CN116224339A - S, C and X-band radar precipitation networking fusion method - Google Patents
S, C and X-band radar precipitation networking fusion method Download PDFInfo
- Publication number
- CN116224339A CN116224339A CN202211614606.5A CN202211614606A CN116224339A CN 116224339 A CN116224339 A CN 116224339A CN 202211614606 A CN202211614606 A CN 202211614606A CN 116224339 A CN116224339 A CN 116224339A
- Authority
- CN
- China
- Prior art keywords
- radar
- precipitation
- band
- observation
- echo
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/95—Radar or analogous systems specially adapted for specific applications for meteorological use
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
- G01S7/414—Discriminating targets with respect to background clutter
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01W—METEOROLOGY
- G01W1/00—Meteorology
- G01W1/14—Rainfall or precipitation gauges
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Landscapes
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Radar, Positioning & Navigation (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Electromagnetism (AREA)
- Hydrology & Water Resources (AREA)
- Atmospheric Sciences (AREA)
- Biodiversity & Conservation Biology (AREA)
- Ecology (AREA)
- Environmental Sciences (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
The invention discloses a S, C and X-band radar precipitation networking fusion method, which belongs to the technical field of weather radar observation, and comprises the steps of carrying out real-time observation by using a weather radar, calculating and removing influence of radar on radar inversion precipitation due to terrain and building shielding, counting to obtain S, C-band and X-band radar dual-polarization precipitation inversion operators suitable for a region where the weather radar is located, generating a radar dual-polarization mixed precipitation inversion method, carrying out coordinate conversion from a radar polar coordinate system to a ground coordinate system, calculating and obtaining the ground coordinates of radar observation pixels, carrying out jigsaw on precipitation information of a plurality of radars, reducing discontinuity of fusion precipitation products, generating a smooth precipitation rate field, selecting multiple rainfall processes in a jigsaw region, and utilizing rainfall observation by using a rain gauge.
Description
Technical Field
The invention belongs to the technical field of weather radar observation, and particularly relates to a S, C and X-band radar precipitation networking fusion method.
Background
In the past decades, weather radar has been widely applied to disastrous weather monitoring and other aspects, the weather radar can obtain precipitation information with high space-time resolution, the weather radar has the unique advantage in the aspect of precipitation monitoring and early warning, nowadays, long-wave radar with S and C wave bands is selected as an important observation instrument device for weather monitoring and weather forecasting in many countries, radar networking is performed, nationwide radar network monitoring is formed, and in the past 30 years, along with the introduction of new technologies such as dual polarization and the like, the monitoring capability of the radar network is greatly improved.
However, one significant drawback of the S or C band radar apparatus is the inability to capture the low level weather processes of the weather system due to the effects of earth curvature and terrain blockage. For example, new generation of Chinese Doppler weather radar (CINAAD), S and C band radar form a Chinese CINAAD radar monitoring network, the average interval between radar stations is 200km in the eastern part of China, the Western part of China, especially in Tibet, qinghai and Xinjiang, most areas are not covered by radar, the interval distance between radar stations is larger, and the lowest elevation angle (0.50 DEG) electromagnetic wave beam is about 5.1km higher than the ground in the range of 200 km. The low-level observation of the weather system is lost, the spatial resolution of a far radial distance is low, and the scanning speed of the traditional mechanical radar is low, so that the capability of finely detecting and identifying weather features is seriously affected. In order to make up for the defects of S-band and C-band business weather radar monitoring, urban waterlogging disaster forecasting and early warning works are performed in China, and an X-band dual-polarization Doppler weather radar monitoring network is also built in many cities. The construction of the X-band dual-polarization Doppler weather radar monitoring network can provide finer precipitation observation than that of S-band and C-band business weather radars, so that the X-band dual-polarization radar has huge application potential in the aspects of monitoring and early warning of disastrous weather processes such as heavy rain and the like. The national science foundation for atmospheric collaboration adaptive induction engineering research Center (CASA) introduced an innovative, collaborative and dynamic sensing mode, called distributed collaborative adaptive observation (DCAS), and built an X-band radar observation network to overcome the limitations of resolution and detection range of conventional weather radar networks (McLaughlin, et al, 2009). The feasibility of DCAS observation mode was demonstrated by high spatial-temporal resolution observations, individual studies, and multidisciplinary fundamental studies during five years of operation of the CASA X-band radar. CASA has built the first urban exemplary X-band radar observational network in the dallas-austenitic (DFW) city since the spring 2012. Dallas-woburg (DFW) city is one of the largest inland metropolitan cities in the united states, which experiences various natural disasters and weather events such as urban inland inundation, tornadoes, freezing and tornadoes each year.
However, in the current process of developing practical service application by using the X-band radar, the following problems occur: the X-band radar detection range is small, the monitoring, forecasting and early warning advance is insufficient, the S/C-band radar detection range is large, but the spatial resolution is lower, and the requirement of fine monitoring of precipitation in cities is not met.
Disclosure of Invention
Problems to be solved
Aiming at the problems that the existing X-band radar has small detection range, insufficient monitoring, forecasting and early warning advance, large S/C-band radar detection range and lower spatial resolution, and is insufficient for meeting the requirement of fine monitoring of precipitation in cities, the invention provides a S, C and X-band radar precipitation networking fusion method.
Technical proposal
In order to solve the problems, the invention adopts the following technical scheme.
