Analysis method for polarization remote sensing oil contamination detection influenced by atmosphere

Abstract

The invention provides an analysis method for polarization remote sensing oil contamination detection influenced by atmosphere. The method comprises the following steps of: A1, coupling a bidirectional polarization reflectivity model of a sea surface into a vector radiation transmission model; a2, simulating and calculating atmosphere top polarization radiation information after seawater and atmosphere are coupled under different atmosphere conditions by using the coupled vector radiation transmission model; a3, the complex refractive index of seawater is set to be the complex refractive index of oil, and the coupled vector radiation transmission model is used for simulating and calculating atmosphere top polarization radiation information after oil and atmosphere are coupled under the atmosphere condition; a4, calculating atmosphere top polarization information differences of seawater-atmosphere coupling and oil-atmosphere coupling under corresponding observation geometry and atmosphere conditions; and A5, comparing the difference change conditions of the seawater-atmosphere coupling atmosphere top polarization information and the oil-atmosphere coupling atmosphere top polarization information under different atmosphere conditions, and analyzing the influence of the atmosphere on oil contamination detection based on the polarization information. The method can be used for analyzing the influence of atmosphere on satellite polarization remote sensing sea surface oil spill detection, and can be widely applied to the field of polarization remote sensing sea surface target detection.

Description

(I) Technical field

[0001] The invention relates to an analysis method of atmospheric influence on polarization remote sensing oil pollution detection, which analyzes the influence of atmosphere on satellite polarization remote sensing sea surface oil spill detection and belongs to the field of polarization remote sensing. (II) Background technology

[0002] Oil spill at sea is a serious marine pollution factor, which will cause the destruction of marine ecosystems, damage the quality of seawater, endanger human health, and hinder basic human activities at sea. For example, some sudden accidents have caused large areas of seawater to be covered with oil films, resulting in the death of a large number of marine organisms, seriously affecting the use value of marine products. After the oil spill on the sea surface, whether the scope and area of ​​the oil spill can be detected in a timely and accurate manner is of great significance to controlling the spread of the oil spill, carrying out rescue work and protecting the marine ecology. It is also helpful for the treatment and loss assessment of oil spill pollution accidents on the sea surface. Under the irradiation of the sun, the oil film on the sea surface will appear brighter or darker than the background water body in different reflection areas. This is closely related to the observation geometry of optical remote sensing (solar zenith angle, satellite zenith angle, relative azimuth angle), and has become an important theoretical basis for the detectability of optical remote sensing of oil spill on the sea surface.

[0003] In the reflected optical information of oil spills on the sea surface, its polarization information has great differences. This significant difference in electromagnetic characteristics can serve as an effective supplement to the spectral response characteristics and band reflectivity information, which helps optical remote sensing technology to better detect oil spills on the sea surface. There are significant differences in optical polarization signals between oil spills on the sea surface and background seawater. Polarization remote sensing is also an important way to detect oil spills on the sea surface. Marine oil spill detection based on polarization information mainly distinguishes between sea oil and oil based on polarization information differences such as the difference in bidirectional polarization reflection between seawater and oil. However, for satellite remote sensing, the polarization information of seawater and oil detected by the detector has been coupled with the atmosphere, and is not the polarization information of real oil and seawater. The presence of the atmosphere will affect the detection of oil pollution on the sea surface based on polarization information. However, there is currently no method to quantitatively analyze the impact of the atmosphere on the detection of oil pollution on the sea surface based on polarization information.

[0004] The present invention discloses an analysis method for the atmospheric influence on polarized remote sensing oil spill detection. The method couples a bidirectional polarized reflection model of seawater and oil into a vector radiation transmission model, and respectively simulates and calculates polarization information of the top of the atmosphere in two cases where the underlying surface is seawater or oil under different atmospheric conditions. The influence of the atmosphere on the sea surface oil spill detection based on polarization information is analyzed by utilizing the difference between the polarization information of the seawater-atmosphere coupling and the polarization information of the oil-atmosphere coupling as the atmosphere changes. (III) Summary of the invention

[0005] The purpose of the present invention is to provide a method capable of quantitatively analyzing the influence of atmospheric aerosols on sea surface oil spill detection based on polarization information.

