KR101451548B1 - Apparatus and method for determination of the optimum multiple elevation angles - Google Patents

Abstract

The present invention relates to an apparatus and a method for determining optimum multiple elevation angles. The apparatus for determining optimum multiple elevation angles according to one embodiment of the present invention includes a weather radar data collection part which collects weather radar observational data; an optimum elevation angle mask generation part which generates ab optimum elevation angle mask; and an optimum multiple elevation angle mask generation part which generates an optimum multiple elevation angle mask. More particularly, in an aspect of the present invention, the apparatus for determining optimum multiple elevation angles which has weather radar observational data can include other embodiments.

Description

[0001] The present invention relates to an apparatus and a method for determining an optimal multiple elevation angle,

The present invention relates to a rainfall estimation technique, and more particularly, to a rainfall estimation technique for estimating an accurate rainfall amount by minimizing an error factor in estimating a rainfall amount using a weather radar, And more particularly, to a multi-height angle determination apparatus and method.

In general, radar beams observe importers floating in the air, so it is different from the actual precipitation on the ground. Therefore, when estimating rainfall with a weather radar, radar observations should be used as close to the ground as possible. However, as the weather radar is closer to the ground the beam is contaminated by terrain shielding and terrain echo. It can also be contaminated from non-rainfall echoes by insects or birds and bright bands.

Therefore, in Korea, where there are many mountainous terrain, most of the weather radar is installed at the mountain top. However, due to the difference between the height and the land surface of the observed weather radar data, errors may occur when estimating the rainfall using the weather radar.

Therefore, for accurate ground-based rainfall estimation using weather radar, it is important to use the nearest elevation angle to the ground without being contaminated by beam shielding, topography echoes and non-rainfall echoes.

In order to solve the above-mentioned conventional problems, the present invention has been made to solve the above-described problems by using a dual polarized radar to avoid beam shielding by the terrain and to avoid radar gates of the lowest altitude angle closest to the ground without being influenced by the terrain echo and non- and a radar gate for generating an optimal multi-angle altitude mask.

According to another aspect of the present invention, there is provided a method for monitoring weather radar, comprising: collecting weather radar observation data; Generating a beam shield optimal altitude angle mask consisting of radar gates of the lowest altitude angle without beam shielding using the digital altitude model data; Generating a terrain echo optimal altitude angle mask consisting of radar gates of the lowest altitude angle without the terrain echo using the collected vapor laser observation data; Generating a rainfall echo area optimum altitude angle mask consisting of radar gates of the lowest altitude angle in which there is no non-rainfall area using the collected weather radar observation data; The generated beam shielding optimum altitude angle mask, the topography echo optimum altitude angle mask, and the rainfall echo area optimal altitude determining a maximum altitude angle at a selected radar gate of each mask at an optimal multiple altitude angle; And generating an optimal multiple altitude angle mask consisting of a radar gate having a determined optimal multiple altitude angle.
The step of generating the beam shielding optimum altitude angle mask may include a step 1-1 of calculating a beam shielding quality index for each altitude from a numerical simulation of the shielding of the radar beam by the terrain using the digital elevation model data, ; Comparing the computed beam shielding quality indices for each of the high altitudes with a set threshold value; As a result of comparison, if the beam shielding quality index at the selected lowest altitude angle exceeds the set threshold value, the radar gate of the lowest altitude angle is selected and if the set value is below the set threshold value, Comparing the shielding quality index with a preset threshold value; And generating a beam shielding optimal altitude angle mask having a beam shielding quality index that is equal to or greater than a set threshold value and having a radar gate at an altitude close to the ground level as a result of the comparison.

The step of generating the terrain echo optimum altitude angle mask may include a step 2-1 of generating a terrain echo map for each altitude by averaging cumulative reflectance data of the collected weather radar observations for a clear day, ; 2-2 step of comparing the reflectivity and the set reflectivity threshold value at the selected radar gate among the generated altitude-specific geographical echo maps; And generating a terrain echo optimal altitude angle mask consisting of a radar gate of the lowest altitude angle closest to the ground with a reflectivity less than the set reflectivity threshold as a result of the comparison.

Meanwhile, the step of generating the rainfall echo area optimum altitude angle mask may include a step 3-1 of obtaining observation variables including reflectance, differential reflectance, differential phase difference, and cross correlation coefficient from the real-time collected weather radar observation data; A step 3-2 of determining whether or not an observation parameter exists for the selected radar gate; If there is no observation variable in the selected radar gate, classifies the selected radar gate as no observation variable, and if there is an observation variable in the selected radar gate, 3-3 to classify regions or non-rain areas; 3-4 step of generating a rainfall echo area mask for each elevation according to the classified rainfall area, non-rainfall area and no observation parameter area; And a step 3-5 of generating a rainfall echo area optimum altitude angle mask consisting of a rainfall area or a radar gate having a lowest altitude angle with no observation variable using the generated altitude angle rainfall echo area mask.

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According to the present invention, it is possible to derive the lowest altitude data closest to the ground while minimizing the error factor occurring in estimating the rainfall amount using the weather radar.

