1. An atmospheric degradable water yield inversion method is characterized by comprising the following steps:

determining the radiant brightness temperatures corresponding to three channels of a target area under a clear sky condition based on the radiant brightness data of the three channels of the target area acquired by a preset satellite; wherein the three channels comprise: two thermal infrared split window channels and one other thermal infrared channel; the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 and 13 mu m, and the other thermal infrared channels are channels which are sensitive to water vapor values except the thermal infrared splitting window channels;

inputting the radiant brightness temperature, the target ground surface pressure and the auxiliary information corresponding to the three channels into an atmospheric water reducible quantity inversion model, and performing inversion to obtain a target atmospheric water reducible quantity;

wherein the auxiliary information comprises: time information, spatial information, and observation angle information; the atmospheric water reducible quantity inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

2. The atmospheric degradable water yield inversion method according to claim 1, wherein the determining, based on radiance data of three channels of a target area acquired by a preset satellite, radiance temperatures corresponding to the three channels of the target area under a clear sky condition specifically includes:

respectively screening out the radiance data of the three channels under the clear sky condition of the target area based on the radiance data and the cloud detection data of the three channels of the target area acquired by the preset satellite;

and determining the corresponding radiant brightness temperatures of the three channels under the clear sky condition of the target area based on the radiant brightness data of the three channels under the clear sky condition of the target area.

3. The atmospheric degradable water yield inversion method according to claim 1, wherein before the step of inputting the radiance temperature, the target surface pressure and the auxiliary information corresponding to the three channels into the atmospheric degradable water yield inversion model and obtaining the target atmospheric degradable water yield through inversion, the method further comprises:

determining the simulated radiance temperature of the sample based on the atmospheric profile and the corresponding earth surface information; the earth surface information is used for reflecting earth surface characteristics corresponding to the atmospheric profile;

determining an atmospheric water reducible quantity inversion model based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity;

wherein the sample assistance information comprises: sample time information, sample space information, and sample observation angle information.

4. The atmospheric degradable water content inversion method according to claim 2,

the surface information includes: surface pressure, surface temperature, surface type and surface emissivity;

correspondingly, the determining the simulated radiance temperature of the sample based on the atmospheric profile and the corresponding surface information specifically includes:

and calculating simulated brightness and temperature according to a rapid radiation transmission mode based on the atmospheric profile and the corresponding ground surface pressure, ground surface temperature, ground surface type and ground surface specific radiance, selecting a sensor coefficient file used by the preset satellite, and determining the simulated radiation brightness and temperature of the sample corresponding to the three channels.

5. The atmospheric degradable water yield inversion method according to any one of claims 1 to 4, wherein the radiation brightness temperature, the target surface pressure and the auxiliary information corresponding to the three channels are input into an atmospheric degradable water yield inversion model, and the inversion is performed to obtain the target atmospheric degradable water yield, specifically comprising:

determining a target multivariate nonlinear regression model matched with the target region based on the space region division standard and the space information; the target multivariate nonlinear regression model is a sub-model which is obtained by the atmospheric degradable water yield inversion model according to a space region division standard and is matched with the space information direction;

and inputting the radiance temperature, the target earth surface pressure and the auxiliary information corresponding to the three channels into a target multiple nonlinear regression model, and performing inversion to obtain the target atmospheric water reducible quantity.

6. The atmospheric degradable water yield inversion method according to any one of claims 1 to 4, wherein the preset satellite is a wind cloud number three D star, and a sensor for acquiring the radiance data is a medium-resolution spectral imager type II; the thermal infrared split window channel comprises: a channel having a center wavelength of 10.8 μm and a channel having a center wavelength of 12.0 μm; the other thermal infrared channels are channels with the central wavelength of 7.2 mu m;

correspondingly, before the steps of inputting the radiance temperature, the target surface pressure and the auxiliary information corresponding to the three channels into the atmospheric water reducible quantity inversion model and obtaining the target atmospheric water reducible quantity through inversion, the method further comprises the following steps:

based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water-reducing quantity, constructing an atmospheric water-reducing quantity inversion model according to parametric analysis, and determining an atmospheric water-reducing quantity expression;

substituting the target sample simulated radiation brightness temperature, the target sample ground surface pressure, the target sample auxiliary information and the target sample atmospheric degradable water volume matched with the target area into an atmospheric degradable water volume expression to obtain each fitting coefficient value in the atmospheric degradable water volume expression;

substituting the fitting coefficient values into the atmospheric degradable water amount expression to determine the atmospheric degradable water amount inversion model;

wherein the atmospheric water-reducible expression is:

TPW＝C₀+C₁T_B7.2+C₂T_B10.8+C₃T_B12.0+C₄T_B7.2 ²+C₅T_B12.0 ²+C₆(T_B12.0-T_B10.8)+C₇(T_B12.0-T_B10.8)²+C₈ps+C₉mon+C₁₀lat+C₁₁zen；

in the formula, C₀-C₁₁As fitting coefficient, T_B7.2、T_B10.8And T_B12.0Respectively representing the radiant brightness temperature corresponding to the subscript channel, ps being the earth surface pressure, mon being the time information, lat being the space information, and zen being the observation angle information.

7. The atmospheric degradable water yield inversion method according to claim 6, wherein the determining, based on radiance data of three channels of a target area acquired by a preset satellite, radiance temperatures corresponding to the three channels of the target area under a clear sky condition specifically includes:

respectively screening out the radiance data of the three channels under the clear sky condition of the target area based on the radiance data and the cloud detection data of the three channels of the target area acquired by the preset satellite; wherein the resolution of the channel with the central wavelength of 10.8 μm and the channel with the central wavelength of 12.0 μm is 250 m; the resolution of a channel with a central wavelength of 7.2 mu m is 1 km;

based on the radiance data of the three channels under the clear sky condition of the target area, interpolating the radiance data of the channel with the central wavelength of 7.2 μm to the resolution of 250m according to a spatial interpolation method, and determining the radiance data of the target three channels under the condition that the resolution is the same as 250 m;

and determining the radiant brightness temperatures corresponding to the three channels under the clear sky condition of the target area based on the radiant brightness data of the three channels of the target.

8. An atmospheric water reducible quantity inversion system, comprising: a data processing unit and a data inversion unit;

the data processing unit is used for determining the radiant brightness temperatures corresponding to the three channels under the clear sky condition of the target area based on the radiant brightness data of the three channels of the target area acquired by a preset satellite; wherein the three channels comprise: two thermal infrared split window channels and one other thermal infrared channel; the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 and 13 mu m, and the other thermal infrared channels are channels which are sensitive to water vapor values except the thermal infrared splitting window channels;

the data inversion unit is used for inputting the radiation brightness temperature, the target ground surface pressure and the auxiliary information corresponding to the three channels into an atmospheric water reducible quantity inversion model and performing inversion to obtain a target atmospheric water reducible quantity;

wherein the auxiliary information comprises: time information, spatial information, and observation angle information; the atmospheric water reducible quantity inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

9. An electronic device, comprising a memory and a processor, wherein the processor and the memory communicate with each other via a bus; the memory stores program instructions executable by the processor, the processor invoking the program instructions to perform the atmospheric water reducible inversion method of any one of claims 1 to 7.

10. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the computer program, when executed by a processor, implements the method of atmospheric precipitation inversion according to any one of claims 1 to 7.

Background

The Total degradable Water (TPW), also called Total moisture amount, refers to the Total amount of atmospheric degradable Water in the direction perpendicular to the air column under clear air conditions. The knowledge of the spatial distribution is of great importance for the study of water circulation, energy balance and climate change in the world, region and local.

In addition, the amount of atmospheric water degradable is also an important input parameter for weather and climate patterns, and the accuracy of rainfall areas, hurricane routes and intensity predictions can be improved through pattern assimilation. Is a vital meteorological factor for monitoring and forecasting global or local temperature change, climate change and medium and small scale severe weather. The accurate determination of the content and the change condition of the amount of the atmospheric degradable water has great significance for the development of the fields of weather forecast, climate change monitoring, hydrological monitoring, resource remote sensing, geodetic survey and the like.

The conventional observation means of the existing atmospheric degradable water content is restricted by a detection station and environmental factors, the detection precision cannot meet the requirement of the spatial and temporal resolution of the atmospheric degradable water content, the water vapor time and the spatial distribution condition cannot be described in detail, the detection precision is limited, and the error of the atmospheric degradable water content value obtained by inversion is large.

