METEOROLOGY

Otago Witness, Issue 3593, 23 January 1923, Page 66

METEOROLOGY

SCIENTIFIC INVESTIGATIONS. WELLINGTON, January 16. The subject of wind frequencies which has an important bearing upon meteorological observations and weather forecasts, was discussed by the meteorological section at the Science Congress, when some interesting papers were presented. Captain Kidson, of Melbourne, in his presidential address, dealt will the advances made by the Scandinavians, especially Norwegians, in meteorology as the result of being compelled to maintain their forecasting service without reports from belligerent countries during the Great War. What had hitherto been regarded as a typical cyclone was now recognised as one stage only in the life history of a cyclone. It was possible to recognise from the characteristics of an individual cyclone, its age, and its further developments. Thus it might be possible to say that a “low” which had been reported as moving eastward from Australia accompanied by gales of wind, would diminish in intensity as it approached New Zealand, with a corresponding moderation of winds and seas. On the other hand, if the depression were recognised as a young one, it would be possible to warn snipping to expect increasing winds and rough seas. The theory also gave a complete account of the various ways in which rainfall is produced. This was worked out in great detail. The results of observations of winds of the upper atmosphere at Wellington and at Apia (Samoa) wero presented by Professor E. Marsden, who described the experiments conducted at Victoria College during the last six months with balloons. By means of t.heodolytes ho was able to ascertain wind velocities at various heights. The most interesting result was. that although the most prevalent wind at the surface was northerly, yet above 6000 ft it was southerly. He found that a very abrupt change occurred in the direction of the wind between a 5000 ft and 7000 ft altitude. This, he remarked, was quite peculiar to Wellington, and it looked as though Wellington’s winds were really confined to the surface levels alone. Higher up the wind conditions were no worse than in other centres. It appeared as if cyclones in the lover levels were sucked into the harbour through the straits, and the city being near the centre of activity, experienced greater winds than would be the case otherwise. This data will be used in the testing of Captain Kidson’s theory. If the theory is proved correct it will be possible to make weather forecasts two or three weeks ahead. Similar observations at Apia (Samoa) showed that the south-east trade wind at the surface changed ir to a steady west-south-west wind at 40 miles per hour above the height of 19,000 ft. The result was that it would be advantageous in travelling by aeroplane to Fiji or Samoa to follow the lower levels and to take the higher levels above 15,000 ft on the return journey, which would afford a steady 40 or 50 miles per hour wind. The authorities at the Samoan Observatory, he stated, had considered these results, and had decided to continue investigations everc day during the present year, with the, object of working out complete data.