JPH10311883A - Method and device for forecasting meteorological image and recording medium recording meteorological image forecast program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably forecast a meteorological radar image with high accuracy. SOLUTION: A meteorological radar image is input (step 401), and a local speed field of an echo is calculated (402). Individual precipitation areas are extracted from the meteorological radar image (step 403), and the candidates for moving speeds are calculated for each of the areas (step 404). The degrees of retention and movement of the precipitation areas are judged from the candidates for the moving speeds of the precipitation areas and the local speed field of the echo (step 405). The moving speeds of the precipitation areas for use in forecast are estimated from the degrees and the candidates for the moving speeds of the precipitation areas (step 406), and a forecasted image is created using the estimated moving speeds of the precipitation areas (step 407).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a weather radar image obtained from a weather radar apparatus to predict local and short-time weather radar images for the purpose of predicting weather phenomena such as precipitation and cloudiness. The present invention relates to a weather image prediction method and a device therefor.

[0002]

2. Description of the Related Art Conventional prediction methods using weather radar images are described in reference [1] Yoshio Yuma, Katsuhiro Kikuchi, Imahisa:
“Echo Movement Speed by Simple Weather Radar”, Hokkaido University Geophysical Research Report, Vol. 44, Octob
er, 1984, pp.35-51. and References [2] Yoshio Yuma, Katsuhiro Kikuchi, Imahisa: "Short-term snowfall prediction experiment using simple weather radar (1)", Hokkaido University Geophysical Research Report,
Vol. 44, October, 1984, pp. 35-51. The cross-correlation method is widely used.

In a weather radar image, large or small echo clumps or groups thereof are present. Here, the lump or group of echoes is called a precipitation area. Although the echoes in weather radar images move roughly along the flow of the atmosphere, they repeatedly deform, generate, and disappear. Therefore, there is a property that the local velocity of the echo does not always coincide with the global moving velocity of the rainfall area, which is a group thereof.
For example, in the case of FIG. 6, the echo appears at a certain position,
It moves in a line and disappears at a certain position. However, the global movement of these groups of echoes, the rainfall region, is very slow compared to the local speed of the echoes.

In the methods of the above-mentioned documents [1] and [2], two frames of weather radar images are used, and one is shifted,
The cross-correlation value between the images is calculated, and the moving speed of the echo pattern is estimated from the maximum deviation width. Therefore, there is a problem that the local speed of the echo is confused with the global movement speed of the precipitation area, and the movement speed of the precipitation area cannot be accurately obtained.

Further, a local velocity field is obtained from a weather radar image, the image is divided based on the similarity, a precipitation area is extracted, its moving speed is estimated, and a prediction image is extrapolated using extrapolation. (Japanese Patent Application No. 8-333763). In this method, the moving speed of the echo is obtained from the local speed field, and the global speed of the precipitation area extracted based on the division of the speed field is obtained from the displacement of the center of gravity between frames.

However, when the moving speed of the rainfall area is relatively low, the influence of the generation, extinction and deformation of the echo becomes relatively large, and as a result, the estimated moving speed of the rainfall area becomes inconsistent. Tends to be accurate. Therefore, a method is adopted in which the rainfall area is classified into two types, a mobile type and a stagnant type, and only in the case of the mobile type rainfall region, the rainfall area is moved to generate a predicted image. However, since a simple threshold processing of the speed in the rainfall area is used to distinguish between the mobile type and the stagnant type, the problem that the prediction result becomes unstable when the speed is near the threshold still remains. there were.

[0007]

The prior art described above is
The local velocity of the echo in the weather radar image is confused with the global velocity of the precipitation area, and the accurate velocity of the precipitation area cannot be obtained. There is a problem that the predicted image becomes unstable because it is classified into two categories and the moving speed in the precipitation area is determined.

An object of the present invention is to provide a stable and highly accurate weather radar image prediction method and apparatus, and a recording medium on which a weather image prediction program is recorded.

[0009]

SUMMARY OF THE INVENTION A meteorological image prediction method according to the present invention estimates a moving speed of a rainfall area to be used for prediction on the basis of properties of a cluster of echoes and a group of the rainfall areas in a weather radar image. Having.

According to the embodiment of the present invention, the property of the precipitation area is the degree of mobility and stagnation, which is the nature of the movement of the cluster of echoes in the weather radar image and the group of precipitation areas.

