ENG-1976 — Page 279

THE ENVIRONMENT

The Royal Observatory

199

The Royal Observatory is the government department responsible for meteoro- logy and geophysics. Weather forecasting and storm warning services are particularly important in Hong Kong because an average of 24 tropical cyclones form each year within an area where they could disrupt the international shipping or aviation on which local trade and tourism so largely depend.

In order to provide weather services, the observatory collects about 10,000 weather reports each day from land stations, ships and aircraft. Coded meteorological information arrives on teleprinter links and is fed into a computer system where it is sorted, decoded, printed and archived. A new two-way teleprinter link with Peking was opened in December 1975 as part of a United Nations plan for a global tele- communications system. Since April 1976,-automatic message switching of meteoro- logical data between Bangkok, Peking, Tokyo and Hong Kong has been carried out by an IBM S/7 computer.

Hong Kong's own weather observing network continued to expand during the year and a variety of weather observations are now made regularly at nine stations, while rainfall is measured over a dense network of 150 raingauges. An increasing proportion of the data is now being analysed by computer.

Close liaison is maintained with ships visiting Hong Kong and some 37 selected ships are provided with instruments by the Royal Observatory to encourage them to transmit weather reports which are used in the preparation of forecasts and for locating tropical cyclones. On average, 42 weather reports are received each day from various ships through Hong Kong's two coastal radio stations. All reports are dis- seminated to other centres and also punched onto cards for use in the computer system. Special weather bulletins are broadcast for shipping and fishermen.

All aircraft leaving Hong Kong are given briefings, forecasts, and weather charts. A continuous watch is kept on the weather at airports and along air routes. Opera- tional information and forecasts are exchanged with 35 other airports in 19 countries.

The tropical cyclone warning service is one of the most important functions of the observatory. Whenever a tropical cyclone is located between latitudes 10°-30°N and longitudes 105°-125°E, warnings for shipping are issued every three hours. These provide information on the strength of the circulation, the position and movement of the centre, and the 24-hour forecast position. Objective forecasts prepared on the observatory's computer system are issued to neighbouring countries. Reports from ships and reconnaissance aircraft are received at the observatory and used to locate the centre, and to evaluate the intensity of the tropical cyclone. Cloud pictures, both visual and infra-red, are received directly from orbiting meteorological satellites. The pictures help forecasters and they are also analysed to give information on the loca- tions and intensities of tropical cyclones.

When tropical cyclones approach Hong Kong, warnings are widely distributed by visual signals, telephone, radio and television. Information and forecasts are broadcast at frequent intervals. Advisory bulletins and recommended precautions are also put out to the public. If the centre of a tropical cyclone comes within 240