WO2023100316A1 - Snow cover amount estimation system and snow cover amount estimation method - Google Patents

Snow cover amount estimation system and snow cover amount estimation method Download PDF

Info

Publication number
WO2023100316A1
WO2023100316A1 PCT/JP2021/044262 JP2021044262W WO2023100316A1 WO 2023100316 A1 WO2023100316 A1 WO 2023100316A1 JP 2021044262 W JP2021044262 W JP 2021044262W WO 2023100316 A1 WO2023100316 A1 WO 2023100316A1
Authority
WO
WIPO (PCT)
Prior art keywords
snow
optical fiber
temperature
section
amount estimation
Prior art date
Application number
PCT/JP2021/044262
Other languages
French (fr)
Japanese (ja)
Inventor
千尋 鬼頭
優介 古敷谷
大輔 飯田
Original Assignee
日本電信電話株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本電信電話株式会社 filed Critical 日本電信電話株式会社
Priority to PCT/JP2021/044262 priority Critical patent/WO2023100316A1/en
Publication of WO2023100316A1 publication Critical patent/WO2023100316A1/en

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V8/00—Prospecting or detecting by optical means
    • G01V8/10—Detecting, e.g. by using light barriers
    • G01V8/12—Detecting, e.g. by using light barriers using one transmitter and one receiver
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V8/00—Prospecting or detecting by optical means
    • G01V8/10—Detecting, e.g. by using light barriers
    • G01V8/12—Detecting, e.g. by using light barriers using one transmitter and one receiver
    • G01V8/16—Detecting, e.g. by using light barriers using one transmitter and one receiver using optical fibres
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V8/00—Prospecting or detecting by optical means
    • G01V8/10—Detecting, e.g. by using light barriers
    • G01V8/20—Detecting, e.g. by using light barriers using multiple transmitters or receivers
    • G01V8/24—Detecting, e.g. by using light barriers using multiple transmitters or receivers using optical fibres
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01W—METEOROLOGY
    • G01W1/00—Meteorology
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01W—METEOROLOGY
    • G01W1/00—Meteorology
    • G01W1/14—Rainfall or precipitation gauges
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Definitions