According to the embodiment of the present invention, the degree of mobility / stagnation, which is the nature of the movement of the precipitation area, which is a cluster of echoes in a weather radar image, and the locality of the echoes in the weather radar image are determined. Is determined by the similarity between the set of general velocities and the global velocities in the precipitation area.

According to the embodiment of the present invention, the degree of mobility / stagnation, which is the nature of the movement of the echo mass and the group of precipitation areas in the weather radar image, is determined based on the locality of the echo in the weather radar image. Is determined as a function of the magnitude of the difference between the velocity vector representing the typical velocity and the velocity vector representing the velocity in the precipitation area.

According to the embodiment of the present invention, a future weather radar image is predicted based on the speed of the precipitation area obtained by weighting the values of the degrees of mobility and stagnation.

[0014] A weather image prediction apparatus according to the present invention comprises: an image input means for inputting a time series weather radar image obtained by a weather radar apparatus; a mass of echoes in the weather radar image input by the image input means; Precipitation area property determination means for determining the properties of the precipitation area that is the group, precipitation area movement speed estimation means for estimating the movement rate of the precipitation area based on the properties of the precipitation area obtained by the precipitation area property determination means, A predictive image generating means for generating a predicted image using the moving speed of the precipitation area obtained by the area moving speed estimating means.

According to the embodiment of the present invention, the precipitation area property determining means determines the degree of mobility and stagnation, which is the nature of the movement of the precipitation area, based on the local velocity of the echo in the weather radar image and the precipitation area. Is determined from the similarity in global speed of

According to the embodiment of the present invention, the precipitation area property judging means uses the degree of mobility / stagnation, which is the nature of the movement of the precipitation area, as a velocity representing the local velocity of the echo in the weather radar image. It is determined as a function of the magnitude of the difference between the vector and the global velocity vector in the rainfall area.

According to the embodiment of the present invention, there is further provided a rainfall area speed candidate calculating means for obtaining a candidate for the speed of the rainfall area in the weather radar image, wherein the rainfall area moving speed estimating means performs the precipitation area speed candidate calculation in advance. The velocity of the rainfall area calculated by the means is weighted by the degree of mobility and stagnation, which is the nature of the movement of the rainfall area obtained by the rainfall area property judgment means, and the movement speed of the rainfall area used for prediction Is estimated.

According to the embodiment of the present invention, the precipitation area speed candidate calculating means calculates the moving speed of the precipitation area based on the displacement of the center of gravity of the precipitation area between frames in the time series weather radar image.

As a property of a weather radar image, in a highly mobile precipitation area, the local velocity of the echo and the global velocity of the precipitation area are often similar in both direction and magnitude, In a rainy region with large rainfall, the effect of generation and annihilation is more significant than the movement of the echo, and the local speed of the echo is disturbed in both direction and size, and often does not match the global speed of the rainfall region Is mentioned.

In the precipitation area property determining means, the degree of mobility and stagnation, which are the properties of the precipitation area in such a weather radar image, are determined by the similarity between the local velocity of the echo and the global velocity of the precipitation area. It is determined based on As a result, it is possible to more reliably determine the tendency of the stagnation or movement of the precipitation area in accordance with the actual phenomenon.

The precipitation area moving speed estimating means estimates the moving speed of the precipitation area used for the prediction by multiplying the degree of mobility and stagnation of the precipitation area by the moving velocity calculated in advance.
Therefore, in the case of stagnation where the effects of generation, extinction, deformation, etc. are large, the speed of the precipitation area is reduced to reduce
Unstable factors such as disappearance and deformation can be suppressed, and a stable moving speed can be estimated. Further, when it is determined that the rainfall area is mobile, a future weather radar is used by using a velocity relatively close to the movement velocity calculated from the displacement of the center of gravity of the precipitation area by the precipitation area velocity candidate calculation means. It is possible to accurately predict an image.

Further, in the precipitation area property determining means, in order to determine the degree of mobility and stagnation, the degree of mobility and stagnation are calculated as a function of the difference between the local velocity of the echo and the global velocity vector of the precipitation area. It uses a function that changes smoothly. Therefore, even when the characteristics of the echo slightly vary, a stable weather radar image can be predicted.

