Microwave atmospheric transmittance calculation method, device, electronic device and storage medium

Abstract

The present invention provides a method, device and electronic device for calculating microwave atmospheric transmittance, the method comprising: obtaining atmospheric data of an atmospheric sounding station, and obtaining a liquid water profile in the cloud of the atmospheric data; inputting the atmospheric data and the liquid water profile in the cloud into a millimeter wave transmission model and a Mie scattering model, and obtaining an oxygen absorption coefficient in the atmosphere, a water vapor absorption coefficient and a liquid water extinction coefficient in the cloud; obtaining the atmospheric extinction coefficient and calculating a first microwave atmospheric transmittance of the atmospheric sounding station; according to the cloud coverage, respectively calculating the first microwave atmospheric transmittance based on a first calculation method and a second calculation method, obtaining a second microwave atmospheric transmittance of a clear sky area and a third microwave atmospheric transmittance of a cloud-covered area, and obtaining a comprehensive microwave atmospheric transmittance based on the second microwave atmospheric transmittance and the third microwave atmospheric transmittance. The present invention can correct and reduce the influence of the atmosphere on microwave signals according to the comprehensive microwave atmospheric transmittance.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave atmospheric transmittance calculation, and in particular to a microwave atmospheric transmittance calculation method, device and electronic equipment. Background Art

[0002] The application research of satellite-borne passive microwaves shows that the atmospheric influence cannot be ignored in the inversion calculation of geophysical parameters in the case of clear sky and cloud cover over land. In the case of precipitation scattering, the underlying surface information is basically polluted by scattered clouds and rain. When only non-scattering clouds and rain are considered, the water vapor in the atmosphere and liquid water in the clouds have a greater impact on the microwave high-frequency band. When using satellite-borne microwave radiometers to invert surface parameters, the atmosphere is often regarded as transparent, and the influence of the atmosphere on the brightness temperature of microwave observations is ignored, which will bring errors to the traditional land surface parameter inversion results. At the same time, based on the statistics of satellite observations, it is found that at any given time, about 60% of the earth's surface is covered by clouds. The study of the influence and correction of the atmosphere on satellite-borne passive microwave signals has important application value.

[0003] Therefore, how to calculate the transmittance of atmospheric data in the microwave high-frequency band, thereby reducing the impact of the atmosphere on satellite-borne passive microwave signals, is an issue that needs to be urgently addressed in the current research. Summary of the invention

[0004] The present invention provides a microwave atmosphere transmittance calculation method, device and electronic equipment, which are used to solve the defect that it is difficult to calculate the microwave atmosphere transmittance in the prior art, and realize the calculation of the microwave atmosphere transmittance, thereby reducing the influence of the atmosphere on the microwave signal.

[0005] The present invention provides a method for calculating microwave atmospheric transmittance, comprising:

[0006] Acquire atmospheric data of an atmospheric sounding site, and determine whether there is cloud cover in the atmosphere based on the atmospheric data and a critical humidity function;

[0007] When cloud cover is confirmed, the atmospheric data is input into a calculation model of liquid water in the cloud to obtain a liquid water profile in the cloud of the atmospheric data;

[0008] The atmospheric data and the liquid water profile in the cloud are input into the millimeter wave transmission model to obtain the oxygen absorption coefficient and water vapor absorption coefficient in the atmosphere; and the atmospheric data and the liquid water profile in the cloud are input into the Mie scattering model to obtain the liquid water extinction coefficient in the cloud;

[0009] Based on the oxygen absorption coefficient, the water vapor absorption coefficient and the extinction coefficient of liquid water in the cloud, an atmospheric extinction coefficient is obtained, and based on the atmospheric extinction coefficient, a first microwave atmospheric transmittance of the atmospheric sounding station is calculated;

[0010] According to the degree of cloud coverage, the first microwave atmospheric transmittance is calculated based on the first calculation method and the second calculation method respectively to obtain the second microwave atmospheric transmittance of the clear sky area and the third microwave atmospheric transmittance of the cloud coverage area, and the comprehensive microwave atmospheric transmittance is obtained based on the second microwave atmospheric transmittance and the third microwave atmospheric transmittance.

[0011] According to a method for calculating microwave atmospheric transmittance provided by the present invention, the atmospheric data is based on a critical humidity function to determine whether there is cloud cover in the atmosphere, specifically comprising:

[0012] Comparing the atmospheric data with the critical humidity parameter of the critical humidity function to determine whether the relative humidity of the atmospheric data is greater than a preset humidity threshold;

[0013] When the relative humidity of the atmospheric data is greater than or equal to a preset humidity threshold, confirming that there is cloud cover;

[0014] When the relative humidity of the atmospheric data is less than a preset humidity threshold, it is confirmed to be a clear sky state.

[0015] According to a method for calculating microwave atmospheric transmittance provided by the present invention, the atmospheric data is input into a calculation model for liquid water in clouds to obtain a liquid water profile in clouds of the atmospheric data, specifically comprising:

[0016] Inputting the atmospheric data into a calculation model of liquid water in clouds, and obtaining the air temperature of the horizontal layer of the atmospheric layer where the atmospheric data is located and the height relative to the cloud bottom;

[0017] Based on the air temperature and humidity, obtain the proportion of liquid water in the cloud;

[0018] The liquid water profile in the cloud of the atmospheric data is obtained according to the air temperature, humidity, height relative to the cloud base and the proportion of liquid water in the cloud.

[0019] According to a method for calculating microwave atmospheric transmittance provided by the present invention, the first microwave atmospheric transmittance of the atmospheric sounding station is calculated based on the atmospheric extinction coefficient and specifically includes:

[0020] The atmospheric optical thickness is calculated based on the atmospheric extinction coefficient;

[0021] The first microwave atmospheric transmittance of the atmospheric sounding site is obtained based on the atmospheric optical thickness and the satellite sensor observation angle.

