Rainfall intensity estimation device and rainfall intensity estimation program

Abstract

To simplify a radar type radio rain gauge for downsizing and cost reduction, as well as heighten the accuracy of calculating a rain attenuation amount in a reciprocal path of a rainfall region between the radar type radio rain gauge and each position, heighten the accuracy of correcting reflection intensity from rainfall at each position, and heighten the accuracy of estimating the rainfall intensity of rainfall at each position.SOLUTION: The present disclosure subtracts the intensity of reflection from a reference reflection object R at a "rainfall time" from the intensity of reflection from the reference reflection object R at a "fine weather time", and calculates a rain attenuation amount (reference rain attenuation amount) in the reciprocal path of a rainfall region between a radar type radio rain gauge 1 and the reference reflection object R. It then calculates, taking the reference rain attenuation amount as an "upper limit," a rain attenuation amount (rain attenuation amount at each position) in a reciprocal path in the rainfall region between the radar type radio rain gauge 1 and each position located in a "near distance" as compared with the reference reflection object R.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a technique for estimating rainfall intensity using a radar-type radio rain gauge. [Background technology]

[0002] Technologies for estimating rainfall intensity using a radar radio rain gauge are disclosed in Patent Document 1 and Non-Patent Documents 1 and 2, etc. Here, the reflection intensity from rainfall at each position is affected by the amount of rain attenuation (the amount of rain at each position) on the round trip path of the rainfall area between the radar radio rain gauge and each position. Therefore, Patent Document 1 and Non-Patent Documents 1 and 2 add the amount of rain at each position to the reflection intensity from rainfall at each position to correct the reflection intensity from rainfall at each position. Then, the rainfall intensity of rainfall at each position is estimated based on the relationship between the reflection intensity and the rainfall intensity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-208195 A [Non-patent literature]

[0004] [Non-Patent Document 1] Hitschfeld, W., & Bordan, J. (1954). Errors inherent in the radar measurement of rainfall at attenuating wavelengths. JAS, 11(1), 58-67. [Non-Patent Document 2] Gorgucci, E., & Chandrasekar, V. (2005). Evaluation of attenuation correction methodology for dual-polarization radars: Application to X-band systems. JTECH, 22(8), 1195-1206. Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, when calculating the rain attenuation at each location, the rain attenuation is accumulated on the round trip path of the rain area near each location, starting from a short distance and moving to a long distance. However, the longer the distance and the higher the frequency used, the larger the accumulation error of the rain attenuation becomes. Therefore, the accuracy of the correction of the reflection intensity decreases, and the accuracy of the estimation of the rain intensity decreases.

[0006] In Non-Patent Document 1, when calculating the rain attenuation at each position, the rain attenuation is not integrated one by one as in Patent Document 1, but a differential equation modeled on Patent Document 1 is solved. However, the larger the rain attenuation is, the more likely the solution is to diverge, and the larger the calculation error of the rain attenuation becomes. This reduces the correction accuracy of the reflection intensity and the estimation accuracy of the rain intensity.

[0007] In Non-Patent Document 2, when calculating the rain attenuation at each position, the reception phase difference between orthogonal polarized waves due to the shape of the raindrop is measured. This improves the accuracy of correcting the reflection intensity and the accuracy of estimating the rainfall intensity. However, this makes the radar-type radio rain gauge more complicated, larger, and more expensive.

[0008] Therefore, in order to solve the above problems, the present disclosure aims to simplify, miniaturize, and reduce the cost of a radar-type radio rain gauge, as well as to increase the calculation accuracy of rain attenuation on the round-trip path of the rainfall area between the radar-type radio rain gauge and each location, to increase the correction accuracy of the reflection intensity from rainfall at each location, and to increase the estimation accuracy of the rainfall intensity of rainfall at each location. [Means for solving the problem]

[0009] To solve the above problem, the reflection intensity from a reference reflector "during rainfall" is subtracted from the reflection intensity from the reference reflector "during fine weather" to calculate the rain attenuation (reference rain attenuation) on the round trip path in the rain area between the radar radio rain gauge and the reference reflector. Then, the rain attenuation (rain attenuation at each position) on the round trip path in the rain area between the radar radio rain gauge and each position that is "closer" than the reference reflector is calculated, with the reference rain attenuation being set as the "upper limit."

