The Hong Kong tropical cyclone warning signals (traditional Chinese: 熱帶氣旋警告信號) or informally typhoon signals (颱風信號) are a set of signals used to indicate the threat or effects of a tropical cyclone. Hong Kong ( officially the Hong Kong Special Administrative Region, is a territory located on China 's south coast on the Pearl River Delta, and borders A tropical cyclone is a storm system characterized by a low pressure center and numerous Thunderstorms that produce strong winds and Flooding The Hong Kong Observatory issues the warning signal if a tropical cyclone is centred within 800 kilometres (500 miles) of Hong Kong and may affect Hong Kong later. Hong Kong Observatory ( known as the Royal Observatory ( before 1997, is a department of the Hong Kong Government. A very similar system, which is maintained by the Direcção dos Serviços Meteorológicos e Geofisicos de Macau, is used in Macau. For a topic outline on this subject see List of basic Macau topics.
The signals are represented as a set of numbers, symbols and lights.
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History
Beginning in 1884, a combination of drums, balls and cones was hoisted to alert mariners in the harbour of an approaching tropical cyclone. Year 1884 ( MDCCCLXXXIV) was a Leap year starting on Tuesday (link will display the full calendar of the Gregorian calendar (or a Leap year The drum is a member of the percussion group technically classified as a Membranophone. BALL ( Biochemical Algorithms Library) is a C++ library containing common algorithms used in Biochemistry and Bioinformatics. Victoria Harbour is a natural landform Harbour situated between Hong Kong Island and the Kowloon Peninsula in Hong Kong. On the other hand, the warning was given to the general public using a typhoon gun. The gun was replaced by bombs in 1907, as the bombs made louder sounds and were considered an improvement. Year 1907 ( MCMVII) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian calendar (or a Common year The last typhoon bomb was detonated in 1937. Year 1937 ( MCMXXXVII) was a Common year starting on Friday (link will display the full calendar of the Gregorian calendar.
The first numbered warning signal system was introduced in 1917. Year 1917 ( MCMXVII) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Common year The numbers ranged from 1 to 7, with 2 to 5 signifying gale force winds expected from the four quadrants. The system was amended in 1931 with the numbers 1, 5, 6, 7, 8, 9 and 10, with 5 to 8 signifying gales from the four quadrants. Year 1931 ( MCMXXXI) was a Common year starting on Thursday (link will display full 1931 calendar of the Gregorian calendar. The No. 3 Strong Wind Signal was introduced in 1956 as an intermediate warning between the No. Year 1956 ( MCMLVI) was a Leap year starting on Sunday (link will display full calendar of the Gregorian calendar. 1 Stand By Signal and the gale signals.
In the past, the signals were physically hoisted at many locations in Hong Kong; there were 42 signal stations around the territory in the 1960s. A sea mark, also seamark and Navigation mark, is a Pilotage aid which identifies the approximate position of a maritime channel hazard The 1960s decade refers to the years from the beginning of 1960 to the end of 1969 However, as radio and television weather reports became increasingly effective, the need to hoist physical signals diminished. Radio is the transmission of signals by Modulation of electromagnetic waves with frequencies below those of visible Light. Television ( TV) is a widely used Telecommunication medium for sending ( Broadcasting) and receiving moving Images, either monochromatic Weather Report was an influential Jazz fusion band of the 1970s and early 1980s combining Jazz and Latin jazz with Art music, The last signal station, Cheung Chau aeronautical meteorological station on Cheung Chau, was decommissioned on 1 January 2002. Cheung Chau ( Pinyin: Chángzhōu lit "Long Island" is a small Island 10 km southwest of Hong Kong Island. New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC See also 2002 (disambiguation Year 2002 ( MMII) was a Common year starting on Tuesday of the Gregorian calendar. Accordingly, the observatory has replaced the word hoist with issue in its official terminology, although the phrase "Signal No. __ has been hoisted" is still widely used by the public and the mass media.