[0022] According to a method for calculating microwave atmospheric transmittance provided by the present invention, after obtaining the first microwave atmospheric transmittance of the atmospheric sounding station, the method further comprises:

[0023] According to the degree of cloud coverage, the atmosphere is divided into cloud-covered areas and clear sky areas;

[0024] In the clear sky area, obtaining a second microwave atmospheric transmittance based on the first calculation method using the first microwave atmospheric transmittance;

[0025] In the cloud-covered area, calculating the first microwave atmospheric transmittance based on a second calculation method to obtain a third microwave atmospheric transmittance;

[0026] According to the second microwave atmosphere transmittance and the third microwave atmosphere transmittance, the comprehensive microwave atmosphere transmittance is obtained.

[0027] According to a method for calculating microwave atmospheric transmittance provided by the present invention, the method of calculating the first microwave atmospheric transmittance based on a first calculation method to obtain a second microwave atmospheric transmittance specifically includes:

[0028] Extracting MODIS atmospheric precipitable water data of the atmospheric sounding station, performing linear regression on the atmospheric precipitable water data and the first microwave atmospheric transmittance, and obtaining regression coefficients under different bands and different time conditions;

[0029] According to the regression coefficient, a second microwave atmospheric transmittance of a microwave imager or a microwave radiometer carrying channel of a specified spatial resolution is obtained;

[0030] The step of calculating the first microwave atmospheric transmittance based on the second calculation method to obtain a third microwave atmospheric transmittance specifically includes:

[0031] Extracting MODIS cloud and water vapor data, Cloudsat cloud type and cloud profile data and relevant data provided by microwave hygrometer at the atmospheric sounding station;

[0032] Based on the relevant data and the first microwave atmospheric transmittance, construct a microwave atmospheric transmittance lookup table for different cloud types and cloud water contents, different microwave bands, different polarizations and different times;

[0033] Based on the microwave atmospheric transmittance lookup table, a third microwave atmospheric transmittance of a microwave imager or a microwave radiometer carrying channel with a specified spatial resolution is obtained.

[0034] The present invention also provides a microwave atmospheric transmittance calculation device, comprising:

[0035] An atmospheric data acquisition module is used to acquire atmospheric data of an atmospheric sounding site and determine whether there is cloud cover in the atmosphere based on the atmospheric data and a critical humidity function;

[0036] A cloud liquid water acquisition module is used to input the atmospheric data into a cloud liquid water calculation model to obtain a cloud liquid water profile of the atmospheric data when cloud cover is confirmed;

[0037] The absorption coefficient acquisition module is used to input the atmospheric data and the liquid water profile in the cloud into the millimeter wave transmission model to obtain the oxygen absorption coefficient and the water vapor absorption coefficient in the atmosphere; and input the atmospheric data and the liquid water profile in the cloud into the Mie scattering model to obtain the liquid water extinction coefficient in the cloud;

[0038] A first microwave atmospheric transmittance calculation module, used to obtain an atmospheric extinction coefficient based on an oxygen absorption coefficient, a water vapor absorption coefficient, and an extinction coefficient of liquid water in clouds, and to calculate a first microwave atmospheric transmittance of the atmospheric sounding site based on the atmospheric extinction coefficient;

[0039] The comprehensive microwave atmospheric transmittance calculation module is used to obtain the second microwave atmospheric transmittance of the clear sky area and the third microwave atmospheric transmittance of the cloud coverage area based on the first calculation method and the second calculation method according to the cloud coverage degree, and obtain the comprehensive microwave atmospheric transmittance based on the second microwave atmospheric transmittance and the third microwave atmospheric transmittance.

[0040] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of any of the above-mentioned methods for calculating microwave atmospheric transmittance are implemented.

[0041] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of any of the above-mentioned methods for calculating microwave atmospheric transmittance are implemented.

[0042] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of any of the above-mentioned methods for calculating microwave atmospheric transmittance are implemented.

[0043] The microwave atmospheric transmittance calculation method, device and electronic device provided by the present invention determine whether there is cloud coverage in the atmosphere, obtain the liquid water profile in the cloud according to the liquid water calculation model in the cloud, and successively obtain the oxygen absorption coefficient, the water vapor absorption coefficient and the liquid water extinction coefficient in the cloud based on the atmospheric data and the water profile in the cloud based on the millimeter wave transmission model and the Mie scattering model, thereby obtaining the atmospheric extinction coefficient, calculating the first microwave atmospheric transmittance, and according to the cloud coverage degree, the first microwave atmospheric transmittance is calculated by different calculation methods to obtain the microwave atmospheric transmittance of the clear sky area and the cloud coverage area, so that the influence of the atmosphere on the microwave signal can be corrected and reduced according to the comprehensive microwave atmospheric transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 This is one of the flow charts of the microwave atmospheric transmittance calculation method provided by the present invention;

[0046] Figure 2 This is the second flow chart of the method for calculating microwave atmospheric transmittance provided by the present invention;

[0047] Figure 3 This is the third flow chart of the method for calculating microwave atmospheric transmittance provided by the present invention;

[0048] Figure 4 This is one of the schematic diagrams of the effect of the microwave atmospheric transmittance calculation method provided by the present invention;

[0049] Figure 5 This is the second schematic diagram of the effect of the microwave atmosphere transmittance calculation method provided by the present invention;

[0050] Figure 6 This is the third schematic diagram of the effect of the microwave atmospheric transmittance calculation method provided by the present invention;

[0051] Figure 7 It is a structural schematic diagram of the microwave atmospheric transmittance calculation device provided by the present invention;

[0052] Figure 8 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] Combine the following Figure 1-Figure 6 The microwave atmosphere transmittance calculation method provided by the present invention is described.