[0010] Specifically, the present disclosure relates to a rainfall intensity estimation device that estimates rainfall intensity using a radar radio rain gauge, the rainfall intensity estimation device including a reference rain attenuation calculation unit that subtracts a reflection intensity from a reference reflector during rainfall from a reflection intensity from the reference reflector during fine weather to calculate rain attenuation (reference rain attenuation) on a round trip path in a rainy area between the radar radio rain gauge and the reference reflector, and a reference rain attenuation calculation unit that calculates a reference rain attenuation between the radar radio rain gauge and the reference reflector, the reference rain attenuation calculated by the reference rain attenuation calculation unit being set as an upper limit. This rain intensity estimation device is characterized by comprising: an each-position rain attenuation calculation unit that calculates the rain attenuation (each-position rain attenuation) on a round-trip path of a rainfall area between each position that is closer to the reference reflector than the reference reflector; and a rain intensity estimation unit that adds the each-position rain attenuation calculated by the each-position rain attenuation calculation unit to the reflection intensity from the rain at each position, corrects the reflection intensity from the rain at each position, and estimates the rain intensity of the rain at each position based on the relationship between the reflection intensity and the rain intensity.

[0011] According to this configuration, the rain attenuation amount at each position is calculated using the reference rain attenuation amount as the upper limit, so the rain attenuation amount at each position is not overcalculated, the reflection intensity is not overcorrected, and the rain intensity is not estimated to be an abnormal value. Furthermore, since it is not necessary to measure the reception phase difference between orthogonal polarized waves due to the shape of the raindrop when calculating the rain attenuation amount at each position, the radar type radio wave rain gauge can be simplified, miniaturized, and reduced in cost.

[0012] The present disclosure also relates to a rain intensity estimation device, characterized in that the each-position rain attenuation calculation unit divides the reference rain attenuation calculated by the reference rain attenuation calculation unit by the rain range of the rain area between the radar radio rain gauge and the reference reflector to calculate the reference rain attenuation per unit distance, and calculates the each-position rain attenuation.

[0013] According to this configuration, when the rainfall area between the radar radio rain gauge and the reference reflector is uniform and the rainfall is light, the rain attenuation at each position can be calculated easily.

[0014] The present disclosure also provides a rain intensity estimation device that further includes a rain attenuation accumulation unit that estimates the amount of rain attenuation in a round trip path of the rain area near each position at a closer distance based on the reflection intensity from rain at each position at a closer distance, estimates the reflection intensity from rain at each position at a farther distance, repeats the same process as for the short distance for the farther distance, accumulates the amount of rain attenuation in a round trip path of the rain area near each position at the close distance and the farther distance, and estimates the reference rain attenuation amount and the rain attenuation amount for each position, wherein the each position rain attenuation calculation unit calculates a correction amount for the rain attenuation amount for each position estimated by the rain attenuation accumulation unit, with the difference amount between the reference rain attenuation amount calculated by the reference rain attenuation calculation unit and the reference rain attenuation amount estimated by the rain attenuation accumulation unit as an upper limit.

[0015] According to this configuration, even when the rainfall area between the radar radio rain gauge and the reference reflector is non-uniform or there is a lot of rain, the rain attenuation at each position can be calculated with high accuracy.

[0016] The present disclosure also relates to a rainfall intensity estimation device, characterized in that the standard rain attenuation calculation unit calculates the standard rain attenuation by subtracting the reflection intensity from the reference reflector during rainfall and the atmospheric attenuation on a round-trip path in a clear-weather area between the radar-type radio rain gauge and the reference reflector from the reflection intensity from the reference reflector during clear weather.

[0017] According to this configuration, even when both rainfall areas and clear weather areas are distributed between the radar radio wave rain gauge and the reference reflector, the rain attenuation amount at each position can be calculated with high accuracy.

[0018] The present disclosure also relates to a rain intensity estimation device, characterized in that, when allocating the reference rain attenuation calculated by the reference rain attenuation calculation unit as rain attenuation on a round trip path of multiple divided rain areas between the radar type radio rain gauge and the reference reflector, the reference rain attenuation estimated by its own processing unit based on the reflection intensity from rain at each position corrected by the rain intensity estimation unit is equal to the reference rain attenuation calculated by the reference rain attenuation calculation unit.

[0019] With this configuration, even when multiple separate rainfall areas are distributed between the radar radio rain gauge and the reference reflector, the reference rain attenuation amount calculated using a single reference reflector can be distributed among the multiple separate rainfall areas, making it possible to calculate the rain attenuation amount at each position with high accuracy.