  • the present disclosure relates to a snow accumulation estimation system and method for remotely measuring snow accumulation.
  • Surveillance cameras and disaster prevention cameras can also be used as a means of grasping snow conditions. If the amount of accumulated snow can be grasped using a camera, staff members will no longer need to patrol every day, and the above-mentioned requirements can be met.
  • the snow amount estimation system utilizes the fact that the temperature change in snow is smaller than the outside air temperature change.
  • the snow amount estimation system is an optical fiber having at least one raised section connecting the ground and the sky; a temperature measuring device that measures the temperature of the optical fiber as a distribution in the longitudinal direction of the optical fiber; Analysis processing for detecting a section from the ground side where the temperature change of the optical fiber is smaller than other sections from among the raised sections when there is a temperature change in the atmosphere during snowfall, and estimating the amount of snow accumulation from the length of the section. Department and Prepare.
  • the snow amount estimation method includes: Measuring the temperature of an optical fiber having at least one pull-up section connecting the ground and the sky as a distribution in the longitudinal direction of the optical fiber; Comparing the distribution before and after atmospheric temperature change during snow cover, detecting a section from the ground side in which the temperature change of the optical fiber is smaller than the others among the raised sections, and snow accumulation from the length of the section. to estimate the
  • the temperature distribution of an optical fiber stretched upwards from the ground is measured with a temperature measuring instrument that uses Raman scattered light, etc., and sections with little temperature change are detected in response to fluctuations in outside air temperature. presume.
  • the amount of accumulated snow can be measured remotely because optical fibers are used. Therefore, the present invention can provide a snow amount estimation system and a snow amount estimation method capable of remotely measuring the amount of snow accurately and economically.
  • the optical fiber is connected to the temperature measurement device at one end and the other end. Arranged in a loop.
  • the optical fiber may have a star shape with a plurality of ends when viewed from the temperature measuring device.
  • the present invention can provide a snow amount estimation system and a snow amount estimation method that can accurately and economically measure the snow amount remotely.
  • BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. It is a figure explaining the scattered light waveform which the snow amount estimation system which concerns on this invention measures. It is a figure explaining the scattered light waveform which the snow amount estimation system which concerns on this invention measures. It is a figure explaining the snow amount estimation method which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. BRIEF
  • the snow amount estimation system measures the temperature of the optical fiber based on the intensity dependence of the Raman scattering light on the temperature, associates the position of the optical fiber in the longitudinal direction with the arrival time of the returned light, Grasp the estimated amount of snow at the measurement point from the temperature distribution.
  • Raman scattered light has intensity dependence on temperature.
  • R-OTDR Renishaw Optical Time Domain Reflectometry
  • the temperature of the optical fiber can be estimated by observing the intensity of the Raman scattered light.
  • the present snow amount estimation system can measure the temperature distribution in the longitudinal direction of the optical fiber (see, for example, references).
  • the optical fiber that has been laid includes underground sections that are buried underground, aerial sections that are stretched in the air with utility poles, etc., and between underground sections and aerial sections, the optical fibers are carried from the ground to the air by utility poles (that There is a pull section to move (or vice versa).
  • the temperature change in the optical fiber between the overhead section and the raised section follows the outside air temperature change, while the temperature change in the optical fiber in the underground section is smaller than the temperature change in the optical fiber between the overhead section and the raised section. . Therefore, by comparing the temperature distribution in the longitudinal direction of the optical fiber before and after the outside air temperature change occurs, it is possible to remotely grasp the position of the pulling section.
  • the temperature change in the snow is small relative to the outside air temperature change. less than Therefore, by comparing the temperature distribution in the longitudinal direction of the optical fiber before and after the outside air temperature change occurs, it is possible to remotely grasp the length of the snow-buried portion in the lifting section, that is, the amount of accumulated snow.
  • the snow amount estimation system can remotely monitor the snow amount using the lifted section of the optical fiber network.
  • FIG. 1 is a diagram for explaining the snow amount estimation system 301 of this embodiment.
  • the snow amount estimation system 301 is an optical fiber 50 having at least one pull-up section 50a connecting the ground 20 and the sky; a temperature measuring device 11 that measures the temperature of the optical fiber 50 as a distribution in the longitudinal direction of the optical fiber 50; When there is a change in the temperature of the atmosphere during snowfall, an analysis process of detecting a section of the pulling-up section 50a from the ground 20 side where the temperature change of the optical fiber 50 is smaller than the others, and estimating the amount of snow accumulation from the length of the section. Part 12; Prepare.
  • reference numeral 25 means accumulated snow.
  • the optical fiber 50 may be embedded in the optical cable 51 .
  • the optical fiber 50 has an underground section 50b laid underground, an overhead section 50c bridged by the utility pole 13, and a raised section 50a connecting the underground section 50b and the overhead section 50c by the utility pole 13. do.
  • the temperature measuring device 11 and the analysis processing unit 12 can be arranged in the communication building 10, which is a base for snow cover management.
  • the temperature measuring device 11 is a device capable of measuring the temperature of the optical fiber 50 in a distributed manner.
  • the temperature measuring device 11 is, for example, a Raman OTDR or a Brillouin OTDR. Note that the temperature measuring device 11 has sufficiently high measurement accuracy (for example, measurement is possible in units of 1° C.) with respect to the amount of change in the outside air temperature.
  • the temperature measuring device 11 has a sufficient distance resolution (for example, a distance resolution of 1 m when measuring a 1-m change in snow cover) for measuring the amount of change in snow cover.
  • the optical fiber 50 in the pull-up section 50a is an optical cable housed in a pull-up pipe connected from the underground manhole 14 to the utility pole 13, a premises cable laid on the wall surface of the building, or a new utility pole 13 or the like for snowfall measurement. It is an optical fiber included in an optical cable to be laid.
  • the optical fiber 50 in the section 50b connecting the raised section 50a and the temperature measuring device 11 is an optical fiber included in the underground optical cable 51 pulled out from the communication building 10.
  • the section 50b is the underground optical cable and the section 50c is the overhead optical cable, but the reverse is also possible. That is, the section 50b connecting the raising section 50a and the temperature measuring device 11 may be an overhead cable, and the section 50c may be an underground cable.
  • FIG. 2A is a diagram for explaining the relative temperature distribution of the optical fiber 50 measured by the temperature measuring device 11 when snow is not covered.
  • the solid line is the relative temperature distribution at an arbitrary time
  • the dashed line is the relative temperature distribution at the time when the outside air temperature is lower than the arbitrary time.
  • FIG. 2B is a diagram for explaining the difference between the relative temperature distribution at an arbitrary time and the relative temperature distribution when the outside air temperature drops.
  • the distance Z0 from the communication building 10 to the raised section (the base of the utility pole 13) is obtained when there is no snow cover.
  • the difference in temperature above ground between day and night is greater than that below ground. Therefore, the temperature distribution of the optical fiber 50 (solid line in FIG. 2A) measured by the temperature measuring device 11 when the temperature is high (daytime) and the temperature measuring device 11 when the temperature is low (nighttime)
  • a difference from the temperature distribution of the optical fiber 50 (broken line in FIG. 2(A)) is obtained (FIG. 2(B)). From FIG.
  • the section where the temperature difference of the optical fiber 50 is small between daytime and nighttime is the underground section 50b
  • the section where the temperature difference of the optical fiber 50 is large is the above-ground section (the raised section 50a and the overhead section 50c).
  • Z0 be the boundary between the two sections.
  • an optical fiber vibration distribution measuring device (DAS: Distributed Acoustic Sensing) is connected to the optical fiber 50 in the communication building 10, and an operator strikes the base of the utility pole 13 while measuring the vibration distribution waveform.
  • Z0 may be the position at which the maximum magnitude of vibration is obtained.
  • the distance Z1 is determined by the length of the raised section 50a from Z0, so it can be calculated by measuring the length from the base of the utility pole 13 to the bridge point with a tape measure or by using a design value.
  • FIG. 3(A) is a diagram explaining the relative temperature distribution of the optical fiber 50 measured by the temperature measuring device 11 when it is covered with snow.
  • the solid line is the relative temperature distribution at an arbitrary time
  • the dashed line is the relative temperature distribution at the time when the outside air temperature is lower than the arbitrary time.
  • FIG. 3B is a diagram for explaining the difference between the relative temperature distribution at an arbitrary time and the relative temperature distribution when the outside air temperature drops.
  • the temperature measuring device 11 measures the temperature distribution (solid line in FIG. 3A) when the temperature is high (daytime) and the temperature when the temperature is low (nighttime) in the raised section 50a (Z0 to Z1).
  • the distribution (dashed line in FIG. 3(A)) is measured.
  • FIG. 3(B) shows the difference between the two temperature distributions (solid line and broken line in FIG. 3(A)).
  • the temperature change is small even if the outside temperature changes. Therefore, it can be said that the section 50s (between Z0 and Zs) in FIG. 3B, in which the temperature of the optical fiber has little change, is buried in snow (amount of accumulated snow).
  • the amount of accumulated snow does not change significantly between the times when the temperature distribution of the optical fiber 50 is measured twice. Specifically, the change in the amount of accumulated snow must be sufficiently small relative to the spatial resolution of the temperature measuring device 11 .
  • the optical fiber 50 is perpendicular to the ground 20 in the pulling section 50a. Even if the optical fiber 50 is not perpendicular to the ground 20 in the pulling section 50a, if the inclination angle can be grasped, the amount of accumulated snow can be calculated from the length from Z0 to Zs and the inclination angle.
  • FIG. 4 is a flow chart for explaining the snow amount estimation method performed by the snow amount estimation system 301 .
  • This estimation method is Measuring the temperature of the optical fiber 50 having at least one pull-up section 50a connecting the ground 20 and the sky as a distribution in the longitudinal direction of the optical fiber 50 (steps S11 and S12); Comparing the distributions before and after atmospheric temperature changes during snow cover, detecting a section 50 s in which the temperature change of the optical fiber 50 from the ground 20 side is smaller than the others in the raised section 50 a, and snow cover from the length of the section 50 s estimating the amount (step S13) I do.
  • step S10 the position of the pulling section 50a is grasped (step S01).
  • step S01 Z0 corresponding to the distance from the communication building 10 to the base of the utility pole 13 is obtained when snow is not accumulated.
  • Z0 must be the actual length determined by optical measurement.
  • the actual length of Z0 is obtained by one of the following methods. (1) Z0 is acquired by comparing the temperature distribution of the optical fiber 50 acquired before and after the outside air temperature change, as described with reference to FIG. (2) An optical fiber vibration distribution measuring device is connected to the optical fiber 50, the base of the utility pole 13 is intentionally hit, and Z0 is obtained from the vibration waveform.
  • the actual length Z1 from the communication building to the utility pole crossing point is obtained when snow is not covered.
  • the actual length of Z1 is obtained by one of the following methods. (1) Measure the distance from the base of the utility pole 13 to the bridge point with a tape measure, and add the measured value to Z0. (2) Add the design value of the distance from the base of the utility pole 13 to the bridge point to Z0.
  • a section 50a is taken from Z0 to Z1.
  • Step S11 and subsequent steps are performed when it is desired to measure the amount of accumulated snow.
  • step S11 the temperature distribution in the pulling section 50a is measured by the temperature measuring device 11 at an arbitrary time during snowfall (solid line in FIG. 3A). Also, the outside air temperature T0 at an arbitrary time is recorded.
  • step S12 the temperature distribution of the pulling-up section 50a is measured by the temperature measuring device 11 at the time when the temperature changes with respect to the outside air temperature T0 during snow cover (broken line in FIG. 3A).
  • step S13 the amount of accumulated snow is obtained from the temperature distribution of the raised section 50a in which the temperature change is relatively small (section 50s in FIG. 3(B)).
  • Emodiment 3 In the first embodiment, an example of measuring the amount of accumulated snow at one location has been described.
  • the amount of snow accumulation estimation system according to the present invention can also measure the amount of snow accumulation at a plurality of locations. 5 and 6 show the configuration of the snow amount estimation system for measuring multiple points.
  • FIG. 5 shows a snow amount estimation system 302 in which a plurality of snow amount measurement points are connected by a single optical fiber 50 in a unicursal manner.
  • the measurable measurement point interval is set to be equal to or greater than the positional resolution of the temperature measuring device 11 (for example, 100 m or greater).
  • FIG. 6 shows a snow amount estimation system 303 in which an optical fiber 50 is laid to each of a plurality of snow amount measurement points.
  • the snow amount estimation system 303 includes an optical switch 15 and measures the snow amount at each measurement point by switching the optical switch 15 .
  • FIG. 7 is a diagram illustrating the snow amount estimation system 304 of this embodiment. Snow amount estimation system 304 is different from snow amount estimation system 302 in FIG. .
  • a Raman OTDA, Brillouin OTDA, or Brillouin OCDA can be used as the temperature measuring device 11 . Therefore, the snow amount estimation system 304 has higher positional resolution and temperature accuracy than the snow amount estimation system 302 .
  • a plurality of looped optical fibers 50 may be provided using the optical switch 15 as in the snow amount estimation system 303 of FIG.
  • FIG. 8 is a diagram for explaining the snow amount estimation system 305 of this embodiment. Unlike the snow amount estimation system 302 in FIG. 5, the snow amount estimation system 305 is characterized in that it has a star shape with a plurality of terminals when viewed from the temperature measuring device 11 .
  • the present invention is implemented using a premises cable laid on the wall of a building.
  • the topology of the optical fiber network may be a star with optical splitters 16 .
  • the present invention can be implemented by placing a reflector 17 at the end of the optical fiber and using ERA (End Reflection Assisted)-BOTDA.
  • the snow amount estimation system uses an optical fiber sensing technology that can measure the temperature of the optical cable in a distributed manner. Measure the amount of time change in the temperature distribution of an optical cable laid on an inclined plane. As the optical cables laid perpendicular to the road surface, etc., use up/down cables of the existing optical cable network, in-house cables installed on the walls of buildings, or cables newly laid on utility poles, etc. to measure the amount of snow. It is possible. In other words, according to the present invention, it becomes possible to remotely monitor the amount of accumulated snow using the existing optical cable network.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • General Physics & Mathematics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Atmospheric Sciences (AREA)
  • Environmental Sciences (AREA)
  • Ecology (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Engineering & Computer Science (AREA)
  • Hydrology & Water Resources (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)