[0055] Reference Figure 1The microwave atmospheric transmittance calculation method provided by the present invention includes but is not limited to the following steps:

[0056] Step 110: Acquire atmospheric data of an atmospheric sounding site, and use the atmospheric data based on a critical humidity function to determine whether there is cloud cover in the atmosphere.

[0057] Specifically, the atmospheric sounding sites in this embodiment are 121 radio atmospheric sounding sites in my country, and the atmospheric data include atmospheric sounding data collected in real time and atmospheric sounding data after reanalysis. Among them, the atmospheric data includes but is not limited to: vertical height, temperature, humidity, pressure, height and wind speed, etc. Then the acquired atmospheric data is passed through the cloud detection model, that is, based on the critical humidity function, to determine whether there are clouds.

[0058] The critical humidity function is shown in the following formula:

[0059] U c =1-αδ(1-α)[1+β(δ-0.5)] (1)

[0060] Among them, α and β are fixed values, α = 1, δ is the ratio of the atmospheric pressure at the height of the layer to the atmospheric pressure at the surface. If the humidity measured in a layer in the atmospheric expansion line is higher than the calculated critical humidity value, the atmospheric layer is considered to be in the cloud, which means that there is cloud cover in the atmosphere.

[0061] Step 120: When cloud cover is confirmed, the atmospheric data is input into a calculation model for liquid water in the cloud to obtain a liquid water profile in the cloud of the atmospheric data.

[0062] Specifically, after judging the atmospheric data based on the critical humidity function, the atmospheric data meets the condition of cloud coverage, and the liquid water profile of the atmospheric data in the cloud is calculated based on the liquid water calculation model in the cloud (Salonen-Uppala), that is, the distribution of liquid water in the cloud is obtained. Among them, the parameters of the liquid water calculation model in the cloud are all predetermined.

[0063] Step 130: Input the atmospheric data and the liquid water profile in the cloud into the millimeter wave transmission model to obtain the oxygen absorption coefficient and the water vapor absorption coefficient in the atmosphere; and input the atmospheric data and the liquid water profile in the cloud into the Mie scattering model to obtain the liquid water extinction coefficient in the cloud.

[0064] Specifically, based on the millimeter wave transmission model and the Mie scattering model, the atmospheric data and the absorption coefficients of the liquid water profile in the cloud are obtained, which are respectively: the oxygen absorption coefficient and the water vapor absorption coefficient in the atmosphere and the extinction coefficient of liquid water in the cloud.

[0065] Among them, the millimeter wave transmission model and Mie scattering model are calculated based on the configuration of the FY3D satellite observation platform height, incident angle, and the observation parameters and sensitivity of the MWRI instrument.

[0066] Step 140: Based on the oxygen absorption coefficient, the water vapor absorption coefficient and the extinction coefficient of liquid water in the cloud, the atmospheric extinction coefficient is obtained, and the first microwave atmospheric transmittance of the atmospheric sounding site is calculated based on the atmospheric extinction coefficient.

[0067] Among them, the passive microwave signal on the ground surface must be absorbed and scattered by the atmospheric medium (dry gas, atmospheric water vapor, liquid water in clouds, rain and snow, etc.) before reaching the satellite sensor. The atmospheric extinction coefficient refers to the coefficient of the atmosphere after absorption and scattering. As shown in the following formula:

[0068]

[0069] Among them, k wv is the water vapor absorption coefficient, k O2 is the oxygen absorption coefficient, k clw is the extinction coefficient of liquid water in the cloud, k g is the atmospheric extinction coefficient.

[0070] Step 150: According to the degree of cloud coverage, the first microwave atmospheric transmittance is calculated based on the first calculation method and the second calculation method respectively to obtain the second microwave atmospheric transmittance of the clear sky area and the third microwave atmospheric transmittance of the cloud coverage area, and the comprehensive microwave atmospheric transmittance is obtained based on the second microwave atmospheric transmittance and the third microwave atmospheric transmittance.

[0071] The microwave in this embodiment refers to electromagnetic waves with a frequency between 300 MHz and 300 GHz, which have the characteristics of being easy to gather into a beam, highly directional, and propagating in a straight line, and can be used to transmit high-frequency signals in a free space with unobstructed line of sight.

[0072] The microwave atmospheric transmittance calculation method provided by the present invention determines whether there is cloud coverage in the atmosphere, obtains the liquid water profile in the cloud according to the calculation model of liquid water in the cloud, and successively obtains the oxygen absorption coefficient, the water vapor absorption coefficient and the liquid water extinction coefficient in the cloud based on the atmospheric data and the water profile in the cloud based on the millimeter wave transmission model and the Mie scattering model, thereby obtaining the atmospheric extinction coefficient, calculating the first microwave atmospheric transmittance, and according to the cloud coverage degree, the first microwave atmospheric transmittance is calculated by different calculation methods to obtain the microwave atmospheric transmittance of the clear sky area and the cloud coverage area, so that the influence of the atmosphere on the microwave signal can be corrected and reduced according to the comprehensive microwave atmospheric transmittance.

[0073] Based on the above embodiment, judging whether there is cloud cover in the atmosphere based on the atmospheric data based on the critical humidity function specifically includes:

[0074] Comparing the atmospheric data with the critical humidity parameter of the critical humidity function to determine whether the relative humidity of the atmospheric data is greater than a preset humidity threshold;

[0075] When the relative humidity of the atmospheric data is greater than or equal to a preset humidity threshold, confirming that there is cloud cover;

[0076] When the relative humidity of the atmospheric data is less than a preset humidity threshold, it is confirmed to be a clear sky state.

[0077] This embodiment compares the humidity of the atmospheric data with the threshold of the critical humidity function to determine the humidity, and determines whether the atmospheric condition is covered with clouds or not covered with clouds according to the humidity.