The recording medium storing the weather image prediction program according to the present invention includes a weather radar image input process for inputting a time series weather radar image obtained by a weather radar device and a weather radar image input process. Precipitation area property determination processing that determines the properties of the echo clusters and the group of precipitation areas in the input weather radar image, and the movement speed of the precipitation area based on the properties of the precipitation area obtained by the precipitation area property determination processing Region moving speed estimation process for estimating the rainfall, a predicted image generation process for generating a predicted image using the moving speed of the precipitation region obtained by the precipitation region moving speed estimation process, and a predicted image output for outputting the predicted image to an output device It records a weather image prediction program with processing.

[0024]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a weather image prediction device according to an embodiment of the present invention.

The weather image prediction apparatus of the present embodiment has an input unit 1
00, a processing unit 200, and an output unit 300.

The input unit 100 includes a weather radar device 101
And a file device 102 for storing weather radar images.

The processing unit 200 calculates the local velocity of the echo of the weather radar image.
And a precipitation area speed candidate calculation unit 202 that calculates a candidate of the velocity of the precipitation area in the weather radar image, and a property of the precipitation area (the stagnation of the precipitation area And the degree of stagnation / mobility, which is the property of the determined precipitation area,
It is composed of a precipitation area moving speed estimation unit 204 that determines the speed of the precipitation area from the precipitation area candidate velocity, and a prediction image generation unit 205 that generates a prediction image using the estimated movement speed of the precipitation area.

The output unit 300 includes a display device 301 and a file device 302 for displaying and storing the generated predicted radar image.

FIG. 2 is a flowchart showing the operation of the weather image prediction device of FIG. A weather radar image is input (step 401), a local velocity field of an echo is calculated (step 402), and individual precipitation areas are extracted from the weather radar image (step 403). Calculation (step 404), the degree of stagnation and mobility of the precipitation area is determined from the candidate movement velocity of the precipitation area and the local velocity field of the echo (step 405), and the degree and the candidate movement velocity of the precipitation area are determined. , The moving speed of the precipitation area used for prediction is estimated (step 406), and a predicted image is generated using the estimated moving speed of the precipitation area (step 40).
7).

Next, each section of the processing section 200 will be described in detail.

The echo velocity field calculation unit 201 receives the weather radar image I _t (t = 0, 1,..., T) of the (T + 1) th frame forming a time series from the weather radar device 100, and [I _t−1 , I _t ] (t = 1, 2,...)
, T), each block B _t (i, j), (i = 1, 2,..., M) of the image divided into M × N blocks;
For each j = 1, 2,..., N), a local velocity vector V _t (i, j) of the echo is calculated.

As an example of the realization, a method using the cross-correlation value of the image density can be used.

Now, the block B _t between adjacent frames
Using the weather radar images R ₁ and R ₂ cut out around (i, j) and B _t−1 (i, j), the cross-correlation value between the images is calculated while shifting one image R ₂ ( (See FIG. 3).

[0035]

(Equation 1) Here, the areas where the correlation is obtained are A and B, and the difference between the two weather radar images R ₁ and R ₂ when calculating the correlation value is (k, l). , And the thick line at the center indicates the moving direction of the echo pattern of the arrow).

Then, the deviation width (K,
From L) the velocity vector of the echo is

[0037]

(Equation 2) Can be calculated. Here, V _x and V _v indicate an x component and a y component of the velocity vector, respectively, and Δt indicates a time interval at which a radar image is measured.

Such a calculation is performed for each block to calculate a local velocity field of the echo.

Note that methods other than those described above can be used.

The precipitation area speed candidate calculation unit 202 obtains a candidate for the velocity of the precipitation area in the weather radar image. here,
As an example, the local velocity of the echo obtained by the echo velocity field calculation unit 201 is used to extract from the image as one precipitation area of a region having a similar velocity, and the displacement amount of the center of gravity between those frames The method of calculating the candidate of the speed of the rainfall area from is shown.

First, using the velocity field calculated by the echo velocity field calculation unit 201 as an input, spatial and temporally adjacent blocks are compared with each other in their velocity vectors. Divide the area so that
Here, the velocity vector V ₁ of two adjacent blocks
As a measure of the similarity between (v _x1 , v _y1 ) and V ₂ (v _x2 , v _y2 ), the ratio of the average length of two vectors to the length of the difference vector in two vectors

[0042]

(Equation 3) Using

[0043]

(Equation 4)1 if they are similar, and if they are not similar
Is a function S (V ₁ , V_Two ). However
Then TH_v Is a threshold. Also, similarity calculation method
Other criteria such as vector dot product are also available.
You.

