CN105928620B - A kind of thermal infrared atmospheric correction parametric method based on look-up table - Google Patents
A kind of thermal infrared atmospheric correction parametric method based on look-up table Download PDFInfo
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Abstract
The invention discloses a kind of thermal infrared atmospheric correction parametric method based on look-up table, is made of following seven steps: the pretreatment of thermal infrared atmospheric correction, the layer-by-layer optical thickness estimation of constituent of atomsphere, optical thickness parameterized model coefficient determine, the calculating of layer-by-layer Atmospheric Characteristics parameter, the evaluation of integrals of Atmospheric Characteristics parameter, drift correction coefficient determines, Atmospheric Characteristics parameter error corrects.The present invention is by the way that SEQUENCING VERTICAL to be layered, the influence of linear steam, continuous steam and other gas components to thermal infrared observation data is considered respectively, again Atmospheric Characteristics parameter is successively parameterized, and combine thermal infrared parameterized model Coefficient Look-up Table, Atmospheric Characteristics parameter needed for high-precision acquisition thermal infrared atmospheric correction, that is atmospheric transmittance and atmosphere uplink and downlink spoke brightness, shorten the processing time of thermal infrared atmospheric correction, the efficiency for improving thermal infrared atmospheric correction realizes the real-time high-precision processing of thermal infrared atmospheric correction.
Description
Technical Field
The invention relates to an atmospheric correction method, in particular to a thermal infrared atmospheric correction parameterization method based on a lookup table.
Background
The primary task of the quantitative thermal infrared remote sensing research is to invert the surface temperature and emissivity with high precision, however, due to the existence of the atmosphere, the electromagnetic wave in the thermal infrared spectrum still reacts with various gas molecules and particles in the atmosphere even when passing through the atmosphere under the clear air condition, so that the thermal infrared radiation value of the surface is changed when reaching the sensor, and therefore, in order to accurately obtain the surface temperature and emissivity, the atmospheric information, namely the atmospheric transmittance and the up-down radiance, must be accurately obtained, further the influence of the atmosphere is eliminated, and accurate atmospheric correction is realized.
At present, the thermal infrared atmospheric correction method is mainly divided into two methods, namely an empirical-semi-empirical statistical method and a physical method. For the experience-semi-experience statistical method, the estimation of the atmospheric transmittance and the atmospheric uplink and downlink radiance is carried out by utilizing the quadratic statistical relationship between the total content of atmospheric water vapor and atmospheric parameters on the basis of obtaining the total content of atmospheric water vapor; the statistical method is lack of interpretation of a physical mechanism, a statistical regression coefficient depends on training data, the change of the atmospheric vertical section temperature and humidity cannot be effectively considered, the accuracy of atmospheric correction has high uncertainty, and the regional characteristic of the regression coefficient makes the empirical-semi-empirical statistical method not suitable for global-scale thermal infrared atmospheric correction. For the physical method, mainly on the basis of obtaining the synchronous atmospheric temperature and humidity profile, the atmospheric parameters under given conditions are simulated by using a radiation transmission model (such as MODTRAN), and the estimation of atmospheric transmittance and atmospheric uplink and downlink radiance is completed; although the physical method can fully consider the vertical change of the atmospheric temperature and humidity, and has high accuracy of atmospheric correction, the physical method cannot be effectively applied and popularized because the input parameters of the radiation transmission model used by the physical method are complex and cannot be easily mastered by non-professional personnel, and the execution speed is low, so that the real-time thermal infrared atmospheric correction requirement cannot be met.
Disclosure of Invention
In order to solve the defects of the technology, the invention provides a thermal infrared atmospheric correction parameterization method based on a lookup table.
In order to solve the technical problems, the invention adopts the technical scheme that: a thermal infrared atmospheric correction parameterization method based on a lookup table comprises the following seven steps:
s1, thermal infrared atmospheric correction pretreatment: according to the time and place of data acquired by the thermal infrared sensor, selecting a space-time matched atmospheric temperature and humidity profile corresponding to the pixel, converting the unit of potential height ZM of atmospheric temperature and humidity profile data into kilometers, converting the unit of atmospheric pressure P into hectopascal, and converting the unit of atmospheric temperature T into Kelvin and atmospheric humidity H2The units of O are converted to grams per cubic meter; dividing the atmosphere into 25 layers vertically, then linearly interpolating the potential height, the atmospheric temperature and the atmospheric humidity of the obtained atmospheric temperature and humidity profile to a reference atmospheric pressure position, and simultaneously obtaining the observation zenith angle of the pixel;
s2, atmospheric component layer-by-layer optical thickness estimation: the atmospheric air is vertically layered, and the optical thickness of the atmospheric layer I of the ith channel of the thermal infrared sensor is expressed as the contribution of three parts, namely linear absorption of water vapor, continuous absorption of water vapor and other gas absorption, and is expressed by the formula (1):
wherein, taul,iThe total optical thickness of the ith channel atmosphere layer I atmosphere of the thermal infrared sensor,the optical thickness of the atmospheric layer of the linear water vapor ith channel,the optical thickness of the ith layer of the atmosphere is the continuous vapor ith channel,the optical thickness of the atmosphere I layer is the ith channel of other gases;
optical thickness of linear water vaporCan be obtained by calculation of formula (2):
wherein,an optical thickness calculation function representing linear water vapor;andis linear water vapor parameterizationModel coefficients, the values of which depend on the mean atmospheric temperature T of the l-th layerlAverage atmospheric pressure PlAnd a thermal infrared sensor channel i; exp represents an exponential function with a natural constant as the base; log represents a logarithmic function with a natural constant as a base;is the water vapor content on the vertical path of the first layer of the atmosphere; thetavObserving a zenith angle;
in the formula (2)Can be expressed as:
wherein ZMl,topAnd ZMl,botRespectively representing the potential heights of the top and the bottom of the first layer of the atmosphere; h2Ol,topAnd H2Ol,botRespectively, the atmospheric humidity at the top and bottom of the first layer of atmosphere; log represents a logarithmic function with a natural constant as a base; rat is the model intermediate variable with a value of (H)2Ol,top-H2Ol,bot)/H2Ol,bot。
II, optical thickness of continuous water vaporCan be obtained by calculation of formula (4):
wherein,an optical thickness calculation function representing continuous water vapor;andcontinuous water vapor parameterized model coefficients, the values of which depend on a thermal infrared sensor channel i; TFAC, AMTPselfAnd AMTPfrgnAre all model intermediate variables, and their values are respectively expressed as:
wherein, Pl,topAnd Pl,botRespectively representing the top and bottom atmospheric pressures of the first layer of the atmosphere; t isl,topAnd Tl,botRespectively representing the top and bottom atmospheric temperatures of the first layer of the atmosphere; ZMl,topAnd ZMl,botRespectively representing the top and bottom potential heights of the first layer of the atmosphere; log represents a logarithmic function with a natural constant as a base; thetavObserving a zenith angle;and(orAnd) Are model intermediate variables representing the water vapor self-broadening and the added broad absorption contribution of the top (or bottom) of the first layer of the atmosphere, respectively, and the values of the two are expressed as follows:
wherein, Pl,topAnd Pl,botRespectively representing the top and bottom atmospheric pressures of the first layer of the atmosphere; t isl,topAnd Tl,botRespectively representing the top and bottom atmospheric temperatures of the first layer of the atmosphere; h2Ol,topAnd H2Ol,botRespectively representing the top and bottom atmospheric humidity of the first layer of atmosphere; WHtopAnd WHbotIs a model intermediate variable whose value can be expressed as:
wherein, Tl,topAnd Tl,botRespectively representing the top and bottom atmospheric temperatures of the first layer of the atmosphere; exp denotes an exponential function with a natural constant as the base.
