METEOROLOGY

Otago Daily Times, Issue 18763, 17 January 1923, Page 7

METEOROLOGY

QUESTION OF WIND VARIATIONS. SCIENTIFIC INVESTIGATIONS. (Peb United Peess Association.) 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 pr®r sidontial address, dealt win, the advances made by the Scandinavians, especially Nor-’ wegians, in meteorology as tne 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 J 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 accom- i panied 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 shipping to expect increasing winds and rough seas. The ■ theory, also gave a complete account of the ' various ways in which rainfall is produced. ‘1 This was worked out in great detail. j Ihe results of observations of winds of the j upper atmosphere at Wellington and at Apia ) (.Samoa) were presented by Professor B. .* JVlarsden, who described the experiments conducted at Victoria College during the last six months with balloons. By means of ' theodolytes 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 belween a 6000 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 cyclonesin the lover levels were sucked into the barhour through the straits, and the city heing ; ' ‘ near the centre of activity, experienced’’' , greater winds than would be the case other- ‘ wise. This data will be used in the testing of 1 Captain Kidson’s theory. If the theory is proved correct it will be possible to make weather forecasts two or threte weeks ahead. Similar observations at Apia. (Samoa) showed that the south-east trade wind at the surface" ’ changed into a steady west-south-west wind • : at 40 miles per hour above the height dF’ 19,000 ft. The result was that it would bo’ -' advantageous in travelling by aeroplane to/V-' Fiji or Samoa to follow the lower levels 1 and to take the higher levels above 15,000 f t: 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 every • day during the present year, with the object , of working out complete data.