Further, according to the present invention, by using the terrain information, altitude angle information and observation parameters of the dual polarized radar, it is possible to provide a high-quality minimum altitude angle that is not affected by terrain type beam shielding, terrain echo and non- rainfall echo And the accuracy of the estimation of the amount of rainfall near the surface of the earth can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing an overall system of an optimum multi-elevation angle determining apparatus according to an embodiment of the present invention; Fig.
2 is a diagram for explaining a method for determining an optimum multiple altitude angle according to an embodiment of the present invention.
FIG. 3 is a diagram for explaining in detail the beam masking optimum altitude angle mask generation process shown in FIG.
4 is a diagram for explaining the concept of beam shielding.
FIG. 5 is a view illustrating an example of a beam shielding quality index obtained by applying the beam shielding quality index calculating process shown in FIG. 3 to an actual case.
FIG. 6 is an exemplary view illustrating a beam-shielding optimum altitude angle mask generated using the beam shielding quality index obtained in the process of calculating the beam shielding quality index shown in FIG.
FIG. 7 is a diagram for explaining in detail the process of generating the terrain echo optimum altitude angle mask shown in FIG.
FIG. 8 is an exemplary view showing a topographical echo map for each altitude obtained by applying the terrain echo optimum altitude angle mask generation process according to the present invention shown in FIG. 7 to actual cases.
FIG. 9 is an exemplary view showing the topographical echo optimum altitude angle mask obtained through the process of generating the terrain echo optimum altitude angle mask according to the present invention shown in FIG. 7; FIG.
FIG. 10 is a view for explaining a process of generating an optimum altitude angle mask of the rainfall echo area shown in FIG. 2. FIG.
11 is an exemplary view illustrating a rainfall echo area mask for each altitude generated according to an optimal altitude angle mask generation process of the rainfall echo area of FIG.
FIG. 12 is a detailed view illustrating an optimum altitude angle mask generation process of the rainfall echo area shown in FIG.
13 is an exemplary view showing an optimum altitude angle mask of the rainfall echo area generated according to the process of generating an optimal altitude angle mask of the rainfall echo area of Fig.
FIG. 14 is an exemplary view showing an optimum multiple altitude angle mask generated according to the optimum multiple altitude angle mask generation process shown in FIG. 2. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing an overall system of an optimum multi-elevation angle determining apparatus according to an embodiment of the present invention; Fig.

Referring to FIG. 1, the optimum multi-altitude angle determining apparatus 1 according to the present invention collects weather radar observation data from a weather radar system 2, and uses the collected weather radar observation data to perform beam shielding, You can create an optimal multi-elevation angle mask consisting of the lowest altitude angles nearest to the terrain echo and non-rainfall echo-free terrain.

The optimum multi-angle altimeter determining apparatus 1 includes a weather radar data collecting unit 11, a beam-shielding optimum altitude angle mask generating unit 12, a terrain echo optimum altitude angle mask generating unit 13, Each mask generation unit 14 and an optimum multiple altitude angle mask generation unit 15.

First, the weather radar data collection unit 11 can collect observation data of the weather radar observed in the weather radar system 2 and perform quality control on the data. Here, the weather radar is a dual polarized radar, and the observation data is the dual polarization observation data and the radar altitude angle information.

Then, the beam-shielding optimum altitude angle mask generating unit 12 generates a numerical simulation result on the shielding of the radar beam by the terrain using the digital elevation model (DEM) data providing the terrain information To calculate a beam blocking index (Q _BK ). That is, the beam-shielding optimum altitude angle mask generating section 12 calculates the shielding degree (F _shield ) of the radar beam when the imaginary radar beam is emitted at a specific altitude angle, and calculates the beam shielding quality The index (Q _BK ) can be calculated.

The beam-shielding optimum altitude angle mask generating section 12 calculates the minimum altitude angles at which the calculated beam shield quality index Q _BK is equal to or higher than the set threshold and is nearest to the ground, that is, It is possible to generate a beam-shielded optimum altitude angle mask by selecting each radar gate.

The terrain echo optimum altitude angle mask generation unit 13 generates a terrain echo map for each altitude by averaging the reflectance data of a clear day example among the weather radar observation data for a long period of time, Can be used to generate a terrain echo-optimal altitude angle mask by selecting the lowest altitude angles nearest to the ground without radar echoes at each altitude angle for each radar gate.

The rainfall echo area optimum altitude angle mask generation unit 14 calculates the double polarization observation variables (reflectivity, differential reflectance, differential phase difference and cross correlation coefficient) from observation data of the double polarized radar observed in real time, Using the characteristics of the polarization observation parameters, it is possible to generate a rainfall echo area optimum altitude angle mask by selecting the lowest altitude angles nearest to the ground by radar gates while minimizing the influence of non rainfall echoes and bright bands.

The optimum multi-altitude angle mask generation unit 15 uses the optimum altitude angle masks generated by the optimum altitude angle mask generation units 12, 13 and 14 so that there is no influence of beam shielding and topography in each radar gate The optimal altitude angle mask can be generated by determining the lowest altitude angles nearest to the ground that are not affected by rainfall echoes.

