WEATHER FORECASTS.

New Zealand Herald, Volume LXVII, Issue 20669, 15 September 1930, Page 10

WEATHER FORECASTS.

SCIENTIFIC DIFFICULTIES. WORLD-WIDE STUDY NEEDED. PROBLEM OF SEASONAL REPORTS. Tho importance of accurato weather forecasts and the difficulties attached to their preparation are reviewed in the annual report of the Department of Scientific and Industrial Research.

An understanding of the mctcorologi cal processes of the world as a whole )S needed, says the report. For this re.xSOtl, it is desirablo to support world organisations, and especially expeditions devoted to research in the Antarctic re gions, where there is a largo and important area, which must exercise a potent influence on the weather of the world, but concerning which our knowledge was slight. Ono of the principal functions of the Meteorological Office is to issue predictions of the nature of the coming weather for as long a period ahead as conditions and existing knowledge seem to warrant, the report states. Since tho efforts of tho meteorologist in this direction are continually before the public it is apt to be considered his sole duty, but the collection of statistics is really the more important. There is always a tendency to snok from the meteorologist a prediction for a longer peiiod than it is safe for him to venture. Methods in the Tropics. I In tropical and sub-tropical countries,! there has been some success in devising methods by which seasonal forecasts may be prepared, ari example being the anticipation of the amount by which the rainfall in the critical period of the year may differ from the average. Even in tropical countries, however, comparatively little practical advantage has been derived from these forecasts, while in temperate' regions there has been practically no material gain. "There is nothing yet known which would lead to the expectation that seasonal forecasts of any high degree of accuracy arc likely to be possible in New Zealand in the near future," it is stated. "The financial year has given a good illustration of tho complexity of the problem. There have certainly been per sistently low temperatures since June last year, but in tho more important factor of precipitation, there have been rapid variations from one extreme to the other. Changes in Conditions. "To have forecasted the season accurately would have required extraordinary precision. Conditions passed back and forth from one extreme to the other, yet, on the whole, the season was a I remarkably good one and the rainfall net far from the average. Had a difference of two months occurred in the wet and dry spells, there would have been a different storv to tell.

"Although we wish to emphasise that seasonal forecasting is not yet possible, it is clear that the meteorologist must give earnest attention to such an important problem. In this connection the first need is for long and accurate statistics, and in New Zealand these are to a large extent lacking. Observations have been made at some places for long periods, but they have been vitiated through changes of observation site, periods of broken or careless records, or the use of unsatisfactory or unsatisfactorily exposed instruments It is only through public interest that this state of affairs can be remedied."