Therefore, how to provide an atmospheric degradable water content inversion method and system, an electronic device and a storage medium, effectively realize the inversion of continuous space-time distribution and high spatial resolution of the atmospheric degradable water content, and improve the accuracy of the inversion of the atmospheric degradable water content becomes a problem to be solved urgently.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an atmospheric degradable water content inversion method and system, electronic equipment and a storage medium.

The invention provides an atmospheric degradable water content retrieval method, which comprises the following steps:

determining the radiant brightness temperatures corresponding to three channels of a target area under a clear sky condition based on the radiant brightness data of the three channels of the target area acquired by a preset satellite; wherein the three channels comprise: two thermal infrared split window channels and one other thermal infrared channel; the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 and 13 mu m, and the other thermal infrared channels are channels which are sensitive to water vapor values except the thermal infrared splitting window channels;

inputting the radiant brightness temperature, the target ground surface pressure and the auxiliary information corresponding to the three channels into an atmospheric water reducible quantity inversion model, and performing inversion to obtain a target atmospheric water reducible quantity;

wherein the auxiliary information comprises: time information, spatial information, and observation angle information; the atmospheric water reducible quantity inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

According to the inversion method of the atmospheric degradable water yield, the radiance temperatures corresponding to the three channels of the target area under the clear sky condition are determined based on radiance data of the three channels of the target area acquired by the preset satellite, and the method specifically comprises the following steps:

respectively screening out the radiance data of the three channels under the clear sky condition of the target area based on the radiance data and the cloud detection data of the three channels of the target area acquired by the preset satellite;

and determining the corresponding radiant brightness temperatures of the three channels under the clear sky condition of the target area based on the radiant brightness data of the three channels under the clear sky condition of the target area.

According to the atmospheric degradable water yield inversion method provided by the invention, before the step of inputting the radiation brightness temperature, the target earth surface pressure and the auxiliary information corresponding to the three channels into the atmospheric degradable water yield inversion model and obtaining the target atmospheric degradable water yield by inversion, the method further comprises the following steps:

determining the simulated radiance temperature of the sample based on the atmospheric profile and the corresponding earth surface information; the earth surface information is used for reflecting earth surface characteristics corresponding to the atmospheric profile;

determining an atmospheric water reducible quantity inversion model based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity;

wherein the sample assistance information comprises: sample time information, sample space information, and sample observation angle information.

According to the atmospheric degradable water yield inversion method provided by the invention, the surface information comprises the following steps: surface pressure, surface temperature, surface type and surface emissivity;

correspondingly, the determining the simulated radiance temperature of the sample based on the atmospheric profile and the corresponding surface information specifically includes:

and calculating simulated brightness and temperature according to a rapid radiation transmission mode based on the atmospheric profile and the corresponding ground surface pressure, ground surface temperature, ground surface type and ground surface specific radiance, selecting a sensor coefficient file used by the preset satellite, and determining the simulated radiation brightness and temperature of the sample corresponding to the three channels.

According to the inversion method of the atmospheric degradable water yield provided by the invention, the radiation brightness temperature, the target surface pressure and the auxiliary information corresponding to the three channels are input into an atmospheric degradable water yield inversion model, and the target atmospheric degradable water yield is obtained through inversion, and the inversion method specifically comprises the following steps:

determining a target multivariate nonlinear regression model matched with the target region based on the space region division standard and the space information; the target multivariate nonlinear regression model is a sub-model which is obtained by the atmospheric degradable water yield inversion model according to a space region division standard and is matched with the space information direction;

and inputting the radiance temperature, the target earth surface pressure and the auxiliary information corresponding to the three channels into a target multiple nonlinear regression model, and performing inversion to obtain the target atmospheric water reducible quantity.

According to the atmospheric degradable water yield inversion method provided by the invention, the preset satellite is a wind cloud number three D satellite, and the sensor for collecting the radiance data is a medium-resolution spectral imager type II; the thermal infrared split window channel comprises: a channel having a center wavelength of 10.8 μm and a channel having a center wavelength of 12.0 μm; the other thermal infrared channels are channels with the central wavelength of 7.2 mu m;

correspondingly, before the steps of inputting the radiance temperature, the target surface pressure and the auxiliary information corresponding to the three channels into the atmospheric water reducible quantity inversion model and obtaining the target atmospheric water reducible quantity through inversion, the method further comprises the following steps:

based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water-reducing quantity, constructing an atmospheric water-reducing quantity inversion model according to parametric analysis, and determining an atmospheric water-reducing quantity expression;

substituting the target sample simulated radiation brightness temperature, the target sample ground surface pressure, the target sample auxiliary information and the target sample atmospheric degradable water volume matched with the target area into an atmospheric degradable water volume expression to obtain each fitting coefficient value in the atmospheric degradable water volume expression;

substituting the fitting coefficient values into the atmospheric degradable water amount expression to determine the atmospheric degradable water amount inversion model;

wherein the atmospheric water-reducible expression is:

TPW＝C₀+C₁T_B7.2+C₂T_B10.8+C₃T_B12.0+C₄T_B7.2 ²+C₅T_B12.0 ²+C₆(T_B12.0-T_B10.8)+C₇(T_B12.0-T_B10.8)²+C₈ps+C₉mon+C₁₀lat+C₁₁zen；

in the formula, C₀-C₁₁As fitting coefficient, T_B7.2、T_B10.8And T_B12.0Respectively representing the radiant brightness temperature corresponding to the subscript channel, ps being the earth surface pressure, mon being the time information, lat being the space information, and zen being the observation angle information.

According to the inversion method of the atmospheric degradable water yield, the radiance temperatures corresponding to the three channels of the target area under the clear sky condition are determined based on radiance data of the three channels of the target area acquired by the preset satellite, and the method specifically comprises the following steps:

respectively screening out the radiance data of the three channels under the clear sky condition of the target area based on the radiance data and the cloud detection data of the three channels of the target area acquired by the preset satellite; wherein the resolution of the channel with the central wavelength of 10.8 μm and the channel with the central wavelength of 12.0 μm is 250 m; the resolution of a channel with a central wavelength of 7.2 mu m is 1 km;

based on the radiance data of the three channels under the clear sky condition of the target area, interpolating the radiance data of the channel with the central wavelength of 7.2 μm to the resolution of 250m according to a spatial interpolation method, and determining the radiance data of the target three channels under the condition that the resolution is the same as 250 m;

and determining the radiant brightness temperatures corresponding to the three channels under the clear sky condition of the target area based on the radiant brightness data of the three channels of the target.

The invention also provides an atmospheric degradable water content inversion system, which comprises: a data processing unit and a data inversion unit;

the data processing unit is used for determining the radiant brightness temperatures corresponding to the three channels under the clear sky condition of the target area based on the radiant brightness data of the three channels of the target area acquired by a preset satellite; wherein the three channels comprise: two thermal infrared split window channels and one other thermal infrared channel; the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 and 13 mu m, and the other thermal infrared channels are channels which are sensitive to water vapor values except the thermal infrared splitting window channels;

the data inversion unit is used for inputting the radiation brightness temperature, the target ground surface pressure and the auxiliary information corresponding to the three channels into an atmospheric water reducible quantity inversion model and performing inversion to obtain a target atmospheric water reducible quantity;

wherein the auxiliary information comprises: time information, spatial information, and observation angle information; the atmospheric water reducible quantity inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

The invention also provides electronic equipment which comprises a memory and a processor, wherein the processor and the memory finish mutual communication through a bus; the memory stores program instructions executable by the processor, the processor invoking the program instructions to perform the steps of the above-described method for reducible water content inversion.

The present invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the above method for inverting the amount of airborne water.

