THE ENVIRONMENT
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A telemetry network of three modern short-period seismographs is being set up at Tsim Bei Tsui, Chi Ma Wan and Yuen Ng Fan to improve knowledge of regional seismology and to adequately monitor seismic activity. The seismographs will be installed in early 1978.
Three strong-motion accelerographs also will be installed on bedrock, decomposed granite and reclaimed land to study the response of different geological structures to seismic waves. Sites have been chosen at Tate's Cairn, the observatory headquarters and the Royal Hong Kong Auxiliary Police Headquarters in Wan Chai.
In co-operation with the University of Hong Kong, the observatory continued to take geomagnetic measurements during the year at a station near Tate's Cairn. The observatory also monitors radioactivity. Regular measurements of beta and gamma activity in the atmosphere, in rainfall and in tap water have been made since 1961 at the King's Park Meteorological Station. The general-level of atmospheric radioac- tivity for the first part of 1977 was low, although a marked increase was noted after the Chinese nuclear explosion in September.
Daily air pollution measurements at King's Park were started during the year to measure the concentration of particulates and sulphur dioxide in the atmosphere. This information is needed for a scientific study on the effects of local weather on the concentration of pollutants. A Pollution Meteorology Unit within the observatory is planned to study microscale meteorology in places ear-marked for development as part of environmental impact investigations.
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The observatory maintains meteorological instruments at various locations through- out Hong Kong. Anemometers at 12 sites record wind information, which is specially important during tropical cyclones and also useful in connection with a variety of engineering projects. The observatory co-operates with the University of Hong Kong in operating wind towers at Cape D'Aguilar to record the vertical structure of winds, particularly in relation to wind stress on buildings. Because the majority of these instruments both electronic and non-electronic are unique in Hong Kong, all repairs, calibration and maintenance are done by observatory staff.
Special meteorological instruments are operated at Hong Kong International Airport, where the safety of aircraft depends on reliable and accurate meteorological measurements. Three anemometers will soon be installed in the aircraft approaches as part of an operational wind shear project. When fully operational, the project will provide pilots with warnings on variations in winds during the critical take-off and landing periods.
Research
Investigations and basic research in applied meteorology and geophysics were carried out during the year in support of local industry and government activities. Mete- orological data and climatological information were routinely supplied to other government departments, and to local and overseas institutes and organisations. More than 220 technical papers have been published by the observatory on various aspects of local weather and on a wide variety of geophysical subjects.
In 1977, the observatory was involved in numerical modelling by computer of storm surges - abnormal tide levels that occur during tropical cyclones. The findings will be used to produce the best design levels for sea walls, reclamation and drainage