GEOGRAPHY AND CLIMATE
RESEARCH
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Investigations were carried out on various aspects of geophysics and meteorology to meet the planning and design requirements for development projects in the Colony. These included a detailed analysis of surface winds over Hong Kong in connection with the construction of the container terminal at Kwai Chung and a study of meteorological factors that affect the operation of the Instrumental Landing System and Precision Approach Radar at Hong Kong International Airport. A comparison was made between winds from Waglan Island and Cape D'Aguilar for the planning of the new Cable and Wireless satellite ground station.
Many early statistical analyses of tropical cyclones were revised and updated and tracks of all tropical cyclones which occurred in the western Pacific and China Seas area during the period 1884– 1969 were compiled for each standard five-day period of the year. Considerable efforts were also devoted to the improvement of existing techniques of forecasting rainfall amount and new methods were being developed for predicting the movement of tropical cyclones for more than 24 hours.
Time lapse pictures of radar echoes taken during several severe rainstorms were analysed for the purpose of studying the fine struc- ture of rainfall distribution associated with these disturbances.
The Royal Observatory co-operated with several overseas scien- tific institutes in various special studies in seismology, radioactivity, marine climatology and atmospheric chemistry. The first marine climatological summary to be published by any country in the world was completed during the year.
THE YEAR'S WEATHER
1971 will probably be remembered for typhoon Rose which caused the highest fatalities and heaviest damage to property in Hong Kong since typhoon Wanda in 1962. The year was also notable for the unusually high number of tropical cyclones which affected the Colony. Out of 36 tropical cyclones which formed over the western Pacific and South China Sea, nine came sufficiently close to Hong Kong to necessitate the hoisting of storm signals. The weather for the year was generally warmer, drier and sunnier than usual with the second lowest mean relative humidity on record.
January to May were typical of winter and spring months in Hong Kong with outbreaks of cold and dry northerly air alternating with periods of dull and humid weather. The Strong Monsoon Signal