According to the atmospheric degradable water content inversion method and system, the electronic device and the storage medium, the radiation brightness temperatures corresponding to the channels under the clear sky condition are determined according to the radiation brightness data of the channels acquired by the satellite, and the radiation brightness temperatures, the ground surface pressure and the auxiliary information are used as the input of the predetermined atmospheric degradable water content inversion model to obtain the output inversion atmospheric degradable water content. The inversion of continuous space-time distribution and high spatial resolution of the atmospheric degradable water content can be effectively realized, and the inversion precision of the atmospheric degradable water content is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a flow chart of an atmospheric water reducible quantity inversion method provided by the present invention;

FIG. 2 is a schematic flow chart of an atmospheric water reducible quantity inversion method provided by the present invention;

FIG. 3 is a North American GPS site map provided by the present invention;

FIG. 4 is a graph comparing the inversion of the amount of atmospheric water reducible to the water vapor value of a foundation GPS provided by the present invention;

FIG. 5 is a schematic structural diagram of an atmospheric degradable water content inversion system provided by the invention;

fig. 6 is a schematic physical structure diagram of an electronic device provided in the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The radiosonde is a conventional weather sounding instrument. The radio sounding observation is a conventional observation means for atmospheric water-reducing capacity, and the water-reducing capacity can be obtained by carrying out layering integration according to sounding data by using specific humidity. The data of the measuring station is objective and accurate, so the method is often used for verifying the resolving result of other methods. However, the radio sounding observation stations are unevenly distributed in the world, the stations are sparsely distributed, the time resolution is low, the detection precision cannot meet the requirement of the space-time resolution of the atmospheric degradable water volume, and the cost for maintaining the observation system is high.

The ground-based GPS remote sensing atmospheric water-reducible quantity utilizes a GPS receiver on the ground to measure the atmospheric delay quantity caused when a GPS satellite signal longitudinally passes through the atmosphere and reaches the ground, and then the accumulation quantity of the atmospheric water-reducible quantity on the whole atmosphere in the zenith direction is inverted. The method has no restriction of environmental factors, and can utilize the established GPS reference station data accurately and quickly. However, the atmospheric precipitation amount on the observation path can only be telemetered, and the total amount of atmospheric precipitation in a certain spatial region cannot be estimated.

The atmospheric degradable water volume inverted by utilizing the satellite data is superior to radiosonde data and foundation GPS data in the aspects of continuous spatial distribution, wide spatial range and the like, and has higher application value. Existing inversion algorithms can be classified into a visible light/near infrared method, a microwave method, and a thermal infrared method according to a channel used. The visible light/near infrared method utilizes the solar reflection light as a radiation source, and can detect the atmospheric water-reducing amount in the clear sky at the land and the sea in the daytime but cannot detect the night data through the inversion of the atmospheric water-reducing amount absorption difference of the atmospheric water-reducing amount weak absorption area and the window area channel near 1 mu m.

The thermal infrared method is the main method for obtaining regional atmospheric precipitation content at night. The traditional thermal infrared method for inverting atmospheric degradable water is to invert by observing the difference generated by the influence of atmospheric degradable water by a split window channel near 11 mu m of an imager. At present, the thermal infrared atmospheric degradable aquatic products of Fengyun No. two and Fengyun No. three in China are obtained by the method. With the technical development of the sensor, a channel with the sensitivity of 7.2 mu m to atmospheric degradable water and cloud parameters is added to a new generation meteorological satellite on the basis of a traditional split window, and the inversion accuracy of the atmospheric degradable water content is further increased. However, 1km or 250m atmospheric precipitation service products and related algorithms based on multiple thermal infrared channels of FY-3D/MERSI, especially integrating FY-3D/MERSI split window channels and atmospheric precipitation channels, have not been reported.

The microwave method utilizes microwave absorption frequency bands of atmospheric degradable water content such as 10GHz, 19GHz and 23GHz to observe, and can invert all-weather atmospheric degradable water content in day and night, but the method is generally used for atmospheric degradable water content in the sea due to complex surface emissivity of a microwave spectrum, and has low spatial resolution and limited application at present.

In summary, in order to solve the problems in the prior art and improve the space-time resolution and inversion accuracy of the atmospheric degradable water content inversion, the invention provides an atmospheric degradable water content inversion method based on satellite data.

Before explaining the present invention in detail, related concepts related to embodiments of the present invention will be explained.

The FY-3D (wind cloud three D weather satellite) is the earth observation satellite with the highest spectral resolution in China at present, greatly improves the acquisition capacity of earth atmospheric power, thermal parameters and greenhouse gases, and improves the capacity and level of China for medium and long-term numerical weather forecast, global climate resource general survey and climate change.

The FY-3D is loaded with a medium-resolution spectral imager 2(MERSI2), the medium-resolution spectral imager 2 integrates the functions of two imaging instruments (MERSI-1 and VIRR) of the original wind and cloud three-satellite, is the first imaging instrument in the world capable of acquiring information of a global 250-meter resolution infrared split window area, can acquire a global 250-meter resolution true color image seamlessly every day, and realizes high-precision quantitative inversion of atmospheric, land and ocean parameters such as cloud, aerosol, atmospheric water reducible quantity, land surface characteristics, ocean water color and the like.

The meteorological satellite has the characteristics of high time resolution and spatial resolution, can obtain the time-space change characteristics of atmospheric rainfall, and is an important means for inverting large-range atmospheric rainfall. MERSI-II (middle resolution ratio spectral imager II type) is one of core instruments of a new generation of polar orbit meteorological satellite Fengyun No. three D stars in China, integrates the functions of two imaging instruments (MERSI-1 and VIRR) of the original Fengyun No. three satellite, and has a spectrum covering 25 spectral channels of 412nm to 12.0 mu m.

Meanwhile, MERSI-II is also the first imaging instrument in the world capable of acquiring information of a global 250-meter resolution infrared split window area, and can acquire global 250-meter resolution infrared split window data seamlessly every day to realize high-precision quantitative inversion of atmospheric degradable water content. The newly-added 7.2-micron channel sensitive to atmospheric precipitation is fully utilized, an atmospheric precipitation signal is added on the basis of two infrared 250-meter resolution split window channels, the inversion accuracy of the atmospheric precipitation can be effectively improved, but the current business product is inverted on the basis of the traditional visible light/near infrared channel and is limited by sunlight, the inversion at night cannot be carried out, and the resolution of the product is 5 km. Atmospheric precipitation business products and related algorithms based on multiple thermal infrared channels of FY-3D/MERSI, particularly integrating a FY-3D/MERSI250m resolution of 10.8 μm, a 12.0 μm split window channel and a 7.2 μm atmospheric precipitation channel, have not been reported.

The Seebor profile library is a global clear sky atmosphere profile training sample (SeeBor version5.0) of Wisconsin university, and comprises profile information of 15704 corresponding 101 laminated strength layers in the world under the clear sky atmosphere state, wherein the profile information comprises the temperature, the atmospheric degradable water content, ozone, longitude and latitude, time information, earth surface pressure, earth surface temperature, earth surface type, atmospheric degradable water content, earth surface specific radiance and the like of a vertical pressure layer. The RTTOV is a rapid radiation transmission mode developed by the European middle-term weather forecast center (ECMWF), and all versions behind the RTTOV7 can simulate the data of a new-generation InfraRed high-spectral-resolution satellite detector such as an Atmospheric InfraRed detector (AIRS). In the scheme, RTTOV is utilized to simulate the radiation bright temperature of FY 3D/MERSI-II.

The ECMWF reanalysis data is European meteorological center data ERA5 data, and two sets of data are provided, wherein one set of data is assimilation analysis data, and the other set of data is forecast data. The data was analyzed for 6 hour intervals, cycled every 12 hours, and contained surface information such as surface pressure.

Fig. 1 is a flowchart of an atmospheric degradable water content inversion method provided by the present invention, and fig. 2 is a flowchart of an atmospheric degradable water content inversion method provided by the present invention, as shown in fig. 1 and fig. 2, the present invention provides an atmospheric degradable water content inversion method, which includes:

step S1, determining the corresponding radiance temperature of three channels of a target area under a clear sky condition based on radiance data of the three channels of the target area acquired by a preset satellite; wherein the three channels comprise: two thermal infrared split window channels and one other thermal infrared channel; the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 and 13 mu m, and the other thermal infrared channels are channels which are sensitive to water vapor values except the thermal infrared splitting window channels;

step S2, inputting the radiant brightness temperature, the target earth surface pressure and the auxiliary information corresponding to the three channels into an atmospheric water reducible quantity inversion model, and performing inversion to obtain a target atmospheric water reducible quantity;

wherein the auxiliary information comprises: time information, spatial information, and observation angle information; the atmospheric water reducible quantity inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

Specifically, the satellite data is acquired by using an FY-3D (wind cloud three D meteorological satellite) and a middle resolution spectral imager 2(MERSI-II), and the invention is explained in detail. The FY-3D/MERSI-II design contains 25 channels of 0.47 μm to 12.0 μm, covering visible, near infrared, mid-wave infrared and far infrared multiband. It is understood that, considering the problem of the satellite service life, besides using FY-3D, the method provided by the present invention is also applicable to other preset satellites with the same function, and is not limited herein.

