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COMMUNICATIONS

three stations being primarily concerned with the needs of aviation. Upper-air soundings of wind, temperature and humidity are carried out from King's Park, and numerous rain gauges are operated in the Colony by Government employees and private individuals on the Observatory's behalf. The results of the observations made at the Observatory and at King's Park are published annually and those from the other stations are recorded on punched cards to facilitate rapid analysis.

Throughout the day and night a forecast service is provided at the airport where aircrews are briefed and given documents depict- ing the meteorological conditions relevant to their flights. Informa- tion is also sent to other weather centres and to aircraft in flight, either by direct radio communication or by special aviation broadcasts.

Weather bulletins for shipping and local fishermen are broadcast over Radio Hong Kong and over special channels for shipping. Liaison Officers visit merchant and Royal Navy ships in port to check their barometers and other meteorological instruments, to supply daily weather charts and to assist in other ways. The Hong Kong fleet of weather observing ships totals 68; and during a year voluntary observers on board make over 24,000 valuable observa- tions for the Observatory.

One of the most important functions of the Central Forecast Office is to issue warnings of tropical cyclones. Whenever a tropical depression, tropical storm or typhoon is located within the region bounded by the latitudes 10° and 30° North and the longitudes 105° and 125° East, six-hourly and often three-hourly bulletins are issued. These include information on the storm's intensity and expected development, the position and movement of its centre and the forecast position for 24 hours ahead. Reliable reports from ships and storm reconnaissance aircraft help to locate storms accurately. When the Colony itself is threatened, the local storm warning system is brought into use and warnings are widely distributed by means of visual signals, telephone, radio and Rediffusion. While gale signals are hoisted, statements are issued and broadcast at intervals of 30 minutes.

Time Service and Seismology. Time signals originating at the Observatory are sent out over Radio Hong Kong for the public, and in special broadcasts for aviation and shipping. A visual time