JP2010164383A - Precipitation radar synthesis processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precipitation radar synthesis processor of which the measurement accuracy is improved. <P>SOLUTION: The precipitation radar synthesis processor 1 includes: an initial setting part 2 for calculating an average received power Pr of each of meshes MEs, r obtained by dividing a measuring area 53 of an X-band radar 51 into a plurality of parts in a sector direction and a plurality of parts in a range direction; an attenuation correction term calculating part 4 for calculating an attenuation correction term based on the average received power Pr; a complex attenuation determination processing part 7 in which, in each sector, a range number r of the mesh nearest to the X-band radar 51 is decided as an attenuation start range number r<SB>st</SB>out of the meshes MEs, r having an attenuation correction term KIR greater than a standard value KIRst, and a range number r of the mesh nearest to the X-band radar 51 is decided as an attenuation start range number r<SB>st</SB>out of the meshes having an average received power Pr smaller than a threshold value Th<SB>Pr</SB>; and a synthesis processing part 10 for synthesizing rainfall data based on the attenuation start range number r<SB>st</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rain radar synthesis processing apparatus that synthesizes rainfall data of an X band radar rain gauge and another band radar rain gauge.

  2. Description of the Related Art Conventionally, a rainfall radar rain gauge for measuring rainfall is known (see, for example, Patent Document 1). Furthermore, a plurality of types of radar rain gauges such as an X-band radar rain gauge (hereinafter referred to as X-band radar) and a C-band radar rain gauge (hereinafter referred to as C-band radar) are known as this rain radar rain gauge.

  The X-band radar can capture the rainfall situation with a fine mesh and in a short time. For this reason, the X-band radar is effective for monitoring disaster prevention. However, there is a problem that during heavy rain, radio waves are attenuated and sufficient rain observation is not possible.

  On the other hand, the C-band radar has a coarser mesh than the X-band radar, but has less rain attenuation and can observe a wide range.

  When it is introduced for stormwater drainage and disaster prevention at the municipal level, there are many cases where an X-band radar that can be installed relatively easily and captures the rainfall situation with a fine mesh and in a short time. However, during heavy rain, due to attenuation, it may not be possible to observe the rainfall situation beyond the heavy rain region. To compensate for this, install multiple radar rain gauges and complement them with synthesis processing, or purchase C rain data for C-band radar from other weather-related organizations and combine it with X-band radar X-rainfall data. The method is adopted (for example, refer nonpatent literature 1).

  The above-described rain data composition process cannot be grasped of the attenuation state of the X-band radar, and if it is simply combined, a donut-shaped display may occur. In order to avoid this, processing methods such as maximum value synthesis and average value synthesis of received power are known, but observation values of C-band radar are easily adopted, and the advantage of X-band radar cannot be utilized.

  Here, a method is known that uses an attenuation correction term as a material for determining a region that employs X-band radar data and a region that employs C-band radar data. In this determination method, the attenuation correction term of the X-band radar is calculated by substituting the average received power into the radar equation for obtaining the rainfall intensity, and the attenuation correction term is compared with a reference value. The area where the attenuation correction term is equal to or greater than the reference value employs X-band radar data, and the other area employs C-band radar data.

JP-A-6-230118

Published by Japan Sewage New Technology Promotion Organization, “Joint Research Report on Common Fine Radar Rainfall Information System Technology”, June 1996, p64-p68

  However, in the above-described conventional technology, when calculating the rainfall intensity, it is determined which data is to be adopted based only on the attenuation correction term considering attenuation due to raindrops, attenuation due to atmospheric gas, and the like. Therefore, there is a problem that accuracy is low.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a rain radar synthesis processing apparatus capable of improving accuracy.