The channel for collecting the radiant brightness data of the atmospheric degradable water quantity inversion method provided by the invention comprises two thermal infrared splitting window channels and one other thermal infrared channel, wherein the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 mu m and 13 mu m, and the other thermal infrared channel is a channel which is sensitive to the water vapor value and is arranged outside the thermal infrared splitting window channels.

The product L1 of FY-3D/MERSI-II is earth observation data which is carried on a Fengyun three-D star medium-resolution spectral imager 2(MERSI-II) and is subjected to radiometric calibration pretreatment. And taking the position where the atmospheric water yield inversion needs to be carried out as a target area.

In step S1, reading satellite observation radiance data in an L1 product of FY-3D/mers i-II, screening the obtained radiance data of the three channels based on radiance data of the three channels of the target area acquired by the satellite, selecting only radiance data corresponding to the three channels of the target area under a clear sky condition, and converting the radiance data into radiance temperatures to obtain radiance temperatures corresponding to the multiple channels.

In step S2, auxiliary information such as time information (e.g., month), spatial information (longitude and latitude), observation angle information (satellite angle information), and the like corresponding to the image element of the target area in the satellite data is read.

And reading ECMWF (European Central for Medium-Range Weather means ECMWF for short) and analyzing the ground pressure data in the data, and performing time and space matching on the ground pressure data after interpolation processing and the L1 data of FY-3D/MERSI-II to obtain ground pressure data corresponding to the target area pixel in the L1 data as the target ground pressure.

And inputting the radiant brightness temperature, the target ground surface pressure and the auxiliary information corresponding to the three channels collected in the step S1 into an atmospheric water reducible quantity inversion model, and performing inversion to obtain the target atmospheric water reducible quantity. The auxiliary information includes: temporal information, spatial information, and observation angle information.

Before inversion is performed by using the atmospheric degradable water content inversion model, the atmospheric degradable water content inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric degradable water content. The sample assistance information includes: sample time information, sample space information, and sample observation angle information. The atmospheric water degradable quantity inversion model is a mathematical model and can reflect the correlation between the input data radiance temperature, the earth surface pressure and auxiliary information and the output atmospheric water degradable quantity.

Secondly, in the invention, the target area can be a target point or a target area, when the atmospheric degradable water yield inversion of the target area is carried out, all data in the target area are obtained as a data set, and the corresponding inversion atmospheric degradable water yield can be obtained for the data corresponding to each pixel in the data set. However, since the satellite precision is limited, when the target area data is acquired, matching needs to be performed in space to determine the pixel corresponding to the target area.

Besides, observation angle information plays an important role in processing and application of remote sensing data. First, differences in the angles of observation of the satellites can result in differences in the path of the atmosphere in the transmission of radiation. Second, when there is relief, the viewing angle also has a large effect on the geometric characteristics of the image. The observation angle information (satellite angle information) includes: satellite zenith and azimuth angles. The satellite zenith angle is used in the present invention.

Compared with radio sounding observation and ground GPS atmospheric degradable water data, the atmospheric degradable water quantity inversion method provided by the invention has the advantages of more continuous spatial distribution, wider spatial range and higher spatial resolution. Compared with a visible light/near infrared method, the atmospheric water reducible quantity inversion method provided by the invention can simultaneously invert atmospheric water reducible quantity in clear sky at day and night. Compared with the traditional thermal infrared split window method, the method makes full use of more channels sensitive to atmospheric precipitation, and the spatial resolution is remarkably improved. Compared with a microwave method, the atmospheric degradable water content inversion method provided by the invention can be used for land atmospheric degradable water content inversion, and has high spatial resolution and good application prospect.

According to the inversion method of the atmospheric degradable water content, the radiation brightness temperatures corresponding to the channels under the clear sky condition are determined according to the radiation brightness data of the channels acquired by the satellite, and the radiation brightness temperatures, the earth surface pressure and the auxiliary information corresponding to the channels are used as the input of the predetermined inversion model of the atmospheric degradable water content to obtain the output inversion atmospheric degradable water content. The method can effectively reflect the influence of the time-space information, observation angle information and surface pressure information on the atmospheric degradable water yield, realize the inversion of the continuous time-space distribution and high spatial resolution of the atmospheric degradable water yield and improve the inversion precision of the atmospheric degradable water total amount.

Optionally, according to the inversion method of the atmospheric degradable water content provided by the present invention, the determining, based on the radiance data of the three channels of the target area acquired by the preset satellite, radiance temperatures corresponding to the three channels of the target area under a clear sky condition specifically includes:

respectively screening out the radiance data of the three channels under the clear sky condition of the target area based on the radiance data and the cloud detection data of the three channels of the target area acquired by the preset satellite;

and determining the corresponding radiant brightness temperatures of the three channels under the clear sky condition of the target area based on the radiant brightness data of the three channels under the clear sky condition of the target area.

Specifically, based on the radiance data of three channels of the target area collected by a preset satellite, determining radiance temperatures corresponding to the three channels of the target area under a clear sky condition specifically includes:

because weather conditions (such as clear sky, cloud and rainy days) can cause interference on the inversion of the atmospheric water-degradable amount, clear sky pixel screening needs to be carried out on radiance data acquired by a satellite based on cloud detection data before the inversion of the atmospheric water-degradable amount is carried out.

Cloud detection data of the FY-3D/MERSI-II are FY-3D/MERSI-II global cloud detection section products, and the products are track products with the resolution of 1 km.

Based on the radiation brightness data and the cloud detection data of the three channels of the target area acquired by FY-3D, the radiation brightness data and the cloud detection data are subjected to space matching, and the radiation brightness data of the multiple channels of the target area under the clear sky condition of the target area are screened out.

Based on the screened radiance data of the three channels under the clear sky condition of the target area, the radiance data is converted into radiance temperature (steps of scaling, brightness-temperature conversion, coefficient correction and the like are carried out), and the radiance temperature corresponding to the three channels under the clear sky condition of the target area is determined.

It should be noted that, the specific method for converting the radiance data into the radiance temperature may be selected according to the actual situation, and the present invention is not limited to this.

According to the inversion method of the amount of water degradable in the atmosphere, provided by the invention, on the basis of cloud detection data matched with a target area, clear sky pixel screening is carried out on the radiance data of a plurality of channels acquired by a satellite, the radiance data is converted into radiance temperatures, the radiance temperatures corresponding to the channels under the clear sky condition are determined, and the influence of weather change on the inversion of the amount of water degradable in the atmosphere is avoided. And taking the radiant brightness temperature, the surface pressure and the auxiliary information corresponding to the channels as the input of a predetermined atmospheric water reducible quantity inversion model to obtain the output inversion atmospheric water reducible quantity. The method can effectively reflect the influence of the time-space information, the observation angle information and the earth surface pressure information on the atmospheric degradable water yield, realize the inversion of the continuous time-space distribution and the high spatial resolution of the atmospheric degradable water yield, and improve the inversion precision of the atmospheric degradable water yield.

Optionally, according to the inversion method of the atmospheric degradable water content provided by the present invention, before the step of inputting the radiation brightness temperature, the target surface pressure and the auxiliary information corresponding to the three channels into the inversion model of the atmospheric degradable water content and obtaining the target atmospheric degradable water content by inversion, the inversion method further includes:

determining the simulated radiance temperature of the sample based on the atmospheric profile and the corresponding earth surface information; the earth surface information is used for reflecting earth surface characteristics corresponding to the atmospheric profile;

determining an atmospheric water reducible quantity inversion model based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity;

wherein the sample assistance information comprises: sample time information, sample space information, and sample observation angle information.

