ENG-1989 — Page 384

THE ENVIRONMENT

Particular importance is attached to the effective dissemination of up-to-date weather information to the public, the media and other users. In 1989, weekly weather programmes were presented on television by forecasters of the Royal Observatory to provide an in-depth discussion of recent weather events. Two special bulletins with weather charts as illustrations were prepared for the press each day. When warranted, live interviews and briefings were given by forecasters over radio and television. For members of the public requiring instant access to weather forecasts or tropical cyclone information, the observatory has implemented a dial-a-weather service. The demand for this service has continued to grow and there are now seven Chinese and one English dial-a-weather lines in operation and on average 4 100 calls are handled daily with up to 460 calls per hour at times. Around one and a half million calls were received in 1989. Tailor-made weather information for special users is supplied through teletype, telex or telefax. The Royal Observatory also provides information to the INFOTEX and INFOFAX, which make available to telex and telefax terminal holders a large variety of routine weather in- formation, including pictorial information such as the daily weather map.

Weather Monitoring and Prediction

To provide a wide range of meteorological services, the Royal Observatory monitors local weather round the clock. 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 Royal Navy at Tai O and by the Royal Air Force at Sek Kong.

A network of automatic weather stations designed and built by the observatory telemeters weather data to the Central Forecasting Office in the observatory headquarters from Ta Kwu Ling, Lau Fau Shan, Tsing Yi, Sha Tin, Tuen Mun, Aberdeen and Waglan Island. These stations help to provide more localised weather information to the densely-populated new towns. In collaboration with the Guangdong Meteorological Bureau, the observatory operates an automatic weather station at Huangmao Zhou, an island 40 kilometres south of Lantau Island, to monitor vital information when tropical cyclones approach from the south.

Rainfall information has always been important in Hong Kong because of its relation to water supply and also because of the susceptibility of slopes to landslips in heavy rain. A dense network of about 140 raingauge stations over Hong Kong provides comprehensive coverage for information on rainfall intensity and distribution. In this network, 67 stations are equipped with up-to-the-minute automatic raingauges relaying information for moni- toring flooding and landslips in the territory. Rain intensity within 500 kilometres of Hong Kong is monitored with a digital radar system which also produces objective short-term rainfall estimates at selected places. A lightning detection system locates cloud-to-ground lightning within a range of about 130 kilometres and a spheric recorder is used to register thunderstorm activity within about 100 kilometres.

Besides land-based observations, upper-air atmospheric conditions can be measured by radiosondes carried by balloons launched at King's Park Meteorological Station. For a hemispheric overview of weather systems, hourly high resolution satellite cloud pictures are received in Hong Kong from the Japanese Geostationary Meteorological Satellite. The availability of hourly imageries greatly facilitates the monitoring of weather systems, especially when they are in close range.

For the real-time monitoring of floods in the north-west New Territories, water-level and rainfall information at Kam Tin has been relayed directly to the observatory headquarters

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