  In order to achieve the above object, an invention according to claim 1 of the present invention is a method for synthesizing rain data of X-band radar and rain data of long-wave band radar using a radio wave having a longer wavelength than X-band radar. In the precipitation radar synthesis apparatus, initial setting means for calculating the average received power of each mesh obtained by dividing the measurement region of the X-band radar into a plurality of sector directions and a plurality of range directions, and attenuation correction based on the average received power Attenuation correction term calculation means for calculating a term, and in each sector, among the meshes where the attenuation correction term is larger than a reference value, the range number of the mesh closest to the X-band radar is determined as the attenuation start range number, Among meshes whose average received power is smaller than the average received power threshold, attenuate the range number of the mesh closest to the X-band radar A composite-determination means for determining a starting range number, on the basis of the attenuation start range number, which is precipitation radar synthesis processing apparatus, characterized in that a synthesizing process means for synthesizing the rainfall data.

  Further, the invention according to claim 2 of the present invention is provided with a rainfall integration means for calculating an integrated rainfall, and the combined attenuation determination means is only when the integrated rainfall is larger than an integrated rainfall threshold for determining fine rain, The rainfall radar synthesis processing apparatus according to claim 1, wherein the average received power is compared with the average received power threshold.

  Further, in the invention according to claim 3 of the present invention, the average received power of the mesh having the attenuation start range number is larger than the average received power of the mesh adjacent in the sector direction, and is larger in the sector direction. The rain radar according to claim 1 or 2, further comprising attenuation determination result processing means for correcting the attenuation start range number when the average received power of adjacent meshes is within a predetermined range. It is a synthesis processing device.

  The invention according to claim 4 of the present invention further comprises heavy rain occurrence frequency counting means for counting the number of heavy rain occurrence times where heavy rain has occurred in the same sector, wherein the combined attenuation determination means is the heavy attenuation determination means. 4. The range number of a mesh closest to the X-band radar among meshes having the number of rain occurrences equal to or greater than a threshold value is determined as an attenuation start range number. 5. This is a rain radar synthesis processing apparatus.

  According to the present invention, the accuracy can be improved by adopting the attenuation correction term and the average received power for each sector as the determination material for determining the attenuation start range.

It is a block diagram which shows the whole structure by 1st Embodiment. It is a figure explaining the mesh by which the measurement area of X band radar was divided. It is a figure explaining the determination process of the attenuation correction term of the sector to be determined. It is a figure explaining the determination process of the average received power of the sector of determination object. It is a flowchart explaining the attenuation determination process of a synthetic | combination process. It is a flowchart explaining the attenuation start range number correction process of an attenuation determination process. It is a figure which shows the determination result by the attenuation | damping determination process which used only the attenuation | damping correction term as the determination material. It is a figure which shows the determination result by the attenuation determination process which concerns on 1st Embodiment which used the attenuation correction term and average received power as a determination material. It is the measurement result of the rainfall by X band radar. It is the measurement result of the rainfall by C band radar. It is a result of the composition processing method by only the conventional attenuation correction term. It is a result of the synthetic | combination processing method which concerns on 1st Embodiment. It is a figure explaining the determination process of the average received power of the sector of determination object.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration according to the first embodiment. FIG. 2 is a diagram for explaining a mesh obtained by dividing the measurement region of the X-band radar. FIG. 3 is a diagram for explaining the determination process of the attenuation correction term of the sector to be determined. FIG. 4 is a diagram for explaining the process of determining the average received power of the sector to be determined.

  The rain radar synthesis processing apparatus 1 according to the first embodiment synthesizes the X rain data Dx input from the X band radar 51 and the C rain data Dc input from the C band radar 52. Here, the X-band radar 51 transmits radio waves having a wavelength of 3 cm. On the other hand, the C-band radar 52 transmits a radio wave having a wavelength of 5 cm.

  As shown in FIG. 1, the rainfall radar synthesis processing device 1 includes an initial setting unit 2, a rainfall intensity calculation unit 3, an attenuation correction term calculation unit 4, a rain amount accumulation unit 5, a reference value / threshold setting unit 6, and the like. The composite attenuation determination processing unit 7, the attenuation determination result processing unit 8, the attenuation map creation unit 9, and the synthesis processing unit 10 are provided. Each configuration includes hardware such as an arithmetic processing unit such as a CPU, a storage unit capable of storing various information and programs, a connection unit for connecting them, and an input / output unit for inputting / outputting each information to / from the outside. (Not shown).