As described above, the optimum multi-altitude angle determination apparatus 1 according to the present invention can use the beam-shielded optimum altitude angle mask without influence of beam shielding, the terrain echo optimum altitude angle mask without influence of the terrain, and the rainfall- The optimal altitude angle of the lowest altitude nearest to the ground can be determined as the optimum altitude angle without influence of the beam shielding, the topography, and the non-rainfall region for each radar gate.

Thus, the present invention can help to estimate accurate rainfall using the reflectivity and differential reflectivity at a good minimum altitude angle that is free of beam shielding and terrain and is unaffected by non-rainfall echoes.

2 is a diagram for explaining a method for determining an optimum multiple altitude angle according to an embodiment of the present invention. Here, the method for determining the optimum multiple altitude angle according to the present invention can be implemented by the apparatus for determining the optimum multiple altitude angle shown in FIG.

Referring to FIG. 2, the method for determining the optimal multi-angle altitude according to the present invention comprises the steps of (a) collecting a weather radar observation data, (S100) collecting the weather radar observation data and the terrain information, (S200, S300, S400), and determines the optimum multi-elevation angle without any influence of the beam shielding, the topography, and the non-rainfall echo from each optimum altitude angle mask, (S500 and S600).

Specifically, in the method of determining the optimal multiple altitude angle according to the present invention, the observed weather radar observation data is first collected from the weather radar system (S100). Here, the weather radar system is a dual polarized weather radar system, and the weather radar observation data is a double polarized observation data, which may be data observed in the past or data observed in real time.

Then, a numerical simulation of the shielding of the radar beam by the terrain is performed by using the altitude information and the digital elevation model (DEM) data of the weather radar observation data, and the beam shielding optimum altitude angle mask (S200).

In addition, the weather radar observations are accumulated for a certain period for each altitude, and then the cumulative reflectance is averaged to generate a terrain echo map for each altitude, and the terrain echo optimum altitude angle obtained by removing the terrain echo using each altitude terrain echo map A mask is generated (S300).

Also, an observation parameter including the reflectance, differential reflectance, differential phase difference, and cross correlation coefficient is calculated from the weather radar observation data, and the optimal altitude angle mask of the rainfall echo area is obtained by removing the non-rainfall area using the calculated observation variables (S400).

Then, an optimum altitude angle that does not affect all of the beam shielding, the topography, and the non-rainfall echo is determined for each radar gate in each optimal altitude angle mask (S500), and an optimum multiple altitude angle mask is generated (S600).

As described above, according to the present invention, an optimum altitude angle determination mask composed of the lowest altitude angles in which beam shielding does not exist is generated using the beam shielding numerical simulation data, We use a terrain echo map to generate an optimal altitude angle mask consisting of the lowest elevation angles without any influence by the terrain, and also the presence of rainfall echoes using the characteristics of the dual polarization observations, The minimum altitude angles are determined for each radar gate that are not affected by beam shielding, topography, and non-rainfall echoes using each of the generated altitude angles masks by creating an optimal altitude angle mask consisting of the lowest altitude angles Thereby generating the optimum multiple altitude angle mask.

First, the beam-generating optimal altitude angle mask generating process shown in FIG. 2 will be described with reference to FIGS. 3 to 6. FIG.

FIG. 3 is a view for explaining the beam-generating optimal altitude angle mask generation process shown in FIG. 2 in detail; FIG. 4 is a view for explaining the concept of beam shielding, in which (a) (B) is a vertical section of the result of the beam shielding simulation, and (c) is a conceptual diagram of the beam shielding simulation.

Referring to FIG. 3, a beam shielding optimal altitude angle mask generation process (S200) according to the present invention first receives an observed altitude angle of a weather radar (S201).

Then, a beam shield quality index is generated for each altitude (S202). Here, the beam blockage index (Q _BK ) can be calculated using a result of numerical simulation (see FIG. 4 (c)) of the shielding of the radar beam by the terrain.

For this purpose, a horizontal resolution of 3 "(~ 90 m) and a height elevation error of 16 m or less (CGIAR-CSI) of" Consultative Group on International Agricultural Research-Consortium for Spatial Information digital elevation model (DEM) data was used. In order to simulate the progress of the radar beam close to the real world, energy was concentrated to the nearest Gaussian shape to the actual beam pattern of the weather radar, (Eg, Bellon and Zawadzki, 2006), and the Gaussian beam pattern can be calculated using Equation 1 below.

Here, g (θ) is the intensity of the radar signal at the radar transmitting and receiving strength, g ₀ of the signal beam center according to the angular distance (θ) from the beam center, θ is the radar beam width (°), σ is a standard Gaussian distribution The deviation is θ / 2.354.

According to Equation 1, as shown in FIG. 4A, a Gaussian beam pattern is a pattern in which energy of a radar wave is concentrated at the center of a beam, and energy is sharply reduced in a Gaussian form .

Further, in this embodiment, the propagation of the atmospheric beam is assumed to be based on the assumption that radar beam propagation in a standard atmosphere (Doviak and Zrinc, 1993, Kucera et al., 2004; Jung et al., 2007) And the height h of the beam along the distance from the radar is calculated according to Equation 2 below.

