JPH0460490A - Rain/snow discrimination - Google Patents

Abstract

PURPOSE:To enable an en bloc treatment of kinds of meteorological observation data and rain/snow discrimination by comparing a judgement value defined by comparison of the maximum temperature variance of stored water surface periphery of a rain gauge during a certain time duration, to a precipitation amount during the same period, to a standard value. CONSTITUTION:A signal processing system is provided with two temperature measuring parts 10 and 11, a difference signal circuit 12 that outputs temperature difference data from the temperature difference measured by the temperature measuring parts 10 and 11, a signal processing part 13 that discriminates rain or snow based upon the temperature difference data from the circuit 12 and precipitation data from a over-turn measure 3, a recording part 14 that records the data processed by the processing part 13, and a judgment standard value setting part 15. The temperature measuring parts 10 and 11 output oscillation signal of corresponding frequency to the temperature which is measured by temperature sensors 6 and 7, and the like. The difference signal circuit 12 outputs signal of which frequency is equivalent to frequency difference between output signal frequencies of oscillation circuits 8 and 9 of the temperature measuring parts 10 and 11 and thereafter directly outputs the measured temperature difference data of the sensors 6 and 7. The signal processing part 13 is mainly constituted of a CPU, calculates the judgement value by a predetermined equation, compares the judgement value to a standard value, conducts rain/snow discrimination and finally outputs judgement result to the recording part 14.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a rain/snow discrimination method for determining whether the precipitation is rain or snow when there is precipitation.

(Prior Art) The applicant of the present application previously proposed in Japanese Patent Application No. 62-132832 (Japanese Unexamined Patent Publication No. 64-485) that, for example, an overflow rain gauge (a rainwater storage tank with a constant up to a bell) A rain gauge with a structure that collects rainwater) has a temperature change trend within a certain period of time measured by a temperature sensor installed near the stored water surface, or a temperature difference trend measured by a pair of temperature sensors installed near the stored water surface. We proposed a method for snow discrimination.

In this method, the final judgment on rain/snow discrimination is based on empirical observation of analog waveforms plotting temperature changes or temperature differences.

(Problems to be Solved by the Invention) In the above-mentioned prior art, the final judgment of rain and snow discrimination is based on observation of the observed waveform output from the processing device, so the speed of rain and snow discrimination is slow, and the rain g discrimination There is a problem that automatic processing, automatic recording, etc. are difficult.

The present invention has been proposed to solve the above-mentioned problems, and an object of the present invention is to provide a rain/snow discrimination method that enables automation of rain/snow discrimination using a computer.

(Disclosure of the Invention) The inventor of the present invention has discovered that the maximum temperature difference change (maximum value of temperature difference and (difference between the minimum value) or the maximum temperature change (difference between the maximum and minimum measured temperature) at one measurement point near the reservoir water surface within a certain period of time, and the amount of precipitation at that time. As a result of taking multiple measurements and analyzing the measurement results, we found that the above maximum temperature difference change or maximum temperature change not only correlates with the difference in rainfall or snowfall, but also has a correlation with the amount of precipitation. We found that the ratio between temperature change and rainfall amount can be classified with high accuracy between rainy and snowy periods.

In other words, the maximum temperature difference change or maximum temperature change is ΔT
When the amount of precipitation within a certain period of time is R, the relationship between the judgment value S defined by the following formula % formula % (1) and the number of times rain or snowfall is observed is shown in a graph as shown in Figure 1. (However, in Figure 1, the judgment value S is determined using the maximum temperature difference change measured by a pair of temperature sensors as ΔT.) As is clear from Figure 1, , when the judgment value S is about 1.0, the number of observations of rain and snowfall is almost equal, and when the judgment value is about 1.0 or less, the number of observations of rain increases,
When it is about 1.0 or more, the number of snowfall observations increases.
The distribution of the number of observations can be clearly distinguished between rain and snow. Based on this, a reference value S0 is determined for the determination value S, and by comparing the determination value S during rain with the personal reference value S0, it becomes possible to distinguish between rain and snow.

