Evaporation waveguide diagnosis method under unstable condition

Abstract

The invention provides an evaporation waveguide diagnosis method under an unstable condition. The method comprises the following steps: acquiring sea surface meteorological and hydrological data; on the basis of the sea surface meteorological and hydrological data, boundary layer characteristic parameters are calculated through a non-iterative flux algorithm; according to a flux corridor line relation determined by the boundary layer characteristic parameters, the evaporation waveguide height is calculated; and reconstructing an atmosphere correction refractive index corridor line according to the evaporation waveguide height. Thus, the height of the evaporation waveguide can be calculated under the unstable condition, the near sea surface atmosphere correction refractive index profile is reconstructed, and the reconstruction accuracy of the atmosphere correction refractive index profile is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of environmental monitoring, and in particular to an evaporation waveguide diagnosis method under unstable conditions. Background Art

[0002] The atmospheric refractive index structure caused by the combined effect of seawater evaporation and turbulent vertical diffusion will cause the propagation direction of electromagnetic waves to bend downward. When the bending curvature is smaller than the curvature of the earth, a waveguide effect is formed, which we call an evaporation waveguide.

[0003] The evaporation duct height is an important characteristic of the evaporation duct, an important parameter to characterize the duct strength, and an important parameter to determine the impact of the evaporation duct on electronic equipment. There are many existing technologies for determining the evaporation duct height, such as PJ mode, MGB mode, Babin mode, NPS mode, etc., but their basic principles are the same, all relying on the Monin-Obukhov similarity theory, but the methods used to determine the near-surface flux and characteristic scale are different.

[0004] The general evaporation duct diagnostic model is obtained from the atmospheric momentum conservation equation. The flux profile relationship applicable to horizontal stable conditions is obtained by applying the scaling method, algebraic transformation and other processes. However, in coastal areas, the horizontal atmosphere is not uniform due to the effects of sea and land breezes, terrain, etc., so this relationship is no longer applicable. Therefore, a method that can calculate the evaporation duct height under unstable conditions is urgently needed. Summary of the invention

[0005] The purpose of the present invention is to provide an evaporation duct diagnostic method under unstable conditions, which can calculate the evaporation duct height under unstable conditions and reconstruct the near-sea surface atmospheric corrected refractive index profile, thereby effectively improving the accuracy of atmospheric corrected refractive index profile reconstruction.

[0006] In order to achieve the above object, the present invention provides an evaporation waveguide diagnosis method under unstable conditions, comprising the steps of:

[0007] Obtain sea surface meteorological and hydrological data;

[0008] Based on the sea surface meteorological and hydrological data, boundary layer characteristic parameters are calculated by a non-iterative flux algorithm;

[0009] Calculating the evaporation duct height according to the flux corridor relationship determined by the boundary layer characteristic parameters;

[0010] The atmospheric correction refractive index corridor is reconstructed according to the evaporation duct height.

[0011] Furthermore, the calculating of boundary layer characteristic parameters by a non-iterative flux algorithm based on the sea surface meteorological and hydrological data includes:

[0012] The atmospheric stratification state is divided into regions according to the aerodynamic roughness length and thermodynamic roughness length in the sea surface meteorological and hydrological data, and the formula R ib =∑C mn log m (L 0 )(L 0i -L 0 ) n and Calculate the overall Richardson number R ib and parameter ξ; where L 0i =log(z / z 0i ), z is the height, i is marked as q or m, z 0q represents the water vapor roughness length, z 0m represents the aerodynamic roughness length, C mn and C ijk is a preset constant;

[0013] By introducing nonlinear correction factors under unstable conditions of the equations of the stability correction function, the stability correction function and the MO length are calculated;

[0014] Calculating the wind speed characteristic scale, the temperature characteristic scale and the humidity characteristic scale according to the wind speed, the potential temperature and the humidity in the sea surface meteorological and hydrological data and the difference of the wind speed, the potential temperature and the humidity at the sea-air interface;

[0015] Calculating turbulent flux and sensible heat flux according to the wind speed characteristic scale and the temperature characteristic scale;

[0016] The coefficients of the flux corridor relationship are calculated according to the turbulent flux and the sensible heat flux.

