FORECASTING THE WEATHER

Ashburton Guardian, Volume 69, Issue 77, 11 January 1949, Page 2

FORECASTING THE WEATHER

System in New Zealand 70 PER CENT. SUCCESS CLAIMED (PA.) WELLINGTON, Jan. 10. Forecasts are not a guarantee of future weather, but a pretty sure indication of it.” This was stated to-day by the Research Officer .for Meteorology in’New Zealand, Mr J. W. Hutchings, who enumerated some of the difficulties met. Seventy per cent, of the forecasts, at least, he said, were correct, although the public found it natural to remember the errors more. There could be no certainty in forecasts while meteorology remained a comparatively undeveloped science less than -100 years old, which had always been expected to do more than it was capable of doing, he said. When the first system of weather forecasts met with criticism in the House of Commons for unreliability, and because the forecasts were printed in newspapers instead of being used for the benefit of only the wind-driven ships of the Navy, which was their original purpose, the founder of the system, Admiral Fltzroy, -committed suicide.

The system used to-day, 80 years after Admiral Fitzroy’s death, was basically the same as his, and still suffered from the same great handicap—a lack of accurate data from which to gauge all th,e ways in which an approaching high or low pressure area might behave. There was usually not enough indication to tell when a high or low depression was going to blow itself out of existence, as did the depression which fooled the Weathei\ Office on New Year’s Eve, -The same unfortunate depression had been delayed off the coast by a large high pressure ahead of it, while the forecasters watched it in apprehension. Such delays happened and ended with little warning. Once that depression did reach, the coast of the North Island it might have followed the coastline down until its centre passed through Cook Strait, for weather formations were sometimes deflected by mountains and coastlines. Forecasters could estimate the future position of a high or a low pressure area from its past speed and direction, but often there was insufficient warning to tell .when the weather formation was suddenly going to change speed or direction or disappear. . \ Our weather was moving around the earth from west to east in a changing succession of “highs” and “lows” which brought their own weather conditions with them. Wellington was in far worse position than Sydney, for Sydney received data from weather observers over the whole of Australia, whereas Wellington had its weather approaching over the wide, open spaces of the Tasman, and information on its passage could be obtained only from Lord Howe and Norfolk Islands and an occasional ship. During the war in the Pacific, and in the Atlantic now, weather ships were stationed in their respective areas to give accurate information on temperature, pressure, humidity, cloud and so on, he said.

Radiosonde Equipment

The weather ships gave not only surface information but reported on conditions up through atmosphere into the stratosphere. This important upper air data was gathered by radiosonde equipment. There were now only two stations in New Zealand where radiosonde was used—Whenuapai and Hokitika.

Weather office men said that New Zealand needed many more before sufficient information could be gained on the state of upper air for reliable forecasts.

Since imports from the United States were blocked'radiosonde transmitters had been in short supply and according, to a research officer they would stay that way until they were made locally at a sufficiently lowcost. The transmitters were sent up attached to balloons whose position was traced by radar, while the transmitter sent back automatic signals on pressure, temperature, and humidity. Aeroplane flights a fl'om day to day were another way of getting the upper air data which New Zealand lacked. The daily meteorological flight from Rongotai during the war gave valuable insight into Cook Strait weather. “In making forecasts, a personal knowledge of the topography in all districts is essential, especially in New Zealand where the' topography is so varied,” said Mr Hutchings. “The broken nature of the North Island has a breaking effect on the uniformity of weather conditions so that weather forecasts were for much smaller districts in the North Island than in the South Island where there was not so much variety in topography, and where the usual weather conditions in the mountain ranges meant many sharp distinctions between “cloud” and “clear” and so greatly complicate forecasts. “More important than the lack of time in making forecasts is the lack of accurate scientific knowledge of New Zealand weather. In meteorology as in all science in New Zealand there is a great need for a big, wellequipped research team,” said Mr Hutchings. “Probably we need it more than any other branch of science because other branches of science, such as chemistry, can make full use of overseas findings while the meteorologist in New Zealand has to deal with many weather conditions that are peculiar to this country.”