Furthermore, as the amount of precipitation R increases, the correlation between the maximum temperature difference change or the maximum temperature change and the amount of precipitation R weakens (
When the rainfall or snowfall that falls on the rainwater storage water surface becomes heavy,
It becomes smaller while the temperature of the reservoir water surface changes. When the amount of precipitation R exceeds the constant value R0, the constant value R0 is used as the amount of precipitation R when determining the determination value S of the equation (1).

Next, in determining the above reference value So, the relationship between the judgment value S and the observed probability of rain or snowfall is determined from Figure 1, as shown in Figure 2, and it is clear from Figure 2. So, the standard value S.

When is set to about 0.65, it is possible to distinguish between rain and snow with an accuracy of about 93% for both the probability of rain and the probability of snow. In addition, when placing emphasis on rainfall discrimination, the standard value S is used.

For example, set the value of S to a value higher than the above 0.65. =0.
8, the rainfall determination accuracy is 95% and the snowfall determination accuracy is 88%), when placing emphasis on snowfall determination, the standard value S0
Set the value to be lower than the above 0.65 (for example, 5o=0
．． 5, the snowfall determination accuracy is 95% and the rainfall determination accuracy is 88%).

(Embodiment) Figures 3 and 4 show the structure of a flood gauge and a block diagram of a signal processing system used in implementing the present invention.

As shown in Fig. 3, the overflow type rain gauge has a cylindrical water receiving tube 1 with a bottom to store precipitation, and an overflow structure 2 including an overflow pipe 21 is attached to the center of the cylinder. . The lower end 211 of the overflow vibrator 21 opens into the storage section 11, and the upper end 212 opens above the center of the overflow structure 2.
Rainwater is stored in the storage section 11 up to the level of the upper end 212 of the overflow pipe 21 .

Further, a discharge port 22 is provided at the lower end of the overflow structure 2 to discharge rainwater overflowing from the overflow pipe 21, and a tipping box 3, for example, is provided below the discharge port 22 to measure the amount of rainwater discharged. .

A snow melting heater 4 is provided at the bottom of the storage section 11, and the temperature of rainwater in the storage section 11 is always maintained at 4 to 5 degrees Celsius for snow melting during snowfall.

Furthermore, oil 5 is spread over the entire water surface a of the storage section 11 to prevent rainwater from evaporating.

The above configuration is a general structure of a flood gauge, but
In order to implement the present invention, a pair of temperature sensors 6.7 are provided near the reservoir water surface a of the reservoir 11. The installation positions of the temperature sensors 6 and 7 are determined based on the stepping motion that will descend through the snow or oil 5 during snowfall and will almost completely melt, and the intervals between them are set to approximately 10 mm. It is.

This temperature sensor 6.7 has high sensitivity because it is necessary to measure extremely instantaneous and minute temperature changes when raindrops or snowflakes that have fallen into the opening 12 of the water tank 1 reach the stored water surface a. For example, a temperature sensor with a fast response speed, such as a crystal temperature sensor or a small thermistor, is used.

Rain or snow that has fallen into the opening 12 of the water tank 1 passes through the oil 5 and eventually joins the water stored in the storage section 11.

In the case of snowfall, the temperature of the stored water is set to 4 to 5 by the heater 4.
Because it is kept at ℃, it melts and joins the stored water. When the amount of stored water increases as described above, the stored water overflows from the overflow pipe 21, the overflowing water is discharged from the discharge port 22, and the amount of discharged water is measured by the tipping box 3 to measure the amount of precipitation.

On the other hand, the temperature at two points near the reservoir water surface a during precipitation is measured by a pair of temperature sensors 6.7, and the temperature difference between the two locations is measured.

As described above, when using a pair of temperature sensors 6.7, the local temperature difference of the stored water surface a is used as basic data for rain/snow discrimination. The difference between the highest and lowest temperatures, that is, the temporal temperature difference, can be used as basic data for rain/snow discrimination. In this case, only one temperature sensor is installed near the reservoir water surface a ( Temperature sensor 6.7) may be used.

Next, the signal processing system and its operation will be explained with reference to FIG.

The signal processing system includes two temperature measurement units 10 and 11, a difference signal circuit 12 that calculates the difference between the temperatures measured by the temperature measurement units 10 and 11 and outputs temperature difference data, and a temperature signal from the difference signal circuit 12. A signal processing unit 13 that performs rain/snow discrimination based on the difference data and precipitation data from the overturned square 3, a recording unit 14 that records data processed by the signal processing unit 13 (rain/snow discrimination data, etc.), and the determination criteria. S. It includes a determination reference value setting section 15 for setting.