  As shown in FIG. 2, the initial setting unit 2 divides the measurement region 53 of the X-band radar 51 into a sector direction (circumferential direction: azimuth) and a range direction (radial direction: distance). Then, the initial setting unit 2 performs the numbering of the sector number s and the range number r for each mesh MEs, r. In FIG. 2, the center of the measurement region 53 is a position where the X-band radar 51 is arranged.

  The initial setting unit 2 uses the X rainfall data Dx supplied from the X band radar 51 to calculate the average received power Pr of each mesh MEs, r divided by the sector number s and the range number r. Here, the average received power Pr is a received power averaged by a radar apparatus such as the X-band radar 51 measuring each mesh MEs, r n times. The number of times of measurement is the number of times the radar can physically rotate in accordance with the observation period. For example, in the case of X-band radar, it is generally about 3 times. The average received power is used as the received power of the X-band radar input to the rainfall radar synthesis processing apparatus 1. Note that the received power is a radio wave transmitted from the X-band radar 51 that is reflected by rain and received. The initial setting unit 2 uses the average received power Pr associated with the sector number s and the range number r as the rainfall intensity calculation unit 3, the reference value / threshold setting unit 6, the composite attenuation determination processing unit 7, and the attenuation determination result processing unit. 8 is output as data.

  The initial setting unit 2 performs initial setting of various parameters and outputs them.

The rainfall intensity calculation unit 3 calculates the rainfall intensity Rr by substituting the input average received power Pr and each parameter of each mesh MEs, r into the following radar equation (1). The rainfall intensity calculation unit 3 outputs the calculated rainfall intensity Rr as data to the attenuation correction term calculation unit 4, the rain accumulation unit 5, the composite attenuation determination processing unit 7, and the attenuation determination result processing unit 8.

The attenuation correction term calculation unit 4 calculates the attenuation correction term KIR by substituting the rainfall intensity Rr and the attenuation constant Ka into the following equation (2). The attenuation correction term calculation unit 4 outputs the calculated attenuation correction term KIR to the composite attenuation determination processing unit 7.

  The rainfall accumulation unit 5 accumulates the input rainfall intensity Rr in the range (distance) direction to calculate an integrated rainfall ZRr. The rainfall accumulation unit 5 outputs the calculated accumulated rainfall ZRr as data to the composite attenuation determination processing unit 7 and the attenuation determination result processing unit 8.

  The reference value / threshold setting unit 6 sets a reference value KIRst for the attenuation correction term KIR. The reference value KIRst of the attenuation correction term KIR is for determining the attenuation of the received power.

The reference value / threshold setting unit 6 sets a threshold Th _ZRr for the accumulated rainfall ZRr. The threshold Th _ZRr of the accumulated rainfall ZRr is used for determining whether the weather is fine or heavy rain.

The reference value / threshold setting unit 6 sets the threshold Th _Pr of the average received power Pr associated with the range number r. The average received power Pr decreases as the range number r increases. Thus, the threshold value Th _Pr average received power Pr is also set to decrease with range number r. Threshold Th _Pr average received power Pr is for determining the attenuation of the received power.

The reference value / threshold setting unit 6 outputs the reference value KIRst, the threshold Th _ZRr , and the threshold Th _Pr to the composite attenuation determination processing unit 7.

  The composite attenuation determination processing unit 7 performs an attenuation determination in combination from the attenuation correction term KIR, the accumulated rainfall ZRr, and the average received power Pr.

As shown in FIG. 3, the composite attenuation determination processing unit 7 determines whether or not the attenuation correction term KIR is greater than or equal to a reference value KIRst as basic determination processing. If the attenuation correction term KIR is equal to or greater than the reference value KIRst, the composite attenuation determination processing unit 7 determines that the received power is attenuated beyond the corresponding mesh MEs, r and is invalid. The composite attenuation determination processing unit 7 stores the range number r of the mesh MEs, r as the attenuation start range number _rst .