Abstract

The purpose of the present invention is to provide a snow cover amount estimation system and a snow cover amount estimation method which enable accurate, economical, and remote measurement of snow cover amount.　A snow cover amount estimation system 301 according to the present invention is provided with: an optical fiber 50 which has at least one pull-up section 50a that connects the ground 20 and the sky; a temperature measuring instrument 11 for measuring temperatures of the optical fiber 50 as a distribution in the longitudinal direction of the optical fiber 50; and an analysis processing unit 12 that, in the case where the atmospheric temperature has changed during snowing, detects, in the pull-up section 50a from the ground 20 side, a segment having a lesser change in temperature of the optical fiber 50 than other segments, and estimates the snow cover amount on the basis of the length of the segment.

Description

積雪量推定システム及び積雪量推定方法Snow amount estimation system and snow amount estimation method
　本開示は、積雪量を遠隔から測定する積雪量推定システム及びその方法に関する。 The present disclosure relates to a snow accumulation estimation system and method for remotely measuring snow accumulation.
　豪雪地方での除雪作業において、地方自治体の職員が日中帯に車両走行によるパトロールを実施し、深夜帯に実施する除雪対象道路を決定している。当該パトロールは、冬季の凍結路面を日々、長距離（７０～８０ｋｍ程度）走行するため、危険作業であり、人手不足が深刻な地方においては、サステナブル、省エネ、安全且つ効率的に積雪状態を把握することが求められる。 During snow removal work in regions with heavy snowfall, local government officials patrol vehicles during the day and decide which roads to remove snow at night. This patrol is dangerous work because it travels long distances (about 70 to 80 km) on frozen roads in winter every day, and in regions where there is a serious shortage of personnel, it is possible to grasp snow conditions in a sustainable, energy-saving, safe and efficient manner. are required to do so.
　積雪状態を把握する手段として監視カメラや防災カメラを利用することもできる。カメラを利用して積雪量を把握できれば職員が日々パトロールする必要が無くなり、上述した要求を満たすことができる。 Surveillance cameras and disaster prevention cameras can also be used as a means of grasping snow conditions. If the amount of accumulated snow can be grasped using a camera, staff members will no longer need to patrol every day, and the above-mentioned requirements can be met.
　しかし、監視カメラや防災カメラを利用する手段は、雪深い郊外地域に多数のカメラを設置しなければならない。さらに、撮影したカメラ画像から積雪量を正確に把握することが困難である。これは、カメラの特性上、白色の雪面の凹凸は判別が難しいことが理由である。さらに、濃霧時、降雪時等の気象条件によっては、さらに積雪量の把握が困難になる。つまり、積雪量の遠隔把握にカメラを利用する手段には、多数のカメラを設置するという経済的な課題、及び把握する積雪量の正確性に課題があった。 However, using surveillance cameras and disaster prevention cameras requires installing a large number of cameras in snowy suburban areas. Furthermore, it is difficult to accurately grasp the amount of accumulated snow from the captured camera images. This is because it is difficult to distinguish unevenness on the surface of white snow due to the characteristics of the camera. Furthermore, depending on weather conditions such as heavy fog or snowfall, it becomes even more difficult to grasp the amount of accumulated snow. In other words, the means of using cameras to remotely grasp the amount of accumulated snow has the economic problem of installing a large number of cameras and the problem of the accuracy of the amount of accumulated snow.
　そこで、本発明は、前記課題を解決するために、正確に且つ経済的に積雪量を遠隔で測定できる積雪量推定システム及び積雪量推定方法を提供することを目的とする。 Therefore, in order to solve the above problems, it is an object of the present invention to provide a snow amount estimation system and a snow amount estimation method that can accurately and economically measure the snow amount remotely.
　上記目的を達成するために、本発明に係る積雪量推定システムは、雪中の温度変化が外気温変化に対して小さいことを利用する。 In order to achieve the above object, the snow amount estimation system according to the present invention utilizes the fact that the temperature change in snow is smaller than the outside air temperature change.
　具体的には、本発明に係る積雪量推定システムは、
　地面と上空とを結ぶ引き上げ区間を少なくとも１か所持つ光ファイバと、
　前記光ファイバの温度を前記光ファイバの長手方向の分布として測定する温度測定器と、
　積雪時に大気の温度変化があったときに、前記引き上げ区間のうち、前記地面側から前記光ファイバの温度変化が他より少ない区間を検出し、前記区間の長さから積雪量を推定する解析処理部と、
を備える。 Specifically, the snow amount estimation system according to the present invention is
an optical fiber having at least one raised section connecting the ground and the sky;
a temperature measuring device that measures the temperature of the optical fiber as a distribution in the longitudinal direction of the optical fiber;
Analysis processing for detecting a section from the ground side where the temperature change of the optical fiber is smaller than other sections from among the raised sections when there is a temperature change in the atmosphere during snowfall, and estimating the amount of snow accumulation from the length of the section. Department and
Prepare.
　また、本発明に係る積雪量推定方法は、
　地面と上空とを結ぶ引き上げ区間を少なくとも１か所持つ光ファイバの温度を前記光ファイバの長手方向の分布として測定すること、
　積雪時における大気の温度変化前後の前記分布を比較し、前記引き上げ区間のうち、前記地面側から前記光ファイバの温度変化が他より少ない区間を検出すること、及び
　前記区間の長さから積雪量を推定すること
を行う。 Moreover, the snow amount estimation method according to the present invention includes:
Measuring the temperature of an optical fiber having at least one pull-up section connecting the ground and the sky as a distribution in the longitudinal direction of the optical fiber;
Comparing the distribution before and after atmospheric temperature change during snow cover, detecting a section from the ground side in which the temperature change of the optical fiber is smaller than the others among the raised sections, and snow accumulation from the length of the section. to estimate the
　ラマン散乱光等を利用する温度測定器で地面から上方へ張った光ファイバの温度分布を測定し、外気温変動に対して温度変化の少ない区間を検出し、その区間の長さから積雪量を推定する。光ファイバを用いるので遠隔で積雪量を測定することができる。従って、本発明は、正確に且つ経済的に積雪量を遠隔で測定できる積雪量推定システム及び積雪量推定方法を提供することができる。 The temperature distribution of an optical fiber stretched upwards from the ground is measured with a temperature measuring instrument that uses Raman scattered light, etc., and sections with little temperature change are detected in response to fluctuations in outside air temperature. presume. The amount of accumulated snow can be measured remotely because optical fibers are used. Therefore, the present invention can provide a snow amount estimation system and a snow amount estimation method capable of remotely measuring the amount of snow accurately and economically.
　なお、積雪量の測定地点である前記引き上げ区間の位置を把握することを予め行うことが好ましい。 It should be noted that it is preferable to previously grasp the position of the lifting section, which is the point for measuring the amount of accumulated snow.
　位置分解能や温度測定精度を高めることができるラマンＯＴＤＡ、Ｂ－ＯＴＤＡ、Ｂ－ＯＣＤＡを温度測定器として用いる場合、前記光ファイバは、一端と他端とが前記温度測定器に接続されるようにループ状に配置される。 When a Raman OTDA, B-OTDA, or B-OCDA capable of enhancing positional resolution and temperature measurement accuracy is used as a temperature measurement device, the optical fiber is connected to the temperature measurement device at one end and the other end. Arranged in a loop.
　前記光ファイバは、前記温度測定器から見た末端が複数であるスター型としてもよい。ＥＲＡ－ＢＯＴＤＡとすることで多数の測定地点の積雪量を同時に測定することができる。 The optical fiber may have a star shape with a plurality of ends when viewed from the temperature measuring device. By using ERA-BOTDA, it is possible to simultaneously measure the amount of accumulated snow at a large number of measurement points.
　なお、上記各発明は、可能な限り組み合わせることができる。 The above inventions can be combined as much as possible.
　本発明は、正確に且つ経済的に積雪量を遠隔で測定できる積雪量推定システム及び積雪量推定方法を提供することができる。 The present invention can provide a snow amount estimation system and a snow amount estimation method that can accurately and economically measure the snow amount remotely.