Specifically, in the step of determining the atmospheric degradable water cut inversion model, sample data needs to be determined first. Inputting the radiance temperature, the target surface pressure and the auxiliary information corresponding to the three channels into an atmospheric water reducible quantity inversion model, and before the step of obtaining the target atmospheric water reducible quantity by inversion, the method further comprises the following steps:

and reading a global atmosphere profile seebor database, and acquiring 15704 groups of global high-precision atmosphere profiles (temperature, humidity and ozone) and corresponding surface information, wherein the surface information is used for reflecting surface characteristics corresponding to the atmosphere profiles. And based on the atmospheric profiles and the corresponding earth surface information, calculating the simulated brightness temperature of each group of atmospheric profiles and the corresponding earth surface information by applying a rapid radiation transmission mode (RTTOV), and determining the simulated radiation brightness temperature of the sample.

And determining an atmospheric water reducible quantity inversion model based on the obtained sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity. The sample assistance information includes: sample time information, sample space information, and sample observation angle information.

Furthermore, it can be understood that after the simulated brightness temperature is calculated by applying the rapid radiation transmission mode RTTOV and the simulated radiation brightness temperature of the sample is determined, white gaussian noise can be added to the calculated brightness temperature, where the white gaussian noise is an ideal model for analyzing channel additive noise, so that the deviation between the simulated brightness temperature data and the measured brightness temperature data can be effectively reduced, and the simulated brightness temperature data and the measured brightness temperature data are closer to the brightness temperature data of the target area during inversion.

The determination of the Gaussian white noise can be determined according to the error of the rapid radiation transmission mode and the observation error of the sensor. Specifically, a white gaussian noise matrix with the center r (k) is constructed:

r²＝f²+e²；

and f is a mode error, and is the average deviation of the simulated brightness temperature and the observed brightness temperature matched with time and space under the condition of clear sea and air with more uniform emissivity and temperature than the land. e is the observation error of the sensor and the instrument sensitivity NEDT of MERSI-II. For example, for three channels of 7.2, 10.8, and 12.0 μm, 0.3k, 0.4k, and 0.4k, respectively. Two main error sources are comprehensively considered, and Gaussian white noise is added to the simulated brightness temperature channel by channel, so that the simulated brightness temperature is closer to the observed brightness temperature data of the target area during inversion.

It should be noted that, in the present invention, the sample data is a data set, where each pixel has a corresponding sample simulated radiance temperature, sample surface pressure, sample auxiliary information, and sample atmospheric water reducible amount.

According to the method, the step of determining the simulated radiation brightness temperature of the sample through the atmospheric profile and the corresponding earth surface information is actually used for simulating the brightness temperature which can be observed under the current atmospheric transmittance during satellite observation, which is equivalent to the simulation of the forward evolution brightness temperature, and the method can be helpful for improving the accuracy during inversion by using an atmospheric water reducible quantity inversion model subsequently.

The method for inverting the amount of water in the atmosphere capable of being reduced is based on a cloud detection product matched with a target area, clear sky screening and spatial resampling are carried out on a plurality of channels of radiance data collected by a satellite, the radiance data are converted into radiance temperatures, and the radiance temperatures corresponding to the channels under the clear sky condition are determined. And taking the radiant brightness temperature, the surface pressure and the auxiliary information corresponding to the channels as the input of a predetermined atmospheric water reducible quantity inversion model to obtain an output atmospheric water reducible quantity inversion value. The method can effectively reflect the influence of the time-space information, the observation angle information and the ground surface pressure information on the atmospheric degradable water yield, realize the inversion of the continuous time-space distribution and the high spatial resolution of the atmospheric degradable water yield, and improve the inversion precision of the atmospheric degradable water yield.

Optionally, according to the atmospheric degradable water yield inversion method provided by the present invention, the surface information includes: surface pressure, surface temperature, surface type and surface emissivity;

correspondingly, the determining the simulated radiance temperature of the sample based on the atmospheric profile and the corresponding surface information specifically includes:

and calculating simulated brightness and temperature according to a rapid radiation transmission mode based on the atmospheric profile and the corresponding ground surface pressure, ground surface temperature, ground surface type and ground surface specific radiance, selecting a sensor coefficient file used by the preset satellite, and determining the simulated radiation brightness and temperature of the sample corresponding to the three channels.

Specifically, the surface information includes: surface pressure, surface temperature, surface type, and surface emissivity. The step of determining the simulated radiance temperature of the sample based on the atmospheric profile and the corresponding surface information specifically comprises the following steps: and reading a global atmospheric profile library Seebor, and acquiring 15704 groups of high-precision atmospheric profiles (temperature, humidity and ozone) and corresponding surface information (surface pressure, surface temperature, surface type and surface emissivity) in the global world.

And (3) calculating the simulated brightness temperature of each group of atmospheric profiles and corresponding earth surface information (earth surface pressure, earth surface temperature, earth surface type and earth surface emissivity), applying a rapid radiation transmission mode RTTOV (RTTOV), selecting a coefficient file suitable for an FY-3D/MERSI-II (medium resolution ratio spectral imager 2) sensor, and simulating to obtain the simulated radiation brightness temperature of the sample.

According to the inversion method of the atmospheric degradable water yield, the three channels of radiance data collected by the satellite are screened in clear sky based on the cloud detection product matched with the target area, the radiance data are converted into radiance temperatures, the radiance temperatures corresponding to the channels under the clear sky condition are determined, and the influence of weather change on the inversion of the atmospheric degradable water yield is avoided. And taking the radiant brightness temperature, the surface pressure and the auxiliary information corresponding to the channels as the input of a predetermined atmospheric water reducible quantity inversion model to obtain the output inversion atmospheric water reducible quantity. The method can effectively reflect the influence of the time-space information, observation angle information and surface pressure information on the atmospheric degradable water yield, realize the inversion of the continuous time-space distribution and high spatial resolution of the atmospheric degradable water yield and improve the inversion precision of the atmospheric degradable water total amount.

Optionally, according to the inversion method of the atmospheric degradable water content provided by the present invention, the inputting the radiation brightness temperature, the target surface pressure and the auxiliary information corresponding to the three channels into an atmospheric degradable water content inversion model, and performing inversion to obtain the target atmospheric degradable water content specifically includes:

determining a target multivariate nonlinear regression model matched with the target region based on the space region division standard and the space information; the target multivariate nonlinear regression model is a sub-model which is obtained by the atmospheric degradable water yield inversion model according to a space region division standard and is matched with the space information direction;

and inputting the radiance temperature, the target earth surface pressure and the auxiliary information corresponding to the three channels into a target multiple nonlinear regression model, and performing inversion to obtain the target atmospheric water reducible quantity.

Specifically, because the atmospheric degradable water content is in areas with different longitudes and latitudes (spatial positions), the rules of the atmospheric degradable water content are different, the atmospheric degradable water content inversion model can be divided according to the preset spatial region division standard based on the spatial region division standard, and the atmospheric degradable water content inversion model is divided into a plurality of multivariate nonlinear regression models.

For example, the world is divided into 6 latitude zones according to the latitude, which are respectively-5 to 35 degrees N, 25 to 65 degrees N, 55 to 90 degrees N, -35 to 5 degrees S, -25 to-65 degrees S, and-55 to-90 degrees S. Correspondingly, the atmospheric water-reducible quantity inversion model is divided into 6 multi-element nonlinear regression models, and the models respectively correspond to the latitude division areas.

After the atmospheric water-reducible quantity inversion model is divided according to a space region division standard (the atmospheric water-reducible quantity inversion model is divided into a first to a sixth multiple nonlinear regression models according to the above rules), a target regression model matched with a target region is determined according to the space region division standard according to the space information (longitude and latitude) corresponding to the target region (for example, the target region is determined to be within-5 to 35 degrees N, and the target regression model is determined to be the first regression model).

And inputting the acquired corresponding radiance temperature, target earth surface pressure and auxiliary information of the three channels of the target area under a clear sky condition into a target regression model to obtain the inversion atmospheric water reducible quantity.

It should be noted that besides the division according to the latitude, various division methods such as the division together of the north-south hemisphere and the latitude information may be used, a model may be directly established according to the spatial position of the target position region, and the specific preset spatial region division standard may be adjusted according to the actual situation, which is not limited in the present invention.

It can be understood that before determining the regression model corresponding to the target region based on the spatial region division standard to perform the atmospheric degradable water yield inversion, the multiple nonlinear regression model needs to be determined in advance based on the spatial region division standard. The atmospheric degradable water yield inversion model can be divided according to a preset space region division standard, and the atmospheric degradable water yield inversion model is divided into a plurality of multivariate nonlinear regression models.

