JPH0734036B2 - Automatic snow depth measurement method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic snow depth measuring method for measuring appropriate snow depth data for all fields related to snow, such as the field of weather data management, the field of installation design in the snowy region. .

[0002]

2. Description of the Related Art Conventionally, the depth of snow is the depth of snow accumulated on a plate, which is called a snow plate and is manually discharged at a specified time, and then at a specified time later. Most of the observations are made by human power reading the scale. In recent years, a device that can automatically measure the snowfall depth by rotating the plate as a mechanical type, or calculate the snowfall depth from the time difference of the snowfall depth by an ultrasonic snow depth meter and automatically measure it has been tried. ing.

[0003]

By the way, in the former of the conventional snow depth measuring apparatus, the rotating plate needs to be installed at a position higher than the ground, and the catch rate of snowflakes due to the wind deteriorates. The accuracy of the snow depth can be calculated correctly, but it cannot be ensured by the conventional ultrasonic snow depth meter, and the function of the subsidence coefficient of snow has not been established. The depth accuracy is poor and it has not been put to practical use. Therefore, the snowfall depth can be calculated from the time difference of the snowfall depth.
We couldn't secure enough accuracy to calculate correctly.

An object of the present invention is to solve the drawbacks of the prior art and to provide an automatic snow depth measuring method which is put into practical use by establishing the subsidence coefficient of snow and improving the accuracy of snow depth. .

[0005]

In order to achieve the above object, the present invention provides a constant snow depth data (H) in mm unit detected by a lightwave type snow cover (3) continuously or at regular time intervals. The increment of the snow depth within the time is used as the initial value of the thickness of the snow layer, and this thickness is the temperature data (Ti) detected by the thermometer (4) and the time when the increment of the snow depth is detected continuously or at regular intervals. The settling coefficient of the snow cover, which is determined by the time from, is repeatedly multiplied at regular time intervals, and the process of calculating the thickness of the snow cover layer on a regular basis is repeated over multiple layers. It is an automatic snow depth measurement method characterized by continuous and continuous measurement.

Further, according to the present invention, the increment of the snow depth within a fixed time is calculated from the snow depth data (H) in mm unit detected by the light wave type snow meter (3) continuously or at fixed intervals, and the thickness of the snow layer is increased. As an initial value of, the thickness of the snow is continuously measured or at fixed time intervals, the temperature data (Ti) detected by the thermometer (4) and the snow weight data (Pi) detected by the snow scale (6), and the snow depth. The process of calculating the thickness of the snow layer on time is repeated over multiple layers by repeatedly multiplying by the settling coefficient of snow cover determined by the time from the time when the increment of is detected, and the total thickness of each layer on time is added. The automatic snow depth measuring method is characterized by automatically and continuously measuring the snow depth.

[0007]

By employing the snow depth automatic measuring method of the present invention, the snow depth can be measured automatically and continuously with high accuracy.
Therefore, it contributes to the elimination of manpower shortage, continuous measurement is possible under any weather condition for 24 hours, reduction of the fluctuation of the measurement value by manpower, the necessary number can be installed in a wide range of necessary places, and detailed weather information Can be obtained, and it will be of great significance socially.

[0008]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory diagram of the configuration of this embodiment,
A measurement unit 3 as a lightwave type snow depth gauge is provided on the upper portion of the support 1 which is erected on the ground GL via a support mounting bracket 2 at a downward slope (for example, 20 degrees with respect to the support 1). It is supported. In addition, at an appropriate height position of the pillar 1, a temperature gauge 4
Is installed. The light wave emitted from the measuring unit 3 and further modulated passes through the route indicated by the wavy line 5, is reflected on the snow surface, and is received by the measuring unit 3 through the route indicated by the same wavy line 5.

The snow scale 6 is provided on the ground GL, and a liquid (for example, antifreeze) is filled in four flat containers (for example, L2000 × W1000 × D12) made of stainless thin plates called metal wafers, and snow is filled. The weight is captured over the entire area, the pressure inside the container is converted into an electric signal by the pressure gauge 7, and the snow weight per unit area is measured.

The snow depth is measured in mm from the phase difference between the light emission and the light reception from the measuring unit 3. The snow depth data, the temperature data, and the snow weight data measured by the meter side unit 3, the temperature meter 4, and the snow weight meter 6 are input to the calculation unit 8 every second. The input data, according to the flow described later,
The data is stored, calculated, and displayed by the data storage unit 8A, the arithmetic unit 8B, and the display 8C, and is output via the interface 8D.

