利用者:Balaeniceps/sandbox
現在のシステム
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No. 3以上のシグナルが発令されると、香港では法と慣習に従ってすべての行政機関は業務を停止し、学校は直ちに授業を中断し、金融市場及び大多数の民間企業は臨時休業となる。帰宅ラッシュによる交通機関の混乱を避けるため、急務のある従業員以外は帰宅を命じられる。海上、陸上および高速道路上の輸送機関は通常、シグナル発令時には運転を続けるが、急遽運休となる可能性もある。No. 8以上のシグナル発令中に従業員を業務に就かせる場合、雇用主は安全に仕事ができる環境と、勤務終了時に交通機関が運休になった場合に備えて宿泊所を用意しなければならない。そのような場合の措置については、事前に雇用主と従業員との間で 取り決めておく必要がある[1]。混乱を最小限に抑えるため、香港天文台は1987年よりNo. ８シグナル発令の２時間前に発令予告を出すことを慣例としているが、そのような予告はNo. ８シグナル発令の緊急性を示す指標ではない[2]。
当初このシグナルは船員のために開発されたもので、ビクトリア湾で計測した風速に基づいて発令されていた。後年、都市部住民へのサービスが中心になると、その観測結果は実情に合わないものとみなされるようになった[3]。 2006年、台風プラピルーンが香港を襲った際、No. 3 シグナルが妥当であると判断されたビクトリア湾岸に比べて都市部の被害状況が極めて深刻であったため、香港天文台は批判の的となった。そのため香港天文台は2007年より香港近海の8ヶ所の風速計を情報網に加えた[4]。
2017年、台風ハトが香港を襲った際にはシグナル10が発令され、航空機の遅延や欠航が相次いだが、台風の収束とともに再開し、一晩かけて遅れを取り戻した。香港MTRは地上部での運転を運休とし、トンネル内ではダイヤを変更して運転を維持した。すべての学校が終日休校となり、政府は臨時の避難所を解説した。倒木と洪水により被害が発生した。株式市場（とその他のビスネス）は終日、もしくは数時間にわたり業務が停止された[5]。
2018年9月、台風マンクット襲来ではシグナル10が発令され、航空機の遅延や欠航が相次いだが、台風の収束とともに再開し、一晩かけて遅れを取り戻した。MTRは地上部での運転を運休とし、トンネル内ではダイヤを変更して運転を維持した。すべての学校が終日休校となり、政府は臨時の避難所を解説した。倒木と洪水により被害が発生した。株式市場（とその他のビスネス）は終日、もしくは数時間にわたり業務が停止された。窓ガラスの被害を防ぐためマスキングテープが用いられたが、多くの窓ガラスが強風のために破損した。
Meaning of signals
[編集]The Saffir–Simpson hurricane wind scale is a classification used for some Western Hemisphere tropical cyclones. Hong Kong has a similar official five-level definition warning signals, which uses descriptions of winds taken from the Beaufort Scale, as shown in the table below. The Hong Kong levels, however do not correspond to the Beaufort Scale which has 12 levels.
The lowest level of the Hong Kong system No. 1 doesn't correspond to any wind strength. Instead it is an alert based on the distance of a storm.
The highest level, Hurricane Signal No. 10, is issued infrequently. There have been 16 No. 10 warnings since 1946, of which three have occurred in the 2010s thus far, for Typhoon Vicente in 2012, Typhoon Hato in 2017, and Typhoon Mangkhut in 2018.[6] No. 10 warnings generally occur in intervals of around four years or less, except for the period from the 1980s to 2000s when only two such signals were issued, for Typhoon Ellen in 1983 and Typhoon York in 1999.
Signals numbers will change in accordance with the conditions. The Hong Kong Observatory website gives live updates of issue and cancel times for signals.[7]
| Signal Number |
Signal Name |
Symbol | Meaning |
|---|---|---|---|
| 1 | Standby (戒備) |
|
No. 1 signal is purely advisory. It is a standby signal and calls attention to the fact that there is a tropical cyclone centred within about 800 kilometres of Hong Kong which might later affect Hong Kong. If strong winds are not expected within 24 hours, the issuance of the signal may be delayed until the circulation moves closer or intensifies, but it should not be assumed that there will be a 24-hour interval between the issuance of No. 1 signal and the onset of strong winds.
When No. 1 signal is issued, staff required to take precautions during tropical cyclones should report to their offices and remain on call. Small crafts should remain within reach of shelter. Attention should be paid to weather bulletins as records show there are three chances in four that No. 1 signal will be followed by strong wind or gale warnings. Weather at this time is generally fine and hot. The No. 1 signal may also be issued when a tropical cyclone is departing Hong Kong but strong winds are still affecting offshore waters. |
| 3 | Strong Wind (強風) |
|
No. 3 signal is a definite warning that a tropical cyclone is expected to come near enough to Hong Kong to cause strong winds in Hong Kong. Strong winds range from 41 to 62 kilometres per hour, but gusts may exceed 110 kilometres per hour. The warning refers to the general condition near sea level within Hong Kong, but winds on exposed hilltops and offshore waters may reach gale force.
No. 3 signal normally gives about 12 hours warning of strong winds generally over Hong Kong at sea level, but in exposed areas, winds may become strong sooner. Sailing craft, lighters and ships without power should be secured. Ships with power should move or prepare to move to typhoon buoys or anchorages. Contractors should see that all scaffolding, hoardings and other temporary structures are secured. Gutters and storm drains should be cleared of leaves and rubbish. Doors and windows should be checked to make sure that they can be securely fastened. Owners of small craft should complete arrangements for safety of their boats. Ferry services may soon be affected by wind or waves. Scheduled services to outlying districts may be cancelled in anticipation of worsening conditions. |
| 8NW | Gale or Storm (烈風或暴風) |
|
No. 8 signals give warning of a gale or storm from one of the four quadrants. A gale ranges from 63 to 87 kilometres per hour and storm from 88 to 117 kilometres per hour. Gusts may exceed 180 kilometres per hour.