[0006] The purpose of the present invention is achieved through the following technical means:

[0007] An analysis method for atmospheric influence on polarization remote sensing oil pollution detection, comprising:

[0008] A1, coupling the bidirectional polarization reflectivity model of the sea surface to the vector radiative transfer model;

[0009] A2, using the coupled vector radiation transfer model to simulate and calculate the polarized radiation information of the top of the atmosphere after the coupling of seawater and atmosphere under different atmospheric conditions;

[0010] A3, the complex refractive index of seawater is set to the complex refractive index of oil, and the coupled vector radiation transfer model is used to simulate and calculate the polarized radiation information of the top of the atmosphere after the oil and atmosphere are coupled under atmospheric conditions;

[0011] A4, calculate the difference in top-of-atmosphere polarization information between seawater-atmosphere coupling and oil-atmosphere coupling under corresponding observation geometry and atmospheric conditions;

[0012] A5. Compare the changes in the top-of-atmosphere polarization information of seawater-atmosphere coupling and oil-atmosphere coupling under different atmospheric conditions, and analyze the impact of the atmosphere on oil pollution detection based on polarization information.

[0013] Furthermore, the sea surface and oil bidirectional polarization reflectivity (BPDF) model in A1 is calculated by the Cox-Munk model, and the BPDF can be expressed as:

[0014]

[0015] in

[0016] in and It can be further calculated by the following formula

[0017]

[0018] Among them, θ i and θ t are the angle of incidence and the angle of refraction respectively; n 1 and n 2 are the atmospheric refractive index and the complex refractive index of seawater (or oil) respectively.

[0019] When the Cox-Munk model is used to calculate the BDPF of seawater and oil under the same observation conditions, only the complex refractive index is different. Therefore, the BPDF of seawater and oil can be calculated by modifying the corresponding refractive index. The calculation results are as follows:Figure 1 shown.

[0020] Furthermore, the vector radiation transfer model used in the coupling of the BPDF and the vector radiation transfer model in A1 is a Monte Carlo vector radiation transfer model, which can simulate and calculate the polarization radiation characteristics after ground-atmosphere coupling based on the BPDF model.

[0021] Furthermore, the polarization information difference in A4 is the difference between the polarization information of seawater and the polarization information of oil simulated under the same observation geometry (solar zenith angle, observation zenith angle, solar azimuth angle, observation azimuth angle) and the same atmospheric conditions (same aerosol type and optical thickness), i.e., the degree of polarization difference ΔDOP, the polarization reflectivity difference ΔRp, etc. Figure 2 Demonstrates polarization differences.

[0022] The beneficial effects of the present invention are as follows: the present invention is a method for analyzing the influence of the atmosphere on sea surface oil spill detection based on polarization information based on radiation simulation data. The method can quantitatively analyze the influence of atmospheric aerosol optical thickness on polarization remote sensing sea surface oil pollution detection, and can effectively guide the applicable environment and atmospheric correction ideas for sea surface oil spill detection based on polarization information, thereby improving the accuracy of sea surface oil spill detection. (IV) Description of the drawings

[0023] Figure 1 The BPDFs of seawater and oil are calculated based on the Cox-Munk model, with the solar zenith angle set to 53°, the wind speed set to 1 m / s, the refractive index of seawater set to 1.33, and the refractive index of oil set to 1.5.

[0024] Figure 2 is the difference in polarization degree between seawater and oil, with the solar zenith angle set to 53°, the wind speed set to 1 m / s, the refractive index of seawater set to 1.33, and the refractive index of oil set to 1.5.

[0025] Figure 3 The present invention is a flow chart of an analysis method of atmospheric influence on polarized remote sensing oil pollution detection. (V) Specific implementation methods

[0026] The present invention will be further described below in conjunction with specific embodiments.