III, optical thickness of other gasesThe calculation formula of (2) is as follows:
wherein f isotherAn optical thickness calculation function representing other gases; d is the vertical thickness of the first layer of the atmosphere and is expressed as D ═ ZMl,top-ZMl,bot；ZMl,topAnd ZMl,botRespectively representing the potential heights of the top and the bottom of the first layer of the atmosphere;andare coefficients of a parameterized model of the optical thickness of the other gases, the values of which depend on the mean atmospheric temperature T of the l-th layerlAverage atmospheric pressure PlAnd a thermal infrared sensor channel i.
S3, determining the parameterized model coefficient of the optical thickness: the parameterized model coefficients of the linear water vapor and the optical thickness of other gases are obtained in a layer-by-layer determined mode, and the parameterized model coefficients of the continuous water vapor optical thickness are obtained in a non-layered integrally determined mode; if the parameterized model coefficients corresponding to the optical thickness of the thermal infrared sensor channel i have been obtained in advance, step S3 may be skipped directly;
constructing different atmospheric condition combinations in the process of obtaining the model coefficients; setting the observation zenith angles to be 0 degrees, 33.56 degrees, 44.42 degrees, 51.32 degrees, 56.25 degrees and 60 degrees respectively, using a radiation transmission model MODTRAN, considering the channel response function of a thermal infrared sensor channel i, and simultaneously obtaining the channel optical thickness of linear water vapor, continuous water vapor and other gases under different conditionsAndobtaining linear water by using least square mathematical optimization technology and layer-by-layer data regressionThe parameterized model coefficients of the optical thicknesses of the steam and other gases are obtained, all data are regressed to the parameterized model coefficients of the optical thicknesses of the continuous water vapor, a parameterized model coefficient lookup table of the optical thicknesses is established, and the parameterized model coefficients of the optical thicknesses of the linear water vapor, the continuous water vapor and other gases are stored;
s4, calculating the atmospheric characteristic parameters layer by layer: reading the interpolated atmospheric temperature and humidity profile and the observation zenith angle of the pixel of the thermal infrared sensor, and then calculating the optical thickness of the required atmospheric component layer by layer;
for the linear water vapor optical thickness, selecting the parameterized model coefficient of the corresponding channel according to the actual atmospheric temperature and atmospheric pressure of each layer, carrying out bilinear interpolation of the atmospheric temperature and the atmospheric pressure on the constructed parameterized model coefficient of the linear water vapor optical thickness to obtain the linear water vapor parameterized model coefficient corresponding to the actual atmospheric condition, and calculating the linear water vapor optical thickness
For the continuous water vapor optical thickness, calculating the continuous water vapor optical thickness according to the actual atmospheric temperature and atmospheric pressure of each layer and the parametric model coefficient of the corresponding channel and combining the constructed parametric model coefficient of the continuous water vapor optical thickness
For other gas optical thicknesses, selecting the parameterized model coefficients of the corresponding channels according to the actual atmospheric temperature and atmospheric pressure of each layer, performing bilinear interpolation of the atmospheric temperature and the atmospheric pressure on the constructed parameterized model coefficients of the other gas optical thicknesses to obtain other gas parameterized model coefficients corresponding to the actual atmospheric conditions, and calculating the optical thicknesses of other gases
Atmospheric permeability layer by layer<tl,i(θv)>The calculation of (2):
wherein,<tl,i(θv)>representing the estimated atmospheric first layer atmospheric transmission rate of the ith channel of the thermal infrared sensor; thetavRepresenting an observed zenith angle of the pixel; (ii) aRepresenting the estimated linear water vapor optical thickness of the ith channel atmospheric ith layer of the thermal infrared sensor;representing the estimated continuous water vapor optical thickness of the ith channel atmospheric ith layer of the thermal infrared sensor;indicating the estimated optical thickness of other gases of the ith channel atmospheric ith layer of the thermal infrared sensor;
II, atmospheric ascending radiance layer by layerThe calculation of (2):
wherein,representing the estimated ascending radiance of the ith channel atmosphere and the l layer atmosphere of the thermal infrared sensor;<tl,i(θv)>representing observation zenith angleθvEstimating the atmospheric first layer atmospheric transmission rate of the ith channel of the thermal infrared sensor; b is a Planck function; t islIs the average atmospheric temperature of the first layer of the atmosphere and is expressed as Tl＝0.5Tl,top+0.5Tl,bot，Tl,top、Tl,botRespectively the atmospheric temperature at the top and the bottom of the first layer of the atmosphere; lambda [ alpha ]iThe equivalent center wavelength of the ith channel of the thermal infrared sensor;
III, atmospheric descending radiance layer by layerThe calculation of (2):
wherein,representing the estimated descending radiance of the ith channel atmosphere and the l layer atmosphere of the thermal infrared sensor;<tl,i(θ53°)>the atmospheric air transmission rate of the ith channel of the thermal infrared sensor is estimated by adopting a formula (12) and setting the observation zenith angle theta to 53 degrees; b is a Planck function; t islIs the average atmospheric temperature of the first layer of the atmosphere and is expressed as Tl＝0.5Tl,top+0.5Tl,bot，Tl,top、Tl,botRespectively representing the atmospheric temperature at the top and the bottom of the first atmospheric layer; lambda [ alpha ]iThe equivalent center wavelength of the ith channel of the thermal infrared sensor;
s5, integral estimation of atmospheric characteristic parameters: the method for estimating the integral characteristic parameters according to the layer-by-layer atmospheric characteristic parameters comprises the following steps:
total atmospheric transmittance<ti(θv)>The calculation of (2):
wherein,<ti(θv)>for estimated observed zenith angle thetavThe total atmospheric transmittance of the ith channel of the corresponding thermal infrared sensor; pi is a mathematical successive multiplication symbol;<tl,i(θv)>for observing zenith angle thetavEstimating the atmospheric first layer atmospheric transmittance of the ith channel of the thermal infrared sensor;
II, total upward radiance of atmosphereThe calculation of (2):