本発明に係る積雪量推定システムを説明する図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. 本発明に係る積雪量推定システムが測定する散乱光波形を説明する図である。It is a figure explaining the scattered light waveform which the snow amount estimation system which concerns on this invention measures. 本発明に係る積雪量推定システムが測定する散乱光波形を説明する図である。It is a figure explaining the scattered light waveform which the snow amount estimation system which concerns on this invention measures. 本発明に係る積雪量推定方法を説明する図である。It is a figure explaining the snow amount estimation method which concerns on this invention. 本発明に係る積雪量推定システムを説明する図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. 本発明に係る積雪量推定システムを説明する図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. 本発明に係る積雪量推定システムを説明する図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention. 本発明に係る積雪量推定システムを説明する図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the snow amount estimation system which concerns on this invention.
　添付の図面を参照して本発明の実施形態を説明する。以下に説明する実施形態は本発明の実施例であり、本発明は、以下の実施形態に制限されるものではない。なお、本明細書及び図面において符号が同じ構成要素は、相互に同一のものを示すものとする。 An embodiment of the present invention will be described with reference to the attached drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In addition, in this specification and the drawings, constituent elements having the same reference numerals are the same as each other.
［発明の特徴］
　本発明に係る積雪量推定システムは、ラマン散乱光の温度に対する強度依存性で光ファイバの温度を測定し、戻ってきた光の到着時間で光ファイバの長手方向の位置を対応付け、光ファイバの温度分布から測定地点の積雪量を推定を把握する。
　ラマン散乱光は温度に対して強度依存性を持つ。Ｒ－ＯＴＤＲ（Ｒａｍａｎ　Ｏｐｔｉｃａｌ　Ｔｉｍｅ　Ｄｏｍａｉｎ　Ｒｅｆｒｅｃｔｏｍｅｔｒｙ）は、光ファイバに入射したパルス光により生じたラマン散乱光を観測する光反射計測技術である。ラマン散乱光の強度を観測することで光ファイバの温度を推定することができる。
　また、ＯＴＤＲなので、パルス光で生じたレイリー散乱光の到着時間で光ファイバの長手方向の位置を対応付けすることができる。
　このように、本積雪量推定システムは、光ファイバの長手方向に温度分布を測定することができる（例えば、参考文献を参照。）。
［参考文献］岡本和弘、光ファイバによる温度分布計測、レーザー解説、平成６年４月 [Features of the invention]
The snow amount estimation system according to the present invention measures the temperature of the optical fiber based on the intensity dependence of the Raman scattering light on the temperature, associates the position of the optical fiber in the longitudinal direction with the arrival time of the returned light, Grasp the estimated amount of snow at the measurement point from the temperature distribution.
Raman scattered light has intensity dependence on temperature. R-OTDR (Raman Optical Time Domain Reflectometry) is an optical reflectometry technique for observing Raman scattered light generated by pulsed light incident on an optical fiber. The temperature of the optical fiber can be estimated by observing the intensity of the Raman scattered light.
In addition, since it is an OTDR, it is possible to associate the longitudinal position of the optical fiber with the arrival time of the Rayleigh scattered light generated by the pulsed light.
In this way, the present snow amount estimation system can measure the temperature distribution in the longitudinal direction of the optical fiber (see, for example, references).
[Reference] Kazuhiro Okamoto, Temperature distribution measurement by optical fiber, Laser commentary, April 1994
　一方、敷設された光ファイバには、地下に埋設された地下区間、電柱などで空中に張られた架空区間、地下区間と架空区間との間で電柱により光ファイバを地中から空中へ（その逆の場合もある）移動させる引き上げ区間が存在する。 On the other hand, the optical fiber that has been laid includes underground sections that are buried underground, aerial sections that are stretched in the air with utility poles, etc., and between underground sections and aerial sections, the optical fibers are carried from the ground to the air by utility poles (that There is a pull section to move (or vice versa).
　積雪が無い状態であれば、架空区間と引き上げ区間の光ファイバの温度変化は外気温変動に追従する一方、地下区間の光ファイバの温度変化は架空区間と引き上げ区間の光ファイバの温度変化より小さい。このため、外気温変化が生じた前後で光ファイバの長手方向の温度分布を比較することで引き上げ区間の位置を遠隔で把握することができる。 If there is no snow cover, the temperature change in the optical fiber between the overhead section and the raised section follows the outside air temperature change, while the temperature change in the optical fiber in the underground section is smaller than the temperature change in the optical fiber between the overhead section and the raised section. . Therefore, by comparing the temperature distribution in the longitudinal direction of the optical fiber before and after the outside air temperature change occurs, it is possible to remotely grasp the position of the pulling section.
　また、積雪時であれば、外気温変動に対して雪中の温度変化は小さいので、引き上げ区間の光ファイバの内、雪に埋もれている部分の温度変化は雪に埋もれていない部分の温度変化より小さい。このため、外気温変化が生じた前後で光ファイバの長手方向の温度分布を比較することで引き上げ区間における雪で埋もれた部分の長さ、すなわち積雪量を遠隔で把握することができる。 Also, when it snows, the temperature change in the snow is small relative to the outside air temperature change. less than Therefore, by comparing the temperature distribution in the longitudinal direction of the optical fiber before and after the outside air temperature change occurs, it is possible to remotely grasp the length of the snow-buried portion in the lifting section, that is, the amount of accumulated snow.
　従って、本発明に係る積雪量推定システムは、光ファイバ網の引き上げ区間を利用して遠隔から積雪量の監視を行うことができる。 Therefore, the snow amount estimation system according to the present invention can remotely monitor the snow amount using the lifted section of the optical fiber network.
［実施形態１］
　図１は、本実施形態の積雪量推定システム３０１を説明する図である。積雪量推定システム３０１は、
　地面２０と上空とを結ぶ引き上げ区間５０ａを少なくとも１か所持つ光ファイバ５０と、
　光ファイバ５０の温度を光ファイバ５０の長手方向の分布として測定する温度測定器１１と、
　積雪時に大気の温度変化があったときに、引き上げ区間５０ａのうち、地面２０側から光ファイバ５０の温度変化が他より少ない区間を検出し、前記区間の長さから積雪量を推定する解析処理部１２と、
を備える。
　図１において符号２５は積雪を意味する。 [Embodiment 1]
FIG. 1 is a diagram for explaining the snow amount estimation system 301 of this embodiment. The snow amount estimation system 301 is
an optical fiber 50 having at least one pull-up section 50a connecting the ground 20 and the sky;
a temperature measuring device 11 that measures the temperature of the optical fiber 50 as a distribution in the longitudinal direction of the optical fiber 50;
When there is a change in the temperature of the atmosphere during snowfall, an analysis process of detecting a section of the pulling-up section 50a from the ground 20 side where the temperature change of the optical fiber 50 is smaller than the others, and estimating the amount of snow accumulation from the length of the section. Part 12;
Prepare.
In FIG. 1, reference numeral 25 means accumulated snow.
　光ファイバ５０は光ケーブル５１に内蔵されていてもよい。本実施形態では、光ケーブル５１が地中に敷設されている形態を説明する。また、光ファイバ５０は、地中に敷設されている地下区間５０ｂ、電柱１３により架け渡されている架空区間５０ｃ、及び電柱１３により地中区間５０ｂと架空区間５０ｃとを結ぶ引き上げ区間５０ａが存在する。
　また、温度測定器１１と解析処理部１２は、積雪管理を行う拠点である通信ビル１０内に配置することができる。 The optical fiber 50 may be embedded in the optical cable 51 . In this embodiment, a mode in which the optical cable 51 is laid underground will be described. The optical fiber 50 has an underground section 50b laid underground, an overhead section 50c bridged by the utility pole 13, and a raised section 50a connecting the underground section 50b and the overhead section 50c by the utility pole 13. do.
Moreover, the temperature measuring device 11 and the analysis processing unit 12 can be arranged in the communication building 10, which is a base for snow cover management.
　温度測定器１１は、光ファイバ５０の温度を分布的に測定可能な装置である。温度測定器１１は、例えば、ラマンＯＴＤＲ、ブリルアンＯＴＤＲである。なお、温度測定器１１は、外気温の変化量に対して十分高い測定精度（例えば１℃単位で測定可能）を持つ。また、温度測定器１１は、積雪変化量の測定要件に対して、十分な距離分解能（例えば、１ｍの積雪量変化を測定したい場合、１ｍの距離分解能）をもつ。 The temperature measuring device 11 is a device capable of measuring the temperature of the optical fiber 50 in a distributed manner. The temperature measuring device 11 is, for example, a Raman OTDR or a Brillouin OTDR. Note that the temperature measuring device 11 has sufficiently high measurement accuracy (for example, measurement is possible in units of 1° C.) with respect to the amount of change in the outside air temperature. In addition, the temperature measuring device 11 has a sufficient distance resolution (for example, a distance resolution of 1 m when measuring a 1-m change in snow cover) for measuring the amount of change in snow cover.