FIG. 2 is a flow chart showing the calculation procedure of the calculation unit 8, which will be described below with reference to FIG. By turning on the power supply of the calculation unit 8, the calculation of step S1 automatically starts, and the constant set value necessary for the calculation is set to step S2.
Set at. Next, in step S3, snow depth data, in step S4, snow weight data, step 5
In step S6, the temperature data is input for each, and the time tim at which the data is input is 0 minute, 10 minutes, 20 minutes, 30 minutes.
If the unit is 10 minutes such as minutes, 40 minutes, 50 minutes, step S
If the data is stored in the storage unit 8A in step 7 and the processing is completed, if the tim is AM 9:00 in step S8, the daily snow depth calculation is performed in step S9, and if not, the process proceeds to step S10. In step S10, ti
If m is a unit of 60 minutes, the time snow depth calculation of step S11 is performed, and if not, the process proceeds to step S12.

At step S12, if tim is 30 minutes,
Calculate the daily snow depth in step S13, and if not,
In step 14, it is stored in the storage unit 8A. Step S13
After the completion of the calculation of the snowfall intensity in step S14, the calculated daily snowfall data, time snowfall data, and snowfall depth data that is the snowfall intensity data are stored in the storage unit 8A. In step S15, the date, current time, input time tim, snow depth data, intensity data, etc. are displayed on the display 8c.
In step S16, daily snow depth data, hourly snow depth data, and snow intensity data are output. In step S6, t
If im is not in units of 10 minutes, the process proceeds to step S15,
Each data is displayed on the display 8C.

The flow chart in FIG. 2 shows a flow by three parties of snow depth data, temperature data and snow weight data, but in the case of two parties of snow depth data and temperature data, step S4 in FIG. That is, the input of the snow weight data is omitted.

The time snow depth, the daily snow depth, and the snow intensity are the same, except that the number of data to be handled is different. Therefore, first, the snow depth data and the temperature data will be described below.
The temporal snowfall depth based on the person will be described with reference to the snowfall simple increase model shown in FIG.

In FIG. 3, t0 is the start time of the arithmetic symmetric time, and t6 is its end time. 6 from t0 to t6
At 0 minutes, ~ indicates a change in the snow surface, which is measured by the snow depth meter. The dotted line in the figure is a curve predicting subsidence. For example, the wavy line of ~ indicates the expected curve that the snow surface at time t0 subsides by time t6, and ~ is a relatively short time of 10 minutes. Therefore, it is assumed that the sedimentation is zero.

The snow depth H is measured by a snow depth meter, and the 10-minute increment, for example, d11, is multiplied by the sinking function aij to calculate the temporal snow depth by the following formula.
In FIG. 3, the time snowfall depth HH is

[Equation 1] Indicated by. Here, dd6 j indicates an expected value at the time t6 when ddij at time ti decreases with time. As the calculation formula for obtaining this predicted value dd6 j, the following formula using an exponential function with a large attenuation in time is used as an approximation formula.

A6j = exp (−C (t6 −tj)) (2) In the expression (2), a6j is aij at ti time.
Is represented by aij = exp (-C (ti-tj)) (3).

In the equations (2) and (3), it is appropriate that C is represented by a function including parameters of weather conditions.
Here, a functional expression shown below is assumed with the temperature Ti that is considered to have a large effect on the natural subsidence of snow and the upper snow depth indicated by fi in the figure, which is correlated with the load. That is, if the temperature Ti is high, the snow melts easily, and if the temperature Ti is low, the snow does not melt easily. If the weight of the loaded snow is heavy, the snow will shrink easily, and if it is light, the snow will not shrink easily. Furthermore, since snow naturally subsides with the passage of time, the following equation can be obtained when these three types are modeled.

C = C1 × Ti + C2 × fi + C3 (4) Here, Ti is the air temperature at time ti, and is a known value measured by the thermometer, and fi is calculated by the following equation by the calculation unit. It

[0020]

[Equation 2] In the above equation (4), C1, C2, and C3 are constants determined by performing correlation processing by actual measurement experiments.

The time snowfall depth can be accurately measured by performing the calculation at the time t6 using the snow cover data and the temperature data measured by the above formula.

Next, a simple snow depth increase model diagram for the time snow depth based on the three parties of the snow depth data, temperature data and weight data is also shown in FIG. 3, and the initial correction diagram is shown in FIG. There is. First, in FIG. 4, it is necessary to obtain the initial value d _i of the snow depth. That is, since this initial value has a high compression speed, it is necessary to perform initial correction.

First, using the difference h ₀ of the measured snow depth for 10 minutes, A (settling coefficient) from the initial time i to the time i + 1 is obtained, and the back calculation corresponding to the immediately preceding 5 minutes is calculated by the equation (6). An initial value d _i is calculated.

D _i = h ₀ (1 + 1 / A) / 2 (6) The subsidence coefficient A represents a ratio by which the thickness of the snow layer is compressed between dt from an arbitrary time i to an i + 1 time, and (7), (8) ).