wherein,estimating the total upward radiation brightness of the ith channel of the thermal infrared sensor; sigma is a mathematical summation symbol; pi is a mathematical successive multiplication symbol;<tk,i(θv)>for observing zenith angle thetavEstimating the atmospheric transmission rate of the ith channel and the kth layer of the ith channel of the thermal infrared sensor;estimating the ascending radiance of the ith channel atmosphere and the l layer atmosphere of the ith channel of the thermal infrared sensor;
III, total downward radiance of atmosphereThe calculation of (2):
wherein,estimating the total atmospheric downlink radiance of the ith channel of the thermal infrared sensor; sigma is a mathematical summation symbol; pi is a mathematical successive multiplication symbol;<tk,i(θ53°)>the atmospheric transmittance of the kth layer of the ith channel atmosphere of the thermal infrared sensor is estimated by adopting the formula (12) and setting the observation zenith angle to 53 degrees;representing the estimated descending radiance of the ith channel atmosphere and the l layer atmosphere of the thermal infrared sensor;
s6, determining a deviation correction coefficient: for the deviation of the atmospheric characteristic parameter estimation caused by simplification and approximation in the above steps, a statistical regression method is further adopted to construct a corresponding equation set, and the deviation correction coefficient required by regression solution (a)And) Correcting the deviation of the estimated atmospheric characteristic parameters; if the deviation correction coefficient has been obtained in advance, step S6 may be skipped directly;
for the standard atmosphere, the relationship between the radiation transmission model MODTRAN and the total atmospheric transmittance of the channel i estimated by the parameterization method can be approximately represented by a unitary quadratic empirical relationship in formula (18), namely:
wherein,<ti(θv)>MODTRANto consider standard atmosphereCalculating observation zenith angle theta by radiation transmission model MODTRANvThe corresponding total transmittance spectrum is integrated with the spectral response function of the thermal infrared channel to obtain the total atmospheric transmittance of the channel i;<ti(θv)>PMthe method is characterized in that a parameterization method is adopted, and the total atmospheric transmittance of a channel i is obtained through a formula (15);all are deviation correction coefficients of the total transmittance of the channel atmosphere;
and II, aiming at the standard atmosphere, the relationship between the total uplink radiance of the channel atmosphere estimated by the radiation transmission model MODTRAN and the parameterization method can be approximately represented by a unary quadratic empirical relationship in a formula (19), namely:
wherein,the method comprises the steps of considering atmospheric temperature and humidity profiles of all layers of standard atmosphere, calculating an atmospheric total uplink radiance spectrum by adopting a radiation transmission model MODTRAN, and then integrating with a thermal infrared channel spectral response function to obtain a channel i atmospheric total uplink radiance;the method adopts a parameterization method, and finally obtains the total atmospheric upward radiance of a channel i through a formula (16);the deviation correction coefficients are all the deviation correction coefficients of the total upward radiance of the channel atmosphere;
and III, aiming at the standard atmosphere, the relationship between the total downlink radiance of the channel atmosphere estimated by the radiation transmission model MODTRAN and the parameterization method can be approximately represented by a unary quadratic empirical relationship in a formula (20), namely:
wherein,the method comprises the steps of considering atmospheric temperature and humidity profiles of all layers of standard atmosphere, calculating an atmospheric total downward radiation brightness spectrum by adopting a radiation transmission model MODTRAN, and then integrating with a thermal infrared channel spectral response function to obtain a channel i atmospheric total downward radiation brightness;a parameterization method is adopted, and finally, the total atmospheric downlink radiance of the channel i is obtained through a formula (17);andis the deviation correction coefficient of the total descending radiance of the channel atmosphere;
s7, correcting deviation of atmospheric characteristic parameters: correcting the atmospheric characteristic parameter deviation by using the deviation correction coefficient and combining the atmospheric characteristic parameter obtained in the step S5 to obtain the atmospheric transmittance and the uplink and downlink radiance of the high-precision thermal infrared channel, thereby realizing accurate, convenient and quick thermal infrared atmospheric correction;
i, calculating deviation correction of total atmospheric transmittance:
wherein,<ti(θv)>Corris to observe the zenith angle thetavThe corresponding deviation corrected channel i has the total atmospheric transmittance;<ti(θv)>is the total atmospheric transmittance of the channel i obtained by the formula (15) in the step S5; all are deviation correction coefficients of the total transmittance of the channel atmosphere;
II, calculating the deviation correction of the total upward radiance of the atmosphere:
wherein,the deviation is corrected, namely the total upward radiance of the air of the channel i;the total atmospheric upward radiance of the channel i obtained by the formula (16) in the step S5;all are deviation correction coefficients of the total upward radiance of the atmosphere;
III, calculating the deviation correction of the total descending radiance of the atmosphere:
wherein,the deviation is corrected, namely the total atmospheric downlink radiance of the channel i;the total atmospheric downlink radiance of the channel i obtained by adopting the formula (17) in the step S5;are all deviation correction coefficients of the total downward radiance of the atmosphere.
According to the invention, the atmosphere is vertically layered, the influence of linear water vapor, continuous water vapor and other gas components on thermal infrared observation data is respectively considered, the atmospheric characteristic parameters are parameterized layer by layer again, and the atmospheric characteristic parameters required by thermal infrared atmospheric correction, namely the atmospheric transmittance and the atmospheric uplink and downlink radiance, are obtained with high precision by combining a thermal infrared parameterized model coefficient lookup table, so that the processing time of the thermal infrared atmospheric correction is shortened, the efficiency of the thermal infrared atmospheric correction is improved, and the real-time high-precision processing of the thermal infrared atmospheric correction is realized.
