ENG-1970 — Page 274

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GEOGRAPHY AND CLIMATE

The Observatory's weather radar station at Tate's Cairn equipped with a three centimeter radar for detecting showers and local rainstorms and a 10 centimeter radar, for locating larger tropi- cal disturbances up to 240 miles away. The latter radar can also be used to estimate the intensity of rainfall and provides valuable information for forecasting as well as for local hydrological purposes.

The Observatory is also responsible for the Colony's time service. Six pip signals from a special crystal clock, accurate to 0.05 second, are broadcast every 15 minutes on a frequency of 95 MHz and are relayed by the various broadcasting and television stations.

The Observatory operates 12 seismometers, prepares bulletins of all earthquake tremors recorded, and participates in the Pacific Tidal-wave Warning Service. Hong Kong lies just outside the circum- Pacific seismic belt and has not suffered serious earthquake damage since 1918. However an average of two to three tremors may be felt each year by residents in favourable locations such as on balconies of high buildings. No such tremors occurred in 1970.

In order to provide warning of any possible health hazards due to radioactive fallout from nuclear explosions, regular measurements of beta- and gamma-activity in the atmosphere and in rainfall are carried out at King's Park Meteorological Station. The radioactivity of filtered water samples from several reservoirs in the Colony is also regularly monitored.

The Observatory answers numerous requests for climatological and meteorological information from various government depart- ments, firms and the general public and issues certificates for litiga- tion purposes and for insurance claims. The department also acts in an advisory capacity in the planning of many projects in the Colony that may be affected by meteorological conditions. Technical notes and memoirs are published from time to time on various aspects of the weather of Hong Kong and on a wide variety of related subjects.

In 1970, plans were made to computerise the work of the Observ- atory and a great deal of climatological data was transferred onto punch cards and magnetic tapes. In order to facilitate retrieval and to save storage space, plans were also made to microfilm all weather maps and documents.