And dividing sample data (sample simulated radiance temperature, sample surface pressure, sample auxiliary information and sample atmospheric water reducible amount) based on a space region division standard. And respectively determining corresponding regression models based on the divided sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

It should be noted that the sample data is actually a sample data set, and each sample corresponds to a sample simulated radiance temperature, a sample surface pressure, sample auxiliary information, and a sample atmospheric water reducible amount. When dividing, a sample data set is actually divided into different data sets according to the longitude and latitude of the sample data set according to the space region division standard, and the different data sets are respectively and correspondingly divided to obtain regression models. When model training or linear fitting is carried out, the sample data set used for training or fitting corresponds to the multiple nonlinear regression equation one by one.

Compared with a thermal infrared multichannel physical split window algorithm, the method adopts a multiple regression modeling method, utilizes a regression formula to establish the relationship between the bright temperature value, the bright temperature difference, the auxiliary information and the clear air atmosphere water-reducing amount, and is high in calculation speed and high in precision.

According to the atmospheric degradable water content inversion method provided by the invention, the atmospheric degradable water content inversion model is divided into a plurality of multivariate nonlinear regression models through a space region division standard. And selecting a corresponding target multivariate nonlinear regression model based on the spatial information of the target area, and performing atmospheric water reducible quantity inversion based on the data information corresponding to the target area and the target regression model. The method can effectively reflect the influence of the time-space information, the observation angle information and the earth surface pressure information on the atmospheric degradable water yield, realizes the inversion of the continuous time-space distribution and the high spatial resolution of the atmospheric degradable water yield, reflects the atmospheric degradable water yield characteristics of different climates and different regions, has higher effectiveness and practical applicability, and improves the inversion precision of the total amount of the atmospheric degradable water.

Optionally, according to the atmospheric degradable water yield inversion method provided by the invention, the preset satellite is a wind cloud number three D satellite, and the sensor for collecting the radiance data is a medium-resolution spectral imager type II; the thermal infrared split window channel comprises: a channel having a center wavelength of 10.8 μm and a channel having a center wavelength of 12.0 μm; the other thermal infrared channels are channels with the central wavelength of 7.2 mu m;

correspondingly, before the steps of inputting the radiance temperature, the target surface pressure and the auxiliary information corresponding to the three channels into the atmospheric water reducible quantity inversion model and obtaining the target atmospheric water reducible quantity through inversion, the method further comprises the following steps:

based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water-reducing quantity, constructing an atmospheric water-reducing quantity inversion model according to parametric analysis, and determining an atmospheric water-reducing quantity expression;

substituting the target sample simulated radiation brightness temperature, the target sample ground surface pressure, the target sample auxiliary information and the target sample atmospheric degradable water volume matched with the target area into an atmospheric degradable water volume expression to obtain each fitting coefficient value in the atmospheric degradable water volume expression;

substituting the fitting coefficient values into the atmospheric degradable water amount expression to determine the atmospheric degradable water amount inversion model;

wherein the atmospheric water-reducible expression is:

TPW＝C₀+C₁T_B7.2+C₂T_B10.8+C₃T_B12.0+C₄T_B7.2 ²+C₅T_B12.0 ²+C₆(T_B12.0-T_B10.8)+C₇(T_B12.0-T_B10.8)²+C₈ps+C₉mon+C₁₀lat+C₁₁zen；

in the formula, C₀-C₁₁As fitting coefficient, T_B7.2、T_B10.8And T_B12.0Respectively representing the radiant brightness temperature corresponding to the subscript channel, ps being the earth surface pressure, mon being the time information, lat being the space information, and zen being the observation angle information.

Specifically, the preset satellite is a Fengyun three-number D satellite, the sensor for collecting the radiance data is a medium-resolution spectral imager II type, and correspondingly, a channel with the central wavelength of FY-3D/MERS-II being 10.8 microns and a thermal infrared splitting window channel with the central wavelength being 12.0 microns are selected, and thermal infrared channels with the central wavelengths being 7.2 microns respectively are selected. And taking the data acquired by the three channels as data used for subsequently inverting the atmospheric degradable water content.

Correspondingly, before the steps of inputting the radiance temperature, the target surface pressure and the auxiliary information corresponding to the three channels into the atmospheric degradable water yield inversion model and obtaining the target atmospheric degradable water yield through inversion, the method further comprises the following steps:

and constructing an atmospheric degradable water content inversion model based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric degradable water content according to parametric analysis, and determining an atmospheric degradable water content expression.

When an atmospheric water-reducing quantity inversion model is constructed, firstly, a global atmospheric profile library Seebor needs to be read, and 15704 groups of global high-precision atmospheric profiles (temperature, humidity and ozone) and corresponding land surface information (land surface pressure, land surface temperature, land surface type and land surface emissivity) are obtained. And reading the longitude and latitude (space information), the month (time information), the clear sky land water reducing amount (sample atmospheric water reducing amount) and other information corresponding to 15704 group of profiles in the Seebor profile library

And (3) performing simulated brightness temperature calculation on each group of atmospheric profiles and corresponding surface information by using a rapid radiation transmission mode RTTOV (real time optical) and selecting a coefficient file suitable for an FY-3D/MERSI-II sensor, and simulating to obtain 15704 x 6 groups of samples with central wavelengths of 7.2 mu m, 10.8 mu m and 12.0 mu m and 3 channels in the global range.

Further, it can be understood that if the world is divided into 6 regions according to latitude, the regions are respectively-5 to 35 ° N, 25 to 65 ° N, 55 to 90 ° N, -35 to 5 ° S, -25 to-65 ° S, -55 to-90 ° S, and the corresponding Seebor profile data are respectively arranged to be 5001, 5567, 2289, 3240, 2620 and 1354. A multiple nonlinear regression model can be established according to the same method below according to the data corresponding to different latitude areas, respectively, to obtain multiple nonlinear regression models (6 regression model combinations).

And carrying out parametric analysis on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric degradable water content corresponding to each of the three obtained channels, and constructing an atmospheric degradable water content inversion model.

The expression of the atmospheric degradable water yield inversion model is as follows:

wherein, C₀-C₁₁As fitting coefficient, T_B7.2、T_B10.8And T_B12.0Respectively representing the radiation brightness temperature corresponding to the subscript channel, ps is the earth surface pressure, mon is the time information, lat is the space information, zenIs the observation angle information.

And substituting the target sample simulated radiation brightness temperature, the target sample surface pressure, the target sample auxiliary information and the target sample atmospheric degradable water quantity which are corresponding to each channel in the three channels and are matched with the target area into the atmospheric degradable water quantity expression to obtain each fitting coefficient value in the atmospheric degradable water quantity expression.

And substituting each fitting coefficient value into the atmospheric degradable water amount expression to determine the atmospheric degradable water amount inversion model matched with the target area.

The atmospheric water reducible quantity inversion method utilizes the Seebor database in combination with the brightness temperature simulation of the RTTOV infrared radiation transmission model and establishes the sample library. Extracting high-precision profile data and earth surface information in a Seebor profile library, selecting a coefficient file suitable for an FY-3D/MERSI-II sensor, performing brightness temperature simulation on 3 channels of MERSI-II, namely 7.2 microns, 10.8 microns and 12.0 microns, by utilizing a rapid radiation transmission mode RTTOV, and applying the simulation to inversion of atmospheric water reducible quantity for the first time. And carrying out parametric analysis on the sample simulated radiant brightness temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water-degradable quantity corresponding to each channel in the three channels to determine a regression relation, constructing an expression of the atmospheric water-degradable quantity inversion model, and fitting according to the sample data to obtain a fitting coefficient value of the expression. The method can effectively reflect the influence of the time-space information, the observation angle information and the earth surface pressure information on the atmospheric degradable water yield, realize the inversion of the continuous time-space distribution and the high spatial resolution of the atmospheric degradable water yield, and improve the inversion precision of the atmospheric degradable water total amount.