　引き上げ区間５０ａの光ファイバ５０は、地下マンホール１４から電柱１３に接続される引上げ管に収容される光ケーブル、建物の壁面に敷設された構内ケーブル、または積雪量測定のために新たに電柱１３等に敷設する光ケーブルに含まれる光ファイバである。 The optical fiber 50 in the pull-up section 50a is an optical cable housed in a pull-up pipe connected from the underground manhole 14 to the utility pole 13, a premises cable laid on the wall surface of the building, or a new utility pole 13 or the like for snowfall measurement. It is an optical fiber included in an optical cable to be laid.
　引き上げ区間５０ａと温度測定器１１とを接続する区間５０ｂの光ファイバ５０は、通信ビル１０から引き出される地下光ケーブル５１に含まれる光ファイバである。なお、図１では、区間５０ｂが地下光ケーブル、区間５０ｃが架空光ケーブルであるが、逆であってもよい。すなわち、引き上げ区間５０ａと温度測定器１１とを接続する区間５０ｂが架空ケーブルであり、区間５０ｃが地下ケーブルであってもよい。 The optical fiber 50 in the section 50b connecting the raised section 50a and the temperature measuring device 11 is an optical fiber included in the underground optical cable 51 pulled out from the communication building 10. In FIG. 1, the section 50b is the underground optical cable and the section 50c is the overhead optical cable, but the reverse is also possible. That is, the section 50b connecting the raising section 50a and the temperature measuring device 11 may be an overhead cable, and the section 50c may be an underground cable.
　図２から図３を用いて、解析処理部１２が行う処理を説明する。
　図２（Ａ）は、非積雪時に温度測定器１１で測定した光ファイバ５０の相対温度分布を説明する図である。実線が任意時刻における相対温度分布、破線が任意の時刻より外気温が下がった時刻における相対温度分布である。図２（Ｂ）は、任意時刻の相対温度分布と外気温低下時の相対温度分布の差分を説明する図である。 Processing performed by the analysis processing unit 12 will be described with reference to FIGS. 2 and 3. FIG.
FIG. 2A is a diagram for explaining the relative temperature distribution of the optical fiber 50 measured by the temperature measuring device 11 when snow is not covered. The solid line is the relative temperature distribution at an arbitrary time, and the dashed line is the relative temperature distribution at the time when the outside air temperature is lower than the arbitrary time. FIG. 2B is a diagram for explaining the difference between the relative temperature distribution at an arbitrary time and the relative temperature distribution when the outside air temperature drops.
　非積雪時において、通信ビル１０から引き上げ区間（電柱１３の根元）までの距離Ｚ０を求める。日中と夜間とで地上の気温差は地下の温度差より大きい。そこで、気温が高い時刻（日中）に温度測定器１１で測定した光ファイバ５０の温度分布（図２（Ａ）の実線）と気温が下がった時刻（夜間）に温度測定器１１で測定した光ファイバ５０の温度分布（図２（Ａ）の破線）との差分を得る（図２（Ｂ））。図２（Ｂ）より、日中と夜間とで光ファイバ５０の温度差が小さい区間を地下区間５０ｂ、光ファイバ５０の温度差が大きい区間を地上区間（引き上げ区間５０ａと架空区間５０ｃ）とする。両区間の境目をＺ０とする。 The distance Z0 from the communication building 10 to the raised section (the base of the utility pole 13) is obtained when there is no snow cover. The difference in temperature above ground between day and night is greater than that below ground. Therefore, the temperature distribution of the optical fiber 50 (solid line in FIG. 2A) measured by the temperature measuring device 11 when the temperature is high (daytime) and the temperature measuring device 11 when the temperature is low (nighttime) A difference from the temperature distribution of the optical fiber 50 (broken line in FIG. 2(A)) is obtained (FIG. 2(B)). From FIG. 2B, the section where the temperature difference of the optical fiber 50 is small between daytime and nighttime is the underground section 50b, and the section where the temperature difference of the optical fiber 50 is large is the above-ground section (the raised section 50a and the overhead section 50c). . Let Z0 be the boundary between the two sections.
　あるいは、通信ビル１０内にて光ファイバ５０に光ファイバ振動分布測定装置（ＤＡＳ：Ｄｉｓｔｒｉｂｕｔｅｄ　Ａｃｏｕｓｔｉｃ　Ｓｅｎｓｉｎｇ）を接続し、振動分布波形を測定しながら、作業員により電柱１３の根元を打撃し、測定される振動の大きさの最大値をとる位置をＺ０としてもよい。 Alternatively, an optical fiber vibration distribution measuring device (DAS: Distributed Acoustic Sensing) is connected to the optical fiber 50 in the communication building 10, and an operator strikes the base of the utility pole 13 while measuring the vibration distribution waveform. Z0 may be the position at which the maximum magnitude of vibration is obtained.
　距離Ｚ１については、Ｚ０から引き上げ区間５０ａの長さで決定するため、電柱１３の根元から架渉ポイントまでの長さをメジャーで測る、あるいは設計値を使うことで算出できる。 The distance Z1 is determined by the length of the raised section 50a from Z0, so it can be calculated by measuring the length from the base of the utility pole 13 to the bridge point with a tape measure or by using a design value.
　図３（Ａ）は、積雪時に温度測定器１１で測定した光ファイバ５０の相対温度分布を説明する図である。実線が任意時刻における相対温度分布、破線が任意の時刻より外気温が下がった時刻における相対温度分布である。図３（Ｂ）は、任意時刻の相対温度分布と外気温低下時の相対温度分布の差分を説明する図である。 FIG. 3(A) is a diagram explaining the relative temperature distribution of the optical fiber 50 measured by the temperature measuring device 11 when it is covered with snow. The solid line is the relative temperature distribution at an arbitrary time, and the dashed line is the relative temperature distribution at the time when the outside air temperature is lower than the arbitrary time. FIG. 3B is a diagram for explaining the difference between the relative temperature distribution at an arbitrary time and the relative temperature distribution when the outside air temperature drops.
　積雪時において、温度測定器１１により、引き上げ区間５０ａ（Ｚ０からＺ１）について気温が高い時（日中）の温度分布（図３（Ａ）の実線）と気温が下がった時（夜間）の温度分布（図３（Ａ）の破線）を測定する。両温度分布（図３（Ａ）の実線と破線）の差分を図３（Ｂ）に示す。雪中は、外気温が変化しても温度変化が少ない。このため、図３（Ｂ）の光ファイバの温度変化が少ない区間５０ｓ（Ｚ０からＺｓの間）が、雪に埋もれている部分（積雪量）といえる。 During snowfall, the temperature measuring device 11 measures the temperature distribution (solid line in FIG. 3A) when the temperature is high (daytime) and the temperature when the temperature is low (nighttime) in the raised section 50a (Z0 to Z1). The distribution (dashed line in FIG. 3(A)) is measured. FIG. 3(B) shows the difference between the two temperature distributions (solid line and broken line in FIG. 3(A)). In the snow, the temperature change is small even if the outside temperature changes. Therefore, it can be said that the section 50s (between Z0 and Zs) in FIG. 3B, in which the temperature of the optical fiber has little change, is buried in snow (amount of accumulated snow).
　ただし、光ファイバ５０の温度分布を２回測定する時刻間で、積雪量が大きく変化しないことが前提となる。具体的には、温度測定器１１の空間分解能に対して、積雪量の変化が十分小さくなければならない。 However, it is premised that the amount of accumulated snow does not change significantly between the times when the temperature distribution of the optical fiber 50 is measured twice. Specifically, the change in the amount of accumulated snow must be sufficiently small relative to the spatial resolution of the temperature measuring device 11 .
　上記の説明は、引き上げ区間５０ａにおいて光ファイバ５０が地面２０に対して垂直であることを前提として説明している。引き上げ区間５０ａにおいて光ファイバ５０が地面２０に対して垂直でなくとも、傾斜角が把握できていれば、Ｚ０からＺｓの長さと傾斜角から積雪量を計算できる。 The above description assumes that the optical fiber 50 is perpendicular to the ground 20 in the pulling section 50a. Even if the optical fiber 50 is not perpendicular to the ground 20 in the pulling section 50a, if the inclination angle can be grasped, the amount of accumulated snow can be calculated from the length from Z0 to Zs and the inclination angle.
［実施形態２］
　図４は、積雪量推定システム３０１が行う積雪量推定方法を説明するフローチャートである。本推定方法は、
　地面２０と上空とを結ぶ引き上げ区間５０ａを少なくとも１か所持つ光ファイバ５０の温度を光ファイバ５０の長手方向の分布として測定すること（ステップＳ１１及びＳ１２）、
　積雪時における大気の温度変化前後の前記分布を比較し、引き上げ区間５０ａのうち、地面２０側から光ファイバ５０の温度変化が他より少ない区間５０ｓを検出すること、及び
　区間５０ｓの長さから積雪量を推定すること（ステップＳ１３）
を行う。 [Embodiment 2]
FIG. 4 is a flow chart for explaining the snow amount estimation method performed by the snow amount estimation system 301 . This estimation method is
Measuring the temperature of the optical fiber 50 having at least one pull-up section 50a connecting the ground 20 and the sky as a distribution in the longitudinal direction of the optical fiber 50 (steps S11 and S12);
Comparing the distributions before and after atmospheric temperature changes during snow cover, detecting a section 50 s in which the temperature change of the optical fiber 50 from the ground 20 side is smaller than the others in the raised section 50 a, and snow cover from the length of the section 50 s estimating the amount (step S13)