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FIG. 1 is a flowchart illustrating the overall steps of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, the present invention consists of the following seven steps:
s1, thermal infrared atmospheric correction pretreatment: selecting a space-time matched atmospheric temperature and humidity profile corresponding to a pixel according to the time and the place of data acquired by the thermal infrared sensor, converting the unit of the potential height ZM of the atmospheric temperature and humidity profile data into kilometers, and expressing the kilometers; converting the unit of the atmospheric pressure P into a unit of hectopascal and expressing the unit of hectopascal by hPa; will be provided withThe unit of the atmospheric temperature T is converted into Kelvin and is represented by K; the atmospheric humidity H2Conversion of units of O to grams per cubic meter in g/m3Represents; dividing the atmosphere into 25 layers vertically, wherein the boundary layer standard atmospheric pressure of the 25 layers of atmosphere is respectively 20hPa, 50hPa, 100hPa, 150hPa, 200hPa, 250hPa, 300hPa, 350hPa, 400hPa, 450hPa, 500hPa, 550hPa, 600hPa, 650hPa, 700hPa, 750hPa, 800hPa, 825hPa, 850hPa, 875hPa, 900hPa, 925hPa, 950hPa, 975hPa, 1000hPa and 1030 hPa; linearly interpolating the potential height, the atmospheric temperature and the atmospheric humidity of the acquired atmospheric temperature and humidity profile to a reference atmospheric pressure position, and acquiring an observation zenith angle of a pixel with the unit of rad;
s2, atmospheric component layer-by-layer optical thickness estimation: in the thermal infrared band, the atmospheric transmittance is mainly determined by gas absorption, and molecular scattering and aerosol influence can be ignored, so the atmosphere is firstly vertically layered, the optical thickness of the atmospheric l layer of the ith channel of the thermal infrared sensor is expressed as the contribution of three parts, namely water vapor linear absorption, water vapor continuous absorption and other gas absorption, and the formula (1) is used for expressing:
wherein, taul,iThe total optical thickness of the ith channel atmosphere layer I atmosphere of the thermal infrared sensor,the optical thickness of the atmospheric layer of the linear water vapor ith channel,the optical thickness of the ith layer of the atmosphere is the continuous vapor ith channel,the optical thickness of the atmosphere I layer is the ith channel of other gases;
optical thickness of linear water vaporCan be obtained by calculation of formula (2):
wherein,an optical thickness calculation function representing linear water vapor;andare linear water vapor parametric model coefficients whose values depend on the average atmospheric temperature T of the ith layerlAverage atmospheric pressure PlAnd a thermal infrared sensor channel i; exp represents an exponential function with a natural constant as the base; log represents a logarithmic function with a natural constant as a base;is the water vapor content in g/m on the vertical path of the first layer of the atmosphere2；θvObserving a zenith angle;
in the formula (2)Can be expressed as:
wherein ZMl,topAnd ZMl,botRespectively representing the potential heights of the top and the bottom of the first layer of the atmosphere; h2Ol,topAnd H2Ol,botRespectively, the atmospheric humidity at the top and bottom of the first layer of atmosphere; log represents a logarithmic function with a natural constant as a base; rat is the model intermediate variable with a value of (H)2Ol,top-H2Ol,bot)/H2Ol,bot。
II, optical thickness of continuous water vaporCan be obtained by calculation of formula (4):
wherein,an optical thickness calculation function representing continuous water vapor;andcontinuous water vapor parameterized model coefficients, the values of which depend on a thermal infrared sensor channel i; TFAC, AMTPselfAnd AMTPfrgnAre all model intermediate variables, and their values are respectively expressed as:
wherein, Pl,topAnd Pl,botRespectively representing the top and bottom atmospheric pressures of the first layer of the atmosphere; t isl,topAnd Tl,botRespectively representing the top and bottom atmospheric temperatures of the first layer of the atmosphere; ZMl,topAnd ZMl,botRespectively representing the top and bottom potential heights of the first layer of the atmosphere; log represents a logarithmic function with a natural constant as a base; thetavObserving a zenith angle;and(orAnd) Are model intermediate variables representing the water vapor self-broadening and the added broad absorption contribution of the top (or bottom) of the first layer of the atmosphere, respectively, and the values of the two are expressed as follows:
wherein, Pl,topAnd Pl,botRespectively representing the top and bottom atmospheric pressures of the first layer of the atmosphere; t isl,topAnd Tl,botRespectively representing the top and bottom atmospheric temperatures of the first layer of the atmosphereDegree; h2Ol,topAnd H2Ol,botRespectively representing the top and bottom atmospheric humidity of the first layer of atmosphere; WHtopAnd WHbotIs a model intermediate variable whose value can be expressed as:
wherein, Tl,topAnd Tl,botRespectively representing the top and bottom atmospheric temperatures of the first layer of the atmosphere; exp denotes an exponential function with a natural constant as the base.
III, optical thickness of other gasesThe calculation formula of (2) is as follows:
wherein f isotherAn optical thickness calculation function representing other gases; d is the vertical thickness of the first layer of the atmosphere, in km, expressed as D ═ ZMl,top-ZMl,bot；ZMl,topAnd ZMl,botRespectively representing the potential heights of the top and the bottom of the first layer of the atmosphere;andare coefficients of a parameterized model of the optical thickness of the other gases, the values of which depend on the mean atmospheric temperature T of the l-th layerlAverage atmospheric pressure PlAnd a thermal infrared sensor channel i.
S3, determining the parameterized model coefficient of the optical thickness: estimating linear water vapor, continuous water vapor andthe key to other gas optical thicknesses is to obtain the corresponding parametric model coefficients ( And) Coefficient of a parameterized model of linear water vapor optical thickness thereof ( And) And other gas optical thickness parametric model coefficients (CAnd) Are all the atmospheric temperature T of the first layerlAnd atmospheric pressure PlAnd thermal infrared channel i, and continuous vapor optical thickness (f) as a function of the thermal infrared channel iAnd) Only a function of the thermal infrared channel i. Therefore, the parameterized model coefficients of the linear water vapor and the optical thickness of other gases are obtained in a layer-by-layer determined mode, and the parameterized model coefficients of the continuous water vapor optical thickness are obtained in a non-layered integrally determined mode; if the light corresponding to the thermal infrared sensor channel i has been acquired in advanceLearning the parameterized model coefficients of the thickness, step S3 can be skipped directly; in the process of obtaining the parameterized model coefficient of the optical thickness, different atmospheric condition combinations are constructed according to an atmospheric vertical layered warm-humid pressure configuration combination table shown in table 1;
TABLE 1 atmospheric vertical layered warm-humid pressure combination table
Then, the observation zenith angles are respectively set to be 0 degrees, 33.56 degrees, 44.42 degrees, 51.32 degrees, 56.25 degrees and 60 degrees, a radiation transmission model MODTRAN is used, the channel response function of the thermal infrared sensor channel i is considered, and the optical thickness of the channel of linear water vapor, continuous water vapor and other gases under different conditions is obtained simultaneouslyAndand according to the mathematical relationship expressed by the formula (2), the formula (4) and the formula (11), utilizing a least square mathematical optimization technology, performing data regression layer by layer to obtain the parameterized model coefficients of the optical thicknesses of the linear water vapor and other gases, performing data regression on the parameterized model coefficients of the optical thicknesses of the continuous water vapor, creating a parameterized model coefficient lookup table of the optical thicknesses shown in the table 2, and storing the parameterized model coefficients of the optical thicknesses of the linear water vapor, the continuous water vapor and other gases.