[0020] The present disclosure also relates to a rainfall intensity estimation device, wherein the standard rain attenuation calculation unit subtracts the reflection intensity from the reference reflector located at a closer distance during rainfall from the reflection intensity from the reference reflector located at a closer distance during fine weather, thereby calculating the standard rain attenuation between the radar radio rain gauge and a position at the closer distance, and the standard rain attenuation calculation unit subtracts the reflection intensity from the reference reflector located at a farther distance during rainfall from the reflection intensity from the reference reflector located at a farther distance during fine weather, thereby calculating the standard rain attenuation between the radar radio rain gauge and the position at the farther distance.

[0021] With this configuration, even when multiple separate rainfall areas are distributed between the radar radio rain gauge and the reference reflector, the rain attenuation at each position can be calculated with high accuracy based on the reference rain attenuation calculated using multiple reference reflectors (located between multiple rainfall areas).

[0022] The present disclosure also provides a rainfall intensity estimation program for causing a computer to sequentially execute the processing steps executed by each processing unit included in the rainfall intensity estimation device described above.

[0023] According to this configuration, it is possible to provide a program having the above-described effects.

[0024] The above disclosed inventions can be combined to the greatest extent possible. Effect of the Invention

[0025] In this way, the present disclosure can simplify, miniaturize, and reduce the cost of radar-type radio rain gauges, while increasing the calculation accuracy of rain attenuation on the round-trip path of the rainfall area between the radar-type radio rain gauge and each location, increasing the correction accuracy of the reflection intensity from rainfall at each location, and increasing the estimation accuracy of the rainfall intensity of rainfall at each location. [Brief description of the drawings]

[0026] [Figure 1] FIG. 2 is a diagram showing the installation positions of the weather radar system and a reference reflector according to the present disclosure. [Diagram 2] FIG. 1 is a diagram illustrating a configuration of a weather radar system according to the present disclosure. [Diagram 3] FIG. 2 is a diagram showing the procedure of the rainfall intensity estimation process of the present disclosure. [Figure 4] FIG. 13 is a diagram showing a rainfall intensity estimation process using linear correction according to the present disclosure. [Diagram 5] 1 is a diagram showing a rainfall intensity estimation process by integrating rain attenuation according to the present disclosure; [Figure 6] FIG. 13 is a diagram showing a rainfall intensity estimation process by subtracting atmospheric attenuation according to the present disclosure. [Figure 7] 11 is a diagram showing a rainfall intensity estimation process based on allocation of reference rain attenuation according to the present disclosure; FIG. [Figure 8] FIG. 2 illustrates the multiple reference reflector rain rate estimation process of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of the present disclosure, and the present disclosure is not limited to the following embodiments.

[0028] (Configuration of the weather radar system disclosed herein) The installation positions of the weather radar system and the reference reflector of the present disclosure are shown in Fig. 1. Here, the reflection intensity from rainfall P at each position is affected by the amount of rain attenuation on the round trip path of the rainfall area between the weather radar system M and each position (the amount of rain attenuation at each position). Therefore, the amount of rain attenuation at each position is added to the reflection intensity from rainfall P at each position to correct the reflection intensity from rainfall P at each position. Then, based on the relationship between the reflection intensity and the rainfall intensity, the rainfall intensity of rainfall P at each position is estimated.

[0029] In the present disclosure, the reflection intensity from the reference reflector R "during rainfall" is subtracted from the reflection intensity from the reference reflector R "during fine weather" to calculate the rain attenuation (reference rain attenuation) on the round trip path in the rainfall area between the weather radar system M and the reference reflector R. Then, the rain attenuation (rain attenuation at each position) on the round trip path in the rainfall area between the weather radar system M and each position that is "close" compared to the reference reflector R is calculated using the reference rain attenuation as the "upper limit".

[0030] In the present disclosure, when calculating the rain attenuation amount at each position, the reference rain attenuation amount is set as the "upper limit", so that the rain attenuation amount at each position is not "over-calculated", the reflection intensity is not "over-corrected", and the rain intensity is not estimated to be an "abnormal value". Therefore, the calculation accuracy of the rain attenuation amount at each position can be improved, the correction accuracy of the reflection intensity can be improved, and the estimation accuracy of the rain intensity can be improved. Furthermore, when calculating the rain attenuation amount at each position, there is no need to measure the reception phase difference "between orthogonal polarizations" due to the shape of the raindrop, so the weather radar system M can be simplified, miniaturized, and reduced in cost.

[0031] In this disclosure, taking into consideration that the calculation error of the rain attenuation amount at each location increases as the distance from the weather radar system M increases (see Patent Document 1 in particular), a reference reflector R (e.g., a newly installed corner reflector or an existing mountain or tower, etc.) is installed at a long distance from the weather radar system M (e.g., the maximum observation distance in all azimuth directions, etc.).