I do.
　また、ステップＳ１１を行う前に事前処理（ステップＳ１０）として、引き上げ区間５０ａの位置を把握しておく（ステップＳ０１）。
　ステップＳ０１では、非積雪時に、通信ビル１０から電柱１３の根元までの距離に当たるＺ０を求める。Ｚ０は光計測により求めた実長である必要がある。Ｚ０の実長は、以下のいずれかの方法で取得する。
（１）積雪量推定システム３０１を利用し、図２で説明したように、外気温の変化前後で取得した光ファイバ５０の温度分布を比較することでＺ０を取得する。
（２）光ファイバ５０に光ファイバ振動分布測定装置を接続し、意図的に電柱１３の根元を打撃し、その振動波形からＺ０を取得する。 Further, as a preliminary process (step S10) before performing step S11, the position of the pulling section 50a is grasped (step S01).
In step S01, Z0 corresponding to the distance from the communication building 10 to the base of the utility pole 13 is obtained when snow is not accumulated. Z0 must be the actual length determined by optical measurement. The actual length of Z0 is obtained by one of the following methods.
(1) Z0 is acquired by comparing the temperature distribution of the optical fiber 50 acquired before and after the outside air temperature change, as described with reference to FIG.
(2) An optical fiber vibration distribution measuring device is connected to the optical fiber 50, the base of the utility pole 13 is intentionally hit, and Z0 is obtained from the vibration waveform.
　そして、非積雪時に、通信ビルから電柱架渉ポイントまでの実長Ｚ１を求める。Ｚ１の実長は、以下のいずれかの方法で取得する。
（１）電柱１３の根元から架渉ポイントまでの距離をメジャーで測定し、その測定値をＺ０に加算する。
（２）電柱１３の根元から架渉ポイントまでの距離の設計値をＺ０に加算する。 Then, the actual length Z1 from the communication building to the utility pole crossing point is obtained when snow is not covered. The actual length of Z1 is obtained by one of the following methods.
(1) Measure the distance from the base of the utility pole 13 to the bridge point with a tape measure, and add the measured value to Z0.
(2) Add the design value of the distance from the base of the utility pole 13 to the bridge point to Z0.
　Ｚ０からＺ１を引き上げ区間５０ａとする。 A section 50a is taken from Z0 to Z1.
　ステップＳ１１以降は、積雪量を測定したいときに行う。
　ステップＳ１１では、積雪時において、任意の時刻において、温度測定器１１で引き上げ区間５０ａの温度分布を測定する（図３（Ａ）の実線）。また、任意時刻における外気温Ｔ０を記録する。
　ステップＳ１２では、積雪時において、外気温Ｔ０に対して温度変化があった時刻において、温度測定器１１で引き上げ区間５０ａの温度分布を測定する（図３（Ａ）の破線）。
　ステップＳ１３では、引き上げ区間５０ａの温度分布のうち、相対的に温度変化が小さい区間を積雪量として求める（図３（Ｂ）の区間５０ｓ）。 Step S11 and subsequent steps are performed when it is desired to measure the amount of accumulated snow.
In step S11, the temperature distribution in the pulling section 50a is measured by the temperature measuring device 11 at an arbitrary time during snowfall (solid line in FIG. 3A). Also, the outside air temperature T0 at an arbitrary time is recorded.
In step S12, the temperature distribution of the pulling-up section 50a is measured by the temperature measuring device 11 at the time when the temperature changes with respect to the outside air temperature T0 during snow cover (broken line in FIG. 3A).
In step S13, the amount of accumulated snow is obtained from the temperature distribution of the raised section 50a in which the temperature change is relatively small (section 50s in FIG. 3(B)).
［実施形態３］
　実施形態１では、１か所の積雪量を測定する例を説明した。本発明に係る積雪量推定システムは、複数箇所の積雪量も測定可能である。複数箇所を測定する積雪量推定システムの構成を図５及び図６に示す。 [Embodiment 3]
In the first embodiment, an example of measuring the amount of accumulated snow at one location has been described. The amount of snow accumulation estimation system according to the present invention can also measure the amount of snow accumulation at a plurality of locations. 5 and 6 show the configuration of the snow amount estimation system for measuring multiple points.
　図５は、複数の積雪量の測定地点を１本の光ファイバ５０で一筆書き状に接続した積雪量推定システム３０２である。測定可能な測定地点間隔は、温度測定器１１の位置分解能以上（例えば、１００ｍ以上）とする。 FIG. 5 shows a snow amount estimation system 302 in which a plurality of snow amount measurement points are connected by a single optical fiber 50 in a unicursal manner. The measurable measurement point interval is set to be equal to or greater than the positional resolution of the temperature measuring device 11 (for example, 100 m or greater).
　図６は、複数の積雪量の測定地点それぞれへ光ファイバ５０を敷設した積雪量推定システム３０３である。積雪量推定システム３０３は、光スイッチ１５を備え、光スイッチ１５を切り替えることでそれぞれの測定地点の積雪量を測定する。 FIG. 6 shows a snow amount estimation system 303 in which an optical fiber 50 is laid to each of a plurality of snow amount measurement points. The snow amount estimation system 303 includes an optical switch 15 and measures the snow amount at each measurement point by switching the optical switch 15 .
［実施形態４］
　図７は、本実施形態の積雪量推定システム３０４を説明する図である。積雪量推定システム３０４は、図５の積雪量推定システム３０２に対し、光ファイバ５０が、一端と他端とが温度測定器１１に接続されるようにループ状に配置されることを特徴とする。 [Embodiment 4]
FIG. 7 is a diagram illustrating the snow amount estimation system 304 of this embodiment. Snow amount estimation system 304 is different from snow amount estimation system 302 in FIG. .
　温度測定器１１として、ラマンＯＴＤＡ、ブリルアンＯＴＤＡ、又はブリルアンＯＣＤＡを使用することができる。このため、積雪量推定システム３０４は、位置分解能や温度精度が積雪量推定システム３０２に対して高い。なお、図６の積雪量推定システム３０３のように光スイッチ１５を利用してループ状の光ファイバ５０を複数備えてもよい。 A Raman OTDA, Brillouin OTDA, or Brillouin OCDA can be used as the temperature measuring device 11 . Therefore, the snow amount estimation system 304 has higher positional resolution and temperature accuracy than the snow amount estimation system 302 . A plurality of looped optical fibers 50 may be provided using the optical switch 15 as in the snow amount estimation system 303 of FIG.
［実施形態５］
　図８は、本実施形態の積雪量推定システム３０５を説明する図である。積雪量推定システム３０５は、図５の積雪量推定システム３０２に対し、温度測定器１１から見た末端が複数であるスター型であることを特徴とする。 [Embodiment 5]
FIG. 8 is a diagram for explaining the snow amount estimation system 305 of this embodiment. Unlike the snow amount estimation system 302 in FIG. 5, the snow amount estimation system 305 is characterized in that it has a star shape with a plurality of terminals when viewed from the temperature measuring device 11 .
　建物の壁面に敷設された構内ケーブルを用いて本発明を実施する場合もある。このような場合、光ファイバネットワークのトポロジが光スプリッタ１６を有するスター型となることもある。この場合には、光ファイバの末端に反射板１７を配置し、ＥＲＡ（Ｅｎｄ　Ｒｅｆｌｅｃｔｉｏｎ　Ａｓｓｉｓｔｅｄ）－ＢＯＴＤＡを利用することで本発明を実施可能である。 In some cases, the present invention is implemented using a premises cable laid on the wall of a building. In such cases, the topology of the optical fiber network may be a star with optical splitters 16 . In this case, the present invention can be implemented by placing a reflector 17 at the end of the optical fiber and using ERA (End Reflection Assisted)-BOTDA.
［効果］
　本発明に係る積雪量推定システムは、光ケーブルの温度を分布的に測定が可能な光ファイバセンシング技術を用いて、積雪量を測定する路面等に対して垂直方向（傾斜角が既知であるならば傾斜していてもよい）に敷設された光ケーブルの温度分布の時間変化量を測定する。路面等に対して垂直方向に敷設された光ケーブルとして、既設光ケーブル網の引上げ／下げケーブルや建物の壁面設置された構内ケーブル、または、積雪量測定のために新たに電柱等に敷設するケーブルを利用可能である。
　つまり、本発明により、既設光ケーブル網を活用して遠隔から積雪量の監視ができるようになる。 [effect]
The snow amount estimation system according to the present invention uses an optical fiber sensing technology that can measure the temperature of the optical cable in a distributed manner. Measure the amount of time change in the temperature distribution of an optical cable laid on an inclined plane. As the optical cables laid perpendicular to the road surface, etc., use up/down cables of the existing optical cable network, in-house cables installed on the walls of buildings, or cables newly laid on utility poles, etc. to measure the amount of snow. It is possible.
In other words, according to the present invention, it becomes possible to remotely monitor the amount of accumulated snow using the existing optical cable network.
１０：通信ビル
１１：温度測定器
１２：解析処理部
１３：電柱
１４：マンホール
１５：光スイッチ
１６：光スプリッタ
１７：反射板
２０：地面
２５：積雪
５０：光ファイバ
５０ａ：引き上げ区間
５０ｂ：地下区間
５０ｃ：架空区間
５０ｓ：雪中区間
５１：光ケーブル
３０１～３０５：積雪量推定システム 10: Communication building 11: Temperature measuring device 12: Analysis processing unit 13: Utility pole 14: Manhole 15: Optical switch 16: Optical splitter 17: Reflector 20: Ground 25: Snow cover 50: Optical fiber 50a: Lifting section 50b: Underground section 50c: Aerial section 50s: Snow section 51: Optical cable 301-305: Snow amount estimation system

