ENG-2001 — Page 368

THE ENVIRONMENT

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through its telecommunication lines with meteorological centres in Beijing and Tokyo.

Hourly pictures of cloud and water vapour distribution are received from both the Japanese Geostationary Meteorological Satellite and the Chinese Fengyun-2 Satellite for monitoring tropical cyclones, severe storms and frontal systems over most parts of Asia and the western Pacific.

The Observatory's Doppler weather radar at Tai Mo Shan provides high-resolution rainfall and wind data for monitoring severe weather within some 500 kilometres of Hong Kong.

Weather observers and 67 automatic weather stations in Hong Kong provide comprehensive and real-time coverage of regional weather variations, while observations from Voluntary Observing Ships provide valuable information on weather at sea.

Rainfall information is important because of the occurrence of flood and landslips during heavy rain. A network of 111 automatic reporting raingauges provides real- time information on rain distribution and intensity for the operation of rainstorm and landslip warnings. An operational nowcasting system combines radar and raingauge analysis to forecast rainfall in the next two hours.

The Observatory runs high-resolution numerical weather prediction models using a high-speed computer to enhance the capability of rainstorm forecasting. Using guidance from numerical products from both global and limited area models, forecasters can now issue weather forecasts several days ahead with reasonable confidence.

In March, the Observatory issued an experimental forecast on the total rainfall and the number of tropical cyclone affecting Hong Kong in the year, as part of a pilot study on long range forecasting.

The Observatory operates tide gauges to monitor raised sea levels and coastal flooding caused by tropical cyclones. To probe the upper atmosphere, radiosondes carried by balloons are launched three times a day at King's Park to measure weather conditions aloft.

The Observatory exchanges weather radar images with the Guangdong Meteorological Bureau and operates jointly with the bureau four solar-powered automatic weather stations at islands in the Pearl River Estuary area to provide better timing of the approach of hazardous weather such as fronts, squall lines and tropical cyclones.

Aviation Meteorology

The Observatory operates the Airport Meteorological Office (AMO) at the Hong Kong International Airport to provide weather services for civil aviation. The AMO is responsible for the provision of weather services for a designated airspace over the northern part of the South China Sea. It keeps a close watch on the weather and issues warnings on hazardous weather over this airspace. It operates a web-based automatic information service to provide aviation users with flight documents, latest aerodrome forecasts and warnings, and other weather information. Weather briefings are provided to pilots and other users as needed.