Where k _e is the Earth's effective radius (km) considering the refractive index of the electromagnetic wave in the standard atmosphere, r is the distance (km) along the direction of sight of the radar beam, and θ _e is the radar altitude (°), and h _radar represents the altitude (km) of the radar antenna.

The progress of the radar beam according to the refractive index of the standard atmosphere and the beam shielding can be obtained as shown in FIG. 4 (b) using the altitude of the radar beam obtained by the equation (2). As shown in FIG. 4 (b) The black area is the topographic data of the DEM, and the gray area shows the progress of the radar beam considering the beam width. The area marked with X is not shielded by the topography, It can be seen that some beam shielding occurs.

4C, the simulated beam shielding degree (F _shield ) is calculated as A, B, and C according to the degree of shielding by the terrain, and A is the beam shielding degree B is a region where some beam shielding has occurred, and C is a region where beam shielding has completely occurred. That is, the percentage value of the shielded area with respect to the radar beam width has a range of 0.0 to 1.0.

If this beam shielding degree (F _shield ) is 0.0, it is 0% shielding. If it is 1.0, it means 100% complete shielding. Therefore, the beam shield quality index Q _BK is determined by the beam shielding degree (F _shield ) calculated through the shielding simulation result as shown in FIG. 4 (c), and is calculated by the following equation (3).

That is, if the beam shielding quality index (Q _BK ) is 0.0, it means 100% complete shielding, and if 1.0 it means 0% shielding. The beam shielding rate moves away from the radar and passes through the shielding point (topography) and accumulates in the direction of the eye. Therefore, a point near the distance from the radar can have a high beam shielding quality index, and a farther away beam shielding quality index.

Then, the comparison and (S204), the comparison result, the beam shielding Quality Index (Q _BK) is greater than a predetermined threshold value, the beam shielding Quality Index (Q _BK) and the predetermined threshold value calculated in any of the radar gate of the lowest elevation angle ( S205 , Y), the elevation angle of the corresponding radar gate is selected ( S207 ).

On the contrary, if the beam shield quality index Q _BK is less than the set threshold value ( S205 , N), the altitude angle is increased by one and the beam shield quality index Q _BK is compared with the set threshold value. This process is repeated until an altitude angle with a beam shield quality index that exceeds the threshold is detected .

Therefore, a beam shield optimal altitude angle mask is generated using the selected altitude angles (S208). That is, the lowest lowest value with the beam shield quality index exceeding the set threshold It is possible to create a beam-shielded optimal altitude angle mask composed of elevation angle radar gates. Here, the minimum altitude angle data composed of the minimum altitude angles closest to the ground without the influence of beam shielding is defined as a beam-shielded optimal altitude angle mask.

In other words, according to the beam-generating optimal altitude angle mask generation process according to the present invention, a beam-shield quality index is used to find the lowest altitude angles nearest to the ground without the influence of beam shielding, It is possible to create a masking optimal altitude angle mask.

5 is a view illustrating an example of a beam shielding quality index obtained by applying the beam shielding quality index calculation process shown in FIG. 3 to an actual case, wherein (a) to (f) are elevation angles -0.5 DEG, 0.0 DEG, 0.5 DEG, 0.8 DEG, 1.2 DEG, 1.6 DEG) of the beam shielding quality index (Q _BK ).

5 (a) to 5 (f), as the distribution of the beam shield quality index derived from the shielding result simulated by the position information of the Bismuth radar and the observation altitude angle increases, the S shielding effect by the terrain is increased The beam shielding quality index approaches 1.0. The beam shielding quality index value is 1.0 in all regions because the beam shielding effect is not exhibited at an elevation angle of 0.8 DEG or more.

Therefore, the beam-shielding optimum altitude mask composed of the radar gates of the altitude angles (the lowest altitude angles) nearest to the ground with the beam shielding quality index equal to or higher than the threshold value by integrating the beam shielding quality index calculated for each altitude, Can be generated.

FIG. 6 is an exemplary view illustrating a beam-shielding optimum altitude angle mask generated using the beam shielding quality index obtained in the process of calculating the beam shielding quality index shown in FIG. Here, the threshold value of the beam shielding quality index is 0.9, the threshold value of the beam shielding quality index can be changed according to the needs of the user, and the lower the threshold value of the beam shielding quality index is, the more influence The elevation angle radar gates are selected. Each color represents an elevation angle.

The beam-shielded optimum altitude angle mask shown in Fig. 6 shows a radar gate closest to the ground with a beam shielding of less than 10% because the threshold of the beam shielding quality index is 0.9.

Also, the area close to the radar is selected to have a low altitude angle due to the low shielding effect, and at the point about 50 km from the radar, the shielding effect indicates that the upper altitude angle radar gates have been selected.

Next, the process of generating the terrain echo optimum altitude angle mask shown in Fig. 2 will be described with reference to Figs. 7 to 9.

FIG. 7 is a diagram for explaining in detail the process of generating the terrain echo optimum altitude angle mask shown in FIG. Here, the terrain echo appears as the radar beam hits the terrain and has a strong reflectivity, which acts as an error in estimating the rainfall. These topographic echoes have characteristics that appear almost always at fixed locations. Therefore, in the present invention, it is desired to generate a terrain echo optimum altitude angle mask using the characteristics of the terrain echo.