TABLE 2 Parametric model coefficient lookup table for atmospheric composition optical thickness
S4, calculating the atmospheric characteristic parameters layer by layer: and reading the interpolated atmospheric temperature and humidity profile and the observation zenith angle of the thermal infrared sensor pixel, and calculating the atmospheric optical thickness of the required components layer by layer.
For the linear water vapor optical thickness, selecting a parameterized model coefficient corresponding to a channel according to the actual atmospheric temperature and atmospheric pressure of each layer, performing bilinear interpolation of the atmospheric temperature and the atmospheric pressure on the parameterized model coefficient of the linear water vapor optical thickness constructed in the table 2 to obtain a linear water vapor parameterized model coefficient corresponding to the actual atmospheric condition, and calculating the linear water vapor optical thickness by using the formula (2) and the formula (3)
For the continuous water vapor optical thickness, calculating the continuous water vapor optical thickness by using the formulas (4) to (10) according to the actual atmospheric temperature and atmospheric pressure of each layer and the parametric model coefficient of the corresponding channel and combining the parametric model coefficient of the continuous water vapor optical thickness constructed in the table 2
For other gas optical thicknesses, selecting the parameterized model coefficients of corresponding channels according to the actual atmospheric temperature and atmospheric pressure of each layer, performing bilinear interpolation of the atmospheric temperature and the atmospheric pressure on the parameterized model coefficients of other gas optical thicknesses constructed in the table 2 to obtain other gas parameterized model coefficients corresponding to the actual atmospheric conditions, and calculating the other gas optical thicknesses by using the formula (11)
Atmospheric permeability layer by layer<tl,i(θv)>The calculation of (2):
wherein,<tl,i(θv)>representing the estimated atmospheric first layer atmospheric transmission rate of the ith channel of the thermal infrared sensor; thetavRepresenting an observed zenith angle of the pixel; exp represents an exponential function with a natural constant as the base;representing the estimated linear water vapor optical thickness of the ith channel atmospheric ith layer of the thermal infrared sensor;representing the estimated continuous water vapor optical thickness of the ith channel atmospheric ith layer of the thermal infrared sensor;indicating the estimated optical thickness of the other gases of the ith channel atmospheric layer of the thermal infrared sensor.
II, atmospheric ascending radiance layer by layerThe calculation of (2):
wherein,representing the estimated ascending radiance of the ith channel atmosphere and the l layer atmosphere of the thermal infrared sensor;<tl,i(θv)>representing the observed zenith angle thetavEstimated thermal infrared sensorThe atmospheric first layer of the channel atmosphere has the atmospheric transmittance; b is a Planck function; t islIs the average atmospheric temperature of the first layer of the atmosphere and is expressed as Tl＝0.5Tl,top+0.5Tl,bot，Tl,top、Tl,botRespectively the atmospheric temperature at the top and the bottom of the first layer of the atmosphere; lambda [ alpha ]iIs the equivalent center wavelength of the ith channel of the thermal infrared sensor.
III, atmospheric descending radiance layer by layerThe calculation of (2):
wherein,representing the estimated descending radiance of the ith channel atmosphere and the l layer atmosphere of the thermal infrared sensor;<tl,i(θ53°)>the atmospheric air transmission rate of the ith channel of the thermal infrared sensor is estimated by adopting a formula (12) and setting the observation zenith angle theta to 53 degrees; b is a Planck function; t islIs the average atmospheric temperature of the first layer of the atmosphere and is expressed as Tl＝0.5Tl,top+0.5Tl,bot，Tl,top、Tl,botRespectively representing the atmospheric temperature at the top and the bottom of the first atmospheric layer; lambda [ alpha ]iIs the equivalent center wavelength of the ith channel of the thermal infrared sensor.
S5, integral estimation of atmospheric characteristic parameters: the method for estimating the integral characteristic parameters according to the layer-by-layer atmospheric characteristic parameters comprises the following steps:
total atmospheric transmittance<ti(θv)>The calculation of (2):
wherein,<ti(θv)>for estimated observed zenith angle thetavThe total atmospheric transmittance of the ith channel of the corresponding thermal infrared sensor; pi is a mathematical successive multiplication symbol;<tl,i(θv)>for observing zenith angle thetavAnd estimating the atmospheric first layer atmospheric transmission rate of the ith channel of the thermal infrared sensor.
II, total upward radiance of atmosphereThe calculation of (2):
wherein,estimating the total upward radiation brightness of the ith channel of the thermal infrared sensor; sigma is a mathematical summation symbol; pi is a mathematical successive multiplication symbol;<tk,i(θv)>for observing zenith angle thetavEstimating the atmospheric transmission rate of the ith channel and the kth layer of the ith channel of the thermal infrared sensor;the estimated ascending radiance of the ith channel atmosphere and the ith layer atmosphere of the thermal infrared sensor.
III, total downward radiance of atmosphereThe calculation of (2):
wherein,estimating the total atmospheric downlink radiance of the ith channel of the thermal infrared sensor; sigma is a mathematical summation symbol; pi is a mathematical successive multiplication symbol;<tk,i(θ53°)>the atmospheric transmittance of the kth layer of the ith channel atmosphere of the thermal infrared sensor is estimated by adopting the formula (12) and setting the observation zenith angle theta to 53 degrees;and indicating the estimated descending radiance of the ith channel atmosphere and the l layer atmosphere of the thermal infrared sensor.
S6, determining a deviation correction coefficient: because the atmospheric correction parameterization method does not consider the influence of the integration sequence of the channel response function, ignores the atmospheric temperature and humidity profile with the potential height higher than 30km, and sets the observation zenith angle to be 53 degrees to approximately represent the equivalent observation zenith angle in the estimation process of the atmospheric downlink radiance, the simplification and the approximation both cause the deviation of the estimated atmospheric characteristic parameters. And further adopting a statistical regression mode to estimate deviation correction coefficients to correct the deviation of the estimated atmospheric characteristic parameters. Therefore, by means of a standard atmospheric temperature and humidity profile provided by a radiation transmission model MODTRAN, MODTRAN is adopted to obtain actual atmospheric characteristic parameters corresponding to standard atmosphere, formulas (1) - (17) are utilized to obtain atmospheric characteristic parameters estimated by a parameterization method, namely, atmospheric transmittance and atmospheric uplink and downlink radiance, a corresponding equation set is constructed according to a unitary and quadratic empirical relationship provided by formulas (18), (19) and (20), and a deviation correction coefficient (a) required by regression solution is (a) And). If the deviation correction coefficient has been acquired in advance, step S6 may be skipped directly.