[0017] Furthermore, the expression of the equation group of the stability correction function is:

[0018]

[0019] The nonlinear correction factor is:

[0020] The MO length is calculated based on the following formula:

[0021]

[0022] Wherein, a = 6.1, b = 2.5, c = 5.3, d = 1.1; k is the von Karman constant, k = 0.4; is the average value of the potential temperature θ in the vertical direction, Δθ is the difference of the potential temperature θ in the vertical direction, and g is the gravitational acceleration.

[0023] Further, the wind speed characteristic scale, the temperature characteristic scale and the humidity characteristic scale are calculated based on the wind speed, potential temperature, humidity and the difference of the wind speed, the potential temperature and the humidity at the sea-air interface in the sea surface meteorological and hydrological data, including:

[0024] Substitute the wind speed, potential temperature, humidity in the sea surface meteorological and hydrological data and the difference between the wind speed, potential temperature and humidity at the sea-air interface into the formula To calculate the wind speed characteristic scale Temperature characteristic scale and humidity characteristic scale in, k x is the transport coefficient, S is the average wind speed measured by the sensor, C d is the drag coefficient, x′ takes the value of u′, θ′ or q′; u′, θ′ and q′ represent the disturbances of wind speed u, potential temperature θ and humidity q respectively, and Δx represents the difference of the variables wind speed u, potential temperature θ or humidity q at the sea-air interface.

[0025] Furthermore, the turbulent flux is calculated based on the following formula:

[0026]

[0027] The sensible heat flux is calculated based on the following formula:

[0028] H=-ρC·u * ·θ * .

[0029] Where ρ is the gas concentration, C is the drag coefficient, and u * is the characteristic scale of wind speed, θ * Temperature characteristic scale, C = 1.3 × 10 -3 .

[0030] Furthermore, the flux corridor relationship is expressed as:

[0031]

[0032] Among them, z is the height, the coefficient coefficient coefficient coefficient x represents the horizontal distance, k is the von Karman constant, k=0.4.

[0033] Furthermore, the evaporation waveguide height is calculated based on the following formula:

[0034]

[0035] Among them, C 1=0.12, C 2 =0.22, C 3 =0.4, C 4 =0.6; z d is the evaporation waveguide height, k is the von Karman constant, k = 0.4.

[0036] The evaporation duct diagnostic method under unstable conditions of the present invention obtains sea surface meteorological and hydrological data; based on the sea surface meteorological and hydrological data, the boundary layer characteristic parameters are calculated by a non-iterative flux algorithm; the evaporation duct height is calculated according to the flux corridor relationship determined by the boundary layer characteristic parameters; and the atmospheric correction refractive index corridor is reconstructed according to the evaporation duct height. The present invention introduces a nonlinear correction factor and introduces a flux profile relationship under unstable conditions on the basis of the Babin model, so that the evaporation duct height can be calculated under unstable conditions, and the atmospheric correction refractive index profile near the sea surface is reconstructed, which effectively improves the accuracy of the atmospheric correction refractive index profile reconstruction. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A flow chart showing the steps of the evaporation waveguide diagnostic method under unstable conditions provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] It should be noted that references to "one embodiment", "embodiment", "example embodiment", etc. in this specification refer to the embodiment described, which may include specific features, structures or characteristics, but not every embodiment must include these specific features, structures or characteristics. In addition, such expressions do not refer to the same embodiment. Furthermore, when describing specific features, structures or characteristics in conjunction with an embodiment, whether or not there is an explicit description, it has been shown that it is within the knowledge of those skilled in the art to combine such features, structures or characteristics into other embodiments.

[0040] In addition, certain words are used in the specification and subsequent claims to refer to specific components or parts. Those with ordinary knowledge in the relevant field should understand that manufacturers can use different nouns or terms to refer to the same component or part. This specification and subsequent claims do not use differences in names as a way to distinguish components or parts, but use differences in the functions of components or parts as the criteria for distinction. "Including" and "including" mentioned throughout the specification and subsequent claims are open-ended terms and should be interpreted as "including but not limited to". In addition, the word "connected" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connection through other devices.