A S, C and X-band radar precipitation networking fusion method adopts the following steps:
step 1: installing a plurality of weather radars, performing real-time observation by using the weather radars, performing quality control on precipitation echoes, and reducing interference of non-precipitation echoes;
step 2: obtaining the geographical position, the topography and the building information of each weather radar installation site, calculating the condition that different azimuth angles and elevation angles of the radar are shielded, calculating and removing the influence of the radar on radar inversion precipitation due to the shielding of the topography and the building, and complementing the signals lost in shielding;
step 3: using raindrop spectrum observation data, and counting to obtain a S, C band and X band radar dual-polarization precipitation inversion operator applicable to the region where the weather radar is located;
step 4: designing a mixed precipitation inversion method, switching to use a precipitation inversion operator according to the intensity of double polarization amounts, generating a radar double polarization mixed precipitation inversion method, and obtaining a precipitation value of single radar inversion;
step 5: coordinate conversion from a radar polar coordinate system to a geodetic coordinate system is carried out, and geodetic coordinates of radar observation pixels are calculated and obtained;
step 6: according to the height and the width of each radar detection beam, calculating the weight of each grid point radar jigsaw, and jigsaw the precipitation information of a plurality of radars;
step 7: the discontinuity of the fused precipitation product is reduced, the edge of the coverage area of the X-band radar is smoothed, and a smooth precipitation rate field is generated;
step 8: and selecting a plurality of rainfall processes in the jigsaw region, and analyzing and evaluating the data by utilizing rainfall observation of the rainfall gauge to obtain a rainfall evaluation result.
Preferably, in the step 1, the quality control is performed on the precipitation echo, the disturbance of the non-precipitation echo is reduced by using a radar dual polarization observed quantity, the precipitation echo and the non-precipitation echo are identified according to the difference of correlation coefficient, horizontal and vertical continuity of the precipitation echo on radar observation of the precipitation echo and the non-precipitation echo, the non-precipitation echo is removed,
further, the specific flow of the quality control is as follows: and judging the correlation coefficient, judging the texture value of the correlation coefficient when the correlation coefficient is larger than a preset correlation coefficient value, further calculating and judging if the texture value is larger than the preset texture value, judging if the radar to which the correlation coefficient belongs is positioned in a hail zone, a non-uniform stuffing zone and a melting layer when the correlation coefficient is smaller than or equal to the preset correlation coefficient value, and if so, further calculating and judging.
Further, the further calculation and judgment are to perform electromagnetic interference echo removal, and the formula is as follows:
N1>NUM*70％∩N2>NUM*10％
when the effective observed value of the bottommost layer exceeds 70% of the whole radial direction and the effective observed value of the second layer is less than 10% of the whole radial direction, the electromagnetic interference echo is judged and removed.
Still further, the differential calculation of the horizontal and vertical continuity is to observe the signal absence in a window of m×n, when the signal absence exceeds half, the observation is considered to be a non-precipitation echo and the removal is performed, M is the number of radar radial distance bins, N is the number of radar beams, the vertical reflectivity check is performed by calculating the vertical reflectivity gradient, and the gradient calculation formula is as follows:
vgdBZ k ＝(Z k -Z k+1 )/(h k+1 -h k )
h in the formula k For the beam center height of a given distance library at the elevation angle of the k layer, when the reflectivity vertical gradient exceeds a preset value, observing as non-precipitation echo and removing;
and when the residual echo area is smaller than the preset area value, considering that no precipitation exists at the moment, removing the precipitation, and filling the cavity with the area smaller than the preset precipitation area in the precipitation echo by using peripheral observation.
Preferably, in the step 2, the condition that the radar is blocked in different azimuth angles and elevation angles is calculated by using electromagnetic waves for transmitting and receiving, and the formula is as follows:
h c represents the height of the beam center of the electromagnetic wave relative to the radar antenna, R represents the propagation distance of the electromagnetic wave, R 0 R is the actual radius of the earth e Representing the equivalent earth radius, t representing the radar observation elevation angle;
assuming that the beam width of the electromagnetic wave is θ, replacing t in the formula with t+θ/2 and t- θ/2 can obtain the beam top height ht and the beam bottom height hb, respectively, and the vertical section d of the beam at any radial distance can be expressed as:
according to the condition that the electromagnetic wave energy of the radar meets Gaussian distribution on a vertical section, the shielding rate of the terrain to the electromagnetic wave energy can be calculated by combining a high-precision digital elevation model, and the formula is as follows:
wherein P is the radar electromagnetic wave energy shielding rate, x is the horizontal distance from the beam center on the vertical section of the beam, y (x) is the surface elevation relative to the bottom of the electromagnetic wave beam, f (x, y) is the Gaussian distribution function, and the standard deviation sigma is d/6.
The lowest elevation angle with the shielding rate smaller than the preset angle is selected as the elevation angle for precipitation inversion, the radar composite plane scanning elevation angle is formed, the influence of shielding of the radar on radar inversion precipitation due to terrain, buildings and the like is removed, and signals caused by shielding of the area are completed.
Preferably, the calculation formula of each dual-polarization precipitation inversion operator of the S, C band radar and the X band radar in the step 3 is as follows:
wherein a, b and c are respectively the inversion operators of the dual-polarization precipitation of the S, C wave band radar and the X wave band radar.
Preferably, in the step 5, the geodetic coordinates of the radar observation pixels are calculated according to longitude and latitude coordinates of the radar station and observation parameters, and the formula is as follows:
Lat2＝arcsin(sin(Lat1)cos(θ)+cos(Lat1)sin(θ)cos(α))
θ＝s/a
wherein Lat1, lon1, h r Respectively the latitude, the longitude and the antenna height of a radar station, lat2 and Lon2 respectively the latitude and the longitude of radar observation pixels, s is the propagation distance of a radar electromagnetic wave propagation path projected onto the ground, a is the earth radius, R e And r is the radial propagation distance of the radar electromagnetic, and t is the observation elevation angle of the radar.