[0032] The configuration of the weather radar system of the present disclosure is shown in Fig. 2. The procedure of the rainfall intensity estimation process of the present disclosure is shown in Fig. 3. The weather radar system M includes a radar radio rain gauge 1 and a rainfall intensity estimation device 2. The rainfall intensity estimation device 2 includes a reference rain attenuation calculation unit 21, a position-specific rain attenuation calculation unit 22, a rainfall intensity estimation unit 23, and a rain attenuation integration unit 24, and can be realized by installing the rainfall intensity estimation program shown in Fig. 3 in a computer.

[0033] The reference rain attenuation calculation unit 21 subtracts the reflection intensity from the reference reflector R during rainfall from the reflection intensity from the reference reflector R during fine weather, and calculates the rain attenuation (reference rain attenuation) on a round trip path in the rainy region between the radar radio rain gauge 1 and the reference reflector R (steps S1, S2). Here, the reflection intensity from the reference reflector R during fine weather is measured in advance.

[0034] The position-specific rain attenuation calculation unit 22 calculates the rain attenuation (position-specific rain attenuation) on a round trip path in the rain area between the radar radio rain gauge 1 and each position that is closer to the reference reflector R, with the reference rain attenuation calculated by the reference rain attenuation calculation unit 21 as the upper limit (step S3). Here, the details of the process by the position-specific rain attenuation calculation unit 22 will be described with reference to Figs. 4 to 8.

[0035] The rainfall intensity estimation unit 23 adds the rain attenuation at each position calculated by the rain attenuation at each position calculation unit 22 to the reflection intensity from the rainfall P at each position, corrects the reflection intensity from the rainfall P at each position, and estimates the rainfall intensity of the rainfall P at each position based on the relationship between the reflection intensity and the rainfall intensity (steps S4 and S5). Here, the relationship between the reflection intensity Z and the rainfall intensity R is expressed as R=B×Z β Or Z = B × R β(B and β are determined by the raindrop distribution and rainfall conditions) holds.

[0036] (Rainfall intensity estimation process by linear correction according to the present disclosure) The rainfall intensity estimation process by linear correction according to the present disclosure is shown in Fig. 4. In the upper part of Fig. 4, the radar-type radio rain gauge 1 estimates the rainfall intensity at distances 0 to r based on the reflection intensity from rainfall P at each position. 1 and distance r 1 ~r 3 It is estimated that sunny areas and rainy areas are distributed in each of the above.

[0037] Distance r 1 At this point, the observed reflection intensity is Z m (r 1 ) [dB] and the distance r 2 At this point, the observed reflection intensity is Z m (r 2 ) [dB] and the distance r 1 ~r 3 As the distance increases, the observed reflection intensity decreases. 3 A reference reflector R is placed at

[0038] The reference rain attenuation calculation unit 21 subtracts the reflection intensity from the reference reflector R during rainfall from the reflection intensity from the reference reflector R during fine weather, and calculates the rain attenuation (reference rain attenuation) K on the round trip path in the rainy region between the radar-type radio rain gauge 1 and the reference reflector R. ref Calculate [dB].

[0039] In the lower part of FIG. 4, the rain attenuation calculation unit 22 calculates the reference rain attenuation K ref [dB] is the rainfall range r between the radar rain gauge 1 and the reference reflector R 3 -r 1 Divide by [km] to get the standard rain attenuation per unit distance K = K ref / (r 3 -r 1 ) [dB / km] and calculate the rain attenuation at each location.

[0040] Distance r1 At each location, the rain attenuation is 0 dB, and the distance r 2 At each location, the rain attenuation is K p =K(r 2 -r 1 )={K ref / (r 3 -r 1 )}(r 2 -r 1 ) [dB] and the distance r 3 At each position, the rain attenuation is the upper limit of the reference rain attenuation K ref [dB].

[0041] The rainfall intensity estimation unit 23 adds the rain attenuation at each position calculated by the rain attenuation at each position calculation unit 22 to the reflection intensity from the rainfall P at each position, and corrects the reflection intensity from the rainfall P at each position.

[0042] Distance r 1 The corrected reflection intensity is Z(r 1 )=Z m (r 1 ) [dB] and the distance r 2 The corrected reflection intensity is Z(r 2 )=Z m (r 2 )+K p [dB] and the distance r 3 The correction width of the reflection intensity is the upper limit of the standard rain attenuation K ref [dB]. Distance r 3 Even at long distances, the distance r 3 As with close range, linear correction is possible.