The combined attenuation determination processing unit 7 compares the accumulated rainfall ZRr of each mesh MEs, r in the same sector with the accumulated rainfall threshold Th _ZRr . If the integrated rainfall ZRr is larger than the threshold Th _ZRr , it means that there is a certain amount of rainfall. On the other hand, when the integrated rainfall ZRr is smaller than the threshold Th _ZRr , it means that the sky is clear.

As illustrated in FIG. 4, the composite attenuation determination processing unit 7 compares the average received power Pr of the same sector with the threshold Th _{Pr of the} average received power. When the average received power Pr is equal to or greater than the threshold Th _Pr , it is determined that the X rain data Dx of the X band radar 51 is valid. On the other hand, when the average received power Pr is equal to or less than the threshold Th _Pr , it is determined that the data of the X-band radar 51 of the mesh MEs, r farther than the mesh MEs, r is invalid. Then, the range number r of the mesh MEs, r is stored as the attenuation start range number _rst of the sector.

That is, in each sector, the composite attenuation determination processing unit 7 determines the range number r of the mesh closest to the X-band radar 51 among the meshes MEs, r whose attenuation correction term KIR is larger than the reference value KIRst, as the attenuation start range number r. Determine _st . Also, the composite attenuation determination processing unit 7 determines the range number r of the mesh closest to the X-band radar 51 as the attenuation start range number _rst among the meshes whose average received power Pr is smaller than the threshold Th _Pr in each sector. To do.

The attenuation determination result processing unit 8 is for correcting the attenuation start range number _rst . The attenuation determination result processing unit 8 uses the average received power Pr of the correction target mesh MEs, r _st whose range number r is the attenuation start range number r _st , as a comparison target mesh ME (s−1) adjacent in the sector direction. , r _st , ME (s + 1), r _st are compared with the average received power Pr. The average received powers Pr of the comparison target meshes ME (s−1), r _st , ME (s + 1), r _st are within a predetermined range (for example, within 10%), whereas the correction target meshes When the average received power Pr of MEs, r _st differs significantly (for example, 50%) from the average received power Pr of the meshes ME (s−1), r _st , ME (s + 1), r _st to be compared, corrected mesh MEs, determines that the average received power Pr of r _st has passed through the reflected waves from the gap heavy rain. As a result, the attenuation determination result processing unit 8 determines the attenuation start range number r _st of the comparison target sector numbers (s + 1) and (s−1) as the attenuation start range number r _st of the meshes MEs, r _{st to be} determined. _Is corrected as a new attenuation start range number _rst .

The attenuation map creation unit 9 creates an attenuation map based on the determination result of the composite attenuation determination processing unit 7. Here, the attenuation map associates the sector number s with the attenuation start range number _rst .

The synthesis processing unit 10 synthesizes the rain data Dx and Dc based on the attenuation map. Synthesis processing unit 10, the mesh MEs to attenuation start range number _{r st,} the r adopting X rainfall data Dx by X-band radar 51. On the other hand, the synthesis processing unit 10, attenuation start range number _{r st} beyond the mesh MEs, the r adopts a C rainfall data Dc of C-band radar 52.

  Next, a description will be given of the rain data synthesis process of the rain radar synthesis processing apparatus 1 according to the first embodiment described above. FIG. 5 is a flowchart for explaining the attenuation determination process of the synthesis process. FIG. 6 is a flowchart for explaining attenuation start range number correction processing of attenuation determination processing.

  First, in the rain data synthesis process, the attenuation determination process shown in FIG. 5 is started. In the attenuation determination process, the initial setting unit 2 initially sets and calculates each parameter (St1). Here, the parameters that are initially set are “sector number s (= 0)” that specifies the sector of mesh MEs, r, “range number r (= 0)” that specifies the range of mesh MEs, r, and the like. is there. The initial setting unit 2 calculates an average received power Pr that is one of the parameters. Then, the initial setting unit 2 outputs the average received power Pr in association with each mesh MEs, r.