[0078] Based on the above embodiment, the step of inputting the atmospheric data into the cloud liquid water calculation model to obtain the cloud liquid water profile of the atmospheric data specifically includes:

[0079] Inputting the atmospheric data into a calculation model of liquid water in clouds, and obtaining the air temperature of the horizontal layer of the atmospheric layer where the atmospheric data is located and the height relative to the cloud bottom;

[0080] Based on the air temperature and humidity, obtain the proportion of liquid water in the cloud;

[0081] The liquid water profile in the cloud of the atmospheric data is obtained according to the air temperature, humidity, height relative to the cloud base and the proportion of liquid water in the cloud.

[0082] Specifically, this embodiment first obtains the air temperature of the horizontal layer of the atmosphere and the height relative to the cloud bottom based on the calculation model of liquid water in the cloud, and obtains the proportion of liquid water in the cloud according to the temperature, as shown in the following formula:

[0083]

[0084] Among them, P w (t) is the liquid water fraction in the cloud, t is the air temperature;

[0085] The calculation formula of the liquid water profile in the cloud is as follows:

[0086]

[0087] Among them, W0 is 0.17 (g / m 3 ), C is 0.04℃ -1 , t is temperature °C, h r 1500 m, h c Cloud base height (m).

[0088] This embodiment uses a calculation model for liquid water in clouds to obtain the height of air temperature and atmospheric data relative to the cloud base, thereby obtaining the proportion of liquid water in the clouds and further obtaining the liquid water profile in the clouds.

[0089] Based on the above embodiment, the first microwave atmospheric transmittance of the atmospheric sounding site is calculated based on the atmospheric extinction coefficient and specifically includes:

[0090] The atmospheric optical thickness is calculated based on the atmospheric extinction coefficient;

[0091] The first microwave atmospheric transmittance of the atmospheric sounding site is obtained based on the atmospheric optical thickness and the satellite sensor observation angle.

[0092] Specifically, this embodiment obtains the optical thickness of the atmosphere through the atmospheric extinction coefficient, which is implemented based on the following formula:

[0093]

[0094] Where τ0 is the air thickness;

[0095] The microwave atmospheric transmittance is calculated based on the following formula:

[0096]

[0097] Wherein, u=cosθ, θ is the observation angle of the satellite sensor.

[0098] Based on the above embodiment, after obtaining the first microwave atmospheric transmittance of the atmospheric sounding site, the method further includes the following steps:

[0099] According to the degree of cloud coverage, the atmosphere is divided into cloud-covered areas and clear sky areas;

[0100] In the clear sky area, obtaining a second microwave atmospheric transmittance based on the first calculation method using the first microwave atmospheric transmittance;

[0101] In the cloud-covered area, calculating the first microwave atmospheric transmittance based on a second calculation method to obtain a third microwave atmospheric transmittance;

[0102] According to the second microwave atmosphere transmittance and the third microwave atmosphere transmittance, the comprehensive microwave atmosphere transmittance is obtained.

[0103] In this embodiment, the atmosphere is divided into a cloud-covered area and a clear sky area based on the degree of cloud coverage. Different calculation methods are used for the cloud-covered area and the clear sky area to obtain the atmospheric transmission rates of the two areas, and the calculation results of the two areas are combined to obtain the combined microwave atmospheric transmission rate.

[0104] Based on the above embodiment, the step of calculating the first microwave atmospheric transmittance based on the first calculation method to obtain the second microwave atmospheric transmittance specifically includes:

[0105] Extracting atmospheric precipitable water data of the atmospheric sounding station, performing linear regression on the atmospheric precipitable water data and the first microwave atmospheric transmittance, and obtaining regression coefficients under different wavebands and different time conditions;

[0106] According to the regression coefficient, a second microwave atmospheric transmittance of a microwave imager carrying channel with a specified spatial resolution is obtained;

[0107] Specifically, the first calculation method is: extracting atmospheric precipitable water data from the atmospheric sounding station, and performing linear equation regression on the first microwave atmospheric transmittance to obtain regression coefficients in different bands and at different times.

[0108] The microwave atmospheric transmittance of the microwave imager or microwave radiometer carrying channel with a spatial resolution of 1 km is calculated using the regression coefficients of different bands and different times through the atmospheric precipitable water data.

[0109] The step of calculating the first microwave atmospheric transmittance based on the second calculation method to obtain a third microwave atmospheric transmittance specifically includes:

[0110] Extracting cloud and water vapor data from satellite remote sensing (or reanalysis data) of the atmospheric sounding site, Cloudsat cloud type and cloud profile data, and related data provided by microwave hygrometers;

[0111] Based on the relevant data and the first microwave atmospheric transmittance, construct a microwave atmospheric transmittance lookup table for different cloud types and cloud water contents, different microwave bands, different polarizations and different times;

[0112] Based on the microwave atmospheric transmittance lookup table, a third microwave atmospheric transmittance of a microwave imager or a microwave radiometer carrying channel with a specified spatial resolution is obtained.

[0113] Specifically, the second calculation method in this embodiment is: extracting the satellite remote sensing (or reanalysis data) cloud and water vapor products of the atmospheric sounding site and the cloud base height, cloud type, cloud base height and other observation brightness temperature data provided by the FY-3D microwave imager, and combining them with the first microwave atmospheric transmittance to construct a microwave atmospheric transmittance lookup table under different cloud types, different microwave bands, different polarizations and different time conditions. Then, according to the microwave atmospheric transmittance lookup table, the microwave atmospheric transmittance of the microwave imager carrying channel with a specified spatial resolution is calculated.

[0114] This embodiment further calculates based on the first microwave atmospheric transmittance through the first calculation method and the second calculation method to obtain the microwave atmospheric transmittance in the cloud-covered area and the clear sky area.

[0115] The following combination Figure 2-Figure 6 , the microwave atmospheric transmittance calculation method provided by the present invention is described in detail.