Next, for each block in the image, a label L _t (i, j) representing the type of the precipitation area is prepared, and the block is scanned in a raster manner. The same number of labels is assigned to a set of blocks. As a result of such a labeling process, the distribution of the rainfall area becomes the same label L _t
It is obtained as an area having the number (i, j).

Further, for a set of blocks having the same number label (this is simply called a precipitation area), the moving speed of the precipitation area between frames is calculated from the displacement of the center of gravity.

The center of gravity (Gx
_t (s), Gy _t (s))

[0047]

(Equation 5) Can be calculated. Where m _t (s, x, y) is the precipitation area s
Indicates the presence of (X, y) is the coordinate system of the image.
(I, j) is the coordinate system of the block. Then, the amount of displacement of the position of the center of gravity between the frames is

[0048]

(Equation 6) Is obtained.

Then, the candidate moving speed of each precipitation area is
As the average displacement of the center of gravity between frames,

[0050]

(Equation 7) Can be calculated.

It is to be noted that a method of calculating the moving speed of the precipitation area other than the above-described method can be used.

The precipitation area property judging section 203 calculates the precipitation speed from the local velocity field of the echo obtained by the echo velocity field calculation section 201 and the candidate of the moving speed of the precipitation area obtained by the precipitation area candidate calculation section 202. The degree of mobility / stagnation, which is the nature of the movement of the area, is determined.

As a criterion for determination, a criterion that the precipitation area is mobile when the local velocity of the echo and the movement velocity of the precipitation area are close in both direction and magnitude is used, and the similarity between the respective velocity vectors is used. The degree of mobility and stagnation is calculated from.

As a specific example, here, from the echo velocity field V _t (i, j) obtained by the echo velocity field calculation unit 201, the representative value of the velocity of the echo in the area included in each precipitation area s

[0055]

[Outside 1] , The average value of the speed V _t (i, j) is used. In addition,
In addition to the average value, the mode value can also be used. A vector of representative values of the velocity of this local echo

[0056]

[Outside 2] And a candidate movement velocity vector of the precipitation area calculated by the precipitation area velocity candidate calculation unit 202

[0057]

[Outside 3] , The degree of mobility / stagnation P of the precipitation area is defined as the ratio of the magnitude of the difference vector to the average of the magnitudes of the two vectors.

[0058]

(Equation 8) Is calculated. When the degree of mobility / stagnation P is close to 0,
The precipitation area is mobile, and when P is large, the precipitation area is determined to be stagnant. When P is an intermediate value, the nature of the precipitation area is intermediate between mobility and stagnation, and changes smoothly during that time. FIG. 4 shows the state of this determination.

Note that methods other than those described above can also be used.

The precipitation area moving velocity estimating section 204 calculates the precipitation area moving velocity candidates obtained by the precipitation area velocity candidate calculating section 202 and the mobility / stagnation degree P obtained by the precipitation area property determining section 203. From this, the speed of the precipitation area used for prediction is determined.

Here, as a method, a monotonically decreasing function of the degree of mobility / stagnation P is defined, and the value of the function is multiplied by a candidate for the moving speed of the rainfall area, and weighted to obtain a value of the rainfall area. Determine the speed.

The monotone decreasing function includes the following function f

[0063]

(Equation 9) Is available.

Here, a, b, and c are positive constants. FIG. 5 shows the state of the function f.

A function other than this function can be used.

Using the function f, the vector W of the candidate for the moving speed of the precipitation area obtained by the precipitation area speed candidate calculation unit 202, and the degree of mobility / stagnation P obtained by the precipitation area property judgment unit 203, The velocity vector U in the precipitation area is

[0067]

(Equation 10) Can be calculated.

It is to be noted that a speed estimation method other than that described above can also be used.

The predicted image generation unit 205 determines the speed U of the precipitation area obtained by the precipitation area moving speed estimation unit 204 and the input unit 10.
A predicted image after an arbitrary time is generated from the weather radar image obtained at 0.