  Next, the initial setting unit 2 increments the sector number s by “1” in the sector specifying process (St2).

  Next, the initial setting unit 2 initializes the attenuation correction term KIR and the accumulated rainfall ZRr (St3). Specifically, “KIR = 0” and “ZRr = 0” are set.

  Next, the initial setting unit 2 increments the range number r by “1” in the range specifying process (St4).

  Next, the rainfall intensity calculating unit 3 substitutes the average received power Pr and each parameter into the radar equation (1) to calculate the rainfall intensity Rr of the mesh MEs, r (St5). Thereafter, the rainfall intensity calculation unit 3 outputs the rainfall intensity Rr to the composite attenuation determination processing unit 7 and the attenuation determination result processing unit 8.

  Next, the attenuation correction term calculation unit 4 calculates the attenuation correction term KIR of the mesh MEs, r from the equation (2) using the rainfall intensity Rr and each parameter (St6). Thereafter, the attenuation correction term calculation unit 4 outputs the attenuation correction term KIR to the composite attenuation determination processing unit 7.

  Next, the rainfall accumulation unit 5 accumulates the rainfall intensity Rr to calculate the accumulated rainfall ZRr of the mesh MEs, r (St7). Thereafter, the rainfall accumulation unit 5 outputs the accumulated rainfall ZRr to the composite attenuation determination processing unit 7 and the attenuation determination result processing unit 8.

Next, the composite attenuation determination processing unit 7 compares the attenuation correction term KIR of the mesh MEs, r with the attenuation correction term reference value KIR _st . When “KIR> KIR _st ” (St8: Yes), the composite attenuation determination processing unit 7 determines that the X rainfall data Dx beyond the mesh MEs, r is invalid (see FIG. 3). The composite damping determination processing unit 7 proceeds to step St 12, the mesh MEs, stores the range number r of r as attenuation start range number _{r st.} On the other hand, if “KIR ≦ KIR _st ” (St8: No), the process proceeds to Step St9.

Next, the composite attenuation determination processing unit 7 compares the accumulated rainfall ZRr with the threshold Th _ZRr (St9). If “ZRr> Th _ZRr ” (St9: Yes), the composite attenuation determination processing unit 7 proceeds to Step St10. On the other hand, in the case of “ZRr ≦ Th _ZRr ” (St9: No), it means clear sky, and therefore the composite attenuation determination processing unit 7 proceeds to Step St11 without executing Step St10. Thereby, step St10 is not performed in fine weather mesh MEs, r.

Next, the composite attenuation determination processing unit 7 compares the average received power Pr with the threshold value Th _{Pr of the} range number r (St10). In the case of “Pr> Th _Pr ” (St10: Yes), the composite attenuation determination processing unit 7 determines that the X rain data Dx of the mesh MEs, r is valid, and proceeds to Step St11.

On the other hand, when “Pr ≦ Th _Pr ” (St10: No), the composite attenuation determination processing unit 7 determines that the X rain data Dx beyond the mesh MEs, r is invalid (see FIG. 4). The composite damping determination processing unit 7 proceeds to step St 12, the mesh MEs, stores the range number r of r as attenuation start range number _{r st.}

In step St 11, range number r is determined whether the maximum value _{r max.} If it is not the maximum value, the process returns to step St4, the range number r is incremented by "1", and the processes after step St5 are executed.

  On the other hand, when the process of step St12 is completed, it is not necessary to determine the attenuation of the mesh MEs, r farther in the same sector, so the process proceeds to step St13.

Next, in step St13, it is determined whether or not the sector number s is the maximum value s _max . When the sector number s is not the maximum value s _max (St13: No), the process returns to Step St2. Then, the sector number s is incremented by “1” in step St2, and the processing after step St3 is performed.