Claims (5)

  1. 　地面と上空とを結ぶ引き上げ区間を少なくとも１か所持つ光ファイバと、
    　前記光ファイバの温度を前記光ファイバの長手方向の分布として測定する温度測定器と、
    　積雪時に大気の温度変化があったときに、前記引き上げ区間のうち、前記地面側から前記光ファイバの温度変化が他より少ない区間を検出し、前記区間の長さから積雪量を推定する解析処理部と、
    を備える積雪量推定システム。     an optical fiber having at least one raised section connecting the ground and the sky;
    a temperature measuring device that measures the temperature of the optical fiber as a distribution in the longitudinal direction of the optical fiber;
    Analysis processing for detecting a section from the ground side where the temperature change of the optical fiber is smaller than other sections from among the raised sections when there is a temperature change in the atmosphere during snowfall, and estimating the amount of snow accumulation from the length of the section. Department and
    Snow amount estimation system with.
  2. 　前記光ファイバは、一端と他端とが前記温度測定器に接続されるようにループ状に配置されることを特徴とする請求項１に記載の積雪量推定システム。 The snow amount estimation system according to claim 1, wherein the optical fiber is arranged in a loop so that one end and the other end are connected to the temperature measuring device.
  3. 　前記光ファイバは、前記温度測定器から見た末端が複数であるスター型であることを特徴とする請求項１に記載の積雪量推定システム。 The snow amount estimation system according to claim 1, wherein the optical fiber has a star shape with a plurality of ends when viewed from the temperature measuring device.
  4. 　地面と上空とを結ぶ引き上げ区間を少なくとも１か所持つ光ファイバの温度を前記光ファイバの長手方向の分布として測定すること、
    　積雪時における大気の温度変化前後の前記分布を比較し、前記引き上げ区間のうち、前記地面側から前記光ファイバの温度変化が他より少ない区間を検出すること、及び
    　前記区間の長さから積雪量を推定すること
    を行う積雪量推定方法。     Measuring the temperature of an optical fiber having at least one pull-up section connecting the ground and the sky as a distribution in the longitudinal direction of the optical fiber;
    Comparing the distribution before and after atmospheric temperature change during snow cover, detecting a section from the ground side in which the temperature change of the optical fiber is smaller than the others among the raised sections, and snow accumulation from the length of the section. A method of estimating snow cover.
  5. 　前記引き上げ区間の位置を把握することを予め行うことを特徴とする請求項４に記載の積雪量推定方法。 The method for estimating the amount of accumulated snow according to claim 4, wherein the position of the lifted section is grasped in advance.
PCT/JP2021/044262 2021-12-02 2021-12-02 Snow cover amount estimation system and snow cover amount estimation method WO2023100316A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2021/044262 WO2023100316A1 (en) 2021-12-02 2021-12-02 Snow cover amount estimation system and snow cover amount estimation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2021/044262 WO2023100316A1 (en) 2021-12-02 2021-12-02 Snow cover amount estimation system and snow cover amount estimation method