The following method will be described as a specific example. For each of the precipitation areas s extracted by the precipitation area speed candidate calculation unit 202, an image P _s (x, y) is extracted from the latest weather radar image of the corresponding area, and this is used as the precipitation area movement speed estimation unit. A predicted image is generated by performing parallel movement at the speed U of the precipitation area obtained in 204. Then, a predicted image to be output is generated by combining predicted images generated for all precipitation areas.

FIG. 7 is a block diagram of a weather image prediction device according to another embodiment of the present invention, and FIG. 8 is a block diagram of a weather image prediction program recorded on a recording medium 503 in FIG.

The meteorological image predicting apparatus of this embodiment includes an input device 501 corresponding to the meteorological radar device 101 in FIG.
The display device 301 and the file device 302 in FIG.
, A recording medium 503 such as an FD, a CD-ROM, or a semiconductor memory in which a weather image prediction program is recorded, and a weather image prediction program read from the storage medium 503, and a weather radar image is read from the input device 501. And a data processing device 504 for performing processing and outputting the generated predicted image to the output device 502.

As shown in FIG. 8, the weather image prediction program recorded on the recording medium 503 includes a weather radar image input processing 600, an echo velocity field calculation processing 601, a precipitation area candidate calculation processing 602, and a precipitation area property determination processing 603. And a rainfall area moving speed estimation processing 604, a predicted image generation processing 605, and a predicted image output processing 606. The echo velocity field calculation processing 601 to the prediction image generation processing 605 respectively include the echo velocity field calculation section 201, the precipitation area velocity candidate calculation section 202, the precipitation area property determination processing section 203, the precipitation area movement velocity estimation section 204, and the prediction in FIG. This is the same as the processing performed by the image generation unit 205. However, the process of inputting a time-series weather radar image obtained by the weather radar device 101 is performed by the weather radar image input process 600, and the process of outputting the finally obtained predicted image to the output device 502 is performed by a prediction process. This is performed in the image output processing 606.

[0074]

As described above, the present invention estimates the moving speed of a rainfall area used for prediction based on the properties of the rainfall area which is a group of echoes and a group of echoes in a weather radar image. It is possible to reduce adverse effects due to unstable factors such as generation, extinction, and deformation of a radar echo, and there is an effect that a more stable and accurate weather radar image can be predicted.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a weather image prediction device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the weather image prediction device of FIG.

FIG. 3 is a diagram illustrating a state of processing of a cross-correlation technique.

FIG. 4 is a diagram showing how to determine the degree of mobility and stagnation in a rainy region.

FIG. 5 is a diagram illustrating a state of a weighting function for determining a moving speed in a precipitation area.

FIG. 6 is a diagram illustrating an example of a state of an echo and a precipitation area in a weather radar image.

FIG. 7 is a configuration diagram of a weather image prediction device according to another embodiment of the present invention.

8 is a diagram showing a configuration of a weather image prediction program recorded on a recording medium 503 in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Input unit 101 Weather radar device 102 File device 200 Processing unit 201 Echo velocity field calculation unit 202 Precipitation region speed candidate calculation unit 203 Precipitation region property determination unit 204 Precipitation region moving speed estimation unit 205 Prediction image generation unit 300 Output unit 301 Display device 302 File device 401 to 407 Step 501 Input device 502 Output device 503 Recording medium 504 Data processing device 600 Weather radar image input processing 601 Echo velocity field calculation processing 602 Precipitation area velocity candidate calculation processing 603 Precipitation area property determination processing 604 Precipitation area moving speed Estimation processing 605 Predicted image generation processing 606 Predicted image output processing

Claims (15)