When the sector number s is the maximum value s _max (St13: Yes), since the determination of the entire measurement area 53 is completed, the process proceeds to step St14.

In step St 14, correction of the attenuation starting range number r _st shown in FIG. 6 is executed by the attenuation determination result processing unit 8.

  First, the attenuation determination result processing unit 8 sets the sector number s to “0” (St21). Thereafter, the sector number s is incremented by “1” (St22).

Next, the attenuation determination result processing unit 8, corrected mesh MEs, the compared adjacent to _{r st} and sector direction mesh ME (s + 1), the average received power of _{r st} Pr and mesh ME (s-1), comparing the average received power Pr of r _st. Mesh ME (s + 1), the average received power Pr and the mesh ME of _{r st} (s-1), and the average received power Pr of _{r st,} if mutually within a predetermined range (e.g., within 10%), in step St24 Proceed (St23: Yes). On the other hand, the mesh ME (s + 1), the average received power Pr and the mesh ME (s-1) of _{r st,} and the average received power Pr of _{r st,} if not within a predetermined range from each other, the process proceeds to step St27 (St23: No ).

Next, the attenuation determination result processing unit 8, the mesh ME (s + 1), the average received power Pr and the mesh ME of _{r st} (s-1), calculates the average Av of the average received power Pr of _{r st} (St24).

Next, the attenuation determination result processing unit 8 compares the corrected mesh MEs, and the average received power Pr of _{r st} and average Av. Corrected mesh MEs, the average received power Pr of _{r st} is be extremely larger than the average Av (e.g., if more than 50% greater), the process proceeds to step St26 (St25: Yes). This is extremely large correction target mesh MEs, the average received power of r _st Pr described above is due to the received power reflected wave is observed exits from the gap of strong rain, because the correction is deemed necessary is there. On the other hand, the correction target of the mesh MEs, the average received power Pr of _{r st} is within the predetermined range relative to the average Av, the process proceeds to step St27 (St25: No).

Next, in this case, the attenuation determination result processing unit 8 determines the average of the attenuation start range number r _st of the adjacent sector number (s + 1) and the sector number (s−1) as the correction target. to correct the attenuation start range number _{r st} of sector number s (St26).

Next, when the sector number s is not the maximum value s _max , the attenuation determination result processing unit 8 returns to Step St22 (St27: No), and the above-described processing after Step St22 is repeated. on the other hand,

Thereafter, the correction processing is performed in the attenuation start range number _{r st} of all sectors, the sector number s becomes the maximum value _{s max} (St27: Yes), the attenuation starting range number correction process is completed. Next, the attenuation determination result processing unit 8 outputs the corrected attenuation start range number _rst to the composite attenuation determination processing unit 7.

Next, the composite attenuation determination processing unit 7 outputs the attenuation start range number _rst to the attenuation map creating unit 9. Thereafter, the attenuation map generating unit 9 outputs to the combining processing unit 10 to create an attenuation map for correlating the attenuation start range number r _st and each sector (St15). As a result, the attenuation determination process ends.

Then, the synthesis processing unit 10, mesh MEs range number r of less than attenuation start range number _{r st,} the r by applying X rainfall data Dx in the X-band radar 51, the attenuation starting range number _{r st} range than The rain data is synthesized by applying the C rain data Dc of the C band radar 52 to the mesh MEs, r having a large number r.

  As a result, the synthesis process ends.

  A result of the above-described synthesis processing method will be described with reference to the drawings. FIG. 7 is a diagram illustrating a determination result by an attenuation determination process using only an attenuation correction term as a determination material. FIG. 8 is a diagram illustrating a determination result by the attenuation determination process according to the first embodiment using the attenuation correction term and the average received power as determination materials. FIG. 9 shows the measurement results of rainfall by the X-band radar. FIG. 10 shows the measurement results of rainfall by C-band radar. FIG. 11 shows the result of the synthesis processing method using only the conventional attenuation correction term. FIG. 12 shows the result of the synthesis processing method according to the first embodiment.