Preferably, in the step 6, the weight of each grid point radar jigsaw is calculated, the precipitation information of the multiple radars is jigsaw by calculating the weight of each radar jigsaw of each jigsaw grid point according to the height and the width of each radar detection beam, and for a given grid, the weight w is calculated by radar electricityCenter height h of magnetic wave c And beam vertical cross-sectional diameter d b The formula is determined as follows:
preferably, in the step 7, the edge of the coverage area of the X-band radar is smoothed, a transition area with a certain width is set from the edge of the smoothed precipitation rate field to the center of the radar, and the X-band radar weight is adjusted by using the coefficient q for the grid in the transition area, and the formula is as follows:
w′＝q·w
wherein w is the adjusted weight, R is the maximum effective detection distance of the radar, R is the distance between the center of the current grid and the radar station, S buff Is the transition zone width.
A S, C and X-band radar precipitation networking fusion method includes the steps of installing a plurality of weather radars, performing real-time observation by using the weather radars, performing quality control on precipitation echoes, reducing interference of non-precipitation echoes, obtaining geographic position, topography and building information of installation sites of the weather radars, calculating the condition that different azimuth angles and elevation angles of the radars are blocked, calculating and removing influences of the radars on radar inversion precipitation due to topography and building blocking, supplementing missing signals due to blocking, using raindrop spectrum observation data, calculating S, C bands suitable for areas where the weather radars are located and X-band radars, designing a mixed precipitation inversion method, switching by using precipitation inversion operators according to intensity of the double polarization amounts, generating radar double polarization mixed precipitation inversion methods, obtaining precipitation values of single radar inversion, performing coordinate conversion from a radar polar coordinate system to a geodetic coordinate system, calculating and obtaining geodetic coordinates of radar observation pixels, calculating weights of each grid point jigsaw according to heights and widths of radar detection beams, performing jigsaw on precipitation information of the radars, reducing discontinuous edges of products, performing fine analysis on the rain fall in the areas, and realizing the method of the multiple-band precipitation, and realizing the fine-phase precipitation analysis by using the multiple-contrast precipitation, and the method is capable of realizing the fine-level-and-step precipitation measurement range, and the method is suitable for realizing the fine-phase-contrast-and-step precipitation range, and the method is suitable for the large-down-phase-region-and-phase-region-level precipitation detection.
Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention uses a radar composite plane scanning elevation angle forming method. According to the geographic position information of the radar, the terrain, the building information and the electromagnetic wave propagation principle, calculating the shielding condition, eliminating the problem of observation signal missing caused by shielding Lei Dayin, forming a radar composite plane scanning elevation angle, and removing the influence of shielding of the radar on radar inversion precipitation caused by the terrain, the building and the like;
(2) The radar quality control method based on double polarization amounts is adopted, the correlation coefficient is judged, whether the radar is a precipitation echo is judged, consistency check is carried out on the horizontal and vertical directions, the electromagnetic interference echo is removed, non-precipitation echo near the center of the radar is effectively removed, the precipitation echo is reserved, and the reliability of data is improved;
(3) According to the radar dual-polarization mixed precipitation inversion method, the advantages of each inversion method are combined, the precipitation inversion precision and stability are improved, different inversion methods are automatically switched according to the dual-polarization observed quantity signal intensity, and the precipitation inversion precision and stability are improved.
Drawings
In order to more clearly illustrate the technical solutions in embodiments or examples of the present application, the drawings that are required for use in the embodiments or examples description will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application and therefore should not be construed as limiting the scope, and that other drawings may be obtained according to the drawings without inventive effort to those of ordinary skill in the art.
FIG. 1 is a schematic diagram of the steps of the present invention;
FIG. 2 is a schematic flow chart of the technical scheme of the invention;
FIG. 3 is a schematic flow chart of a quality control method of the present invention;
FIG. 4 is a graph of radar reflectivity change before and after quality control in accordance with the present invention;
FIG. 5 is a graph of radar reflectivity before and after adjustment of an X-band radar observation of the present invention;
FIG. 6 is a flow chart of a single-station radar mixed precipitation inversion method of the present invention;
FIG. 7 is a spatial distribution diagram of the fusion radar of the present invention before and after edge smoothing;
FIG. 8 is a graph showing statistical indicators of the different precipitation strengths of the prior art product and the product of the present invention.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments, and that the components of the embodiments of the present application generally described and illustrated in the drawings herein may be arranged and designed in various different configurations.
Thus, the following detailed description of the embodiments of the present application, provided in the accompanying drawings, is not intended to limit the scope of the application as claimed, but is merely representative of selected embodiments of the application, based on which all other embodiments that may be obtained by one of ordinary skill in the art without making inventive efforts are within the scope of this application.
Example 1
As shown in fig. 1, a S, C and X-band radar precipitation networking fusion method adopts the following steps:
installing a plurality of weather radars, performing real-time observation by using the weather radars, performing quality control on the precipitation echo, reducing interference of non-precipitation echo, performing quality control on the precipitation echo, wherein the interference of the non-precipitation echo is obtained by using radar double-polarization observed quantity, and identifying the precipitation echo and the non-precipitation echo according to the difference of correlation coefficient, horizontal and vertical continuity of the precipitation echo and the non-precipitation echo on radar observation, so as to remove the non-precipitation echo;
judging the correlation coefficient, judging the texture value of the correlation coefficient when the correlation coefficient is larger than a preset value of the correlation coefficient, if the texture value is larger than the preset value of the texture, further calculating and judging, and if the correlation coefficient is smaller than or equal to the preset value of the correlation coefficient, judging whether the radar to which the correlation coefficient belongs is positioned in a hail zone, a non-uniform stuffing zone and a melting layer, if so, further calculating and judging;
the further calculation and judgment are to remove electromagnetic interference echo, and the formula is as follows:
N1>NUM*70％∩N2>NUM*10％
when the effective observed value of the bottommost layer exceeds 70% of the whole radial direction and the effective observed value of the second layer is less than 10% of the whole radial direction, the electromagnetic interference echo is judged and removed.