[0043] In this way, when the rainfall area between the radar radio wave rain gauge 1 and the reference reflector R is uniform and the rainfall is light, the rain attenuation at each position can be calculated easily.

[0044] (Rainfall intensity estimation process by accumulating rain attenuation according to the present disclosure) The rainfall intensity estimation process by integrating rain attenuation according to the present disclosure is shown in Fig. 5. In the upper part of Fig. 5, the radar-type radio rain gauge 1 estimates the rainfall intensity at distances 0 to r based on the reflection intensity from rainfall P at each position.1 and distance r 1 ~r 3 It is estimated that sunny areas and rainy areas are distributed in each of the above.

[0045] Distance r 1 At this point, the observed reflection intensity is Z m (r 1 ) [dB] and the distance r 2 At this point, the observed reflection intensity is Z m (r 2 ) [dB] and the distance r 1 ~r 3 As the distance increases, the observed reflection intensity decreases. 3 A reference reflector R is placed at

[0046] The reference rain attenuation calculation unit 21 subtracts the reflection intensity from the reference reflector R during rainfall from the reflection intensity from the reference reflector R during fine weather, and calculates the rain attenuation (reference rain attenuation) K on the round trip path in the rainy region between the radar-type radio rain gauge 1 and the reference reflector R. ref Calculate [dB].

[0047] In the middle part of Fig. 5, the rain attenuation integrating unit 24 estimates the rain attenuation in the round trip path of the rain area near each position at a closer distance based on the reflection intensity from the rain P at each position at a closer distance, and estimates the reflection intensity from the rain P at each position at a farther distance. Then, for the farther distance, the same process as for the near distance is repeated to integrate the rain attenuation in the round trip path of the rain area near each position at the near distance and the farther distance, and estimate the reference rain attenuation and the rain attenuation at each position. In the middle part of Fig. 5, the rain attenuation integration in Patent Document 1 is applied, but as a modification, the modeled differential equation in Non-Patent Document 1 may be applied.

[0048] Distance r 1 At each location, the rain attenuation is 0 dB, and the distance r 2 At each location, the rain attenuation is K p ' [dB] and the distance r 3 In this case, the reference rain attenuation is K ref'[dB]. Distance r 1 The integrated reflected light intensity is Z'(r 1 )=Z m (r 1 ) [dB] and the distance r 2 The integrated reflected light intensity is Z'(r 2 )=Z m (r 2 )+K p ' [dB] and the distance r 3 The correction width of the reflection intensity is the upper limit of the standard rain attenuation K ref 'Equals [dB].

[0049] In the lower part of FIG. 5, the rain attenuation calculation unit 22 calculates the reference rain attenuation K ref [dB] and the reference rain attenuation K estimated by the rain attenuation integrator 24. ref '[dB] and the difference between K ref -K ref The rain attenuation integrating unit 24 calculates a correction amount for the rain attenuation at each position estimated with an upper limit of 1 / 100 [dB].

[0050] Distance r 1 At each position, the correction amount for rain attenuation is 0 [dB], and at distance r 2 In this case, the correction amount for the rain attenuation at each position is K p "={(K ref -K ref ') / (r 3 -r 1 )}(r 2 -r 1 ) [dB] and the distance r 3 The correction amount for the rain attenuation at each position is the difference K between the upper limit reference rain attenuation. ref -K ref 'Equals [dB].

[0051] The rainfall intensity estimation unit 23 adds the rain attenuation at each position calculated by the rain attenuation at each position calculation unit 22 to the reflection intensity from the rainfall P at each position, and corrects the reflection intensity from the rainfall P at each position.

[0052] Distance r 1The corrected reflection intensity is Z(r 1 )=Z m (r 1 ) [dB] and the distance r 2 The corrected reflection intensity is Z(r 2 )=Z'(r 2 )+K p "=Z m (r 2 )+K p '+K p ” [dB] and the distance r 3 The correction range of the reflection intensity is (upper limit of the standard rain attenuation K ref '[dB])+(Difference between upper limit reference rain attenuation K ref -K ref '[dB]) = (Upper limit reference rain attenuation K ref [dB]) (see each row in Figure 5).

[0053] In this way, even when the rainfall area between the radar radio rain gauge 1 and the reference reflector R is non-uniform or there is a lot of rain, the rain attenuation at each position can be calculated with high accuracy.