Current system
Starting from 1 January 1973, signals 5 to 8 were replaced by 8 NW, 8 SW, 8 NE and 8 SE respectively so as to avoid misunderstanding by the public. New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC Year 1973 ( MCMLXXIII) was a Common year starting on Monday (link will display full calendar of the 1973 Gregorian calendar. This system has been in use ever since.
In accordance with legal codes and common practices in Hong Kong, once any signals higher than No. 3 are issued, all government agencies will shut down their operations. Schools will immediately cease their sessions, as well the financial markets and a majority of the private sector. Public transit agencies that operate on the sea or on surface streets and highways will either cease or scale back their operation. In an effort to minimise the disruptions and stress caused by the exodus of office workers from their workplace, the Hong Kong Observatory usually gives the city an advance warning of about two hours before actually issuing Signal No. 8.
As the system was originally intended to serve as warnings for mariners, the issuance of signals were based on wind speeds measured around the Victoria Harbour. Victoria Harbour is a natural landform Harbour situated between Hong Kong Island and the Kowloon Peninsula in Hong Kong. However, the system has also been adopted for use by the public over the years, and with ongoing urbanization, some have come to question the relevance of the warning system's mechanism in this day and age, citing the following reasons:
- The city enters a complete standstill once Signal No. 8 is issued, and economic losses are incurred as a result of disruptions to financial activities.
- An overwhelming majority of buildings in Hong Kong are now built using concrete, and thus are able to withstand substantially higher wind speeds.
- With many tall skyscrapers acting as barriers, wind speeds are slowed, thus minimising the danger that citizens are exposed to.
- The advent of Mass Transit Railway (MTR) has allowed transportation to operate underground, free from weather interferences. MTR, or Mass Transit Railway, is the Rapid transit Railway system in Hong Kong.
- After being released from work due to an impending storm, many officeworkers treat their time off as an opportunity to go out and socialize, as evident by full restaurants and queues outside cinemas, rather than to go home and ride out the storm, exemplifying the minimal danger a cyclone poses.
Starting from the tropical cyclone season in 2007, the signals will be issued based on a network of 8 near sea-level reference anemometers over Hong Kong. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.
Meaning of signals
The official definitions of the signals are as follows:
| Signal Number | Signal Name | Sustained Wind Speed (km/h, (mph, Beaufort scale)) | Gusts (km/h (mph)) | Signal Sign | Remarks |
1 | Stand-by (戒備) | N/A | N/A |  | A tropical cyclone is centred within 800 kilometres of Hong Kong and may later affect the territory, or there are strong winds in Hong Kong waters |
3 | Strong winds (強風) | 41 - 62 (26-37, Beaufort Force 6-7) | may exceed 110 (69) |  | Strong winds are expected or blowing generally in Hong Kong near the sea level, and the wind condition is expected to persist |
8 NW | Gale or storm force winds | 63 - 117 (38-73, Beaufort Force 8-11) | may exceed 180 (113) |  | Gale or storm force winds are expected or blowing generally in Hong Kong near the sea level from the NW quadrant, and the wind condition is expected to persist |
8 NE |  | Gale or storm force winds are expected or blowing generally in Hong Kong near the sea level from the NE quadrant, and the wind condition is expected to persist | |||
8 SE |  | Gale or storm force winds are expected or blowing generally in Hong Kong near the sea level from the SE quadrant, and the wind condition is expected to persist | |||
8 SW |  | Gale or storm force winds are expected or blowing generally in Hong Kong near the sea level from the SW quadrant, and the wind condition is expected to persist | |||
9 | Increasing | 88 - 117, increasing (55-73, Beaufort Force 10-11) | N/A |  | Gale or storm force winds are increasing. The Beaufort scale (ˈboʊfət is an Empirical measure for describing Wind speed based mainly on observed sea conditions |
10 | Hurricane (颶風) | >118 (74+, Beaufort Force 12) | may exceed 220 (138) |  | Hurricane force winds. Eye of typhoon may be passing directly over Hong Kong. |
See also
External links
- Website of the Hong Kong Observatory
- Hong Kong's Tropical Cyclone Warning Signals
- Tropical Cyclone Warning Signals of Macau
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