The differential calculation of the horizontal and vertical continuity is to observe signal missing in a window of M x N, when the signal missing is more than half, the observation is considered to be non-precipitation echo and removed, M is the number of radar radial distance banks, N is the number of radar beams, the vertical detection of the reflectivity is carried out by calculating the vertical gradient of the reflectivity, and the gradient calculation formula is as follows:
vgdBZ k ＝(Z k -Z k+1 )/(h k+1 -h k )
h in the formula k For the beam center height of a given distance library at the elevation angle of the k layer, when the reflectivity vertical gradient exceeds a preset value, observing as non-precipitation echo and removing;
and when the residual echo area is smaller than the preset area value, considering that no precipitation exists at the moment, removing the precipitation, and filling the cavity with the area smaller than the preset precipitation area in the precipitation echo by using peripheral observation.
The method comprises the steps of obtaining geographic position, topography and building information of each weather radar installation site, calculating the condition that different azimuth angles and elevation angles of a radar are shielded, calculating and removing the influence of the radar on radar inversion precipitation due to the shielding of topography and building, complementing the signal lost in shielding, and calculating the condition that the different azimuth angles and elevation angles of the radar are shielded by using electromagnetic waves to transmit and receive, wherein the formula is as follows:
h c represents the height of the beam center of the electromagnetic wave relative to the radar antenna, R represents the propagation distance of the electromagnetic wave, R 0 R is the actual radius of the earth e Representing the equivalent earth radius, t representing the radar observation elevation angle;
assuming that the beam width of the electromagnetic wave is θ, replacing t in the formula with t+θ/2 and t- θ/2 can obtain the beam top height ht and the beam bottom height hb, respectively, and the vertical section d of the beam at any radial distance can be expressed as:
according to the condition that the electromagnetic wave energy of the radar meets Gaussian distribution on a vertical section, the shielding rate of the terrain to the electromagnetic wave energy can be calculated by combining a high-precision digital elevation model, and the formula is as follows:
wherein P is the energy shielding rate of the radar electromagnetic wave, x is the horizontal distance from the beam center on the vertical section of the beam, y (x) is the surface elevation relative to the bottom of the electromagnetic wave beam, f (x, y) is a Gaussian distribution function, and the standard deviation sigma is d/6;
the lowest elevation angle with the shielding rate smaller than the preset angle is selected as the elevation angle for precipitation inversion, the radar composite plane scanning elevation angle is formed, the influence of shielding of the radar on radar inversion precipitation due to terrain, buildings and the like is removed, and signals caused by shielding of the area are completed.
Using raindrop spectrum observation data, counting to obtain each double-polarization precipitation inversion operator of the S, C-band and X-band radars applicable to the region where the weather radar is located, wherein the calculation formula of each double-polarization precipitation inversion operator of the S, C-band and X-band radars is as follows:
wherein a, b and c are respectively the inversion operators of the dual-polarization precipitation of the S, C wave band radar and the X wave band radar.
Designing a mixed precipitation inversion method, switching to use a precipitation inversion operator according to the intensity of double polarization amounts, generating a radar double polarization mixed precipitation inversion method, and obtaining a precipitation value of single radar inversion; coordinate conversion from a radar polar coordinate system to a geodetic coordinate system is carried out, the geodetic coordinates of the radar observation pixels are calculated and acquired, and the geodetic coordinates of the radar observation pixels are calculated according to longitude and latitude coordinates and observation parameters of the radar station, wherein the formula is as follows:
Lat2＝arcsin(sin(Lat1)cos(θ)+cos(Lat1)sin(θ)cos(α))
θ＝s/a
wherein Lat1, lon1, h r Respectively the latitude, the longitude and the antenna height of a radar station, lat2 and Lon2 respectively the latitude and the longitude of radar observation pixels, s is the propagation distance of a radar electromagnetic wave propagation path projected onto the ground, a is the earth radius, R e And r is the radial propagation distance of the radar electromagnetic, and t is the observation elevation angle of the radar.
Calculating the weight of each grid point radar jigsaw according to the height and the width of each radar detection beam, jigsaw the precipitation information of a plurality of radars, calculating the weight of each grid point radar jigsaw, wherein the jigsaw of the precipitation information of the plurality of radars is carried out according to the height and the width of each radar detection beam, calculating the weight of each radar jigsaw of each jigsaw grid point, jigsaw the precipitation information of the plurality of radars, and for a given grid, the weight w is represented by the central height h of radar electromagnetic waves c And beam vertical cross-sectional diameter d b The formula is determined as follows:
the method comprises the steps of reducing discontinuity of fused precipitation products, smoothing the edges of coverage areas of an X-band radar to generate a smooth precipitation rate field, smoothing the edges of coverage areas of the X-band radar to generate a smooth precipitation rate field, setting a transition area with a certain width from the edges of the smooth precipitation rate field to the center of the radar, and adjusting the weight of the X-band radar by using a coefficient q to grids in the transition area, wherein the formula is as follows:
w′＝q·w
wherein w is the adjusted weight, R is the maximum effective detection distance of the radar, R is the distance between the center of the current grid and the radar station, S buff Is the transition zone width.
And selecting a plurality of rainfall processes in the jigsaw region, and analyzing and evaluating the data by utilizing rainfall observation of the rainfall gauge to obtain a rainfall evaluation result.