As shown in FIG. 7, when determining the attenuation start range number r _st only as a determination material attenuation correction term KIR, area (mesh) is the X rainfall data Dx in the X-band radar 51 is employed, shown in FIG. 8 larger than the region X rainfall data Dx in the X-band radar 51 when determining the attenuation start range number r _st the first embodiment is employed.

  However, when the X rain data Dx of the X band radar 51 shown in FIG. 9 and the C rain data Dc of the C band radar 52 shown in FIG. 10 are synthesized by a conventional synthesis method using only the attenuation correction term KIR as a judgment material. As shown in FIG. When the rainfall data Dx and Dc are synthesized by the conventional method, a blank portion 54 where the rainfall amount is “0” is displayed in spite of the rain (donut conversion). This is because the average received power Pr is reduced before the attenuation correction term KIR becomes equal to or greater than the reference value KIRst, and the rainfall intensity Rr is calculated as “0”. Thus, when the rainfall intensity Rr is calculated as “0”, it is determined that there is no attenuation because the attenuation term due to raindrops is not effective, and it is determined that the rainfall intensity Rr is “0”. This is because the above-described donut formation occurs. On the other hand, in the first embodiment, the attenuation correction term KIR and the average received power Pr are used as determination materials. Therefore, in the synthesis result according to the first embodiment shown in FIG. It can be seen that the accuracy is improved by suppression.

In FIG. 7, a slit-shaped effective region is formed on the inner side surrounded by a dotted circle 55. On the other hand, in the determination result according to the first embodiment shown in FIG. 8, the slit portion is an invalid area. Here, the slit region shown in FIG. 7 is considered to be a misjudgment based on the average received power observed when the reflected wave passes through the gap of heavy rain. In the first embodiment, since the correction of the attenuation start range number r _st by damping determination result processing unit being performed, it is determined that the slit region also invalid area. As a result, it can be seen that the X rain data Dx of the X band radar 51 can be suppressed from becoming radial.

As described above, in the rain radar synthesis processing apparatus 1 according to the first embodiment, the measurement region 53 is divided in the sector direction, and the attenuation start range number _rst is calculated for each sector number s. Also, precipitation radar synthesis processing apparatus 1, based on the attenuation correction term KIR and the average received power Pr, and determines the attenuation start range number r _st. For this reason, although there is rain, it is possible to improve the accuracy by suppressing donuts and the like where rain is displayed as “0”.

Also, precipitation radar synthesis processing apparatus 1 is provided with a damping determination result processing unit 8 for correcting the attenuation start range number r _st. Thereby, since erroneous determination due to heavy rain can be suppressed, it is possible to suppress the region where the X rain data Dx of the X band radar 51 is employed from becoming radiation.

In addition, the rain radar synthesis processing apparatus 1 decreases the threshold value Th _Pr of the average received power Pr as the range number r increases. As a result, even when the received power is attenuated at a short distance, such as when heavy rain falls directly above the X-band radar 51, it is possible to increase the area where the X rainfall data Dx is adopted.

  As mentioned above, although this invention was demonstrated in detail using embodiment, this invention is not limited to embodiment described in this specification. The scope of the present invention is determined by the description of the scope of claims and the scope equivalent to the description of the scope of claims. Hereinafter, modified embodiments in which the above-described embodiment is partially modified will be described.

  The numerical values and the like of the above-described embodiments can be changed as appropriate.

  In addition, a heavy rain occurrence frequency counting means for calculating the number of occurrences of heavy rain exceeding the threshold for each sector is provided, and the composite attenuation determination processing unit determines attenuation by comparing the occurrence frequency counted in the same sector with the threshold. May be performed. As an example, as shown in FIG. 13, when three or more meshes with heavy rain of 100 mm / h or more occur, the mesh range number is set as the attenuation start range number, and the X band of the mesh farther away. The radar rainfall data may be determined to be invalid.