[0041] Figure 1 An evaporation waveguide diagnostic method under unstable conditions provided by an embodiment of the present invention includes the following steps:

[0042] S101: Acquire sea surface meteorological and hydrological data; specifically, the sea surface meteorological and hydrological data may be acquired through single or combined methods such as ocean observation stations, satellite remote sensing, and ship observation; the sea surface meteorological and hydrological data of this embodiment includes but is not limited to wind speed U, temperature T, humidity Q, roughness length z 0 , thermodynamic roughness length z 0t , water vapor roughness length z 0q , gas concentration ρ, sea surface gas concentration ρ 0 , sea surface temperature T 0 and sea surface wind speed U 0 wait.

[0043] S102: Based on the sea surface meteorological and hydrological data, the boundary layer characteristic parameters are calculated by a non-iterative flux algorithm; the boundary layer characteristic parameters to be calculated in this embodiment include the wind speed characteristic scale u * , temperature characteristic scale θ * , humidity characteristic scale q * , MO length L, potential temperature equation constant (A θ , B θ ) and the humidity equation constant (A q , B q ).

[0044] In specific implementation, step S102 includes:

[0045] S1: The atmospheric stratification state is divided into regions according to the aerodynamic roughness length and thermodynamic roughness length in the sea surface meteorological and hydrological data, and the atmospheric stratification state is divided into regions according to the formula R ib =∑C mn log m (L 0 )(L 0i -L 0 )n and Calculate the overall Richardson number R ib and parameter ξ; where L 0i =log(z / z 0i ), z is the height, i is marked as q or m, z 0q represents the water vapor roughness length, z 0m represents the aerodynamic roughness length, C mn和 C ijk is a preset constant; specifically, when the aerodynamic roughness length z is known 0 , thermodynamic roughness length z 0t and water vapor roughness length Z 0q , according to z / z 0 、z / z 0 The atmospheric stratification state is divided into 8 different regions, as shown in Table 1 below:

[0046] Table 1:

[0047] area <![CDATA[z / z 0 ]]> <![CDATA[z 0 / With 0t ]]> 1 10～160 0.607～100 2 <![CDATA[160~1×10 5 ]]> 0.607～100 3 10～80 <![CDATA[100~1×10 7 ]]> 4 <![CDATA[80~1×10 5 ]]> <![CDATA[100~1x10 7 ]]> 5 10～40 <![CDATA[1x10 7 ~1×10 11 ]]> 6 <![CDATA[40~1×10 5 ]]> <![CDATA[1x10 7 ~1×10 11 ]]> 7 10～40 <![CDATA[1x10 11 ~1.07×10 13 ]]> 8 <![CDATA[40~1×10 5 ]]> <![CDATA[1x10 11 ~1.07×10 13 ]]>

[0048] Furthermore, according to formula R ib =∑C mn log m (L 0 )(L 0i -L 0 ) n and (m, n = 1, 2; i, j, k = 1, 2, 3) calculate the overall Richardson number R ib and parameter ξ, where C mn and C ijk is the preset constant, C mn and C ijk The value of can be obtained by referring to Table 2-Table 3.

[0049] Table 2:

[0050] coefficient C00 C10 C20 C01 C11 C21 C02 C12 Rib 0.3095 -0.285 2 -0.285 2 0.079 55 -0.016 05 0 0 -1.079×10-*

[0051] Table 3:

[0052]

[0053]

[0054] S2: By introducing a nonlinear correction factor under the unstable conditions of the equation group of the stability correction function, the stability correction function and the MO length are calculated.

[0055] The expression of the equation group of the stability correction function is:

[0056]

[0057] The nonlinear correction factor is:

[0058] The MO length is calculated based on the following formula:

[0059]

[0060] Wherein, a = 6.1, b = 2.5, c = 5.3, d = 1.1; k is the von Karman constant, k = 0.4; is the average value of the potential temperature θ in the vertical direction, Δθ is the difference of the potential temperature θ in the vertical direction, and g is the gravitational acceleration.

[0061] That is, this embodiment introduces a nonlinear correction factor a under unstable conditions according to the above equation. v , Thus, the stability correction function can be calculated from the parameter ξ and As well as the MO length L, the vertical temperature difference Δθ can be measured by the sensor, and the value of g is 9.8m / s 2 .

[0062] S3: Calculate the wind speed characteristic scale, the temperature characteristic scale and the humidity characteristic scale according to the wind speed, the potential temperature and the humidity in the sea surface meteorological and hydrological data and the difference of the wind speed, the potential temperature and the humidity at the sea-air interface.