According to the description, in the example, by installing a plurality of weather radars, carrying out real-time observation by using the weather radars, carrying out quality control on precipitation echoes, reducing interference of non-precipitation echoes, obtaining the geographical position, the topography and the building information of each weather radar installation place, calculating the condition that different azimuth angles and elevation angles of the radar are blocked, calculating and removing the influence of the radar on radar inversion precipitation due to topography and building blocking, supplementing missing signals, carrying out statistics by using raindrop spectrum observation data, obtaining each dual-polarization precipitation inversion operator of the S, C-band radar and the X-band radar in the area where the weather radars are located, designing a mixed precipitation inversion method, switching by using a precipitation inversion operator according to the intensity of dual polarization amounts, generating a radar dual-polarization mixed precipitation inversion method, obtaining precipitation values of single radar inversion, carrying out coordinate conversion from a radar polar coordinate system to a geodetic coordinate system, calculating and obtaining the geodetic coordinates of radar observation pixels, carrying out jigsaw-up according to the height and width of each radar detection beam, calculating the weight of each grid point radar, carrying out the precipitation information of the plurality of radars, reducing the discontinuity of the precipitation of the fusion products, carrying out statistics, carrying out analysis on the rainfall in a rainfall region, carrying out the rainfall smoothing region, evaluating and carrying out rainfall analysis, and evaluating the rainfall region, and carrying out the rainfall analysis, and obtaining the rainfall analysis.
Example 2
2-8, installing a plurality of weather radars, performing real-time observation by using the weather radars, performing quality control on the precipitation echo, reducing interference of non-precipitation echo, performing quality control on the precipitation echo, wherein the method is as shown in FIG. 3, reducing interference of the non-precipitation echo is by using radar double polarization observables, and recognizing the precipitation echo and the non-precipitation echo according to the difference of correlation coefficient, horizontal and vertical continuity of the precipitation echo and the non-precipitation echo on radar observation, and removing the non-precipitation echo;
judging the correlation coefficient, judging the texture value of the correlation coefficient when the correlation coefficient is larger than 0.85, if the texture value is larger than a texture preset value, further calculating and judging, and if the correlation coefficient is smaller than or equal to 0.85, judging whether the radar to which the correlation coefficient belongs is positioned in a hail zone, a non-uniform filling zone and a melting layer, and if so, further calculating and judging;
the further calculation and judgment are to remove electromagnetic interference echo, and the formula is as follows:
N1>NUM*70％∩N2>NUM*10％
when the effective observed value of the bottommost layer exceeds 70% of the whole radial direction and the effective observed value of the second layer is less than 10% of the whole radial direction, the electromagnetic interference echo is judged and removed.
The differential calculation of the horizontal and vertical continuity is to observe the signal missing in a window of M x N, when the signal missing is more than half, the observation is considered to be non-precipitation echo and is removed, M is the number of radar radial distance libraries, N is the number of radar beams, N is 3, the vertical detection of the reflectivity is carried out by calculating the vertical gradient of the reflectivity, and the gradient calculation formula is as follows:
vgdBZ k ＝(Z k -Z k+1 )/(h k+1 -h k )
h in the formula k For the beam center height of a given distance library at the elevation angle of the k layer, when the reflectivity vertical gradient exceeds 50dBZ/km, observing as non-precipitation echo and removing;
and when the residual echo area is smaller than the preset area value, considering that no precipitation exists at the moment, removing the precipitation, and filling the cavity with the area smaller than the preset precipitation area in the precipitation echo by using peripheral observation.
Through the above steps, the non-precipitation echo is removed, the precipitation echo is reserved, the quality control is completed, and fig. 4 shows the reflectivity graphs before and after the quality control, it can be seen that the non-precipitation echo near the center of the radar is effectively removed, and the precipitation echo is reserved.
The method comprises the steps of obtaining geographic position, topography and building information of each weather radar installation site, calculating the condition that different azimuth angles and elevation angles of a radar are shielded, calculating and removing the influence of the radar on radar inversion precipitation due to the shielding of topography and building, complementing the signal lost in shielding, and calculating the condition that the different azimuth angles and elevation angles of the radar are shielded by using electromagnetic waves to transmit and receive, wherein the formula is as follows:
h c represents the height of the beam center of the electromagnetic wave relative to the radar antenna, R represents the propagation distance of the electromagnetic wave, R 0 R is the actual radius of the earth e Representing the equivalent earth radius, t representing the radar observation elevation angle;
assuming that the beam width of the electromagnetic wave is θ, replacing t in the formula with t+θ/2 and t- θ/2 can obtain the beam top height ht and the beam bottom height hb, respectively, and the vertical section d of the beam at any radial distance can be expressed as:
according to the condition that the electromagnetic wave energy of the radar meets Gaussian distribution on a vertical section, the shielding rate of the terrain to the electromagnetic wave energy can be calculated by combining a high-precision digital elevation model, and the formula is as follows:
wherein P is the energy shielding rate of the radar electromagnetic wave, x is the horizontal distance from the beam center on the vertical section of the beam, y (x) is the surface elevation relative to the bottom of the electromagnetic wave beam, f (x, y) is a Gaussian distribution function, and the standard deviation sigma is d/6;
the lowest elevation angle with the shielding rate smaller than 50% is selected as the elevation angle for precipitation inversion, the radar composite plane scanning elevation angle is formed, the influence of shielding of the radar on radar inversion precipitation due to terrain, buildings and the like is removed, and signals caused by shielding of the area are completed.
FIG. 5 is a representation of the 0.9 elevation angle of the Shenzhen West Yong radar and the composite plane scanning elevation angle reflectivity, which shows that the North of the West Yong radar is severely missing due to the topography shielding, and the signal caused by the shielding of the area is complemented by using the composite plane scanning elevation angle.