[0054] (Rainfall intensity estimation process by subtracting atmospheric attenuation according to the present disclosure) The rainfall intensity estimation process by subtracting the amount of atmospheric attenuation according to the present disclosure is shown in Fig. 6. In the upper part of Fig. 6, the radar-type radio rain gauge 1 estimates the rainfall intensity at distances 0 to r based on the reflection intensity from rainfall P at each position. 1 , distance r 1 ~r 2 and distance r 2 ~r 3 It is estimated that the clear weather area, the rainy area, and the clear weather area are distributed in the distance r 1 ~r 2 As the distance increases, the observed reflection intensity decreases. 3 In the clear sky area, a reference reflector R is installed.

[0055] The reference rain attenuation calculation unit 21 calculates the reference rain attenuation by subtracting the reflection intensity from the reference reflector R during rainfall and the atmospheric attenuation on the round-trip path in the clear weather area between the radar radio rain gauge 1 and the reference reflector R from the reflection intensity from the reference reflector R during clear weather.

[0056] The difference between the reflection intensity from the reference reflector R on a clear day and the reflection intensity from the reference reflector R on a rainy day is K ref [dB] and the distance from 0 to r 1 At , the atmospheric attenuation is K 1 [dB] and the distance r 2 ~r 3 At , the atmospheric attenuation is K 3 [dB] and the distance r 1 ~r 2 In this case, the reference rain attenuation is K ref -K 1 -K 3 Here, the atmospheric attenuation can be calculated based on the radar frequency and the round-trip propagation distance, without the need for observation.

[0057] In the lower part of FIG. 6, the rain attenuation calculation unit 22 calculates the rain attenuation at each position, with the reference rain attenuation calculated by the reference rain attenuation calculation unit 21 as the upper limit.

[0058] Distance r 1 At each location, the rain attenuation is 0 dB, and the distance r 2 At each position, the rain attenuation is the upper limit of the reference rain attenuation K ref -K 1 -K 3 [dB], and the distance r 1 ~r 2 At each location, the rain attenuation is 0 to K ref -K 1 -K 3 [dB]. Distance r 1 ~r 2 In the above, the rain attenuation at each position can be calculated using the process shown in Figs.

[0059] In this way, even when both rainfall areas and clear weather areas are distributed between the radar radio wave rain gauge 1 and the reference reflector R, the rain attenuation at each position can be calculated with high accuracy.

[0060] (Rainfall intensity estimation process based on allocation of reference rain attenuation amount according to the present disclosure) The rainfall intensity estimation process based on the allocation of the reference rain attenuation amount according to the present disclosure is shown in Fig. 7. In the upper part of Fig. 7, the radar type radio rain gauge 1 estimates the rainfall intensity at distances 0 to r based on the reflection intensity from rainfall P at each position. 1 , distance r 1 ~r 2 , distance r 2 ~r 3 , distance r 3 ~r 4 and distance r 4 ~r 5 It is estimated that the clear sky area, the rainy area, the clear sky area, the rainy area, and the clear sky area are distributed in the distance r 1 ~r 2 and distance r 3 ~r 4 As the distance increases, the observed reflection intensity decreases. 5 A reference reflector R is installed in the upper part of Fig. 7. Although the amount of atmospheric attenuation in the clear sky region is not calculated, as a modified example, the amount of atmospheric attenuation in the clear sky region may be calculated.

[0061] The reference rain attenuation calculation unit 21 subtracts the reflection intensity from the reference reflector R during rainfall from the reflection intensity from the reference reflector R during fine weather to obtain the reference rain attenuation K ref Calculate [dB].

[0062] The rain attenuation calculation unit 22 calculates the reference rain attenuation K ref [dB] is allocated as the amount of rain attenuation on the round trip path of the multiple divided rain areas between the radar type radio rain gauge 1 and the reference reflector R (the allocation ratio is unknown).

[0063] Here, the rain attenuation amount calculation unit 22 for each position estimates the reference rain attenuation amount based on the reflection intensity from the rain P at each position corrected by the rainfall intensity estimation unit 23, and calculates the reference rain attenuation amount K ref [dB] should be equal to

[0064] In the middle part of Figure 7, the distance r 1 ~r 2 In the original standard rain attenuation K ref K in [dB] ref1 [dB] is assigned and the distance r 3 ~r 4 In the original standard rain attenuation K ref K in [dB] ref2 =K ref -K ref1 [dB] is assigned. Distance r 1 At each location, the rain attenuation is 0 dB, and the distance r 2 At each location, the rain attenuation is the upper limit of the rain attenuation K ref1 [dB], and the distance r 1 ~r 2 At each location, the rain attenuation is 0 to K ref1 [dB]. Distance r 3 At each location, the rain attenuation is K ref1 [dB] and the distance r 4 At each position, the rain attenuation is the upper limit of the reference rain attenuation K ref [dB], and the distance r 3 ~r 4 At each location, the rain attenuation is K ref1 ~K ref [dB]. Distance 0~r 5 The estimated reference rain attenuation is K ref "(>The original K ref ) [dB], and the original standard rain attenuation K ref It is presumed that the [dB] allocation ratio was incorrect.

