ENG-1993 — Page 471

THE ENVIRONMENT

warning is now issued whenever Hong Kong is affected by heavy rain which may cause serious road flooding and traffic congestion. The observatory also issues warnings on thunderstorms, flooding, landslips, storm surges, fire danger, strong monsoon winds and

frost.

For people requiring instant access to weather forecasts or tropical cyclone information, the observatory operates a dial-a-weather service. The demand for this service continues to grow. There are now 27 lines for public weather forecasts and four lines for South China coastal waters bulletins. Close to 12 million calls were handled in 1993. On average, more than 30 000 calls were handled daily.

Information is also provided to the INFOTEX and INFOFAX services, which make available by telex and telefax a large variety of routine weather information, including pictorial data such as the daily weather map. Weather information is also made available for access by terminals connected to a commercial communications and paging network.

In response to the difficulties experienced by fishermen in receiving the South China coastal waters bulletins through regular radio broadcasts, a special arrangement has been made with Hongkong Telecom International to broadcast the forecasts three times a day, and up to four times when tropical cyclone warning signals are hoisted.

In planning the meteorological facilities required to support the new airport under construction at Chek Lap Kok, the observatory has taken steps to engage consultants to design and acquire state-of-the-art systems for meteorological data processing, information distribution, and wind shear detection and warning.

Weather Forecasting, Monitoring and Prediction

To provide the wide range of meteorological services described in the previous section, the observatory maintains a weather watch round-the-clock. Weather observers at the Royal Observatory Headquarters and Hong Kong International Airport make regular observations on local weather conditions. Additional observations are made by volunteers and collaborating agencies at other remote locations.

Apart from manual observation, a network of automatic weather stations telemeters real-time weather data to the Central Forecasting Office from Cheung Chau, King's Park, Ta Kwu Ling, Lau Fau Shan, Tsing Yi, Sha Tin, Tuen Mun, Wong Chuk Hang, Tai Po Kau, Sai Kung, Tseung Kwan O, Sha Lo Wan and Waglan Island. These stations provide a comprehensive coverage of regional weather variations. For aviation safety, wind conditions at the airport and its vicinity are monitored continuously by a network of anemometers. In collaboration with the Guangdong Meteorological Bureau, the observatory also operates an automatic weather station at Huangmao Zhou, an island 40 kilometres south of Lantau Island and strategically located for monitoring tropical cyclones approaching from the south.

Rainfall information is important for water resources management and also because of the susceptibility of slopes to landslips in heavy rain. A dense network of 143 raingauge stations provides information on the spatial distribution and intensity of rainfall in various parts of Hong Kong. Sixty-nine of these stations are equipped to provide up-to-the-minute information every five minutes. Rain cloud development, movement and intensity within 512 kilometres of Hong Kong are monitored by a digital radar system which also produces objective short-term rainfall estimates at selected locations. A lightning detection system

407