Optionally, according to the inversion method of the atmospheric degradable water content provided by the present invention, the determining, based on the radiance data of the three channels of the target area acquired by the preset satellite, radiance temperatures corresponding to the three channels of the target area under a clear sky condition specifically includes:

respectively screening out the radiance data of the three channels under the clear sky condition of the target area based on the radiance data and the cloud detection data of the three channels of the target area acquired by the preset satellite; wherein the resolution of the channel with the central wavelength of 10.8 μm and the channel with the central wavelength of 12.0 μm is 250 m; the resolution of a channel with a central wavelength of 7.2 mu m is 1 km;

based on the radiance data of the three channels under the clear sky condition of the target area, interpolating the radiance data of the channel with the central wavelength of 7.2 μm to the resolution of 250m according to a spatial interpolation method, and determining the radiance data of the target three channels under the condition that the resolution is the same as 250 m;

and determining the radiant brightness temperatures corresponding to the three channels under the clear sky condition of the target area based on the radiant brightness data of the three channels of the target.

Specifically, the resolution is 250 meters due to the FY-3D/MERS-II channel with a center wavelength of 10.8 μm and the thermal infrared splitting window channel with a center wavelength of 12.0 μm. Thermal infrared channels with central wavelengths of 7.2 μm each, and a resolution of 1 km. In order to further improve the accuracy of inversion, interpolation processing is performed on data with low resolution.

Correspondingly, based on the radiance data of the three channels of the target area collected by the preset satellite, the radiance temperatures corresponding to the three channels of the target area under a clear sky condition are determined, and the method specifically includes:

based on radiance data and cloud detection data of three channels of a target area acquired by a preset satellite, radiance data of the three channels (channels with central wavelengths of 7.2 μm, 10.8 μm and 12.0 μm respectively) of the target area under a clear sky condition are respectively screened out.

Based on the radiance data of the three channels under the clear sky condition of the target area, according to a spatial interpolation method, the radiance data of the channel with the central wavelength of 7.2 μm is interpolated to the resolution of 250m, and the radiance data of the target three channels under the condition that the resolution is 250m is determined.

Based on the radiance data of the three channels of the target, the radiance data is converted into radiance temperature (steps such as scaling, brightness-temperature conversion, coefficient correction and the like), and the radiance temperature corresponding to the three channels with the resolution of 250 meters under the clear sky condition of the target area is determined.

According to the inversion method of the amount of water degradable in the atmosphere, on the basis of cloud detection data matched with a target area, clear sky pixel screening is carried out on a plurality of channels of radiance data collected by a satellite, all channel resolutions are resampled to 250 meters through spatial interpolation, the radiance data are converted into radiance temperatures, the radiance temperatures corresponding to the channels under the clear sky condition are determined, and the influence of weather changes on the inversion of the amount of water degradable in the atmosphere is avoided. And taking the radiant brightness temperature, the surface pressure and the auxiliary information corresponding to the channels as the input of a predetermined atmospheric water reducible quantity inversion model to obtain the output inversion atmospheric water reducible quantity. The method can effectively reflect the influence of the time-space information, the observation angle information and the earth surface pressure information on the atmospheric degradable water yield, realize the inversion of the continuous time-space distribution and the high spatial resolution of the atmospheric degradable water yield, and improve the inversion precision of the atmospheric degradable water total amount.

For better understanding of the present invention, the present invention will be described in detail by taking the inversion of the atmospheric water reducible amount in north america as an example:

the local area of the United states is selected as a research area, and the GPS atmospheric water-lowering data comprises various data forms such as North American sites, North American grids and the like. Including daily, hourly data, fig. 3 is a north american GPS site map provided by the present invention, as shown in fig. 3, which includes 380 sites, where 12-day data time-matched to FY-3D mers L1 data in 6 months of 2020 is selected. The GPS site was chosen to verify the results of the invention.

And reading the inversion model of the atmospheric water-reducing quantity in the 25-65-degree N region trained according to the preset Seebor sample and the RTTOV model in the invention because the local region of the United states is within the range of 25-65-degree N.

The expression of the atmospheric degradable water yield inversion model is as follows:

specifically, in the 25-65 ° N region, the expression of the multiple nonlinear regression model is:

TPW＝-184.874-3.51T_B7.2+0.001T_B10.8+4.425T_B12.0+0.007T_B7.2 ²-0.008T_B12.0 ²+8.488(T_B12.0-T_B10.8)-0.22(T_B12.0-T_B10.8)²+0.035ps+0.208mon-0.353lat-0.049zen

downloading FY3D/MERSI-II L1 data and corresponding Geo data with resolution of 250m and 1km at the corresponding time and in the border U.S., downloading cloud detection product data corresponding to the time, performing spatial resampling, unifying the cloud detection product data into 250m resolution data, reading the radiant brightness and coordinate information of an L1 product, reading the coordinate information of GPS atmospheric water-reducible data and atmospheric water-reducible information.

And (3) carrying out spatial matching by taking the actually measured data of 250-meter resolution data obtained after resampling of FY3D/MERSI-II and the GPS atmospheric degradable water product as inspection data. And calculating the distance between the longitude and latitude of each pixel in the L1 data and the longitude and latitude of the GPS station, and extracting a point with the minimum distance from the GPS station in the L1 data as a sample point.

It should be noted that, due to the limitation of the distribution position of the GPS base station and the limitation of the satellite accuracy, the GPS base station and the satellite pixels are not necessarily overlapped, and a point with a distance difference of less than 1km from the GPS site in the L1 data is generally selected as a sample point, so as to reduce the accuracy error caused by the spatial deviation.

And performing space matching on the matched sample points and cloud detection products, and extracting 1559 points under a clear air condition. And respectively carrying out calibration, brightness-temperature conversion and coefficient correction on the radiation brightness of 3 channels of 1559 points to obtain brightness-temperature values.

And downloading ECMWF reanalysis data corresponding to the research area and the research time, extracting surface pressure data, performing time and space matching on the data after interpolation processing and 250m data of FY-3D/MERSI-II to obtain surface pressure data corresponding to 1559 sample points.

The brightness temperature data and the auxiliary data (latitude information, time information, satellite angle information and earth surface pressure information) of the 3 channels are input into an atmospheric water reducible quantity inversion model to obtain an inversion result of the atmospheric water reducible quantity, and the inversion result is compared with corresponding GPS atmospheric water reducible quantity data, FIG. 4 is a comparison graph of the inversion atmospheric water reducible quantity and the ground GPS atmospheric water reducible quantity provided by the invention, as shown in FIG. 4, the correlation between the inverted atmospheric water reducible quantity result and the measured atmospheric water reducible quantity of the ground GPS is good, and the correlation coefficient reaches 0.78.

By utilizing the inversion method of the atmospheric degradable water content provided by the scheme, the inversion of continuous space-time distribution and high spatial resolution of the atmospheric degradable water content on clear air lands can be effectively realized, 250 m-resolution infrared data of FY-3D/MERSI-II are utilized for the first time, and the inversion method has the advantages of high calculation precision, simple calculation method, high calculation speed and the like.

The obtained atmospheric degradable water yield is in one-to-one correspondence with pixels in FY-3D/MERSI-II L1 data, the spatial resolution is 250 meters, and the atmospheric degradable water yield is obviously superior to that of the existing atmospheric degradable water product with the resolution of 5 km. The correlation of the inversion result reaches 0.78, and the scheme is verified to have higher application value.

The scheme provides an inversion method of the atmospheric water-degradable amount on the clear air and the land based on FY-3D polar orbit meteorological satellite data, and an inversion model with higher precision and a complete inversion process are established. The data of the MERSI-II sensor carried on the FY-3D is used for inversion work of land atmospheric rainfall under clear sky conditions, and the data can be used as a reference of an FY-3D/MERSI-II water-reducing inversion business algorithm, so that a foundation is laid for subsequent researches on numerical weather forecast, data assimilation and the like.

Fig. 5 is a schematic structural diagram of an atmospheric degradable water content inversion system provided by the present invention, and as shown in fig. 5, the present invention further provides an atmospheric degradable water content inversion system, which includes: a data processing unit 510 and a data inversion unit 520;

the data processing unit 510 is configured to determine, based on radiance data of three channels in a target area acquired by a preset satellite, radiance temperatures corresponding to the three channels in the target area under a clear sky condition; wherein the three channels comprise: two thermal infrared split window channels and one other thermal infrared channel; the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 and 13 mu m, and the other thermal infrared channels are channels which are sensitive to water vapor values except the thermal infrared splitting window channels;

the data inversion unit 520 is configured to input the radiance temperature, the target surface pressure, and the auxiliary information corresponding to the three channels into an atmospheric degradable water yield inversion model, and perform inversion to obtain a target atmospheric degradable water yield;

wherein the auxiliary information comprises: time information, spatial information, and observation angle information; the atmospheric water reducible quantity inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

Specifically, the satellite data is acquired by using an FY-3D (wind cloud three D meteorological satellite) and a middle resolution spectral imager 2(MERSI-II), and the invention is explained in detail. The FY-3D/MERSI-II design contains 25 channels of 0.47 μm to 12.0 μm, covering visible, near infrared, mid-wave infrared and far infrared multiband. It is understood that, considering the problem of the satellite service life, besides using FY-3D, the method provided by the present invention is also applicable to other preset satellites with the same function, and is not limited herein.