[0063] In the specific implementation, the wind speed, potential temperature, humidity in the sea surface meteorological and hydrological data and the difference of the wind speed, potential temperature and humidity at the sea-air interface are substituted into the formula: To calculate the wind speed characteristic scale Temperature characteristic scale and humidity characteristic scale in, k x is the transport coefficient, S is the average wind speed measured by the sensor, C d is the drag coefficient, x′ takes the value of u′, θ′ or q′; u′, θ′ and q′ represent the disturbances of wind speed u, potential temperature θ and humidity q respectively, and Δx represents the difference of the variables wind speed u, potential temperature θ or humidity q at the sea-air interface.

[0064] according to x is m, h or q, from which the transport coefficient K can be calculated m , K h , K q ; and then through S is the average wind speed measured by the sensor, Cd is the drag coefficient, which is 1.3×10 -3 , Indicates the transport coefficient K m , K h , K q 1 / 2 power, where x is selected according to the x′ variable. For example, x′ is replaced by u′, and the characteristic scale of wind speed can be calculated at this time Replace x′ with θ′ and calculate the temperature characteristic scale at this time Replace x′ with q′ to calculate the temperature characteristic scale at this time u′, θ′ and q′ represent the disturbances of wind speed u, potential temperature θ or humidity q, Δx represents the difference of variable wind speed u, potential temperature θ or humidity q at the sea-air interface, and u′, θ′, q′ and Δx can be measured by instruments.

[0065] S4: Calculate the turbulent flux and the sensible heat flux according to the wind speed characteristic scale and the temperature characteristic scale; Combined with the above examples, this embodiment specifically calculates the turbulent flux and the sensible heat flux according to the wind speed characteristic scale u * , temperature characteristic scale θ * The turbulent flux τ and the sensible heat flux H are calculated.

[0066] The turbulent flux is calculated based on the following formula:

[0067]

[0068] The sensible heat flux is calculated based on the following formula:

[0069] H=-ρC·u * ·θ * ;

[0070] Where ρ is the gas concentration, C is the drag coefficient, and u * is the characteristic scale of wind speed, θ * Temperature characteristic scale, C = 1.3 × 10 -3 .

[0071] S5: Calculate the coefficients of the flux corridor relationship according to the turbulent flux and the sensible heat flux.

[0072] The expression of the flux corridor relationship is:

[0073]

[0074]

[0075] After the turbulent flux τ and the sensible heat flux H are calculated in the above step S4, the coefficient k is a constant of 0.4, z is the height, and x is the horizontal distance in meters. and The variable wind speed u, potential temperature θ or humidity q in step S3 can be directly replaced by the difference in the sea-air interface.

[0076] Thus, through step S102, the flux corridor relationship equation can be obtained: A θ , B θ , A q , B q ,θ * ,q * , z is the height, unit is m; the constant k in the above is 0.4.

[0077] S103: Calculating the evaporation duct height according to the flux corridor relationship determined by the boundary layer characteristic parameters. After the expression of the flux corridor relationship is determined, the evaporation duct height is further calculated based on it.

[0078] The evaporation guide height of this embodiment is calculated based on the following formula:

[0079]

[0080] Among them, C 1 =0.12, C 2 =0.22, C 3 =0.4, C 4 =0.6; z d is the evaporation waveguide height, k is the von Karman constant, k = 0.4.

[0081] S104: Reconstructing the atmospheric correction refractive index corridor according to the evaporation duct height. After the evaporation duct height is obtained, the atmospheric correction refractive index corridor is reconstructed based on it:

[0082]

[0083] In summary, the evaporation duct diagnostic method under unstable conditions of the present invention obtains sea surface meteorological and hydrological data; based on the sea surface meteorological and hydrological data, the boundary layer characteristic parameters are calculated by a non-iterative flux algorithm; the evaporation duct height is calculated according to the flux corridor relationship determined by the boundary layer characteristic parameters; and the atmospheric corrected refractive index corridor is reconstructed according to the evaporation duct height. The present invention fully considers the influence of the unstable atmospheric environment, introduces a nonlinear correction factor, and introduces a flux profile relationship under unstable conditions on the basis of the Babin model, so that the evaporation duct height can be calculated under unstable conditions, and the atmospheric corrected refractive index profile of the near-sea surface is reconstructed, which effectively improves the accuracy of the atmospheric corrected refractive index profile reconstruction.