The timing of the issuance of the first of these signals is aimed to give about 12 hours warning of gales generally over Hong Kong near sea level, but the warning may be shorter for exposed areas and on high ground. Unexpected intensification of the tropical cyclone on accelerated movement closer to Hong Kong may reduce the warning period. When these signals are interchanged indicating an anticipated change in the direction of the gale or storm, the wind shift may be expected within a few hours. When one of these signals is issued, ferries generally stop running and all schools and law courts are closed. People away from home should either return immediately or find a safe place and remain there until the danger has passed. Windows and doors should be bolted and shuttered and cars parked in sheltered areas. Full typhoon precautions should be completed as soon as possible as it is extremely dangerous to delay these until No. 9 or No. 10 signal is issued. |
| 8SW | 
| ||
| 8NE | 
| ||
| 8SE | 
| ||
| 9 | Increasing Gale or Storm (烈風或暴風風力增強) |
|
No. 9 signal indicates that the gale or storm is expected to increase significantly in strength.
There are no firm rules as to when the signal may be issued, but the issuance usually implies that wind speeds are expected to reach the range 88 to 117 kilometres per hour, and that the centre of a typhoon will soon pass close to Hong Kong, with the consequent shifting of wind direction. All precautions should have been completed prior to the issuance of No. 9 signal. |
| 10 | Hurricane (颶風) |
|
No. 10 signal gives warning of a hurricane force wind. Hurricane force winds range upwards from 118 kilometres per hour but gusts may exceed 220 kilometres per hour. This signal implies that a typhoon centre will soon pass over or very close to Hong Kong, and hurricane force winds can be expected anywhere near sea level in Hong Kong within a short time of the issuance of the signal.
It is advisable to stay indoors to avoid flying debris. If premises are buffeted by hurricane force winds, all internal doors should be kept tightly shut to lessen the chance of windows or air-conditioning units being blown out or sucked in. It may be useful to reinforce some windows with heavy furniture, props, bars or even mattresses. If people have to go out, they should keep clear of overhead wires and hoardings. Typhoons can cause the tide to rise much higher than normal. There storm surges may occur in enclosed inlets can cause serious flooding of low-lying land. Heavy rain may also cause flooding. Landslides may occur and some buildings may collapse. If you are advised to move to a safe place, it is essential to remain calm and co-operate with the rescue service. Should the eye of a typhoon pass over some part of Hong Kong, a lull may occur, lasting for a few minutes or even some hours. This will be followed by the return of hurricane force winds from a different direction. It is necessary to be prepared for the sudden change in wind direction because places that were well sheltered earlier may now become dangerously exposed. |
Hong Kong Observatory public guidance
[編集]The Hong Kong Observatory has given public guidance when signals are given.[8] This include:
When signal 1 is issued, to take into account in planning activities of a tropical cyclone and to be aware that strong winds may occur over offshore waters.
When signal 3 is issued, secure all loose objects, particularly on balconies and roof tops.
When signal 8 is issued, complete all precautions (such as secure all loose objects) before gales commence.
When signal 9 or 10 is issued, stay indoors and away from exposed windows and doors to avoid flying debris.
Macau counterpart
[編集]In Macau, the territory's Meteorological and Geophysical Bureau maintains a very similar system.[9] The bureau has maintained the practice of hoisting the warning signals (as well as its nighttime light signals), even as Hong Kong abandoned the practice in 2002. The signals are hoisted at Guia Fortress and the Fortaleza do Monte. In 2017, Typhoon Hato also reached Signal number 10, but Macau raised the signal too late, hours after Hong Kong.[10]
See also
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References
[編集]- ^ “Code of Practice in times of Typhoons and Rainstorms”. Labour Department. 2018年12月15日閲覧。
- ^ “Related Advisory Information and Arrangements from Bureaux and Departments in Tropical Cyclone Situations”. Hong Kong Observatory. Template:Cite webの呼び出しエラー：引数 accessdate は必須です。
- ^ “Regional Wind Information”. Hong Kong Observatory. Template:Cite webの呼び出しエラー：引数 accessdate は必須です。
- ^ “Review of the Tropical Cyclone Warning System in 2006 and New Measures in 2007”. Hong Kong Observatory. Template:Cite webの呼び出しエラー：引数 accessdate は必須です。
- ^ https://www.bloomberg.com/news/articles/2017-08-22/hong-kong-braces-for-storm-hato-stock-trading-may-be-disrupted
- ^ http://www.hko.gov.hk/cgi-bin/hko/warndb_e1.pl?opt=1&sgnl=10&start_ym=194609&end_ym=201208&submit=Submit+Query
- ^ http://www.hko.gov.hk/wxinfo/dailywx/wxwarntoday.htm
- ^ http://www.hko.gov.hk/publica/gen_pub/tcws.pdf
- ^ “Meaning of Tropical Cyclone Signals and the relevant recommended safety precautions”. Macao Meteorological and Geophysical Bureau. 15 July 2013閲覧。
- ^ Master, Tyrone Siu and Farah. “Weather boss steps down as Macau struggles to recover from typhoon” (英語). IN 2017年8月26日閲覧。