For the standard atmosphere, the relationship between the radiation transmission model MODTRAN and the total atmospheric transmittance of the channel i estimated by the parameterization method can be approximately represented by a unitary quadratic empirical relationship in formula (18), namely:
wherein,<ti(θv)>MODTRANin order to consider the atmospheric temperature and humidity profile of all layers of standard atmosphere, firstly, a radiation transmission model MODTRAN is adopted to calculate an observation zenith angle thetavThe corresponding total transmittance spectrum is integrated with the spectral response function of the thermal infrared channel to obtain the total atmospheric transmittance of the channel i;<ti(θv)>PMthe method is characterized in that a parameterization method is adopted, and the total atmospheric transmittance of a channel i is obtained through a formula (15);are all deviation correction coefficients of the total transmittance of the channel atmosphere.
And II, aiming at the standard atmosphere, the relationship between the total uplink radiance of the channel atmosphere estimated by the radiation transmission model MODTRAN and the parameterization method can be approximately represented by a unary quadratic empirical relationship in a formula (19), namely:
wherein,the atmospheric temperature and humidity profile of all layers of standard atmosphere is considered, and a radiation transmission model MODTRAN is adoptedCalculating an atmosphere total ascending radiance spectrum, and then integrating the calculated atmosphere total ascending radiance spectrum with a thermal infrared channel spectral response function to obtain channel i atmosphere total ascending radiance;the method adopts a parameterization method, and finally obtains the total atmospheric upward radiance of a channel i through a formula (16);are all deviation correction coefficients of the total upward radiance of the channel atmosphere.
And III, aiming at the standard atmosphere, the relationship between the total downlink radiance of the channel atmosphere estimated by the radiation transmission model MODTRAN and the parameterization method can be approximately represented by a unary quadratic empirical relationship in a formula (20), namely:
wherein,the method comprises the steps of considering atmospheric temperature and humidity profiles of all layers of standard atmosphere, calculating an atmospheric total downward radiation brightness spectrum by adopting a radiation transmission model MODTRAN, and then integrating with a thermal infrared channel spectral response function to obtain a channel i atmospheric total downward radiation brightness;a parameterization method is adopted, and finally, the total atmospheric downlink radiance of the channel i is obtained through a formula (17);andis the deviation correction coefficient of the total descending radiance of the channel atmosphere.
S7, correcting deviation of atmospheric characteristic parameters: and (3) correcting the deviation of the atmospheric characteristic parameters by using the deviation correction coefficient and combining the atmospheric characteristic parameters obtained in the step S5 by using the formulas (21), (22) and (23), and obtaining the atmospheric transmittance and the uplink and downlink radiance of the high-precision thermal infrared channel, thereby realizing accurate, convenient and rapid thermal infrared atmospheric correction.
I, calculating deviation correction of total atmospheric transmittance:
wherein,<ti(θv)>Corris to observe the zenith angle thetavThe corresponding deviation corrected channel i has the total atmospheric transmittance;<ti(θv)>is the total atmospheric transmittance of the channel i obtained by the formula (15) in the step S5; are all deviation correction coefficients of the total transmittance of the channel atmosphere.
II, calculating the deviation correction of the total upward radiance of the atmosphere:
wherein,the deviation is corrected, namely the total upward radiance of the air of the channel i;is the step ofThe total atmospheric upward radiance of the channel i obtained by adopting the formula (16) in the S5;are all deviation correction coefficients of the total upward radiance of the atmosphere.
III, calculating the deviation correction of the total descending radiance of the atmosphere:
wherein,the deviation is corrected, namely the total atmospheric downlink radiance of the channel i;the total atmospheric downlink radiance of the channel i obtained by adopting the formula (17) in the step S5;are all deviation correction coefficients of the total downward radiance of the atmosphere.
According to the thermal infrared atmospheric correction method provided by the invention, atmospheric air is vertically layered, an atmospheric lookup table is combined, the atmospheric transmittance and the atmospheric uplink and downlink radiance are parameterized layer by layer again, and on the basis of considering a sensor channel response function, the atmospheric characteristic parameters of the thermal infrared channel, namely the atmospheric transmittance and the atmospheric uplink and downlink radiance, are obtained by means of integral correction, so that atmospheric correction of observation data of any satellite-borne thermal infrared sensor is realized.
Compared with the prior art, the invention mainly has the following advantages:
(1) through mechanism analysis and mathematical derivation, the influence of continuous water vapor, linear water vapor and other gases on the observation data of the thermal infrared sensor is effectively distinguished, so that the atmospheric correction parameterization method provided by the invention has a strict physical mechanism and certain universality, and the accuracy of thermal infrared atmospheric correction is greatly improved compared with the traditional experience-semi-experience statistical method;
(2) the atmospheric characteristic parameters are parameterized layer by layer through atmospheric vertical layering, and the dependence on a radiation transmission model in a physical method is eliminated by combining a thermal infrared parameterized model coefficient lookup table.
The above embodiments are not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make variations, modifications, additions or substitutions within the technical scope of the present invention.
Claims (4)
1. A thermal infrared atmospheric correction parameterization method based on a lookup table is characterized by comprising the following steps: the method consists of the following seven steps:
s1, thermal infrared atmospheric correction pretreatment: according to the time and place of data acquired by the thermal infrared sensor, selecting a space-time matched atmospheric temperature and humidity profile corresponding to the pixel, converting the unit of potential height ZM of atmospheric temperature and humidity profile data into kilometers, converting the unit of atmospheric pressure P into hectopascal, and converting the unit of atmospheric temperature T into Kelvin and atmospheric humidity H2The units of O are converted to grams per cubic meter; dividing the atmosphere into 25 layers vertically, then linearly interpolating the potential height, the atmospheric temperature and the atmospheric humidity of the obtained atmospheric temperature and humidity profile to a reference atmospheric pressure position, and simultaneously obtaining the observation zenith angle of the pixel;
s2, atmospheric component layer-by-layer optical thickness estimation: the atmospheric air is vertically layered, and the optical thickness of the atmospheric layer I of the ith channel of the thermal infrared sensor is expressed as the contribution of three parts, namely linear absorption of water vapor, continuous absorption of water vapor and other gas absorption, and is expressed by the formula (1):
wherein, taul,iThe total optical thickness of the ith channel atmosphere layer I atmosphere of the thermal infrared sensor,the optical thickness of the atmospheric layer of the linear water vapor ith channel,the optical thickness of the ith layer of the atmosphere is the continuous vapor ith channel,the optical thickness of the atmosphere I layer is the ith channel of other gases;
