JPS59108980A - Forecast of striking by lightning - Google Patents

Abstract

PURPOSE:To realize an economical system structure with emission of an accurate warning against striking by lightning by judging data on changes in the intensity of an electric field and the distance from a thunder cloud at the observation point to obtain the position of the thunder cloud and the distribution of changes in the electric field level. CONSTITUTION:A thunderclap converter section 7 starts operation to send a clock pulse signal to a processor 10 for counting when a ground electric field, namely, the inversion in the polarity of a corona current is detected with a lightning converter section 4 as the strength of a thunder cloud increases and exceeds the critical ground electric field. Subsequently, when a thunder clap arrives and is inputted from a sound collection microphone 5, the transmission of clock pulse signal is stopped. In this case, the time (t) between striking by lightning and the arrival of the thunderclap is calculated from the number of pulse counted while the distance D from the thunder cloud, namely, the point of striking by lightning from an observation point is computed from the relationship of D=c.t (c is sound velocity). The results are outputted as a thunder cloud distance signal from the processor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for predicting lightning strikes by predicting lightning strikes.

BACKGROUND OF THE INVENTION Lightning strike prediction systems have conventionally been implemented using, for example, (1) radar, (2) lightning discharge counter, or (2) field mill. However, although method (3) is the most reliable method, it is systemically complex and expensive, and the measurement operation requires advanced technology, so it has not been widely used.
Although it is suitable for predicting lightning over a wide area, it is difficult to predict local lightning strikes. (2) only counts the number of electric field changes associated with lightning discharges, making it difficult to distinguish between distant lightning and close-in lightning.

Also, protection may be counted using airborne radio waves other than lightning discharges. Method (2) predicts lightning strikes based on the strength of the ground electric field, and although it is highly accurate, it requires a wide, flat installation location to prevent the ground electric field from being disturbed by surrounding objects. In addition, it is expensive, so it has not become widely popular.

Purpose of the Invention The present invention has been made with the aim of eliminating the drawbacks of the prior art.In the present invention, by measuring the corona current passing through a needle electrode having a constant height above the ground, The distance from the lightning strike point to the observation point can be measured by indirectly measuring the ground electric field in the relationship between However, the structure is such that the location and timing of a lightning strike can be predicted by determining changes in the ground electric field and distance.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to preferred embodiments of the present invention shown in the accompanying drawings.

FIG. 1 shows a schematic diagram of a lightning prediction system used in the lightning prediction method of the present invention. In the figure, / is a needle electrode, λ is a coaxial cable, 3 is a grounding wire, and G is an electric converter connected to the needle electrode / via a coaxial cable. On the other hand, on the left is a sound collecting microphone, 6 is an approach cable, and 7 is a thunder conversion section. The electric converter and the thunder converter 7 are connected to a processing device 10 . Regarding the electrical conversion section, please refer to the Journal of the Institute of Electrical Engineers of Japan, April 2007, Volume 3, page 3.3-'10, entitled ``Development of lightning alarm using needle tip corona current.'' This is explained in a paper by Hikaru Nakamura et al.

First, the electric converter constantly monitors and measures the corona current from the needle electrode, and as thunderclouds form, the corona current gradually increases. The relationship between the corona current ■ and the ground electric field E is expressed by the Charmer equation: I=a(E-
b) E (where a and b are constants); lightning strikes occur when the ground electric field E exceeds a critical value; therefore, lightning strikes can be predicted by measuring the corona current. Therefore, the output signal from the electric converter passes through the processing device 10 and is output as a thundercloud level signal. This is usually shown in a graph on a numeral or the like.

The thunder converter 7 starts the operation of the thunder converter 7 and generates a clock pulse when the force of the thundercloud increases and exceeds the critical ground electric field, and the electric converter detects a polarity reversal of the ground electric field, that is, the corona current. Send the signal to the processing device IO,
Perform counting. After that, when a thunderclap arrives and the thunderclap is input from the sound collecting microphone j, the transmission of the clock pulse signal is stopped.

In this case, the processing device/θ calculates the time t from the lightning strike to the arrival of the sound based on the number of counted pulses, and the distance from the thundercloud, that is, the lightning strike point to the observation point, is calculated as D=c−t( c is the speed of sound). This is output as a thundercloud distance signal from the processing device/θ.

In this way, in the system of FIG. 1, by determining the changes in the thundercloud level signal and the thundercloud distance signal,
The former tells you when lightning will strike, and the latter tells you where it's going to strike.Then, you can also issue a warning when thunderclouds are getting closer and closer and within a certain distance. However, even if the thundercloud level signal indicates that no discharge or lightning will occur for some time even if the thundercloud level signal is within a certain distance range, the generation of the warning may be delayed until a certain set level is reached.

Figure 2 shows three lightning observation devices 10θ, 2θθ, and 3
A schematic diagram showing a lightning strike prediction system based on θOK, that is, three-point observation is shown. In this case, the processing device /θ is placed in the central station, and the transmission device ro provided in each observation device and the communication line /θl are connected to each other.

θ/, 30/ are connected to each other. In the case of this three-point observation, the presence of thunderclouds and their movement direction can be discovered in areas where the coverage areas of each observation device overlap, and accurate lightning strike prediction (obtaining information on thundercloud distribution) can be performed.

Effects of the Invention According to the present invention, the position of thunderclouds and the distribution of changes in electric field level can be accurately determined by data on changes in electric field intensity due to thunderclouds (changes in corona discharge current) and changes in distance from observation points. It is possible to issue a lightning warning and realize an economical system configuration.

Further, by using it in combination with weather data such as wind direction, wind speed, temperature, and rainfall, more accurate and comprehensive lightning strike predictions can be made.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a lightning prediction system used in the lightning prediction method according to the present invention, and FIG. 1 is a schematic diagram showing a three-point method lightning prediction system using three observation devices. L: Needle electrode, G: Electrolytic conversion unit, 7: Thunder conversion unit, 1
0... Processing device. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] (1) The first stage of continuously measuring the ground electric field by continuously measuring the corona discharge current flowing through a needle electrode having a certain height above the ground; polarity of the ground electric field during lightning discharge or lightning strike; The first step is to continuously measure the distance from the lightning strike point to the observation point by measuring the time from when it reverses to when the thunder arrives; and, from the change in the ground electric field and the change in the distance, change in the thundercloud. A lightning strike prediction method characterized by comprising: a third step of predicting the timing and location of a lightning strike by observing it, and issuing a warning when a lightning strike is predicted to occur within a certain distance from the observation point. (2) The method according to claim (1), wherein in the third step, a warning is issued when a lightning strike is predicted to occur within a certain period of time. (3) Claim No. 1 in which the number of observation points is plural
) or the method described in paragraph (e).