficient of pure seawater at wavelength λ1, b bw (λ2) is the backscattering coefficient of pure seawater at wavelength λ2.

[0115] (6) Calculate the vertical profile of the dual-wavelength water total absorption coefficient along the lidar trajectory and

[0116]

[0117] (7) Calculate the vertical profile of phytoplankton absorption coefficient along the lidar track

[0118]

[0119] Among them, a w (λ1,z) is the absorption coefficient of pure seawater at wavelength λ1, a w (λ2,z) is the absorption coefficient of pure seawater at wavelength λ2, a dg (λ1,z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ1, a dg (λ2,z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ2, and a0(λ1), a1(λ1), b0(λ2) and b1(λ2) are correlation coefficients.

[0120] (8) Calculate the vertical profile of ocean primary productivity PP along the lidar track HSRL (z):

[0121]

[0122] Wherein, φ is the quantum yield of phytoplankton photosynthesis, and E(λ,z) ​​is the solar irradiance at wavelength λ and depth z. Preferably, λ3 is 440nm.

[0123] The vertical profile distribution of marine primary productivity obtained based on the above calculations can promote research on the driving mechanism of the vertical profile distribution of marine primary productivity, marine ecological environment monitoring, marine carbon cycle and sustainable utilization of biological resources.

[0124] Figure 2 It is the result of the vertical profile of dual-wavelength water optical characteristics obtained by the method proposed in the present invention for inverting the primary productivity of the ocean based on the airborne dual-wavelength Mie scattering lidar remote sensing data. From the figure, it can be seen that the maximum detection depth of the dual-wavelength Mie scattering lidar for the upper ocean can reach 100m, and the vertical profile distribution of the dual-wavelength water diffuse attenuation coefficient can be clearly seen.

[0125] Figure 3This is the result of the marine phytoplankton absorption coefficient obtained by using the method proposed in the present invention for inverting the marine primary productivity based on airborne dual-wavelength Mie scattering lidar remote sensing data. The vertical profile distribution of the marine phytoplankton absorption coefficient can be clearly seen from the figure.

[0126] When using airborne dual-wavelength high-spectral resolution lidar remote sensing data to invert marine primary productivity, the dual-wavelength Brillouin scattering channel and Mie scattering channel lidar backscattering signals are utilized to solve the problem of solving two unknowns in one equation, and the dual-wavelength high-precision vertical profile distribution of water optical properties is obtained, and the high-precision vertical profile of marine phytoplankton absorption coefficient is further obtained, so that the vertical profile of marine primary productivity can be evaluated with high precision; on the other hand, the dual-wavelength high-spectral resolution lidar system uses blue-green wavelengths, which are the optimal bands for near- and far-sea detection, greatly improving the maximum detection depth of the ocean.

[0127] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A method for inverting marine primary productivity based on airborne dual-wavelength lidar remote sensing data, characterized in that: If the airborne dual-wavelength laser radar is an airborne dual-wavelength Mie scattering laser radar, the method comprises the following steps: (1) The laser pulse passes through the surface of the ocean water body and is incident into the ocean water body. The backscattered signal generated in the ocean water body is received by the telescope and divided into a parallel polarized Mie scattering channel and a vertical polarized Mie scattering channel. The received lidar backscattered signal is preprocessed by water body signal extraction, averaging, denoising and distance correction. (2) Assume that the volume scattering coefficient of the ocean water at π radians is β π (λ,z) ​​and the laser radar attenuation coefficient K lidar (λ, z) satisfies β π (λ, z) = AK lidar (λ,z) R , where λ is the laser wavelength emitted by the laser radar, z is the detection depth, A is a related parameter, and R is the laser radar backscattering extinction logarithmic ratio; calculate the laser radar attenuation coefficient, diffuse attenuation coefficient, and vertical profile of the laser radar backscattering coefficient in the dual-wavelength λ1 and λ2 bands corresponding to the airborne dual-wavelength Mie scattering laser radar; (3) Calculate the vertical profile of phytoplankton absorption coefficient; (4) Calculate the vertical profile distribution of ocean primary productivity along the lidar track; If the airborne dual-wavelength laser radar is an airborne dual-wavelength high spectral resolution laser radar, the method comprises the following steps: (1) The laser pulse passes through the surface of the ocean water body and is incident into the ocean water body. The backscattered signal generated in the water body is received by the telescope and divided into a dual-wavelength water body Brillouin scattering channel and a dual-wavelength Mie scattering channel. The Brillouin scattering and Mie scattering channels are pre-processed by water body signal extraction, averaging, denoising and distance correction. (2) The vertical profiles of the lidar attenuation coefficient and diffuse attenuation coefficient are calculated using the echo signal of the dual-wavelength Brillouin scattering channel, and the vertical profile of the lidar backscattering coefficient is further calculated using the echo signal of the dual-wavelength Mie scattering channel; (3) The vertical profile of the phytoplankton absorption coefficient is calculated and finally the vertical profile distribution of the ocean primary productivity along the lidar track is inverted.

