ENG-1984 — Page 364

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THE ENVIRONMENT

Operations and Services The department's most important function is the provision of weather forecasts and tropical cyclone warnings for the public, shipping and aviation. The Central Forecasting Office issues local weather forecasts and warnings of hazardous weather conditions to the press, radio and television broadcasting stations, and government departments. Whenever Hong Kong is threatened by tropical cyclones, frequent warnings with advice on necessary precautions are issued at three-hourly intervals and widely disseminated. Other warnings cover thunderstorms, flooding, landslips, fire danger, strong monsoons and frost. Regular weather bulletins are issued to ships at sea, fishermen in coastal waters and yachtsmen. Specialised forecasts are prepared on request for offshore operations in the South China Sea. Following the successful completion of two Typhoon Operational Experiments in 1982 and 1983, organised under the auspices of an international Typhoon Committee, the usefulness of enhanced exchange of observational data and forecasts among meteoro- logical services in the region during tropical cyclone situations was generally recognised. In 1984, the Royal Observatory continued to participate in the programme of enhanced information exchange.

Services for aviation are provided by the Airport Meteorological Office. About 80 aircraft each day are supplied with prognostic weather charts and landing forecasts. Special warnings are issued for adverse weather. Wind conditions at the airport and its vicinity are monitored continuously using a network of anemometers and a doppler acoustic radar at Lei Yue Mun on the southeastern approach to the airport.

In order to provide these services, meteorological data are received from other places through a computerised telecommunication system. This information is regularly analysed and supplied to forecasters while the coded messages are exchanged automatically with neighbouring countries.

Weather observers at the Royal Observatory headquarters, Hong Kong International Airport and Cheung Chau keep a continuous watch on local conditions. Additional observations are made by the Marine Department at Waglan Island and Green Island, by the Royal Navy at Tai O and by the Royal Air Force at Sek Kong. Fifteen anemometers are operated by the observatory in different locations. Winds recorded at the Star Ferry Pier, Kowloon, and at Waglan Island, representing conditions in Victoria Harbour and offshore respectively, are telemetered to the Central Forecasting Office. A spherics recorder is used to register thunderstorm activity within a range of about 100 kilometres, and a lightning location system provides information on lightning within about 130 kilometres. The observatory also operates a network of more than 100 conventional rain-gauges, mostly read by voluntary observers. Implementation of the plan to supply more up-to-the-minute information to the Central Forecasting Office continued. During the year, two automatic weather stations were set up at Chek Lap Kok and Sha Tin. Both stations sent weather data to the observatory headquarters via telephone lines. An agreement was also reached with the Guangdong Meteorological Bureau to set up an automatic weather station on Huangmao Zhou, an island 40 kilometres to the south of Lantau Island. The network of automatic rain-gauges which report rainfall amounts instantaneously to the observatory through a microprocessor system was expanded during the year. A tide gauge was installed at HMS Tamar and the readings were telemetered to the Central Forecasting Office which also received tide information from Tai Po Kau, North Point, Lok On Pai and Chek Lap Kok. Work was in hand to transmit to the observatory headquarters wave data collected at Waglan Island. Aided by these networks, weather forecasters keep a close watch on the latest developments in weather and issue warnings accordingly.