s3, determining the parameterized model coefficient of the optical thickness: the parameterized model coefficients of the linear water vapor and the optical thickness of other gases are obtained in a layer-by-layer determined mode, and the parameterized model coefficients of the continuous water vapor optical thickness are obtained in a non-layered integrally determined mode; if the parameterized model coefficients corresponding to the optical thickness of the thermal infrared sensor channel i have been obtained in advance, step S3 may be skipped directly;
constructing different atmospheric condition combinations in the process of obtaining the model coefficients; the top angles of the observation sky are respectively set to be 0 degree, 33.56 degree and 44.42 degree51.32 DEG, 56.25 DEG and 60 DEG, using a radiation transmission model MODTRAN and considering a channel response function of a thermal infrared sensor channel i, and simultaneously acquiring the channel optical thickness of linear water vapor, continuous water vapor and other gases under different conditionsAndobtaining parameterized model coefficients of the optical thicknesses of linear water vapor and other gases by using a least square mathematical optimization technology through layer-by-layer data regression, enabling all data to regress the parameterized model coefficients of the optical thicknesses of continuous water vapor, creating a parameterized model coefficient lookup table of the optical thicknesses, and storing the parameterized model coefficients of the optical thicknesses of the linear water vapor, the continuous water vapor and other gases;
s4, calculating the atmospheric characteristic parameters layer by layer: reading the interpolated atmospheric temperature and humidity profile and the observation zenith angle of the pixel of the thermal infrared sensor, and then calculating the optical thickness of the required atmospheric component layer by layer;
for the linear water vapor optical thickness, selecting the parameterized model coefficient of the corresponding channel according to the actual atmospheric temperature and atmospheric pressure of each layer, carrying out bilinear interpolation of the atmospheric temperature and the atmospheric pressure on the constructed parameterized model coefficient of the linear water vapor optical thickness to obtain the linear water vapor parameterized model coefficient corresponding to the actual atmospheric condition, and calculating the linear water vapor optical thickness
For the continuous water vapor optical thickness, calculating the continuous water vapor optical thickness according to the actual atmospheric temperature and atmospheric pressure of each layer and the parametric model coefficient of the corresponding channel and combining the constructed parametric model coefficient of the continuous water vapor optical thickness
For other gas optical thicknesses, selecting the parameterized model coefficients of the corresponding channels according to the actual atmospheric temperature and atmospheric pressure of each layer, performing bilinear interpolation of the atmospheric temperature and the atmospheric pressure on the constructed parameterized model coefficients of the other gas optical thicknesses to obtain other gas parameterized model coefficients corresponding to the actual atmospheric conditions, and calculating the optical thicknesses of other gases
I, layer-by-layer atmospheric transmittance (t)l,i(θv) Calculation of (6):
wherein,<tl,i(θv) The above expression represents the estimated atmospheric first layer atmospheric transmittance of the ith channel of the thermal infrared sensor; thetavIs the observed zenith angle of the pixel; exp is an exponential function with a natural constant as a base;representing the estimated linear water vapor optical thickness of the ith channel atmospheric ith layer of the thermal infrared sensor;representing the estimated continuous water vapor optical thickness of the ith channel atmospheric ith layer of the thermal infrared sensor;indicating the estimated optical thickness of other gases of the ith channel atmospheric ith layer of the thermal infrared sensor;
II, atmospheric ascending radiance layer by layerThe calculation of (2):
wherein,representing the estimated ascending radiance of the ith channel atmosphere and the l layer atmosphere of the thermal infrared sensor;<tl,i(θv) "denotes the observed zenith angle θvEstimating the atmospheric first layer atmospheric transmission rate of the ith channel of the thermal infrared sensor; b is a Planck function; t islIs the average atmospheric temperature of the first layer of the atmosphere and is expressed as Tl＝0.5Tl,top+0.5Tl,bot，Tl,top、Tl,botRespectively the atmospheric temperature at the top and the bottom of the first layer of the atmosphere; lambda [ alpha ]iThe equivalent center wavelength of the ith channel of the thermal infrared sensor;
III, atmospheric descending radiance layer by layerThe calculation of (2):
wherein,representing the estimated descending radiance of the ith channel atmosphere and the l layer atmosphere of the thermal infrared sensor;<tl,i(θ53°)>the atmospheric first layer atmospheric transmittance of the ith channel of the thermal infrared sensor is estimated by applying the formula (12) and setting the observation zenith angle theta to 53 degrees; b is a Planck function; t islIs the average atmospheric temperature of the first layer of the atmosphere and is expressed as Tl＝0.5Tl,top+0.5Tl,bot，Tl,top、Tl,botRespectively representing the atmospheric temperature at the top and the bottom of the first atmospheric layer; lambda [ alpha ]iIs the ith channel of a thermal infrared sensorThe equivalent center wavelength of (d);
s5, integral estimation of atmospheric characteristic parameters: the method for estimating the integral characteristic parameters according to the layer-by-layer atmospheric characteristic parameters comprises the following steps:
total atmospheric transmittance<ti(θv) Calculation of (6):
wherein,<ti(θv) Observed zenith angle theta as estimatedvThe total atmospheric transmittance of the ith channel of the corresponding thermal infrared sensor; pi is a mathematical successive multiplication symbol;<tl,i(θv) Is observing the zenith angle thetavEstimating the atmospheric first layer atmospheric transmittance of the ith channel of the thermal infrared sensor;
II, total upward radiance of atmosphereThe calculation of (2):
wherein,estimating the total upward radiation brightness of the ith channel of the thermal infrared sensor; sigma is a mathematical summation symbol; pi is a mathematical successive multiplication symbol;<tk,i(θv) Is observing the zenith angle thetavEstimating the atmospheric transmission rate of the ith channel and the kth layer of the ith channel of the thermal infrared sensor;estimating the ascending radiance of the ith channel atmosphere and the l layer atmosphere of the ith channel of the thermal infrared sensor;
III, total downward radiance of atmosphereThe calculation of (2):
wherein,estimating the total atmospheric downlink radiance of the ith channel of the thermal infrared sensor; sigma is a mathematical summation symbol; pi is a mathematical successive multiplication symbol;<tk,i(θ53°)>the atmospheric transmittance of the kth layer of the ith channel atmosphere of the thermal infrared sensor is estimated by adopting the formula (12) and setting the observation zenith angle theta to 53 degrees;representing the estimated descending radiance of the ith channel atmosphere and the l layer atmosphere of the thermal infrared sensor;
s6, determining a deviation correction coefficient: for the deviation of the atmospheric characteristic parameter estimation caused by simplification and approximation in the above steps, a statistical regression method is further adopted to construct a corresponding equation set, and the deviation correction coefficient required by regression solution (a)And) Correcting the deviation of the estimated atmospheric characteristic parameters; if the deviation correction coefficient has been obtained in advance, step S6 may be skipped directly;
for the standard atmosphere, the relationship between the radiation transmission model MODTRAN and the total atmospheric transmittance of the channel i estimated by the parameterization method can be approximately represented by a unitary quadratic empirical relationship in formula (18), namely:
wherein,<ti(θv)〉MODTRANin order to consider the atmospheric temperature and humidity profile of all layers of standard atmosphere, firstly, a radiation transmission model MODTRAN is adopted to calculate an observation zenith angle thetavThe corresponding total transmittance spectrum is integrated with the spectral response function of the thermal infrared channel to obtain the total atmospheric transmittance of the channel i;<ti(θv)〉PMthe method is characterized in that a parameterization method is adopted, and the total atmospheric transmittance of a channel i is obtained through a formula (15);all are deviation correction coefficients of the total transmittance of the channel atmosphere;
and II, aiming at the standard atmosphere, the relationship between the total uplink radiance of the atmosphere of the channel i, which is estimated by a radiation transmission model MODTRAN and a parameterization method, can be approximately represented by a unary quadratic empirical relationship in a formula (19), namely:
wherein,the method comprises the steps of considering atmospheric temperature and humidity profiles of all layers of standard atmosphere, calculating an atmospheric total uplink radiance spectrum by adopting a radiation transmission model MODTRAN, and then integrating with a thermal infrared channel spectral response function to obtain a channel i atmospheric total uplink radiance;the method adopts a parameterization method, and finally obtains the total atmospheric upward radiance of a channel i through a formula (16);the deviation correction coefficients are all the deviation correction coefficients of the total upward radiance of the channel atmosphere;
and III, aiming at the standard atmosphere, the relationship between the total downlink radiance of the atmosphere of the channel i, which is estimated by a radiation transmission model MODTRAN and a parameterization method, can be approximately represented by a unary quadratic empirical relationship in a formula (20), namely:
wherein,the method comprises the steps of considering atmospheric temperature and humidity profiles of all layers of standard atmosphere, calculating an atmospheric total downward radiation brightness spectrum by adopting a radiation transmission model MODTRAN, and then integrating with a thermal infrared channel spectral response function to obtain a channel i atmospheric total downward radiation brightness;a parameterization method is adopted, and finally, the total atmospheric downlink radiance of the channel i is obtained through a formula (17);andis the deviation correction coefficient of the total descending radiance of the channel atmosphere;
s7, correcting deviation of atmospheric characteristic parameters: correcting the atmospheric characteristic parameter deviation by using the deviation correction coefficient and combining the atmospheric characteristic parameter obtained in the step S5 to obtain the atmospheric transmittance and the uplink and downlink radiance of the high-precision thermal infrared channel, thereby realizing accurate, convenient and quick thermal infrared atmospheric correction;
i, calculating deviation correction of total atmospheric transmittance:
wherein,<ti(θv)〉Corris to observe the zenith angle thetavThe corresponding deviation corrected channel i has the total atmospheric transmittance;<ti(θv) The "is the total atmospheric transmittance of the channel i obtained by the formula (15) in the step S5; all are deviation correction coefficients of the total transmittance of the channel atmosphere;
II, calculating the deviation correction of the total upward radiance of the atmosphere:
wherein,the deviation is corrected, namely the total upward radiance of the air of the channel i;the total atmospheric upward radiance of the channel i obtained by the formula (16) in the step S5;all are deviation correction coefficients of the total upward radiance of the atmosphere;
III, calculating the deviation correction of the total descending radiance of the atmosphere:
wherein,the deviation is corrected, namely the total atmospheric downlink radiance of the channel i;the total atmospheric downlink radiance of the channel i obtained by adopting the formula (17) in the step S5;are all deviation correction coefficients of the total downward radiance of the atmosphere.
2. The lookup table based thermal infrared atmospheric correction parameterization method of claim 1, characterized in that: optical thickness of the linear vaporCan be obtained by calculation of formula (2):
wherein,calculating a function for the optical thickness of the linear water vapor;andare linear water vapor parametric model coefficients, the values of which depend on the average atmospheric temperature T of the first layerlAverage atmospheric pressure PlAnd a thermal infrared sensor channel i; exp represents an exponential function with a natural constant as the base; log represents a logarithmic function based on natural constants；Is the water vapor content on the vertical path of the first layer of the atmosphere; thetavObserving a zenith angle;
in the formula (2)Can be expressed as:
wherein ZMl,topAnd ZMl,botRespectively representing the potential heights of the top and the bottom of the first layer of the atmosphere; h2Ol,topAnd H2Ol,botRespectively, the atmospheric humidity at the top and bottom of the first layer of atmosphere; log represents a logarithmic function with a natural constant as a base; rat is the model intermediate variable with a value of (H)2Ol,top-H2Ol,bot)/H2Ol,bot。
3. The lookup table based thermal infrared atmospheric correction parameterization method of claim 1, characterized in that: optical thickness of the continuous water vaporCan be obtained by calculation of formula (4):
wherein,an optical thickness calculation function representing continuous water vapor;andcontinuous water vapor parameterized model coefficients, the values of which depend on a thermal infrared sensor channel i; TFAC, AMTPselfAnd AMTPfrgnAre all model intermediate variables, and their values are represented by equations (5), (6), (7), respectively:
wherein, Pl,topAnd Pl,botRespectively representing the top and bottom atmospheric pressures of the first layer of the atmosphere; t isl,topAnd Tl,botRespectively representing the atmosphereTop and bottom atmospheric temperatures of the first layer; ZMl,topAnd ZMl,botRespectively representing the top and bottom potential heights of the first layer of the atmosphere;log represents a logarithmic function with a natural constant as a base; thetavObserving a zenith angle; and (or and) are model intermediate variables respectively representing the water vapor self-widening and the external widening of the top (or the bottom) of the first layer of the atmosphereThe absorption contributions, their values in the l-th layer are expressed by equations (8), (9), respectively:
wherein, Pl,topAnd Pl,botRespectively representing the top and bottom atmospheric pressures of the first layer of the atmosphere; t isl,topAnd Tl,botRespectively representing the top and bottom atmospheric temperatures of the first layer of the atmosphere; h2Ol,topAnd H2Ol,botRespectively representing the top and bottom atmospheric humidity of the first layer of atmosphere; WHtopAnd WHbotIs a model intermediate variable whose value can be expressed as:
wherein, Tl,topAnd Tl,botRespectively representing the top and bottom atmospheric temperatures of the first layer of the atmosphere; exp denotes an exponential function with a natural constant as the base.
4. The lookup table based thermal infrared atmospheric correction parameterization method of claim 1, characterized in that: optical thickness of the other gasThe calculation formula of (2) is as follows:
wherein f isotherAn optical thickness calculation function representing other gases; d is the vertical thickness of the first layer of the atmosphere and is expressed as D ═ ZMl,top-ZMl,bot；ZMl,topAnd ZMl,botRespectively representing the potential heights of the top and the bottom of the first layer of the atmosphere;andare coefficients of a parameterized model of the optical thickness of the other gases, the values of which depend on the mean atmospheric temperature T of the l-th layerlAverage atmospheric pressure PlAnd a thermal infrared sensor channel i.
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