[0025]

[Equation 3] C = C ₁ · T + C ₂ · t ⁿ + C ₃ (8) The initial value d _i is compressed over time. The compressed thickness of the (7), are calculated every 10 minutes by (8), d _e the measurement end time is obtained by equation (9).

D _e = Ad _e-1 (9) Therefore, the time snow depth H is (1
Calculation processing is performed according to the expression (0).

[0027]

[Equation 4] However, A: (a ratio to compress between dt) sedimentation coefficient H: snow depth (mm) P: weight of above layers center point (kg / m ²⁾ T: Initial Temperature (℃) d _e: measurement end time Snow layer thickness (mm) d _i : Snow layer thickness at time i (mm) d _{i + 1} : i + 1 Time snow layer thickness (mm) dt: Difference time (10 minutes) δh: Subsidence amount at dt time (mm) t: elapsed time (hours) from the time of snowfall C ₁ , C ₂ , C ₃ , n: constant obtained from actual measurement experiment The sedimentation coefficient A of the above equation (7) is derived in the following manner.
That is, from the already known literature

[Equation 5] It has been known. If this equation (11) is a difference format,

[Equation 6] Becomes

Here, A (t) = h (t + 1) / h
Assuming (t), the above equation (7) is

Η (t) = P (t) · dt / (1−A (t)) (13)

From the already known literature, η (t) is proportional to exp (t ⁿ ), and log η is temperature T
Since it increases linearly with the decrease of (t), the above equation (13) becomes

Η (8) = P (t) dt / (1-A (t)) = exp (C ₁ T (t) + C ₂ · t ⁿ + C ₃ ) (14) From this equation (14)

Equation 9] the A (t) = 1-P (t) · dt / exp (C 1 · T (t) + C 2 t n + C 3).

In the above equation (14), lo on the left and right sides
Taking g and C,

C = log η (t) = C ₁ T (t) + C ₂ t ⁿ + C ₃ (15)

Equation (14) corresponds to equation (7), and equation (15) corresponds to equation (8). Therefore, the time snowfall depth H can be obtained more accurately than the equations (1) and (3) described above in the equations (7) and (10) in which the weight data is also taken into consideration.

The present invention is not limited to the above-described embodiments, but can be implemented in other modes by making appropriate changes. In this embodiment, the time snowfall depth has been described, but the daily snowfall depth and snowfall intensity can be measured by the same method.

[0033]

As will be understood from the above description of the embodiments, according to the present invention, since the structure is as described in the claims, it is possible to establish the sedimentation coefficient of snow and establish the snow depth. It is possible to improve the accuracy of and to practically use.

Thus, it contributes to the elimination of manpower shortage, continuous measurement is possible under any weather condition for 24 hours, the variation of the measured value by manpower is reduced, and the necessary number can be installed in a wide range of necessary places. You can get detailed weather information.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of an embodiment according to the present invention.

FIG. 2 is a flowchart showing the operation of the method of the present invention.

FIG. 3 is an explanatory diagram of a simple increase model for measuring a time snowfall depth.

FIG. 4 is an explanatory diagram for performing initial correction.

[Explanation of symbols]

 1 Prop 2 Prop mounting bracket 3 Measuring part 4 Temperature gauge 5 Wavy line 6 Snow scale 7 Pressure gauge 8 Calculation part 8A Storage part 8B Calculation part 8C Display

Claims (2)

[Claims] 1. The initial value of the thickness of the snow layer is defined as an increment of the snow depth within a fixed time from the snow depth data (H) in mm unit detected by the lightwave type snow cover (3) continuously or at regular intervals. , This thickness is repeated continuously or at regular time intervals with the air temperature data (Ti) detected by the thermometer (4) and the snowflake sedimentation coefficient determined by the time from the time when the increment of the snow depth is detected. Automatically and continuously measuring snow depth by repeating the process of multiplying and calculating the thickness of the snow layer at regular intervals over a number of layers and adding the thickness of each layer at regular intervals to automatically and continuously measure the snow depth. Method. 2. The initial value of the thickness of the snow layer is defined as the increment of the snow depth within a fixed time from the snow depth data (H) in mm unit detected by the light wave type snow cover (3) continuously or at regular intervals. This thickness is continuously or at regular intervals detected by the temperature data (Ti) detected by the thermometer (4) and the snow weight data (Pi) detected by the snow scale (6), and the increment of the snow depth is detected. The process of repeatedly calculating the settling coefficient of snow cover, which is determined by the time from the specified time, and calculating the thickness of the snow layer at regular intervals is repeated over multiple layers in sequence, and the total thickness of each layer at the scheduled time is added up to determine the snowfall depth. Automatic snowfall measurement method characterized by automatically and continuously measuring snowfall.