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THE ENVIRONMENT
also 23 anemometers installed in different locations, of which 15 are operated by the Royal Observatory and eight by other organisations. Winds recorded at the Star Ferry Pier, Kowloon, representing conditions in the harbour, and winds recorded at Waglan Island, representative of conditions off-shore, are telemetered to the observatory. A spherics recorder is used to register thunderstorm activity within a range of about 100 kilometres.
Tide readings from gauges located at Tai Po Kau, North Point and Lok On Pai are telemetered to the observatory. These provide valuable data for warning floods during the approach of tropical cyclones. A wave recorder installed at Waglan Island gives continuous records of wave height and period. The observatory also provides instruments for about 40 selected voluntary observing ships.
Two Doppler acoustic radars are in operation near Chek Lap Kok to investigate wind shear and turbulence in connection with the planning and design for the proposed new airport. These instruments transmit pulses of sound and record the echoes caused by temperature and wind irregularities in the atmosphere. =
A network of three short-period seismometers at Cheung Chau, High Island and Tsim Bei Tsui are connected to a micro-computer at the Royal Observatory. The system detects earthquake tremors throughout Southeast Asia and calculates the position of the epicentres. Long-period seismographs in a cellar beneath the observatory lawn record tremors from all over the world. Strong motion accelerographs are installed at three locations. While on average only two or three earthquakes are felt by local residents each year, several hundred are detected by the Royal Observatory seismometer network. In 1982, more than 100 earthquakes were detected within 320 kilometres of Hong Kong.
Geomagnetic observations were made during the year at Tate's Cairn in co-operation with the University of Hong Kong. Measurements of Beta and Gamma radio-activity are made at King's Park Meteorological Station and the observatory co-operates with the UK Atomic Energy Research Establishment and the International Atomic Energy Agency in the measurement of radio-active substances in airborne dust and rain.
The observatory operates a caesium beam atomic clock which provides time signals accurate to a few micro-seconds. A six-pip signal is broadcast on 95 MHz every quarter hour.
Research
The Royal Observatory participates in international co-operative programmes to improve the standard of meteorological services. In 1982, during the First Typhoon Operational Experiment organised under the auspices of an international Typhoon Committee, special observations were made in Hong Kong and sent to other countries in Southeast Asia. A senior forecaster was seconded to the International Experiment Centre set up in Tokyo to carry out operational studies during actual typhoon situations.
Considerable effort is devoted by the Royal Observatory to meet the demand for meteorological analyses required by industry and engineering projects. A design rainstorm profile for Hong Kong was published in 1982. During the year, a procedure to determine design wind and wave conditions in off-shore waters was developed and applied to specific locations. A micro-meteorological study was also carried out in Junk Bay to investigate local meteorological conditions which might affect new developments.