2. The method for inverting ocean primary productivity based on airborne dual-wavelength lidar remote sensing data according to claim 1 is characterized in that: If the airborne dual-wavelength laser radar is an airborne dual-wavelength Mie scattering laser radar, the specific implementation process of steps (2) to (4) is as follows: Take the depth of a certain boundary value detected by the laser radar as z B , then the laser radar attenuation coefficient at wavelength λ1 is expressed as: The laser radar attenuation coefficient at wavelength λ2 is expressed as: Where λ1 and λ2 are both laser wavelengths; Based on the laser radar attenuation coefficients in the λ1 and λ2 bands, the diffuse attenuation coefficient K is further obtained. d (λ1, z) and K d (λ2, z); Calculate the volume scattering coefficient β of dual-wavelength lidar π radians π (λ1, z) and β π (λ2, z): Assuming that the volume scattering coefficient of ocean water at π radians is the sum of uniform water optical parameters that do not vary with depth and non-uniform water optical parameters that vary with depth, then: The volume scattering coefficient of ocean water at λ1 wavelength π radians β π (λ1, z) is expressed as: Where S(λ1, z) is the total lidar echo signal generated by the λ1 laser, S h (λ1, z) is the lidar echo signal generated by the λ1 laser in the uniform water body, is the volume scattering coefficient of π radians generated by the λ1 laser in the uniform water body; The volume scattering coefficient of ocean water at λ2 wavelength π radians β π (λ2, z) is expressed as: Where S(λ2, z) is the total lidar echo signal generated by the λ2 laser, S h (λ2, z) is the lidar echo signal generated by the λ2 laser in the uniform water body, is the volume scattering coefficient of π radians generated by λ2 laser in uniform water; Calculate the backscattering coefficient of the lidar based on the volume scattering coefficient of the ocean water body of π radians in the λ1 and λ2 bands and Where χ is the conversion factor between the volume scattering coefficient of the ocean water body and the particle backscattering coefficient, b bw (λ1) is the backscattering coefficient of pure seawater at wavelength λ1, b bw (λ2) is the backscattering coefficient of pure seawater at wavelength λ2; Calculate the vertical profile of the dual-wavelength total water absorption coefficient along the lidar track and Calculate vertical profiles of phytoplankton absorption coefficients along lidar tracks Among them, a w (λ1, z) is the absorption coefficient of pure seawater at wavelength λ1, a w (λ2, z) is the absorption coefficient of pure seawater at wavelength λ2, a dg (λ1, z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ1, a dg (λ2, z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ2, a0(λ1), a1(λ1), b0(λ2) and b1(λ2) are correlation coefficients; Calculate the vertical profile of ocean primary productivity PP along the lidar track lidar (z): where φ is the quantum yield of phytoplankton photosynthesis and E(λ,z) ​​is the solar irradiance at wavelength λ and depth z.

3. The method for inverting ocean primary productivity based on airborne dual-wavelength lidar remote sensing data according to claim 1 is characterized in that: If the airborne dual-wavelength laser radar is an airborne dual-wavelength high spectral resolution laser radar, the corresponding steps (2) to (3) are specifically implemented as follows: Based on the seawater Brillouin scattering echo signal S b (λ, z), calculate the lidar attenuation coefficient The laser radar attenuation coefficient at wavelength λ1 is expressed as: The laser radar attenuation coefficient at wavelength λ2 is expressed as: in, is the Brillouin backscattering coefficient of seawater at λ1, is the Brillouin backscattering coefficient of seawater at λ2, n is the refractive index of seawater, and H is the flight altitude of the airborne laser radar; Based on the lidar attenuation coefficients of the λ1 and λ2 bands, the diffuse attenuation coefficient is further obtained and Based on the attenuation coefficient of dual-wavelength laser radar and The volume scattering coefficient of the dual-wavelength LiDAR at π radians is further obtained through the airborne dual-wavelength Mie scattering LiDAR echo signal. and Volume scattering coefficient of dual-wavelength ocean water based on π radians and Calculating the Backscatter Coefficient of Dual-Wavelength LiDAR )and Where χ is the conversion factor between the volume scattering coefficient of the ocean water body and the particle backscattering coefficient, b bw (λ1) is the backscattering coefficient of pure seawater at wavelength λ1, b bw (λ2) is the backscattering coefficient of pure seawater at wavelength λ2; Calculate the vertical profile of the dual-wavelength total water absorption coefficient along the lidar track and Calculate vertical profiles of phytoplankton absorption coefficients along lidar tracks Among them, a w (λ1, z) is the absorption coefficient of pure seawater at wavelength λ1, a w (λ2, z) is the absorption coefficient of pure seawater at wavelength λ2, a dg (λ1, z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ1, a dg (λ2, z) is the absorption coefficient of debris and colored soluble organic matter at wavelength λ2, a0(λ1), a1(λ1), b0(λ2) and b1(λ2) are correlation coefficients; Calculate the vertical profile of ocean primary productivity PP along the lidar track HSRL (z): where φ is the quantum yield of phytoplankton photosynthesis and E(λ,z) ​​is the solar irradiance at wavelength λ and depth z.

4. The method for inverting ocean primary productivity based on airborne dual-wavelength lidar remote sensing data according to claim 1, characterized in that: The two laser wavelengths of the airborne dual-wavelength laser radar are 532nm and 486nm respectively.

5. The method for inverting ocean primary productivity based on airborne dual-wavelength lidar remote sensing data according to claim 1, characterized in that: The value of λ3 is 440nm.

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