[0116] Reference Figure 2 The microwave atmospheric transmittance calculation method provided by the present invention specifically includes the following process:

[0117] The atmospheric sounding data / atmospheric reanalysis data are judged according to the critical humidity function to determine whether the relative humidity is greater than or equal to the preset threshold value Uc. If so, the cloud coverage is output, and if not, the clear sky is output. After judging the cloud coverage, the atmospheric sounding data / atmospheric reanalysis data are input into the liquid water calculation model in the cloud to obtain the distribution of liquid water in the cloud. The atmospheric sounding data / atmospheric reanalysis data and the distribution of liquid water in the cloud are input into the microwave millimeter wave propagation model (MPM93) and the Mie scattering model, and the point-like microwave atmospheric transmittance is obtained by calculation.

[0118] In the case of clear sky atmosphere, the point-like microwave atmospheric transmittance and atmospheric water data are linearly regressed to obtain the microwave atmospheric transmittance with a resolution of 1 km under clear sky.

[0119] In the case of cloud cover, the atmospheric water vapor, cloud type, cloud base height and microwave hygrometer lookup table are obtained through point-like microwave atmospheric transmittance, satellite cloud products and microwave hygrometer, thereby obtaining the microwave atmospheric transmittance with a resolution of 1 km in the case of cloud cover.

[0120] The planar microwave atmospheric transmittance is obtained based on the microwave atmospheric transmittance with a resolution of 1 km under clear sky and the microwave atmospheric transmittance with a resolution of 1 km under cloud cover.

[0121] The microwave atmosphere transmittance calculation method provided by the present invention also includes: data preprocessing and model parameter configuration.

[0122] Among them, data preprocessing includes: radio sounding observation data preprocessing, satellite remote sensing (or reanalysis data) cloud and water vapor products and CloudSat satellite data preprocessing, and FY-3D Microwave Hygrometer Type II (MWHS-II) data preprocessing.

[0123] The preprocessing of radiosonde observation data is as follows: radiosonde observation data from 121 stations in my country, including vertical profiles of temperature, humidity, pressure, altitude, wind speed and wind direction. The observation time is twice a day, at 11:15 and 23:15 UTC time respectively.

[0124] Firstly, the quality control of atmospheric sounding observation data is carried out. The quality control theory is determined by simulating the value of microwave atmospheric transmittance of satellite-borne microwave radiometer through atmospheric sounding observation data for 3.5 years and analyzing the influence of sounding data on microwave atmospheric transmittance.

[0125] The quality control of each radiosonde data is evaluated by the following methods:

[0126] Eliminate data with a maximum vertical height of less than 9 km from the ground to the atmosphere in arid and semi-arid areas of China;

[0127] Except for arid and semi-arid areas, data with a maximum vertical height of less than 12 km from the ground to the atmosphere were excluded.

[0128] The amount of data eliminated above accounts for about 1.68% of the total data.

[0129] The preprocessing of satellite remote sensing (or reanalysis data) cloud and water vapor products (here MODIS cloud and water vapor products are used as an example) and CloudSat satellite data includes: using the latitude and longitude provided by NASA and the EASA-GRID grid point coordinate conversion method, using the ENVI-IDL program to achieve the strip splicing of 1km MODIS atmospheric precipitable water data (MYD05_L2 and MOD05_L2) and the extraction of atmospheric precipitable water data in the near infrared band. In the same way, the cloud classification data of MODIS (MOD06_L2 and MYD06_L2) cloud top temperature and height, cloud optical thickness and effective particle radius are spliced ​​and extracted. The cloud mask products of MODIS (MOD35_L2 and MYD35_L2) are spliced ​​and extracted to obtain cloud and clear sky areas.

[0130] The program is used to extract the cloud liquid water content, cloud type, cloud optical thickness, and effective radius of cloud particles from the CloudProfile Radar (CPR) of the CloudSat satellite's atmospheric sounding stations in my country.

[0131] The data preprocessing of FY-3D Microwave Humidity Sensor II (MWHS-II) includes: using the latitude and longitude provided by the China Meteorological Administration and the EASA-GRID grid point coordinate conversion method, and using the ENVI-IDL program to realize the data splicing and projection of the MWHS-II / FY3D global orbital brightness temperature observations at 118.75 GHz and 183.31 GHz twice a day.

[0132] Model parameter configuration includes: one-dimensional microwave radiation simulation model parameter configuration scheme.

[0133] Specifically, under the Linux system, the input data in the original model is the atmospheric parameter cube data simulated by the CRM numerical model. The model input interface is modified to enable batch input of data contained in atmospheric sounding profiles, including: vertical height, temperature, humidity, pressure, height, wind speed and other profiles, and satellite sensor observation platform parameters, including: observation angle, platform height, frequency and polarization, etc.

[0134] In this embodiment, the microwave imager MWRI / FY-3D carries five frequency bands: 10.65 GHz, 18.7 GHz, 23.80 GHz, 36.5 GHz and 89.0 GHz, and each frequency has vertical and horizontal polarization modes.

[0135] Reference Figure 3 , Figure 3 Schematic diagram of liquid water in clouds calculated using the Salonen-Uppala cloud detection algorithm and atmospheric sounding data.

[0136] The atmospheric sounding data are compared based on the critical humidity function to determine the relative humidity between the atmospheric sounding data and the critical humidity function Uc. If the relative humidity is greater than or equal to Uc, it means there is cloud cover. The atmospheric sounding data are used based on the cloud base height, water and density ratio to obtain the distribution of liquid water in the cloud.

[0137] Reference Figure 4-Figure 6 , Figure 4-Figure 6 These are the relationship diagrams between the atmospheric transmittance of 19 GHz, 37 GHz and 85.5 GHz microwaves and the atmospheric precipitable water content.

[0138] In the figure, Total precipitable Water is the precipitable water, and Transmittance is the transmittance.