Referring to FIG. 7, a clear day example of the collected weather radar observation data (reflectivity data) is inputted (S301), the reflectance data of the clear day is accumulated for a predetermined period and the reflectivity is accumulated for a predetermined period (S302) And generates a terrain echo map for each altitude (S303).

Then, the terrain echo reflectance of an arbitrary radar gate selected in the terrain echo map of the lowest elevation angle among the generated altitude terrain echo maps is compared with the set threshold value (S304).

If it is determined that the terrain echo reflectivity of the selected radar gate is less than the predetermined threshold value, the corresponding altitude angle is selected (S307). If the selected altitude angle is greater than the threshold value, the terrain echo map The process returns to step S304 to perform the process of comparing the set threshold values (S306).

These processes (S304, S305, and S306) are repeated for each radar gate until altitude angles at which the terrain echo reflectivity is less than a threshold value are detected.

Finally, the generation of the beam-shielded optimal altitude angle mask is performed using the selected altitude angles (S308). Here, the selected altitude angles are altitude angles that are less than the threshold value for which the terrestrial echo reflectance is set and are closest to the ground, and can generate a terrain echo optimal altitude angle mask consisting of corresponding radar gates of these selected altitude angles.

FIG. 8 is a diagram showing an example of a topographic echo map obtained by applying the process of generating the terrain echo optimum altitude angle mask according to the present invention shown in FIG. 7 to an actual case, A geomorphic echo map for elevation angles (-0.5 °, 0.0 °, 0.5 °, 0.8 °, 1.2 °, 1.6 °) generated using 20 Bissulian double polar radar data of 0947 KST ~ 1247 KST Respectively.

Referring to FIG. 8 (a), the terrain at the altitude angle of -0.5 ° caused the terrain to have a high reflectivity due to the terrain echo at a point near 50 km from the radar and at the trial boundary.

8 (a) to 8 (f), it can be seen that as the elevation angle increases, the terrain echo disappears.

FIG. 9 is an exemplary view showing the topographical echo optimum altitude angle mask obtained through the process of generating the terrain echo optimum altitude angle mask according to the present invention shown in FIG. 7; FIG. In the present invention, a terrain echo map is generated for each altitude as shown in FIG. 8 using the reflectance data of the Baysulin dual polarized radar, and the reflectivity threshold value of the terrestrial echo is 20 dBZ. However, the present invention is not limited thereto. The threshold value can be applied differently depending on the quality of the desired terrain echo map. And, the color represents the elevation angle.

Referring to Fig. 9, the terrain echo optimum altitude angle mask is composed of radar gates of altitude angles whose reflectivity of the selected terrain echo is less than 20 dBZ and closest to the ground, using each altitude-specific topographic echo map shown in Fig. 8 .

This geo-echo-optimized altitude angle mask does not increase the altitude angle even if the distance is different from the beam-mask optimal altitude angle mask, and the elevation angle increases only at the radar gate affected by the terrain.

Next, the process of generating an optimum altitude angle mask of the rainfall echo area shown in FIG. 2 will be described with reference to FIGS. 10 to 13. FIG.

FIG. 10 is a view for explaining a process of generating an optimum altitude angle mask of the rainfall echo area shown in FIG. 2. FIG.

Referring to FIG. 10, an observation variable is calculated from real-time collected weather radar observation data (S401). Here, the weather radar observation data is the observation data of the double polarized radar.

)를 포함하는 관측변수를 산출한다. In order to classify rainfall echo and rainfall echoes from double polarized observations, the reflectivity (Z _H ), the differential reflectivity (Z _DR ), the differential phase shift (Φ _DP ) (cross-polar correlation coefficient,

). ≪ / RTI >

Then, when the calculation of the observation parameters is completed, it is determined whether there is an observation variable necessary for the determination of the rainfall echo area in the selected arbitrary radar gate (S402).

As a result of the determination, if there is an observation variable in the selected radar gate (S402, Y), the determination process of the rainfall echo area is performed, and if the observation variable does not exist, it is classified as no observation variable (S409). That is, if there is no observation variable, the observation variable is not present in the rainfall echo area mask.

Then, in order to determine the rainfall echo area in the presence of the observation variable, the cross correlation coefficient value of the corresponding radar gate is compared with the set cross-correlation coefficient threshold value for the region where the observation variable exists, (S403).

As a result of the comparison, if the cross correlation coefficient value of the corresponding radar gate is less than the set threshold value (S403, N), it is classified as a non-rainfall echo area. If the threshold value is exceeded (S403, Y) (S404).

That is, when the number of observation variables in the total (n + 1) radar gates is equal to or smaller than n / 2 (n / 2) (n is a natural number) radar gates before and after the gaze direction on the basis of the radar gate, N), the standard deviation of the point is not calculated and classified as no observation variable (S409).

)의 시선방향에 대한 표준편차를 각각 계산한다.If the cross correlation coefficient value of the radar gate exceeds the set threshold value (S403, Y) and the number of observation variables in the total (n + 1) radar gates exceeds n / 2 (S404, Y) The standard deviation of the observed variables, that is, the standard deviation of the reflectance, the differential reflectance, the differential phase difference, and the cross correlation coefficient, is calculated (S405). That is, the four observation parameters (Z _H, Z _{DR, DP} Φ,

) Are calculated, respectively.