[0084] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for evaporation waveguide diagnosis under unstable conditions, characterized in that: Includes steps: Obtain sea surface meteorological and hydrological data; Based on the sea surface meteorological and hydrological data, boundary layer characteristic parameters are calculated by a non-iterative flux algorithm; Calculating the evaporation duct height according to the flux corridor relationship determined by the boundary layer characteristic parameters; The atmospheric correction refractive index corridor is reconstructed according to the evaporation duct height.

2. The evaporation waveguide diagnostic method under unstable conditions according to claim 1, characterized in that: The calculating of boundary layer characteristic parameters by a non-iterative flux algorithm based on the sea surface meteorological and hydrological data comprises: The atmospheric stratification state is divided into regions according to the aerodynamic roughness length and thermodynamic roughness length in the sea surface meteorological and hydrological data, and the formula R ib =∑C mn log m (L0)(L 0i -L0) n and Calculate the overall Richardson number R ib and parameter ξ; where L 0i =log(z / z 0i ), z is the height, i is marked as q or m, z 0q represents the water vapor roughness length, z 0m represents the aerodynamic roughness length, C mn and C ijk is a preset constant; By introducing nonlinear correction factors under unstable conditions of the equations of the stability correction function, the stability correction function and the MO length are calculated; Calculate the wind speed characteristic scale, the temperature characteristic scale and the humidity characteristic scale according to the wind speed, the potential temperature and the humidity in the sea surface meteorological and hydrological data and the difference of the wind speed, the potential temperature and the humidity at the sea-air interface; Calculating turbulent flux and sensible heat flux according to the wind speed characteristic scale and the temperature characteristic scale; The coefficients of the flux corridor relationship are calculated according to the turbulent flux and the sensible heat flux.

3. The evaporation waveguide diagnostic method under unstable conditions according to claim 2, characterized in that: The expression of the equation group of the stability correction function is: The nonlinear correction factor is: The MO length is calculated based on the following formula: Wherein, a = 6.1, b = 2.5, c = 5.3, d = 1.1; k is the von Karman constant, k = 0.4; is the average value of the potential temperature θ in the vertical direction, Δθ is the difference in potential temperature θ between adjacent atmospheric layers in the vertical direction, and g is the gravitational acceleration.

4. The evaporation waveguide diagnostic method under unstable conditions according to claim 3, characterized in that: The calculation of the wind speed characteristic scale, the temperature characteristic scale and the humidity characteristic scale based on the wind speed, the potential temperature, the humidity and the difference of the wind speed, the potential temperature and the humidity at the sea-air interface in the sea surface meteorological and hydrological data includes: Substitute the wind speed, potential temperature, humidity in the sea surface meteorological and hydrological data and the difference between the wind speed, potential temperature and humidity at the sea-air interface into the formula To calculate the wind speed characteristic scale Temperature characteristic scale and humidity characteristic scale in, k x is the transport coefficient, S is the average wind speed measured by the sensor, C d is the drag coefficient, x′ takes the value of u′, θ′ or q′; u′, θ′ and q′ represent the disturbances of wind speed u, potential temperature θ and humidity q respectively, and Δx represents the difference of the variables wind speed u, potential temperature θ or humidity q at the sea-air interface.

5. The evaporation waveguide diagnostic method under unstable conditions according to claim 4, characterized in that: The turbulent flux is calculated based on the following formula: The sensible heat flux is calculated based on the following formula: H=-ρCu * i * ; Where ρ is the gas concentration, C is the drag coefficient, and u * is the characteristic scale of wind speed, θ * Temperature characteristic scale C = 1.3 × 10 -3 .

6. The evaporation waveguide diagnostic method under unstable conditions according to claim 5, characterized in that: The expression of the flux corridor relationship is: Among them, z is the height, the coefficient coefficient coefficient coefficient k is the von Karman constant, k=0.4, and x represents the horizontal distance.

7. The evaporation waveguide diagnostic method under unstable conditions according to claim 6, characterized in that: The evaporation duct height is calculated based on the following formula: Among them, C1 = 0.12, C2 = 0.22, C3 = 0.4, C4 = 0.6; d is the evaporation waveguide height, and k is the von Karman constant.

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