[0139] In the case of cloud cover, the cloud top height and cloud top temperature provided by MODIS cloud products are introduced, combined with the cloud type and cloud profile distribution (liquid water content in the cloud, ice water content in the cloud, cloud particle radius) provided by CloudSatCPR, and the 118.3GHz and 183.7GHz brightness temperatures of MWHS / FY-3D and the microwave atmospheric transmittance of the site to build a lookup table. Before building the lookup table, the cloud parameters of different heights and types related to microwave atmospheric transmittance are first classified using the K-means clustering method, including high-level clouds, bottom-level clouds, single-layer clouds, multi-layer clouds, and other types. On this basis, a microwave atmospheric transmittance lookup table is built for different cloud scenes, different frequencies, different polarizations, and different times. Finally, the microwave atmospheric transmittance at 1km under cloud cover is calculated by the lookup table method in combination with known satellite cloud products and hygrometer observation data.

[0140] The microwave atmosphere transmittance calculation device provided by the present invention is described below. The microwave atmosphere transmittance calculation device described below and the microwave atmosphere transmittance calculation method described above can be referred to each other.

[0141] Reference Figure 7 The present invention provides a microwave atmospheric transmittance calculation device, including but not limited to the following modules:

[0142] The atmospheric data acquisition module 710 is used to acquire the atmospheric data of the atmospheric sounding site and determine whether there is cloud cover in the atmosphere based on the critical humidity function.

[0143] The cloud liquid water acquisition module 720 is used to input the atmospheric data into the cloud liquid water calculation model to obtain the cloud liquid water profile of the atmospheric data when cloud cover is confirmed;

[0144] The absorption coefficient acquisition module 730 is used to input the atmospheric data and the liquid water profile in the cloud into the millimeter wave transmission model to obtain the oxygen absorption coefficient and the water vapor absorption coefficient in the atmosphere; and input the atmospheric data and the liquid water profile in the cloud into the Mie scattering model to obtain the liquid water extinction coefficient in the cloud;

[0145] The first microwave atmospheric transmittance calculation module 740 is used to obtain the atmospheric extinction coefficient based on the oxygen absorption coefficient, the water vapor absorption coefficient and the liquid water extinction coefficient in the cloud, and calculate the first microwave atmospheric transmittance of the atmospheric sounding site based on the atmospheric extinction coefficient.

[0146] Based on the above embodiments, the atmospheric data acquisition module is specifically used for:

[0147] Comparing the atmospheric data with the critical humidity parameter of the critical humidity function to determine whether the relative humidity of the atmospheric data is greater than a preset humidity threshold;

[0148] When the relative humidity of the atmospheric data is greater than or equal to a preset humidity threshold, confirming that there is cloud cover;

[0149] When the relative humidity of the atmospheric data is less than a preset humidity threshold, it is confirmed to be a clear sky state.

[0150] Based on the above embodiments, the cloud liquid water acquisition module is specifically used for:

[0151] Inputting the atmospheric data into a calculation model of liquid water in clouds, and obtaining the air temperature of the horizontal layer of the atmospheric layer where the atmospheric data is located and the height relative to the cloud bottom;

[0152] Based on the air temperature and humidity, obtain the proportion of liquid water in the cloud;

[0153] The liquid water profile in the cloud of the atmospheric data is obtained according to the air temperature, humidity, height relative to the cloud base and the proportion of liquid water in the cloud.

[0154] Based on the above embodiment, the first microwave atmosphere pass rate calculation module is specifically used for:

[0155] The atmospheric optical thickness is calculated based on the atmospheric extinction coefficient;

[0156] The first microwave atmospheric transmittance of the atmospheric sounding site is obtained based on the atmospheric optical thickness and the satellite sensor observation angle.

[0157] Based on the above embodiment, the following modules are also included:

[0158] A region division module is used to divide the atmosphere into cloud-covered areas and clear sky areas according to the degree of cloud coverage;

[0159] A second microwave atmospheric transmittance acquisition module, in the clear sky area, obtains a second microwave atmospheric transmittance by calculating the first microwave atmospheric transmittance based on a first calculation method;

[0160] A third microwave atmosphere transmittance acquisition module, in the cloud-covered area, obtains a third microwave atmosphere transmittance by calculating the first microwave atmosphere transmittance based on a second calculation method;

[0161] The comprehensive microwave atmosphere transmittance acquisition module obtains the comprehensive microwave atmosphere transmittance according to the second microwave atmosphere transmittance and the third microwave atmosphere transmittance.

[0162] Based on the above embodiment, the second microwave atmosphere transmittance acquisition module is specifically used for:

[0163] Extracting MODIS atmospheric precipitable water data of the atmospheric sounding station, performing linear regression on the atmospheric precipitable water data and the first microwave atmospheric transmittance, and obtaining regression coefficients under different bands and different time conditions;

[0164] According to the regression coefficient, a second microwave atmospheric transmittance of a microwave imager carrying channel with a specified spatial resolution is obtained;

[0165] Based on the above embodiment, the third microwave atmosphere transmittance acquisition module is specifically used for:

[0166] Extracting satellite remote sensing (or reanalysis data) cloud and water vapor data, Cloudsat cloud type and cloud profile data and related data provided by microwave hygrometers at the atmospheric sounding stations;

[0167] Based on the relevant data and the first microwave atmospheric transmittance, construct a microwave atmospheric transmittance lookup table for different cloud types and cloud water contents, different microwave bands, different polarizations and different times;

[0168] Based on the microwave atmospheric transmittance lookup table, a third microwave atmospheric transmittance of a microwave imager carrying channel with a specified spatial resolution is obtained.

