ENG-1993 — Page 473

THE ENVIRONMENT

Climate, Oceanographic and Geophysical Services

The Royal Observatory carries out climate, oceanographic and geophysical studies. Its professional advice is often sought by consultants working on government or private projects. When an engineering project demands substantial data collection and analyses over a prolonged period, special studies are conducted.

A climatological information service is provided to meet the needs of the general public and to cater for the specialised interests of shipping, aviation, agriculture, fisheries, engineering, industry, judicial proceedings, and recreational planning. In particular, analyses on the probabilities of high winds, heavy rain, waves and surges are undertaken, using mathematical models as well as statistics of extremes. The observatory carries out extensive data analyses and research, the results of which are published in various forms. These publications are not only useful in support of the observatory's own operations, but are also very much in demand by engineers working on hydrological forecasting, water resources planning, drainage design, water quality control, reservoir design and operation, irrigation and infrastructure projects.

Climate change is another subject of interest and concern. The observatory participates actively in international climate programmes and, through the World Meteorological Organisation, keeps abreast of the findings and recommendations made by the Inter- governmental Panel on Climate Change.

To monitor earthquakes and seismicity, three short-period seismometers are operated at Cheung Chau, High Island and Tsim Bei Tsui. Long-period seismographs at the observatory's headquarters record tremors occurring throughout the world. Strong-motion accelerographs are operated at the observatory's headquarters and Tate's Cairn. About 130 earth tremors with epicentres within 320 kilometres of Hong Kong are detected annually. Reports of significant tremors are routinely made known to the general public via the media. Seismic data are used by structural engineers in the design of buildings. Such data are also made available to local and overseas scientific institutions for their studies.

The Hong Kong Time Standard is provided by a caesium beam atomic clock at the observatory headquarters. Accuracy within fractions of a microsecond a day is maintained. The time service is operated by relaying a six-pip time signal to Radio Television Hong Kong for broadcast.

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