For example, the standard deviation SD (x) at each radar gate (x) calculates a standard deviation according to the following Equation (4) using a total of (n + 1) In the invention, the standard deviation is calculated using 11 data by applying n = 10, but the present invention is not limited thereto, and n may be different from user to user.

Then, the standard deviation of the four calculated observation variables is compared with the set threshold value (S406). If all the standard deviations of the four observation parameters are less than the set threshold value (S406, Y), the rainfall echo area is classified (S408). If at least one of the standard deviations of the four observation variables is equal to or greater than the set threshold value (S406, N), classification is performed into the non-rainfall echo area (S407).

Here, the threshold value of each standard deviation is selected by using a fuzzy membership function for the terrain echo. The threshold value applied in the present invention is shown in Table 1 below and can be changed by the user.

SD (Z) [dB] SD (Z _DR ) [dB]

)SD (

) SD (陸_DP ) [deg]

30 dBZ <Z 3.5 1.0 0.06 8.5 0.92 20 dBZ? Z? 30 dBZ 4.0 1.5 0.06 8.5 0.90 10 dBZ? Z? 20 dBZ 3.0 1.0 0.07 9.0 0.90 0 dBZ? Z? 10 dBZ 2.5 1.0 0.07 10.5 0.86 Z < 0 dBZ 2.5 2.3 0.13 7.0 0.86

The threshold of Table 1 is the standard deviation of each observation variable at each reflectivity rank when the fuzzy membership function has a membership value of 0.8. The threshold value can be arbitrarily defined by the user depending on the radar.

Next, the rainfall echo area mask is generated using the classified rainfall echo area, the non-rainfall echo area, and the area where the observation parameter does not exist (S410). This rainfall echo area mask is generated at each altitude.

Then, the rainfall echo area optimum altitude angle mask is generated using the generated rainfall echo area mask for each altitude (S411).

FIG. 11 is a diagram illustrating a rainfall echo area mask for each altitude generated according to the process of generating an optimal altitude angle mask in the rainfall echo area of FIG. 10, wherein (a) - (f) 0, 0.5, 0.8, 1.2, 1.6), respectively. Here, the observed data is 1212 KST on August 23, 2012, and the threshold value of cross correlation coefficient is 0.95. In addition, yellow indicates rainfall area, green indicates rainfall area, and gray indicates area without observation variables.

11 (a) to (f), in the rainfall echo area mask, there are many regions identified as non-rainfall echo regions by the topography at low elevation angles, and elevation angles (d ), (f)), it can be seen that there is a rainfall echo area due to the bright band.

FIG. 12 is a detailed view illustrating an optimum altitude angle mask generation process of the rainfall echo area shown in FIG.

Referring to FIG. 12, a rainfall echo area determination is performed for a radar gate arbitrarily selected in the rainfall echo area mask of the optimum altitude angle among the rainfall echo area mask S4111 at each altitude angle (S4112). That is, it is determined whether the selected radar gate is a rainfall echo area, a non-rainfall echo area, or a region where an observation variable does not exist.

As a result of the determination, if the selected radar gate is determined to be the rainfall echo area S4116 or the area S4117 in which no observation variable exists, the altitude angle is selected (S4118).

If it is determined that the selected radar gate is a non-rainfall echo area (S4114), the process returns to step S4112 to perform the process of determining the rainfall echo area of the corresponding radar gate by increasing the altitude angle by one step (S4115). This process is repeated until a radar gate of the rainfall echo area or the area without the observation variable is detected for the non-rainfall echo area.

Finally, a rainfall echo area optimum altitude angle mask composed of selected radar gates at the selected altitude angles is generated (S4119). Thereby, a rainfall echo area optimal altitude angle mask including rainfall echo and non rainfall echo information can be generated.

The rainfall echo area optimum altitude angle mask according to the present invention is generated in real time every volume observation unlike the optimum altitude angle mask using the beam shielding quality index and the terrain echo map.

FIG. 13 is a view showing an optimum altitude angle mask of a rainfall echo area generated according to the process of generating an optimal altitude angle mask of the rainfall echo area of FIG. 12; FIG. The observational data used in the present invention are the observations of the Bismuth dual polarized radar and the 1212 KST case of August 23, 2012 was used.

Next, FIG. 14 is a diagram showing the optimum multiple altitude angle mask generated according to the optimum multiple altitude angle mask generation process shown in FIG. In the present invention, observational data of a bessulin double polarized radar (August 12, 2012, 1212 KST) was used.

Referring to FIG. 14, the area where the shielding is present shows a state in which the elevation angle increases in the direction of the eye, such as the beam shielding quality index optimum angle mask, and the area to which the terrain echo optimum altitude mask is applied, The elevation angle increases sharply in the vicinity of the system. In addition, in some areas, the altitude angle is partially increased by the rainfall echo area optimum altitude mask.

The present invention has been described with reference to the preferred embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Accordingly, the disclosed embodiments are to be considered in an illustrative rather than a restrictive sense, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Further, the apparatus and method according to the present invention can be embodied as computer readable codes on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and a carrier wave (for example, transmission via the Internet). The computer-readable recording medium may also be distributed over a networked computer system so that computer readable code can be stored and executed in a distributed manner.