[0169] Figure 8 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 8 As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830 and a communication bus 840, wherein the processor 810, the communication interface 820 and the memory 830 communicate with each other through the communication bus 840. The processor 810 may call the logic instructions in the memory 830 to execute the microwave atmosphere transmittance calculation method, which includes:

[0170] Acquire atmospheric data of an atmospheric sounding site, and determine whether there is cloud cover in the atmosphere based on the atmospheric data and a critical humidity function;

[0171] When cloud cover is confirmed, the atmospheric data is input into a calculation model of liquid water in the cloud to obtain a liquid water profile in the cloud of the atmospheric data;

[0172] The atmospheric data and the liquid water profile in the cloud are input into the millimeter wave transmission model to obtain the oxygen absorption coefficient and water vapor absorption coefficient in the atmosphere; and the atmospheric data and the liquid water profile in the cloud are input into the Mie scattering model to obtain the liquid water extinction coefficient in the cloud;

[0173] Based on the oxygen absorption coefficient, the water vapor absorption coefficient and the extinction coefficient of liquid water in the cloud, the atmospheric extinction coefficient is obtained, and based on the atmospheric extinction coefficient, the first microwave atmospheric transmittance of the atmospheric sounding site is calculated.

[0174] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0175] On the other hand, the present invention further provides a computer program product, the computer program product comprising a computer program, the computer program can be stored in a non-transitory computer-readable storage medium, when the computer program is executed by a processor, the computer can execute the microwave atmospheric transmittance calculation method provided by the above methods, the method comprising:

[0176] Acquire atmospheric data of an atmospheric sounding site, and determine whether there is cloud cover in the atmosphere based on the atmospheric data and a critical humidity function;

[0177] When cloud cover is confirmed, the atmospheric data is input into a calculation model of liquid water in the cloud to obtain a liquid water profile in the cloud of the atmospheric data;

[0178] The atmospheric data and the liquid water profile in the cloud are input into the millimeter wave transmission model to obtain the oxygen absorption coefficient and water vapor absorption coefficient in the atmosphere; and the atmospheric data and the liquid water profile in the cloud are input into the Mie scattering model to obtain the liquid water extinction coefficient in the cloud;

[0179] Based on the oxygen absorption coefficient, the water vapor absorption coefficient and the extinction coefficient of liquid water in the cloud, the atmospheric extinction coefficient is obtained, and based on the atmospheric extinction coefficient, the first microwave atmospheric transmittance of the atmospheric sounding site is calculated.

[0180] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to perform the microwave atmospheric transmittance calculation method provided by the above methods, the method comprising:

[0181] Acquire atmospheric data of an atmospheric sounding site, and determine whether there is cloud cover in the atmosphere based on the atmospheric data and a critical humidity function;

[0182] When cloud cover is confirmed, the atmospheric data is input into a calculation model of liquid water in the cloud to obtain a liquid water profile in the cloud of the atmospheric data;

[0183] The atmospheric data and the liquid water profile in the cloud are input into the millimeter wave transmission model to obtain the oxygen absorption coefficient and water vapor absorption coefficient in the atmosphere; and the atmospheric data and the liquid water profile in the cloud are input into the Mie scattering model to obtain the liquid water extinction coefficient in the cloud;

[0184] Based on the oxygen absorption coefficient, the water vapor absorption coefficient and the extinction coefficient of liquid water in the cloud, the atmospheric extinction coefficient is obtained, and based on the atmospheric extinction coefficient, the first microwave atmospheric transmittance of the atmospheric sounding site is calculated.

[0185] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0186] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating microwave atmospheric transmittance, characterized in that: include: Acquire atmospheric data of an atmospheric sounding station, and determine whether there is cloud cover in the atmosphere based on the atmospheric data and a critical humidity function; When cloud cover is confirmed, the atmospheric data is input into a calculation model of liquid water in the cloud to obtain a liquid water profile in the cloud of the atmospheric data; The atmospheric data and the liquid water profile in the cloud are input into the millimeter wave transmission model to obtain the oxygen absorption coefficient and water vapor absorption coefficient in the atmosphere; and the atmospheric data and the liquid water profile in the cloud are input into the Mie scattering model to obtain the liquid water extinction coefficient in the cloud; Based on the oxygen absorption coefficient, the water vapor absorption coefficient and the extinction coefficient of liquid water in the cloud, an atmospheric extinction coefficient is obtained, and based on the atmospheric extinction coefficient, a first microwave atmospheric transmittance of the atmospheric sounding station is calculated; According to the cloud coverage, the first microwave atmospheric transmittance is calculated based on the first calculation method and the second calculation method respectively to obtain the second microwave atmospheric transmittance of the clear sky area and the third microwave atmospheric transmittance of the cloud coverage area, and the comprehensive microwave atmospheric transmittance is obtained based on the second microwave atmospheric transmittance and the third microwave atmospheric transmittance; The step of calculating the first microwave atmospheric transmittance of the atmospheric sounding site based on the atmospheric extinction coefficient specifically includes: The atmospheric optical thickness is calculated based on the atmospheric extinction coefficient; Obtaining a first microwave atmospheric transmittance of the atmospheric sounding site based on the atmospheric optical thickness and the satellite sensor observation angle; Wherein, after obtaining the first microwave atmospheric transmittance of the atmospheric sounding site, the method further comprises: According to the degree of cloud coverage, the atmosphere is divided into cloud-covered areas and clear sky areas; In the clear sky area, obtaining a second microwave atmospheric transmittance based on the first calculation method using the first microwave atmospheric transmittance; In the cloud-covered area, calculating the first microwave atmospheric transmittance based on a second calculation method to obtain a third microwave atmospheric transmittance; Obtaining a comprehensive microwave atmospheric transmittance according to the second microwave atmospheric transmittance and the third microwave atmospheric transmittance; The step of calculating the first microwave atmospheric transmittance based on a first calculation method to obtain a second microwave atmospheric transmittance specifically includes: Extracting MODIS atmospheric precipitable water data of the atmospheric sounding station, performing linear regression on the atmospheric precipitable water data and the first microwave atmospheric transmittance, and obtaining regression coefficients under different bands and different time conditions; According to the regression coefficient, a second microwave atmospheric transmittance of a microwave imager or a microwave radiometer carrying channel of a specified spatial resolution is obtained; The step of calculating the first microwave atmospheric transmittance based on the second calculation method to obtain a third microwave atmospheric transmittance specifically includes: Extracting MODIS cloud and water vapor data, Cloudsat cloud type and cloud profile data and relevant data provided by microwave hygrometer at the atmospheric sounding station; Based on the relevant data and the first microwave atmospheric transmittance, construct a microwave atmospheric transmittance lookup table for different cloud types and cloud water contents, different microwave bands, different polarizations and different times; Based on the microwave atmospheric transmittance lookup table, a third microwave atmospheric transmittance of a microwave imager or a microwave radiometer carrying channel with a specified spatial resolution is obtained.