[0065] In the lower part of Fig. 7, the distance r 1 ~r 2 In the original standard rain attenuation K refK in [dB] ref1 '[dB] is assigned and the distance r 3 ~r 4 In the original standard rain attenuation K ref K in [dB] ref2 '=K ref -K ref1 '[dB] is assigned. Distance r 1 At each location, the rain attenuation is 0 dB, and the distance r 2 At each location, the rain attenuation is the upper limit of the rain attenuation K ref1 ' [dB] is equal to the distance r 1 ~r 2 At each location, the rain attenuation is 0 to K ref1 '[dB]. Distance r 3 At each location, the rain attenuation is K ref1 ' [dB] and the distance r 4 At each position, the rain attenuation is the upper limit of the reference rain attenuation K ref [dB], and the distance r 3 ~r 4 At each location, the rain attenuation is K ref1 '~K ref [dB]. Distance 0~r 5 The estimated reference rain attenuation is K ref (=The original K ref ) [dB], and the original standard rain attenuation K ref The allocation ratio of [dB] is presumed to be correct.

[0066] In this way, even when multiple separate rainfall areas are distributed between the radar-type radio wave rain gauge 1 and the reference reflector R, the reference rain attenuation amount calculated using a single reference reflector R can be distributed to the multiple separate rainfall areas, and the rain attenuation amount at each position can be calculated with high accuracy.

[0067] (Rainfall intensity estimation process using multiple reference reflectors according to the present disclosure) The rainfall intensity estimation process using multiple reference reflectors according to the present disclosure is shown in Fig. 8. In the upper part of Fig. 8, the radar-type radio rain gauge 1 estimates the rainfall intensity at distances 0 to r based on the reflection intensity from rainfall P at each position. 1 , distance r 1 ~r2 , distance r 2 ~r 4 , distance r 4 ~r 5 and distance r 5 ~r 6 It is estimated that the clear sky area, the rainy area, the clear sky area, the rainy area, and the clear sky area are distributed in the distance r 1 ~r 2 and distance r 4 ~r 5 As the distance increases, the observed reflection intensity decreases. 3 , r 6 Reference reflectors R' and R are installed in the upper part of Fig. 8. Although the atmospheric attenuation in the clear weather region is not calculated, as a modified example, the atmospheric attenuation in the clear weather region may be calculated.

[0068] The reference rain attenuation calculation unit 21 calculates the distance r 3 From the reflection intensity from the reference reflector R' at 3 The reflection intensity from the reference reflector R' at the distance r is subtracted, and the distance from the radar type radio rain gauge 1 to the 3 The reference rain attenuation K between the position ref3 Calculate [dB].

[0069] The reference rain attenuation calculation unit 21 calculates the distance r 6 From the reflection intensity from the reference reflector R at distance r during rainfall, 6 The reflection intensity from the reference reflector R at the distance r is subtracted, and the radar type radio rain gauge 1 and the distance r are calculated. 6 The reference rain attenuation K between the position ref6 Calculate [dB].

[0070] In the lower part of FIG. 8, the rain attenuation calculation unit 22 calculates the rain attenuation at each position, with the reference rain attenuation calculated by the reference rain attenuation calculation unit 21 as the upper limit.

[0071] Distance r 1 At each location, the rain attenuation is 0 dB, and the distance r 2 At each position, the rain attenuation is the upper limit of the reference rain attenuation K ref3[dB](distance r 3 (observed at a reference reflector R' at distance r 1 ~r 2 At each location, the rain attenuation is 0 to K ref3 [dB]. Distance r 4 At each location, the rain attenuation is K ref3 [dB] and the distance r 5 At each position, the rain attenuation is the upper limit of the reference rain attenuation K ref6 [dB](distance r 6 (observed at a reference reflector R at 4 ~r 5 At each location, the rain attenuation is K ref3 ~K ref6 [dB].