1. Optimal multi-altitude angle determination device 2. Weather radar system

Claims (20)

A weather radar data collection unit for collecting weather radar observation data;
Using the collected weather radar observation data, we select the lowest altitude angle that does not have beam shielding, terrain echo, and non - rainfall area for each radar gate, and select the beam - shielding optimal altitude angle mask composed of the radar gates of the selected altitude angles, An optimum elevation angle mask generating unit for generating a terrain echo optimum altitude angle mask and a rainfall echo area optimum altitude angle mask, respectively; And
Generated Beam Shielding Optimal Elevation Angle Mask, Terrain Echo Optimal Elevation Angle Mask and Rainfall Echo Zone Optimal Elevation The highest elevation angle at each radar gate in each mask is set to the lowest elevation angle that does not exist in both beam shielding, terrain echo and non-rainfall areas And an optimal multiple altitude angle mask generation unit for generating an optimal multiple altitude angle mask composed of the determined lowest altitude angle radar gates. The method according to claim 1,
The optimum altitude angle mask generation unit calculates a beam shielding quality index for each altitude and integrates the calculated beam shielding quality indexes for each altitude to calculate a beam shielding quality index that is equal to or higher than a threshold value, A beam shielding optimum altitude angle mask generating unit for generating an optimum altitude angle mask composed of a radar gate;
The optimal altitude of the generated altitude angular echo map is composed of the radar gates of the elevation angle which is less than the threshold value and the reflectance is below the threshold value at the generated altitude angles. A terrain echo optimum altitude angle mask generating unit for generating each mask; And
The rainfall echo area mask of each elevation angle is generated by using the standard deviation of the calculated observation variables from the collected weather radar observation data, And a rainfall echo area optimal intensity angle mask generating unit for generating a rainfall echo area optimum depth altitude angle mask composed of radar gates of the lowest altitude angles having no regions or observation variables. The method of claim 2,
The beam-shielding optimum altitude angle mask generating unit obtains the degree of beam shielding using the numerical altitude model data, which is a result of shielding simulation of the radar beam by the terrain, and calculates the beam shielding quality index for each altitude through the obtained beam shielding degree Wherein the optimal altitude angle determining device is configured to determine the optimal altitude angle. The method of claim 3,
Wherein the beam shielding optimum altitude angle mask generating unit selects the radar gate of the first elevation angle when the beam shielding quality index exceeds a threshold value at a first elevation angle of the lowest altitude angle, Wherein the step of comparing the beam shield quality index and the threshold value in the radar gate at the second elevation angle at which the elevation angle is increased by one at the first elevation angle is repeated until the beam shielding quality index is more than the threshold value Multiple altitude angular determination device. The method of claim 2,
Wherein the terrain echo optimum altitude angle mask generation unit selects the first radar gate at the first altitude angle when the reflectivity of the first radar gate is lower than the threshold value in the terrain echo map at the first altitude angle with the lowest altitude angle, The process of comparing the reflectivity of the radar gate and the threshold value at the second elevation angle echo map in which the altitude angle is increased by one at the first altitude angle is repeated until the reflectance lower than the threshold value is reached Characterized in that it comprises: The method of claim 2,
Wherein the rainfall echo area optimum altitude angle generator generates the rainfall echo area optimal altitude angle mask in real time using the weather radar observation data collected in real time. The method of claim 6,
The rainfall echo area optimum altitude angle generator generates an observation variable including reflectance, differential reflectance, differential phase difference, and cross correlation coefficient from the real-time collected weather radar observation data, and determines whether or not the observed variable exists for each radar gate And if there is no observation variable, classifies it as no observation variable. If the observation variable exists, it performs a threshold value comparison for each of the observation variable to classify it as a rainfall or non-rainfall area, Rainfall, non-rainfall, and altitude-specific rainfall echo area mask according to the no-observation area. The method of claim 7,
The rainfall echo area optimum altitude angle mask generation unit first compares the threshold value of the cross correlation coefficient when the observation variable exists in the selected radar gate and calculates a total sum (n + 1) before and after the selected line direction of the radar gate, (n is a natural number) radar gates. If the number of observation variables is n / 2 or less in total (n + 1) (n is a natural number) radar gates, / 2 or more, and if the standard deviation is less than the set threshold value, it is classified as a rainfall area, and if the standard deviation is not less than a threshold value, the standard deviation is classified as a non-rainfall area. The method of claim 8,
Wherein the rainfall echo area optimum altitude angle mask generation unit generates the rainfall echo area optimal altitude angle mask by setting the first radar gate at the minimum altitude angle if the first radar gate of the lowest altitude angle in the generated altitude- And if the first radar gate is a radar gate having a non-rain area, checking whether a rain area or an observation variable is present by increasing an altitude angle is performed until a radar gate without a rain area or an observation variable is detected Wherein the first and second altitude angles are repeated. Collecting weather radar observation data;
Generating a beam shield optimal altitude angle mask consisting of radar gates of the lowest altitude angle without beam shielding using the digital altitude model data;