2. The method for calculating microwave atmospheric transmittance according to claim 1, characterized in that: The atmospheric data is used based on the critical humidity function to determine whether there is cloud cover in the atmosphere, specifically including: Comparing the atmospheric data with the critical humidity parameter of the critical humidity function to determine whether the relative humidity of the atmospheric data is greater than a preset humidity threshold; When the relative humidity of the atmospheric data is greater than or equal to a preset humidity threshold, confirming that there is cloud cover; When the relative humidity of the atmospheric data is less than a preset humidity threshold, it is confirmed to be a clear sky state.

3. The method for calculating microwave atmospheric transmittance according to claim 1, characterized in that: Inputting the atmospheric data into a calculation model for liquid water in clouds to obtain a liquid water profile in clouds of the atmospheric data specifically includes: Inputting the atmospheric data into a calculation model of liquid water in clouds to obtain the air temperature, humidity and height relative to the cloud bottom of the horizontal layer of the atmospheric layer where the atmospheric data is located; Based on the air temperature and humidity, obtain the proportion of liquid water in the cloud; The liquid water profile in the cloud of the atmospheric data is obtained according to the air temperature, humidity, height relative to the cloud base and the proportion of liquid water in the cloud.

4. A microwave atmospheric transmittance calculation device, characterized in that: include: An atmospheric data acquisition module is used to acquire atmospheric data of an atmospheric sounding site and determine whether there is cloud cover in the atmosphere based on the atmospheric data and a critical humidity function; A cloud liquid water acquisition module is used to input the atmospheric data into a cloud liquid water calculation model to obtain a cloud liquid water profile of the atmospheric data when cloud cover is confirmed; The absorption coefficient and extinction coefficient acquisition module is used to input the atmospheric data and the liquid water profile in the cloud into the millimeter wave transmission model to obtain the oxygen absorption coefficient and the water vapor absorption coefficient in the atmosphere; and input the atmospheric data and the liquid water profile in the cloud into the Mie scattering model to obtain the liquid water extinction coefficient in the cloud; A first atmospheric transmittance calculation module, used to obtain an atmospheric extinction coefficient based on an oxygen absorption coefficient, a water vapor absorption coefficient, and an extinction coefficient of liquid water in clouds, and calculate a first microwave atmospheric transmittance of the atmospheric sounding site based on the atmospheric extinction coefficient; A comprehensive microwave atmospheric transmittance calculation module is used to obtain a second microwave atmospheric transmittance of a clear sky area and a third microwave atmospheric transmittance of a cloud-covered area based on the first calculation method and the second calculation method according to the cloud coverage degree, and obtain a comprehensive microwave atmospheric transmittance based on the second microwave atmospheric transmittance and the third microwave atmospheric transmittance; Wherein, the device is also used for: The atmospheric optical thickness is calculated based on the atmospheric extinction coefficient; Obtaining a first microwave atmospheric transmittance of the atmospheric sounding site based on the atmospheric optical thickness and the satellite sensor observation angle; Wherein, the device is also used for: According to the degree of cloud coverage, the atmosphere is divided into cloud-covered areas and clear sky areas; In the clear sky area, obtaining a second microwave atmospheric transmittance based on the first calculation method using the first microwave atmospheric transmittance; In the cloud-covered area, calculating the first microwave atmospheric transmittance based on a second calculation method to obtain a third microwave atmospheric transmittance; According to the second microwave atmospheric transmittance and the third microwave atmospheric transmittance, a comprehensive microwave atmospheric transmittance is obtained; Wherein, the device is also used for: Extracting MODIS atmospheric precipitable water data of the atmospheric sounding station, performing linear regression on the atmospheric precipitable water data and the first microwave atmospheric transmittance, and obtaining regression coefficients under different bands and different time conditions; According to the regression coefficient, a second microwave atmospheric transmittance of a microwave imager or a microwave radiometer carrying channel of a specified spatial resolution is obtained; The step of calculating the first microwave atmospheric transmittance based on the second calculation method to obtain a third microwave atmospheric transmittance specifically includes: Extracting MODIS cloud and water vapor data, Cloudsat cloud type and cloud profile data and relevant data provided by microwave hygrometer at the atmospheric sounding station; Based on the relevant data and the first microwave atmospheric transmittance, construct a microwave atmospheric transmittance lookup table for different cloud types and cloud water contents, different microwave bands, different polarizations and different times; Based on the microwave atmospheric transmittance lookup table, a third microwave atmospheric transmittance of a microwave imager or a microwave radiometer carrying channel with a specified spatial resolution is obtained.

5. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the microwave atmospheric transmittance calculation method according to any one of claims 1 to 3 are implemented.

6. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for calculating microwave atmospheric transmittance according to any one of claims 1 to 3 are implemented.

7. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for calculating microwave atmospheric transmittance according to any one of claims 1 to 3 are implemented.

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