The channel for collecting the radiant brightness data of the atmospheric degradable water quantity inversion method provided by the invention comprises two thermal infrared splitting window channels and one other thermal infrared channel, wherein the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 mu m and 13 mu m, and the other thermal infrared channel is a channel which is sensitive to the water vapor value and is arranged outside the thermal infrared splitting window channels.

The product L1 of FY-3D/MERSI-II is earth observation data which is carried on a Fengyun three-D star medium-resolution spectral imager 2(MERSI-II) and is subjected to radiometric calibration pretreatment. And taking the position where the atmospheric water yield inversion needs to be carried out as a target area.

The data processing unit 510 is configured to read satellite observation radiance data in an L1 product of FY-3D/mers i-II, screen the obtained radiance data of the three channels based on radiance data of three channels of a target area acquired by a satellite, select only radiance data corresponding to the three channels of the target area under a clear sky condition, convert the radiance data into radiance temperatures, and obtain radiance temperatures corresponding to multiple channels.

And a data inversion unit 520, configured to read auxiliary information, such as time information (e.g., month), spatial information (longitude and latitude), and observation angle information (satellite angle information), corresponding to the pixel of the target area in the satellite data.

And reading ECMWF (European Central for Medium-Range Weather means ECMWF for short) and analyzing the ground pressure data in the data, and performing time and space matching on the ground pressure data after interpolation processing and the L1 data of FY-3D/MERSI-II to obtain ground pressure data corresponding to the target area pixel in the L1 data as the target ground pressure.

And inputting the radiance temperature, the target earth surface pressure and the auxiliary information corresponding to the three channels acquired by the data processing unit 510 into an atmospheric water reducible quantity inversion model, and performing inversion to obtain the target atmospheric water reducible quantity. The auxiliary information includes: temporal information, spatial information, and observation angle information.

Before inversion is performed by using the atmospheric degradable water content inversion model, the atmospheric degradable water content inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric degradable water content. The sample assistance information includes: sample time information, sample space information, and sample observation angle information. The atmospheric water degradable quantity inversion model is a mathematical model and can reflect the correlation between the input data radiance temperature, the earth surface pressure and auxiliary information and the output atmospheric water degradable quantity.

Secondly, in the invention, the target area can be a target point or a target area, when the atmospheric degradable water yield inversion of the target area is carried out, all data in the target area are obtained as a data set, and the corresponding inversion atmospheric degradable water yield can be obtained for the data corresponding to each pixel in the data set. However, since the satellite precision is limited, when the target area data is acquired, matching needs to be performed in space to determine the pixel corresponding to the target area.

Besides, observation angle information plays an important role in processing and application of remote sensing data. First, differences in the angles of observation of the satellites can result in differences in the path of the atmosphere in the transmission of radiation. Second, when there is relief, the viewing angle also has a large effect on the geometric characteristics of the image. The observation angle information (satellite angle information) includes: satellite zenith and azimuth angles. The satellite zenith angle is used in the present invention.

Compared with radio sounding observation and ground GPS atmospheric degradable water data, the atmospheric degradable water quantity inversion method provided by the invention has the advantages of more continuous spatial distribution, wider spatial range and higher spatial resolution. Compared with a visible light/near infrared method, the atmospheric water reducible quantity inversion method provided by the invention can simultaneously invert atmospheric water reducible quantity in clear sky at day and night. Compared with the traditional thermal infrared split window method, the method makes full use of more channels sensitive to atmospheric precipitation, and the spatial resolution is remarkably improved. Compared with a microwave method, the atmospheric degradable water content inversion method provided by the invention can be used for land atmospheric degradable water content inversion, and has high spatial resolution and good application prospect.

According to the atmospheric degradable water content inversion system provided by the invention, the radiation brightness temperatures corresponding to a plurality of channels under clear sky conditions are determined according to the radiation brightness data of the plurality of channels acquired by the satellite, and the radiation brightness temperatures, the earth surface pressure and the auxiliary information corresponding to the plurality of channels are used as the input of the predetermined atmospheric degradable water content inversion model to obtain the output inversion atmospheric degradable water content. The method can effectively reflect the influence of the time-space information, observation angle information and surface pressure information on the atmospheric degradable water yield, realize the inversion of the continuous time-space distribution and high spatial resolution of the atmospheric degradable water yield and improve the inversion precision of the atmospheric degradable water total amount.

It should be noted that, the atmospheric degradable water content inversion system provided in the embodiment of the present invention is used for executing the above atmospheric degradable water content inversion method, and a specific implementation manner thereof is consistent with a method implementation manner, and is not described herein again.

Fig. 6 is a schematic physical structure diagram of an electronic device provided in the present invention, and as shown in fig. 6, the electronic device may include: a processor (processor)610, a communication interface (communication interface)620, a memory (memory)630 and a communication bus (bus)640, wherein the processor 610, the communication interface 620 and the memory 630 complete communication with each other through the communication bus 640. The processor 610 may invoke logic instructions in the memory 630 to perform the above-described method for atmospheric water reducible inversion, comprising: determining the radiant brightness temperatures corresponding to three channels of a target area under a clear sky condition based on the radiant brightness data of the three channels of the target area acquired by a preset satellite; wherein, three passageways include: two thermal infrared split window channels and one other thermal infrared channel; the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 mu m and 13 mu m, and the other thermal infrared channels are channels which are sensitive to water vapor values except the thermal infrared splitting window channels; inputting the radiant brightness temperature, the target ground surface pressure and the auxiliary information corresponding to the three channels into an atmospheric water reducible quantity inversion model, and performing inversion to obtain a target atmospheric water reducible quantity; wherein the auxiliary information includes: time information, spatial information, and observation angle information; the atmospheric water reducible quantity inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

In addition, the logic instructions in the memory 630 may be implemented in software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and the like.

In another aspect, an embodiment of the present invention further provides a computer program product, where the computer program product includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, and when the program instructions are executed by a computer, the computer can execute the method for inverting the atmospheric degradable water provided by the above-mentioned method embodiments, where the method includes: determining the radiant brightness temperatures corresponding to three channels of a target area under a clear sky condition based on the radiant brightness data of the three channels of the target area acquired by a preset satellite; wherein, three passageways include: two thermal infrared split window channels and one other thermal infrared channel; the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 mu m and 13 mu m, and the other thermal infrared channels are channels which are sensitive to water vapor values except the thermal infrared splitting window channels; inputting the radiant brightness temperature, the target ground surface pressure and the auxiliary information corresponding to the three channels into an atmospheric water reducible quantity inversion model, and performing inversion to obtain a target atmospheric water reducible quantity; wherein the auxiliary information includes: time information, spatial information, and observation angle information; the atmospheric water reducible quantity inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

In yet another aspect, an embodiment of the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program being implemented by a processor to perform the method for atmospheric degradable water content inversion provided in the above embodiments, the method including: determining the radiant brightness temperatures corresponding to three channels of a target area under a clear sky condition based on the radiant brightness data of the three channels of the target area acquired by a preset satellite; wherein, three passageways include: two thermal infrared split window channels and one other thermal infrared channel; the two thermal infrared splitting window channels are two adjacent channels in an atmospheric window between 10 mu m and 13 mu m, and the other thermal infrared channels are channels which are sensitive to water vapor values except the thermal infrared splitting window channels; inputting the radiant brightness temperature, the target ground surface pressure and the auxiliary information corresponding to the three channels into an atmospheric water reducible quantity inversion model, and performing inversion to obtain a target atmospheric water reducible quantity; wherein the auxiliary information includes: time information, spatial information, and observation angle information; the atmospheric water reducible quantity inversion model is determined based on the sample simulated radiance temperature, the sample surface pressure, the sample auxiliary information and the sample atmospheric water reducible quantity.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods of the various embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.