Using raindrop spectrum observation data, counting to obtain each double-polarization precipitation inversion operator of the S, C-band and X-band radars applicable to the region where the weather radar is located, wherein the calculation formula of each double-polarization precipitation inversion operator of the S, C-band and X-band radars is as follows:
wherein a, b and c are respectively the inversion operators of the dual-polarization precipitation of the S, C wave band radar and the X wave band radar.
Designing a mixed precipitation inversion method, wherein the flow is shown in figure 6, switching to use a precipitation inversion operator according to the intensity of double polarization amounts to generate a radar double polarization mixed precipitation inversion method, and obtaining a precipitation value of single radar inversion; coordinate conversion from a radar polar coordinate system to a geodetic coordinate system is carried out, the geodetic coordinates of the radar observation pixels are calculated and acquired, and the geodetic coordinates of the radar observation pixels are calculated according to longitude and latitude coordinates and observation parameters of the radar station, wherein the formula is as follows:
Lat2＝arcsin(sin(Lat1)cos(θ)+cos(Lat1)sin(θ)cos(α))
θ＝s/a
wherein Lat1, lon1, h r Respectively the latitude, the longitude and the antenna height of a radar station, lat2 and Lon2 respectively the latitude and the longitude of radar observation pixels, s is the propagation distance of a radar electromagnetic wave propagation path projected onto the ground, a is the earth radius, R e And r is the radial propagation distance of the radar electromagnetic, and t is the observation elevation angle of the radar.
Calculating the weight of each grid point radar jigsaw according to the height and the width of each radar detection beam, jigsaw the precipitation information of a plurality of radars, calculating the weight of each grid point radar jigsaw, wherein the jigsaw of the precipitation information of the plurality of radars is carried out according to the height and the width of each radar detection beam, calculating the weight of each radar jigsaw of each jigsaw grid point, jigsaw the precipitation information of the plurality of radars, and for a given grid, the weight w is represented by the central height h of radar electromagnetic waves c And beam vertical cross-sectional diameter d b The formula is determined as follows:
the fusion product has the "jump" from X-band radar precipitation rate to S, C wave band radar precipitation rate at X-band radar coverage edge, in order to reduce the discontinuity of fusion precipitation product, smooth X-band radar coverage edge, produce smooth precipitation rate field and set for the transition zone of certain width to radar center at its edge, use coefficient q to the net in the transition zone to adjust X-band radar weight, the formula is as follows:
w′＝q·w
wherein w is the adjusted weight, R is the maximum effective detection distance of the radar, R is the distance between the center of the current grid and the radar station, S buff Is the transition zone width.
FIG. 6 shows the precipitation rate field before and after smoothing, it can be seen that the discontinuity of the precipitation rate field at the junction of different radars is significantly suppressed after smoothing, resulting in a smoother precipitation rate field
And selecting a plurality of rainfall processes in the jigsaw region, and analyzing and evaluating the data by utilizing rainfall observation of the rainfall gauge to obtain a rainfall evaluation result.
Example 3
Figure 8 is a graph of statistical parameter indicators of the intensity of each precipitation during 11 precipitation of business products and products of the invention. It is known that for business products, as precipitation intensity increases, the consistency of the product with the automation station (i.e., CC) gradually decreases, RMSE gradually increases, and the degree of dispersion gradually increases. Systematic deviation (i.e., RMB) of the product changes from positive to negative, indicating that the product is overestimated for weak precipitation and underestimated for strong precipitation. The Relative Mean Absolute Error (RMAE) is greater in > =0.1 mm grade, exceeding 1.0, and the performance is poor, which is related to the serious overestimation of the product in weak precipitation, and the RMAE gradually decreases with the increase of the precipitation intensity. For the product of the invention, the RMBs of two gears of > =5 and > =10mm are inferior to the service product in terms of the total index, and other indexes are superior to the service product. Along with the increase of the rainfall intensity, the consistency of the product of the invention and an automatic station is gradually reduced, but the index value is higher, and the CC (CC) still reaches 0.74 for short-time strong rainfall of more than 20mm, which is superior to service products. The RMSE increases gradually with the increase of the rainfall intensity from 3.2mm/h to 11.54mm/h, but the same gear is smaller than the service product. The variation of RMB and RMAE along with the rainfall intensity is smaller, the RMAE is stabilized at about 0.3, and the RMB is stabilized at about-0.2, which shows that the performance estimated for different rainfall intensities is more stable.
In conclusion, the product formed by the invention can provide accurate precipitation products with high space-time resolution, and the accuracy and the stability of the precipitation products are superior to those of business products.
The foregoing examples have shown only the preferred embodiments of the invention, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that modifications, improvements and substitutions can be made by those skilled in the art without departing from the spirit of the invention, which are all within the scope of the invention.
Claims (10)
1. The S, C and X-band radar precipitation networking fusion method is characterized by comprising the following steps of:
step 1: installing a plurality of weather radars, performing real-time observation by using the weather radars, performing quality control on precipitation echoes, and reducing interference of non-precipitation echoes;
step 2: obtaining the geographical position, the topography and the building information of each weather radar installation site, calculating the condition that different azimuth angles and elevation angles of the radar are shielded, calculating and removing the influence of the radar on radar inversion precipitation due to the shielding of the topography and the building, and complementing the signals lost in shielding;
step 3: using raindrop spectrum observation data, and counting to obtain a S, C band and X band radar dual-polarization precipitation inversion operator applicable to the region where the weather radar is located;
step 4: designing a mixed precipitation inversion method, switching to use a precipitation inversion operator according to the intensity of double polarization amounts, generating a radar double polarization mixed precipitation inversion method, and obtaining a precipitation value of single radar inversion;
step 5: coordinate conversion from a radar polar coordinate system to a geodetic coordinate system is carried out, and geodetic coordinates of radar observation pixels are calculated and obtained;
step 6: according to the height and the width of each radar detection beam, calculating the weight of each grid point radar jigsaw, and jigsaw the precipitation information of a plurality of radars;
step 7: the discontinuity of the fused precipitation product is reduced, the edge of the coverage area of the X-band radar is smoothed, and a smooth precipitation rate field is generated;
step 8: and selecting a plurality of rainfall processes in the jigsaw region, and analyzing and evaluating the data by utilizing rainfall observation of the rainfall gauge to obtain a rainfall evaluation result.