  Alternatively, the moving average rainfall intensity between the rain intensity of the determination target mesh and the rain intensity of the mesh adjacent to the mesh in the radial direction may be calculated, and the attenuation determination may be performed based on the moving average rain intensity. As an example, the average of the rainfall intensity of the determination target mesh and the meshes before and after the mesh in the range direction may be used as a moving average rainfall intensity, and the moving average rainfall intensity may be compared with a threshold value to determine attenuation. .

  Further, the result of attenuation determination associated with the past average received power and range may be stored and used for determination. Specifically, the average reception power at the time of determination and the past attenuation determination result close to the range may be searched, and determination may be made based on the search result. In addition, using statistical methods, data mining, etc., the correlation between past attenuation determination results and average received power and range is stored in a database, and the average received power and range at the time of determination are determined using that database. Attenuation determination may be performed.

  In addition, the threshold setting unit estimates the rain pattern (guerrilla rain, typhoon, rain accompanying the front, etc.) from the surface rainfall conditions and time-series rainfall conditions in the observation range, and sets an appropriate threshold value in real time. You may comprise.

  Also, in the threshold setting unit, the correlation between the average received power and the range and the threshold is made into a database by statistical methods, data mining, etc., and the database is used to appropriately determine the average received power and range at the time of determination. A threshold value may be set in real time.

  Note that the above-described embodiments and modifications can be combined as appropriate.

DESCRIPTION OF SYMBOLS 1 Rain radar synthetic | combination processing apparatus 2 Initial setting part 3 Rain intensity calculation part 4 Attenuation correction term calculation part 5 Rain amount accumulation part 6 Reference value and threshold value setting part 7 Compound attenuation determination processing part 8 Attenuation determination result processing part 9 Attenuation map creation part 10 Compositing processing unit 51 X-band radar 52 C-band radar 53 Measurement area 54 Blank area 55 Correction area Dx X Rain data Dc C Rain data KIR Attenuation correction term KIR _st Attenuation correction term reference value Pr Average received power Th _Pr Average received power Threshold ZRr Accumulated rainfall Th _ZRr Accumulated rainfall threshold Rr Rain intensity MEs, r Mesh s Sector number r Range number r _st Attenuation start range number

Claims (4)

In a rain radar synthesizer for synthesizing rain data of X-band radar and rain data of long-wavelength band radar that uses radio waves having a longer wavelength than X-band radar,
Initial setting means for calculating the average received power of each mesh obtained by dividing the measurement region of the X-band radar into a plurality of sector directions and a plurality of range directions;
An attenuation correction term calculating means for calculating an attenuation correction term based on the average received power;
In each sector, among the meshes whose attenuation correction term is larger than the reference value, the range number of the mesh closest to the X-band radar is determined as the attenuation start range number, and the average received power is greater than the average received power threshold. Compound attenuation determination means for determining a range number of a mesh closest to the X-band radar among small meshes as an attenuation start range number;
A rain radar synthesis processing apparatus comprising: synthesis processing means for synthesizing rain data based on the attenuation start range number. A rain accumulation means for calculating the accumulated rainfall is provided,
2. The composite attenuation determination means compares the average received power with the average received power threshold only when the integrated rainfall is larger than an integrated rainfall threshold for determining clear rain. Rain radar synthesis processor.   The average received power of the mesh of the attenuation start range number is larger than the average received power of the mesh adjacent in the sector direction, and the average received power of the meshes adjacent in the sector direction is within the predetermined range. 3. The rain radar synthesis processing apparatus according to claim 1, further comprising attenuation determination result processing means for correcting the attenuation start range number in some cases. In the same sector, it is provided with a heavy rain occurrence frequency counting means for counting the number of heavy rain occurrence times where heavy rain has occurred,
The composite attenuation determination means determines the range number of the mesh closest to the X-band radar among the meshes having the number of occurrences of heavy rain equal to or greater than a threshold value as the attenuation start range number. The rain radar synthesis processing apparatus according to any one of items 3 to 4.