Generating a terrain echo optimal altitude angle mask consisting of radar gates of the lowest altitude angle without the terrain echo using the collected vapor laser observation data;
Generating a rainfall echo area optimum altitude angle mask consisting of radar gates of the lowest altitude angle in which there is no non-rainfall area using the collected weather radar observation data;
The generated beam shielding optimum altitude angle mask, the topography echo optimum altitude angle mask, and the rainfall echo area optimal altitude determining a maximum altitude angle at a selected radar gate of each mask at an optimal multiple altitude angle; And
And generating an optimal multi-elevation angle mask consisting of a radar gate having a determined optimal multi-elevation angle. The method of claim 10,
Wherein the optimal multiple altitude angle is a minimum altitude angle at which no beam shielding, topographic echo, and non-rainfall regions are present in each radar gate. The method of claim 10,
Wherein the step of generating the beam-
Step 1-1 to calculate the beam shield quality index for each altitude from the result of numerical simulations of radar beam shielding by terrain using digital elevation model data;
Comparing the computed beam shielding quality indices for each of the high altitudes with a set threshold value;
As a result of comparison, if the beam shielding quality index at the selected lowest altitude angle exceeds the set threshold value, the radar gate of the lowest altitude angle is selected and if the set value is below the set threshold value, Comparing the shielding quality index with a preset threshold value; And
Generating a beam shielding optimal altitude angle mask having a beam shielding quality index that is equal to or greater than a set threshold value and having a radar gate at an altitude close to the ground level, Determination method. The method of claim 12,
Wherein the steps 1-3 are repeated until the beam shielding quality index of the corresponding radar gate whose elevation angle is increased exceeds a preset threshold value. The method of claim 10,
Wherein the generating the terrain echo optimal elevation angle mask comprises:
2-1 step of collecting the reflectance data for the clear day case of the collected weather radar data by averaging the accumulated reflectance data for a certain period of time and generating a geographical echo map for each altitude;
2-2 step of comparing the reflectivity and the set reflectivity threshold value at the selected radar gate among the generated altitude-specific geographical echo maps; And
And generating a terrain echo optimum altitude angle mask consisting of radar gates of the lowest altitude angle closest to the ground with a reflectivity lower than a predetermined reflectivity threshold as a result of the comparison, Each determination method. 15. The method of claim 14,
If it is determined that the reflectivity of the selected radar gate is lower than the set reflectivity threshold, determining the elevation angle of the selected radar gate as the lowest elevation angle, Determination method. 16. The method of claim 15,
And returning to step 2-2 to increase the altitude and compare the reflectivity of the selected radar gate with the set threshold if the reflectivity of the selected radar gate is greater than or equal to a preset threshold value A method for determining an optimal multiple altitude angle. The method of claim 10,
Wherein the step of generating the rainfall echo area optimal elevation angle mask comprises:
Step 3-1 to obtain observation variables including reflectance, differential reflectance, differential phase difference, and cross correlation coefficient from the real-time collected weather radar observation data;
A step 3-2 of determining whether or not an observation parameter exists for the selected radar gate;
If there is no observation variable in the selected radar gate, classifies the selected radar gate as no observation variable, and if there is an observation variable in the selected radar gate, 3-3 to classify regions or non-rain areas;
3-4 step of generating a rainfall echo area mask for each elevation according to the classified rainfall area, non-rainfall area and no observation parameter area; And
And generating the rainfall echo area optimum altitude angle mask consisting of the radar gates of the lowest altitude angles that are either the rainfall area or the observation variables using the generated altitude-specific rainfall echo area mask. Altitude angle determination method. 18. The method of claim 17,
Comparing the cross correlation coefficient at the selected gate with a set cross correlation coefficient threshold value if the observation variable exists in the selected radar gate as a result of the determination;
If the cross correlation coefficient at the selected gate is equal to or less than the set cross-correlation coefficient threshold value, it is classified into the non-rain area. If the cross-correlation coefficient at the selected gate is greater than the cross- 1) (n is a natural number) radar gates; And
As a result of checking, if the number of observations is less than n / 2 (n is a natural number) radar gates, n / 2, And if the gaze direction standard deviation of the obtained observation variables is less than the set threshold value, classifying it as a rainfall area, and if the standard deviation is less than the set threshold value, classifying it as a non-rainfall area. 19. The method of claim 18,
The standard deviation of the gaze direction of the observation variables is a standard deviation of the reflectivity, the differential reflectance, the differential phase difference, and the cross correlation coefficient, and the standard deviation of each of the reflectivity, differential reflectivity, differential phase difference and cross correlation coefficient is set for each observation variable And classifying it into a rainfall area only when the rainfall is less than a threshold value. The method of claim 17,
Determining a rainfall echo area of a radar gate selected in the rainfall echo area mask of the lowest altitude angle among the generated high altitude rainfall echo area masks; And
As a result of the determination, if the selected radar gate has a rainfall area or there is no observation variable, the altitude angle of the selected radar gate is selected. If there is a non-rain area in the selected radar gate, the altitude angle is increased to judge a rainfall echo area of the corresponding radar gate And returning to the step of determining the optimum multi-angle altitude.

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