2. The method for combining S, C and X-band radar precipitation networking according to claim 1, wherein the method comprises the following steps: in the step 1, quality control is performed on the precipitation echo, the interference of non-precipitation echo is reduced by using a radar double-polarization observed quantity, and the precipitation echo and the non-precipitation echo are identified according to the difference of correlation coefficient, horizontal continuity and vertical continuity of the precipitation echo on radar observation of the precipitation echo and the non-precipitation echo, so that the non-precipitation echo is removed.
3. The method for combining S, C and X-band radar precipitation networking according to claim 2, wherein the method comprises the following steps: the specific flow of the quality control is as follows: and judging the correlation coefficient, judging the texture value of the correlation coefficient when the correlation coefficient is larger than a preset correlation coefficient value, further calculating and judging if the texture value is larger than the preset texture value, judging if the radar to which the correlation coefficient belongs is positioned in a hail zone, a non-uniform stuffing zone and a melting layer when the correlation coefficient is smaller than or equal to the preset correlation coefficient value, and if so, further calculating and judging.
4. A method for combining S, C and X-band radar precipitation networking according to claim 3, wherein: the further calculation and judgment are to remove electromagnetic interference echo, and the formula is as follows:
N1>NUM*70％∩N2>NUM*10％
when the effective observed value of the bottommost layer exceeds 70% of the whole radial direction and the effective observed value of the second layer is less than 10% of the whole radial direction, the electromagnetic interference echo is judged and removed.
5. The method for combining S, C and X-band radar precipitation networking according to claim 4, wherein the method comprises the following steps: the differential calculation of the horizontal and vertical continuity is to observe signal missing in a window of M x N, when the signal missing is more than half, the observation is considered to be non-precipitation echo and removed, M is the number of radar radial distance banks, N is the number of radar beams, the vertical detection of the reflectivity is carried out by calculating the vertical gradient of the reflectivity, and the gradient calculation formula is as follows:
vgdBZ k ＝(Z k -Z k+1 )/(h k+1 -h k )
h in the formula k For the beam center height of a given distance library at the elevation angle of the k layer, when the reflectivity vertical gradient exceeds a preset value, observing as non-precipitation echo and removing;
and when the residual echo area is smaller than the preset area value, considering that no precipitation exists at the moment, removing the precipitation, and filling the cavity with the area smaller than the preset precipitation area in the precipitation echo by using peripheral observation.
6. The method for combining S, C and X-band radar precipitation networking according to claim 1, wherein the method comprises the following steps: in the step 2, the condition that the radar is shielded in different azimuth angles and elevation angles is calculated by using electromagnetic waves for transmitting and receiving, and the formula is as follows:
h c represents the height of the beam center of the electromagnetic wave relative to the radar antenna, R represents the propagation distance of the electromagnetic wave, R 0 R is the actual radius of the earth e Representing the equivalent earth radius, t representing the radar observation elevation angle;
assuming that the beam width of the electromagnetic wave is θ, replacing t in the formula with t+θ/2 and t- θ/2 can obtain the beam top height ht and the beam bottom height hb, respectively, and the vertical section d of the beam at any radial distance can be expressed as:
according to the condition that the electromagnetic wave energy of the radar meets Gaussian distribution on a vertical section, the shielding rate of the terrain to the electromagnetic wave energy can be calculated by combining a high-precision digital elevation model, and the formula is as follows:
wherein P is the energy shielding rate of the radar electromagnetic wave, x is the horizontal distance from the beam center on the vertical section of the beam, y (x) is the surface elevation relative to the bottom of the electromagnetic wave beam, f (x, y) is a Gaussian distribution function, and the standard deviation sigma is d/6;
the lowest elevation angle with the shielding rate smaller than the preset angle is selected as the elevation angle for precipitation inversion, the radar composite plane scanning elevation angle is formed, the influence of shielding of the radar on radar inversion precipitation due to terrain, buildings and the like is removed, and signals caused by shielding of the area are completed.
7. The method for combining S, C and X-band radar precipitation networking according to claim 1, wherein the method comprises the following steps: in the step 3, the calculation formulas of the double-polarization precipitation inversion operators of the S, C band radar and the X band radar are as follows:
wherein a, b and c are respectively the inversion operators of the dual-polarization precipitation of the S, C wave band radar and the X wave band radar.
8. The method for combining S, C and X-band radar precipitation networking according to claim 1, wherein the method comprises the following steps: the geodetic coordinates of the radar observation pixels are calculated according to longitude and latitude coordinates of the radar station and observation parameters in the step 5, and the formula is as follows:
Lat2＝arcsin(sin(Lat1)cos(θ)+cos(Lat1)sin(θ)cos(α))
θ＝s/a
wherein Lat1, lon1, h r Respectively the latitude, the longitude and the antenna height of a radar station, lat2 and Lon2 respectively the latitude and the longitude of radar observation pixels, s is the propagation distance of a radar electromagnetic wave propagation path projected onto the ground, a is the earth radius, R e And r is the radial propagation distance of the radar electromagnetic, and t is the observation elevation angle of the radar.