[0027] like Figure 3 As shown, the present invention provides an analysis method for atmospheric influence on polarization remote sensing oil pollution detection, comprising:

[0028] A1, coupling the bidirectional polarization reflectivity model of the sea surface to the vector radiative transfer model;

[0029] A2, using the coupled vector radiation transfer model to simulate and calculate the polarized radiation information of the top of the atmosphere after the coupling of seawater and atmosphere under different atmospheric conditions;

[0030] A3, the complex refractive index of seawater is set to the complex refractive index of oil, and the coupled vector radiation transfer model is used to simulate and calculate the polarized radiation information of the top of the atmosphere after the oil and atmosphere are coupled under atmospheric conditions;

[0031] A4, calculate the difference in top-of-atmosphere polarization information between seawater-atmosphere coupling and oil-atmosphere coupling under corresponding observation geometry and atmospheric conditions;

[0032] A5. Compare the changes in the top-of-atmosphere polarization information of seawater-atmosphere coupling and oil-atmosphere coupling under different atmospheric conditions, and analyze the impact of the atmosphere on oil pollution detection based on polarization information.

[0033] Specifically, the sea surface bidirectional polarization reflectivity model in step A1 can be simulated and calculated by the Cox-Munk model, and the coupling of BPDF and the vector radiation transfer model can be calculated using the three-dimensional Monte Carlo vector radiation transfer code (mystic) in the LibRatran software package.

[0034] Specifically, the settings of different atmospheric conditions and observation conditions in step A2 and step A3 can be set with reference to the requirements of mystic for the input file parameter format, wherein the aerosol optical thickness is set to 0-3, and the longest is 0.1; the observation geometry is set to: the solar zenith angle is 0-65° with a step length of 1°, the observation zenith angle is 0-70° with a step length of 1°, and the relative azimuth angle is 0-360° with a step length of 1°; the complex refractive index of water and oil is set according to the actual observation wavelength.

[0035] Specifically, the polarization information difference in step A4 is calculated based on the Stokes obtained by the Mystic simulation calculation, specifically:

[0036]

[0037] Where I, Q, U are Stokes parameters, μ s is the cosine of the solar zenith angle, E 0 is the solar radiation flux at the top of the atmosphere.

[0038] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to specific embodiments, a person skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. An analytical method for atmospheric influence on polarization remote sensing oil pollution detection, characterized in that: The specific process of this method includes the following steps: A1, coupling the bidirectional polarization reflectivity model of the sea surface to the vector radiative transfer model; A2, using the coupled vector radiation transfer model to simulate and calculate the polarized radiation information of the top of the atmosphere after the coupling of seawater and atmosphere under different atmospheric conditions; A3, the complex refractive index of seawater is set to the complex refractive index of oil, and the coupled vector radiation transfer model is used to simulate and calculate the polarized radiation information of the top of the atmosphere after the oil and atmosphere are coupled under atmospheric conditions; A4, calculate the difference in top-of-atmosphere polarization information between seawater-atmosphere coupling and oil-atmosphere coupling under corresponding observation geometry and atmospheric conditions; A5. Compare the changes in the top-of-atmosphere polarization information of seawater-atmosphere coupling and oil-atmosphere coupling under different atmospheric conditions, and analyze the impact of the atmosphere on oil pollution detection based on polarization information.

2. The method for analyzing atmospheric influence on polarization remote sensing oil pollution detection according to claim 1 is characterized by: The bidirectional polarization reflectivity model of the sea surface is coupled to the vector radiation transfer model. By setting the complex refractive index to the complex refractive index of water and the complex refractive index of oil, the coupled vector radiation transfer model is used to calculate the polarization information of the top of the atmosphere after seawater-atmosphere coupling and the polarization information of the top of the atmosphere after oil-atmosphere coupling under different atmospheric conditions, so as to analyze the influence of the atmosphere on oil pollution detection based on the difference in polarization information of oil and seawater.

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