[Claims] 1. A weather image prediction method for predicting a future weather radar image from a weather radar image obtained by a weather radar device for the purpose of predicting a local short-term precipitation, comprising: a mass of echoes in the weather radar image; A meteorological image prediction method, comprising a step of estimating a moving speed of a rainfall area used for prediction based on a property of a rainfall area which is a group. 2. The meteorological image prediction according to claim 1, wherein the property of the precipitation area is a degree of mobility and stagnation, which is a property of a movement of a cluster of echoes in the weather radar image and a group of precipitation areas. Method. 3. The degree of mobility / stagnation, which is the nature of the movement of the clusters of echoes in the weather radar image and the precipitation area as a group thereof, is determined by the local velocity of the echoes in the weather radar image,
The weather image prediction method according to claim 2, wherein the determination is made based on the similarity to a global speed in a rainy region. 4. A velocity vector representing a local velocity of an echo in a weather radar image, the degree of mobility / stagnation, which is the nature of the movement of a cluster of echoes in the weather radar image and its precipitation area. The weather image prediction method according to claim 3, wherein the determination is made as a function of a magnitude of a difference between the speed vector and a speed vector representing a speed of the precipitation area. 5. The weather image prediction method according to claim 4, wherein a future weather radar image is predicted based on the speed of the precipitation area obtained by weighting with the value of the degree of mobility and stagnation. 6. A weather image prediction device for predicting a future weather radar image from a weather radar image obtained by a weather radar device for the purpose of predicting local short-term precipitation, wherein a time series obtained by the weather radar device is Image input means for inputting a weather radar image to be formed; a rainfall area property determining means for determining properties of a precipitation area which is a cluster of echoes and a group of echoes in the weather radar image input by the image input means; A rainfall area moving speed estimating means for estimating the moving speed of the rainfall area based on the properties of the rainfall area obtained by the property determining means; and a prediction image using the rainfall area moving speed obtained by the rainfall area moving speed estimating means. A weather image prediction device, comprising: a prediction image generation unit that generates a prediction image. 7. The apparatus according to claim 6, wherein the property of the precipitation area is a degree of mobility or stagnation, which is a property of a movement of a cluster of echoes and a group of precipitation areas in a weather radar image. 8. The precipitation area property judging means determines the degree of mobility / stagnation, which is the nature of the movement of the precipitation area, based on the local velocity of the echo in the weather radar image and the global velocity of the precipitation area. The weather image prediction device according to claim 7, wherein the determination is performed based on similarity. 9. The precipitation area property determining means determines a degree of mobility / stagnation, which is a property of movement of the precipitation area, by using a velocity vector representing a local velocity of an echo in a weather radar image, The weather image prediction device according to claim 8, wherein the determination is performed as a function of a magnitude of a difference between speed vectors representing speeds. 10. A precipitation area speed candidate calculating means for obtaining a candidate of a speed of a precipitation area in a weather radar image, wherein said precipitation area moving speed estimation means is calculated in advance by said precipitation area speed candidate calculating means. 8. The moving speed of the rainfall area used for prediction is estimated by weighting the speed according to the degree of mobility and stagnation, which is the nature of the movement of the rainfall area obtained by the rainfall area property determining means. Weather image prediction device. 11. The weather image prediction device according to claim 10, wherein said precipitation area speed candidate calculation means calculates the speed of the precipitation area by displacement of the center of gravity of the precipitation area between frames in a time-series weather radar image. 12. A recording medium recording a weather image prediction program for predicting a future weather radar image from a weather radar image obtained by a weather radar device for the purpose of predicting a local short-term precipitation amount, wherein the weather radar device is provided. Input processing for inputting a weather radar image forming a time series obtained by the above, and a rainfall area property for determining properties of a precipitation area which is a cluster of echoes and a group of echoes in the weather radar image input by the image input processing Judgment processing, a precipitation area movement speed estimation processing for estimating the movement speed of the precipitation area based on the properties of the precipitation area obtained by the precipitation area property judgment processing, and a precipitation area obtained by the precipitation area movement speed estimation processing A computer executes a predicted image generation process of generating a predicted image using a moving speed and a predicted image output process of outputting the generated predicted image to an output device. Recording medium for recording a weather image prediction program for. 13. The recording medium according to claim 12, wherein the property of the precipitation area is a degree of mobility or stagnation, which is a property of the movement of the precipitation area as a group of echoes in a weather radar image. 14. The precipitation area property determination processing includes determining the degree of mobility / stagnation, which is the nature of the movement of the precipitation area, based on the local velocity of the echo in the weather radar image and the global velocity of the precipitation area. 14. The recording medium according to claim 13, which is determined based on similarity. 15. A precipitation area speed candidate calculation process for obtaining a candidate of a speed of a precipitation region in a weather radar image, wherein the precipitation region movement speed estimation process is calculated in advance by the precipitation region speed candidate calculation process. 14. The moving speed of the rainfall area used for prediction is estimated by weighting the speed according to the degree of mobility / stagnation, which is the nature of the movement of the rainfall area obtained by the rainfall area property determination process. Recording medium.