Publications (1)

Publication Number Publication Date
WO2023100316A1 true WO2023100316A1 (en) 2023-06-08

Family

ID=86611656

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2021/044262 WO2023100316A1 (en) 2021-12-02 2021-12-02 Snow cover amount estimation system and snow cover amount estimation method

Country Status (1)

Country Link
WO (1) WO2023100316A1 (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04281597A (en) * 1991-03-11 1992-10-07 Matsushita Electric Ind Co Ltd Road freeze detector
JP2001228264A (en) * 2000-02-17 2001-08-24 Mitsubishi Cable Ind Ltd Road-surface freezing predicting system
JP2003114283A (en) * 2001-10-03 2003-04-18 Sparkling Foton:Kk Snow accumulation monitoring device, and ice and snow melting system
JP2003270358A (en) * 2002-03-15 2003-09-25 Nippon Telegr & Teleph Corp <Ntt> Snow accumulation sensor using optical fiber, snow gauge, and snow accumulation measurement method
US20050077455A1 (en) * 2003-08-13 2005-04-14 Townley-Smith Paul A. Perimeter detection
JP2017191044A (en) * 2016-04-14 2017-10-19 株式会社鈴木エンタープライズ Snow coverage detection device and snow coverage detection system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04281597A (en) * 1991-03-11 1992-10-07 Matsushita Electric Ind Co Ltd Road freeze detector
JP2001228264A (en) * 2000-02-17 2001-08-24 Mitsubishi Cable Ind Ltd Road-surface freezing predicting system
JP2003114283A (en) * 2001-10-03 2003-04-18 Sparkling Foton:Kk Snow accumulation monitoring device, and ice and snow melting system
JP2003270358A (en) * 2002-03-15 2003-09-25 Nippon Telegr & Teleph Corp <Ntt> Snow accumulation sensor using optical fiber, snow gauge, and snow accumulation measurement method
US20050077455A1 (en) * 2003-08-13 2005-04-14 Townley-Smith Paul A. Perimeter detection
JP2017191044A (en) * 2016-04-14 2017-10-19 株式会社鈴木エンタープライズ Snow coverage detection device and snow coverage detection system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
HIROSHI TAKAHASHI, ET AL.: "Investigation of Acoustic Wave Excitation Process by Frequency Swept Pulse for Loss Measurement Using Brillouin Scattering", IEICE TECHNICAL REPORT, vol. 116, no. 456 (OFT2016-52), 1 January 2017 (2017-01-01), pages 39 - 44, XP009546769 *
OKAMOTO KAZUHIRO: "Fiber-Optic Distributed-Temperature Sensing", REZA KENKYU - REVIEW OF LASER ENGINEERING., REZA GAKKAI, JP, vol. 22, no. 4, 1 January 1994 (1994-01-01), JP , pages 276 - 283, XP093070000, ISSN: 0387-0200, DOI: 10.2184/lsj.22.276 *

Similar Documents

Publication Publication Date Title
JP7267918B2 (en) Method and system for distributed acoustic sensing
CN106570568B (en) Bridge and tunnel inspection maintenance management system and method based on three-dimensional panorama and GIS map
WO2013103201A1 (en) Disturbance sensor for interference-type optical fiber and sensing method thereof
CN110474677B (en) Method for quickly positioning optical fiber breakpoint
JP7164027B2 (en) OPTICAL FIBER SENSOR, MONITORING SYSTEM, SENSING POSITION CORRECTION METHOD, AND SENSING POSITION CORRECTION PROGRAM
NO310125B1 (en) System for monitoring high voltage cables in air tension
WO2006123977A1 (en) A method for detecting ice on the surface of a fixed structure, a device for performing the method and a fixed structure provided with a device for detecting ice
WO2023100316A1 (en) Snow cover amount estimation system and snow cover amount estimation method
CN111926651B (en) Electric heating ice-proof snow-melting system for road and paving method thereof
Bastianini et al. Discontinuous Brillouin strain monitoring of small concrete bridges: Comparison between near-to-surface and smart FRP fiber installation techniques
WO2022019603A1 (en) Snow removal operation management system using internet of things (iot)
CN102401730A (en) Self-organized optical fiber cable identification instrument
KR102380853B1 (en) Road deiceing solution injection system with autonomous operation function
CN111239842A (en) Rainwater invasion optical cable monitoring system and method based on distributed optical fiber sensing technology
JP2002157676A (en) Road surface state discriminating method of visible image type road surface state grasping device
CN211147591U (en) Mileage calibration device for distributed optical fiber strain sensing system
Li et al. Research and experiment on AI-based co-cable and co-trench optical fibre detection
CN202329986U (en) Self-organization optical fiber and optical cable identification instrument
CN205665360U (en) Filthy monitoring devices of insulator
US11733070B2 (en) Street light operating status monitoring using distributed optical fiber sensing
WO2022176047A1 (en) Utility pole position specification method and aerial fiber optic cable state estimation method
CN107607066B (en) Differential detection method and system for ponding area in underground space building
WO2022220509A1 (en) System and method for making snow removal decision
WO2023100312A1 (en) Snow cover amount estimation system and snow cover amount estimation method
WO2024053069A1 (en) Deposit estimation system and deposit estimation method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21966399

Country of ref document: EP

Kind code of ref document: A1