[0072] In this way, even when multiple separate rainfall areas are distributed between the radar radio rain gauge 1 and the reference reflector R, the rain attenuation amount at each position can be calculated with high accuracy based on the reference rain attenuation amount calculated using multiple reference reflectors R, R' (located between multiple rainfall areas). [Industrial Applicability]

[0073] The rainfall intensity estimation device and rainfall intensity estimation program disclosed herein can simplify, miniaturize, and reduce the cost of radar-type radio rain gauges, while increasing the calculation accuracy of rain attenuation on the round-trip path of the rainfall area between the radar-type radio rain gauge and each location, increasing the correction accuracy of the reflection intensity from rainfall at each location, and increasing the estimation accuracy of the rainfall intensity of rainfall at each location. [Explanation of symbols]

[0074] M: Weather radar system R, R': Reference reflective object P:Rainfall 1: Radar-type radio rain gauge 2: Rainfall intensity estimation device 21: Reference rain attenuation calculation unit 22: Rainfall attenuation calculation section for each position 23: Rainfall intensity estimation part 24: Rain attenuation integrator

Claims

1. A rainfall intensity estimation device that estimates rainfall intensity using a radar-type radio wave rain gauge, a reference rain attenuation calculation unit that calculates rain attenuation (reference rain attenuation) on a round trip path in a rainy area between the radar-type radio wave rain gauge and the reference reflector by subtracting a reflection intensity from the reference reflector when it is raining from a reflection intensity from the reference reflector when it is sunny; a rain attenuation calculation unit for calculating rain attenuation (rain attenuation at each position) on a round trip path in a rain area between the radar radio wave rain gauge and each position that is closer to the reference reflector than the reference rain attenuation calculated by the reference rain attenuation calculation unit, with the reference rain attenuation calculated by the reference rain attenuation calculation unit being used as an upper limit; a rain intensity estimation unit that adds the rain attenuation at each position calculated by the rain attenuation at each position calculation unit to the reflection intensity from the rain at each position, corrects the reflection intensity from the rain at each position, and estimates the rain intensity of the rain at each position based on the relationship between the reflection intensity and the rain intensity; A rainfall intensity estimation device comprising:

2. The rain attenuation calculation unit for each position divides the reference rain attenuation calculated by the reference rain attenuation calculation unit by a rain range of a rain area between the radar radio wave rain gauge and the reference reflecting object to calculate the reference rain attenuation per unit distance, thereby calculating the rain attenuation for each position. The rainfall intensity estimating device according to claim 1 .

3. a rain attenuation integrating unit which estimates the amount of rain attenuation in a round trip path of the rain area near each of the closer positions based on the reflection intensity from the rain at each of the closer positions, estimates the reflection intensity from the rain at each of the farther positions, repeats the same process as for the closer position for the farther positions, integrates the amount of rain attenuation in a round trip path of the rain area near each of the closer and farther positions, and estimates the reference rain attenuation amount and the rain attenuation amount at each of the positions, The rain attenuation calculation unit calculates a correction amount for the rain attenuation at each position estimated by the rain attenuation integration unit, with a difference amount between the reference rain attenuation calculated by the reference rain attenuation calculation unit and the reference rain attenuation estimated by the rain attenuation integration unit as an upper limit. The rainfall intensity estimating device according to claim 1 .

4. The reference rain attenuation calculation unit subtracts the reflection intensity from the reference reflector during rainfall and the atmospheric attenuation on a round trip path in a clear weather area between the radar type radio wave rain gauge and the reference reflector from the reflection intensity from the reference reflector during clear weather to calculate the reference rain attenuation. The rainfall intensity estimating device according to any one of claims 1 to 3.

5. The rain attenuation calculation unit for each position allocates the reference rain attenuation calculated by the reference rain attenuation calculation unit as rain attenuation in a round trip path of a rain area divided into a plurality of areas between the radar type radio wave rain gauge and the reference reflecting object so that the reference rain attenuation estimated by its own processing unit based on the reflection intensity from rain at each position corrected by the rain intensity estimation unit is equal to the reference rain attenuation calculated by the reference rain attenuation calculation unit. The rainfall intensity estimating device according to any one of claims 1 to 3.

6. the reference rain attenuation calculation unit subtracts a reflection intensity from the reference reflector located at a closer distance during rainfall from a reflection intensity from the reference reflector located at a closer distance during fine weather, and calculates the reference rain attenuation between the radar radio wave rain gauge and a position located at the closer distance; The reference rain attenuation calculation unit subtracts the reflection intensity from the reference reflector located at a longer distance during rainfall from the reflection intensity from the reference reflector located at a longer distance during fine weather, and calculates the reference rain attenuation between the radar radio wave rain gauge and the position located at the longer distance. The rainfall intensity estimating device according to any one of claims 1 to 3.

7. A rainfall intensity estimation program for causing a computer to sequentially execute each processing step executed by each processing unit included in the rainfall intensity estimation device according to any one of claims 1 to 3.

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