The temperature measuring section 10.11 is composed of a temperature sensor 6.7 using, for example, a crystal oscillator, and oscillation circuits 8 and 9 using the temperature sensor 6.7 as an oscillation element.
Outputs an oscillation signal with a frequency corresponding to the temperature measured.

The difference signal circuit 12 is an oscillation circuit 8.9 of the temperature measuring section 10.11.
By outputting a signal with a frequency corresponding to the difference between the output signal frequencies of , the temperature difference data measured by the temperature sensor 6.7 is directly output. In addition, when the temporal temperature difference is used as the basic data, only one of the temperature measurement sections 10 and 11 is required, and the difference signal circuit 12 is not required, and the measurement of the temperature measurement section 10 (or 11) The temperature data (output signal of the oscillation circuit 8 or 9) is directly inputted to the signal processing section 13, and the maximum and minimum temperature difference (maximum temperature change) within a certain period of time is calculated by the processing of the signal processing section 13.

The signal processing 1113 is mainly composed of a microprocessor (CPII), and the judgment value S is determined by the above equation (1).
The judgment value S and the reference value S set by the judgment reference value setting section 15 are calculated. Rain/snow discrimination is performed by comparing with In other words, it is determined that S≧S0 is snowfall, and S<
S. When this happens, it is determined that it is raining, and this determination result is output to the recording section 14 and recorded.

(Effects of the Invention) As explained above, the present invention is capable of measuring the maximum temperature change within a certain period of time near the water surface of a rain gauge having a structure in which rainwater is always stored up to a certain level, or between two points near the water surface. Rain and snow discrimination is performed by comparing a judgment value defined as the ratio of the maximum temperature difference change within a certain period of time to the precipitation amount at that time with a reference value. It can be automated with high precision through computer processing, and batch processing of various weather observation data and rain/snow detection is possible.

In addition, it is possible to distinguish between rain and snow by attaching a temperature sensor to a rain gauge that constantly collects rainwater, such as an overflow rain gauge, so there is no need for a rain or snow discrimination sensor as an independent weather observation device. , the cost of observation equipment and its operation cost can be reduced.

[Brief explanation of the drawing]

Figures 1 and 2 are graphs showing the results of the data analysis that led to the present invention, with Figure 1 showing the relationship between the judgment value S and the number of observations of rain or snowfall, and Figure 2. is the judgment reference value S. Fig. 3 is a structural diagram of the overflow type rain gauge used in carrying out the present invention, and Fig. 4 is a block diagram of the signal processing system. (Main symbols) 3... Overturning valve 6.7... Temperature sensor 1
0.11...Temperature measurement section 13...Signal processing section 1
5... Judgment standard value setting department 4 people Figure 1 Figure 2 Judgment value (S)

Claims (1)

[Claims] 1. A temperature sensor is provided near the water surface in the stored water of a rain gauge that has means for constantly storing rainwater up to a certain level, and the temperature detected by the temperature sensor during rain or snow falls within a certain period of time. When ΔT is the difference between the maximum value and the minimum value in A rain/snow discrimination method in which it is determined that it is rain if the standard value S_0 is not exceeded, and that it is snowfall if it is exceeded. 2 In the rain/snow discrimination method according to claim 1, a pair (two) of temperature sensors is used, and ΔT is defined as the maximum value and minimum value of the temperature difference detected by the pair of temperature sensors within a certain period of time. A rain/snow discrimination method based on the difference in values. 3. In the rain/snow discrimination method according to claim 1 or 2, when the amount of precipitation R exceeds a certain value R_0, the certain value R_0 is used as the amount of precipitation R to determine the determination value S. Discrimination method. 4. The rain and snow discrimination method according to claim 1 or 2, wherein the determination reference value S_0 is set to a value such that the rain determination probability and the snowfall determination probability are equal. 5. In the rain/snow discrimination method according to claim 1 or 2, the rain/snow discrimination is configured such that the determination reference value S_0 is changed depending on whether emphasis is placed on rain/snow discrimination or on snowfall discrimination. Method.