9. The method for combining S, C and X-band radar precipitation networking according to claim 1, wherein the method comprises the following steps: in the step 6, the weight of each grid point radar jigsaw is calculated, the precipitation information of a plurality of radars is jigsaw according to the height and the width of each radar detection beam, the weight of each radar jigsaw of each grid point of each jigsaw is calculated, the precipitation information of a plurality of radars is jigsaw, and for a given grid, the weight w is defined by the central height h of radar electromagnetic waves c And beam vertical cross-sectional diameter d b The formula is determined as follows:
10. the method for combining S, C and X-band radar precipitation networking according to claim 1, wherein the method comprises the following steps: in the step 7, the edge of the coverage area of the X-band radar is smoothed, a smooth precipitation rate field is generated by setting a transition area with a certain width from the edge to the center of the radar, and the weight of the X-band radar is adjusted by using a coefficient q for grids in the transition area, wherein the formula is as follows:
w′＝q·w
wherein w is the adjusted weight, R is the maximum effective detection distance of the radar, R is the distance between the center of the current grid and the radar station, S buff Is the transition zone width.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211614606.5A CN116224339A (en) | 2022-12-13 | 2022-12-13 | S, C and X-band radar precipitation networking fusion method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211614606.5A CN116224339A (en) | 2022-12-13 | 2022-12-13 | S, C and X-band radar precipitation networking fusion method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116224339A true CN116224339A (en) | 2023-06-06 |
Family
ID=86586250
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211614606.5A Pending CN116224339A (en) | 2022-12-13 | 2022-12-13 | S, C and X-band radar precipitation networking fusion method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116224339A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116500578A (en) * | 2023-06-29 | 2023-07-28 | 深圳市千百炼科技有限公司 | Weather radar data processing method based on neural network model |
| CN117310716A (en) * | 2023-11-28 | 2023-12-29 | 中国气象科学研究院 | Method and device for estimating precipitation based on multi-band radar fusion |
-
2022
- 2022-12-13 CN CN202211614606.5A patent/CN116224339A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116500578A (en) * | 2023-06-29 | 2023-07-28 | 深圳市千百炼科技有限公司 | Weather radar data processing method based on neural network model |
| CN116500578B (en) * | 2023-06-29 | 2023-09-05 | 深圳市千百炼科技有限公司 | Weather Radar Data Processing Method Based on Neural Network Model |
| CN117310716A (en) * | 2023-11-28 | 2023-12-29 | 中国气象科学研究院 | Method and device for estimating precipitation based on multi-band radar fusion |
| CN117310716B (en) * | 2023-11-28 | 2024-02-20 | 中国气象科学研究院 | Method and device for estimating precipitation based on multi-band radar fusion |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN116224339A (en) | S, C and X-band radar precipitation networking fusion method | |
| Chandrasekar et al. | Principles of high-resolution radar network for hazard mitigation and disaster management in an urban environment | |
| KR101531224B1 (en) | Quantitative precipitation estimation system based dual polarization radars and method thereof | |
| Zhang et al. | Radar quality index (RQI)—A combined measure of beam blockage and VPR effects in a national network | |
| Liang et al. | A composite approach of radar echo extrapolation based on TREC vectors in combination with model-predicted winds | |
| CN108693534A (en) | NRIET X band radars cooperate with networking analysis method | |
| Friedrich et al. | A quality control concept for radar reflectivity, polarimetric parameters, and Doppler velocity | |
| CN109001846B (en) | S-band and X-band radar networking rain measurement method under complex terrain condition | |
| CN110044327B (en) | Infrastructure settlement monitoring method and system based on SAR data and GNSS data | |
| Gou et al. | An improved self-consistent approach to attenuation correction for C-band polarimetric radar measurements and its impact on quantitative precipitation estimation | |
| CN112558076B (en) | Volume scanning mode calculation method based on networking weather radar coverage area and application | |
| CN113311416B (en) | Mountain small-basin radar quantitative precipitation estimation method | |
| McRoberts et al. | Detecting beam blockage in radar-based precipitation estimates | |
| CN112857312B (en) | Fusion method for measuring ground settlement by different time sequence differential interference according to settlement rate | |
| Pham et al. | Characteristics of tropical cyclone precipitating system along central coastal region of Vietnam by TRMM and GSMAP data | |
| Gou et al. | Microphysical processes of super typhoon Lekima (2019) and their impacts on polarimetric radar remote sensing of precipitation | |
| CN113008202B (en) | Ground settlement monitoring method integrating different synthetic aperture radar interferometry | |
| Zhangwei et al. | Research on improving detection capability of small and medium scales based on dual polarization weather radar | |
| Kimpara et al. | Evaluation of the radar-based quantitative precipitation estimation composite in Viet Nam | |
| Suzuki et al. | X-band dual-polarization radar observations of the supercell storm that generated an F3 tornado on 6 May 2012 in Ibaraki Prefecture, Japan | |
| Zhang et al. | Quantitative estimation and fusion optimization of radar rainfall in the Duanzhuang watershed at the eastern foot of the Taihang Mountains | |
| Yu et al. | Application of X-band Polarimetric Phased-array Radars in Quantitative Precipitation Estimation | |
| Iocca et al. | Open-Source Data Processing Chain for Marche Region X-band Weather Radar | |
| Mahavik et al. | Radar Quality Index for a Mosaic of Radar Reflectivity over Chao Phraya River Basin, Thailand | |
| Yoshida et al. | The structure of convective systems observed by phased array radar in the Kinki region, Japan |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |