(All Bights Reserved.) IN THE FAR SOUTH

Otago Daily Times, Issue 21102, 12 August 1930, Page 5

(All Bights Reserved.) IN THE FAR SOUTH

SEVENTY MILES AN HOUR GALES SEA “GROUND TO POWDER.” (By R. G. Simmers.) Assistant Meteorologist to the New Zealand Government Meteorologist, and to the B.A. N.Z. Antarctic Research Expedition. Meteorology during the last 100 years has been lifted from the state of merely being “ weather lore ” to the status of ascience, and, as such, has claimed the earnest attention of numbers of notable physicists. t The deeper study resulting from this "attention has only served to demonstrate what an exceedingly complex subject weather is, and has amply proved that it is only by understanding the fundamental causes of weather that successful weather predicting can be achieved—and it is by successful forecasts that the meteorologist is judged, especially by those three bodies of the public whose very existence is dependent on the vagaries of the weather—namely, farmers, sailors, and the organiser of the church bazaar. So. the problem before the scientific meteorologist of To-day is not so much “what weather is there to be? ” as “ Why is there weather? ’’ and it was with the intention of adding a further contribution to the solution of the latter problem that meteorology was chosen to take a prominent place in the B.A.N.Z. Antarctic Research Expedition. The Discovery proceeded south from Capetown as a fully equipped floating observatory. The ship’s officers in their respective watches co-operated with the expedition meteorologist in carrying out, a comprehensive observational programme. This undertaking involved two main classes of meteorological workrouting observations at regular hours and observations of a more specialised and technical nature to be taken when suitable conditions should prevail. In the first class fell two hourly observations of direction and force of the wind, type, amount, and direction of motion of the clouds, blueness of the sky, and the weather; and four hourly observations of barometric pressure, air temperatures, state and temperature of the sea, and, when in the higher latitudes, ice conditions. To supplement these readings autographic instruments provided continuous records of atmospheric pressure, air .temperature, sea temperature, and humidity of the air. So much for the regular observations, which, in virtue of being standard all the world over, are suitable for comparing with those taken in other places. Measurement of the amount of snowfall and several minor observations normally taken at a climatological station of the first order were omitted, as the necessary standard of accuracy- was not attainable on a vessel such as ours, which at times rolled 40 degrees each side of the vertical. To the second class mentioned above, those of a technical nature, belonged observations of lapse rates (or the rate at which the temperature of the air decreases as one goes higher), . isolation (or the total amount of heat imported by the rays of the sun), the motion of the air in the upper atmosphere, and the type and amount of impurity in the air. This present expedition made a new departure.- As the expedition was planned and conducted as a summer cruise the scope of the meteorological programme realisable day by day depended to a certain extent on the. roughness of the sea. This was specially the case in the first three weeks, when, on the run to Kerguelen the boisterous “ Roaring Forties ” were-traversed. They lived up to their reputation as we approached our destination, when we experienced a gale Which drove us far off our course and kept the ship battling for some days. Kerguelen has a rather unenviable reputation for winds, but during the fortnight spent there in November it quite belied its name, and for the most part we had fine calm days. Not so in February when, on our return from the Antarctic, we again sojourned there, as this time winds were experienced which would well make any place notorious. From a flat calm the wind would rise in a couple of minutes to a 60-mile an hour gale, only to die down again almost as suddenly, an enjoyable calm spell intervening while it worked up energy for the inevitable further bursts. At the end of three weeks of this state of affairs we were well able to appreciate the remarks of one chronicler, who states.that he has seen the sea “ground into powder” by the wind. A very apt description this, as at times squalls shrieking down the fiords with which the coast is indented would ’whip white spray 50 feet in the air. Leaving Kerguelen on November 24 the Discovery headed south, not returning till early •in February, two months of the interval having been spent in the pack ice zone. , December, treated us badly. This is midsummer in the Antarctic, yet there were only four days without snow, and out of a possible 700 hours of sunshine we were favoured with only 75; or only an average of two hours and a*half a day out of a posisble 23. Even this two hours and a-half does not give an exact indication of the monotonous amount of cloud, as, of the 75 hours’ sunshine. 60 occurred on five days, leaving only 16 to be spread over the remaining 26 days. January, however, did its utmost to make amends for the rather churlish treatment meted out to us by February, and we had many cloudless days with brilliant, sunshine. An Antarctic summer’s day is a thing to be remembered, and it was with regret that we were obliged, owing to shortage of coal, to leave for Kerguelen at the end of the month, just when there seemed bright prospects of a continuation of good weather.

Full advantage was taken pf this fine weather to study the conditions of the atmosphere up to, considerable heights. Thermometers carried on the wing struts of the aeroplane recorded the temperature of the air up to 5000 feet. By means of rubber balloons, inflated with hydrogen until they would rise at 700 feet a minute and on release watched with a special theodolite which damps out the motion of the vessel, the direction _of motion of the air up to 53,200 ft —10 miles —was determined. In all 34 of these balloons, pilot balloons they are termed, were flown, and out of these 18 were observed to a height or over 10,000 ft, 13 to over 20,000 ft, and six to over 30,000 ft. An immediately practical use of these flights was the determination of air currents prior to aeroplane flights. • . In addition to these a separate series of observations was carried out on the transparency of the air for comparison with that of the populated regions of the earth. By means of a pyrohelio-meter—-an instrument for measuring the .heat given out by the sun’s rays—it was shown that, with the sun at the same height in the sky in the two places, the Antarctic air let through much more heat than that in the Australian Bight—so per cent, more in fact, Why is this? Outside the atmosphere, say 10 miles up, the intensity of the sun's rays is the same in the two places, but in the air layer they suffer absorption from various agencies —the air itself, dust, water vapour, salt crystals, and bacterial. Our obvious course was to compare the amounts of these impurities both in the Antarctic and ip temperate zones. Wet and dry bulb temperatures show that the difference in water vapour content in the two places explains much of the difference, the greater amount in the warmer air causing a blanketing effect. Our medical ofli cer proved that there was no bacteria in the Antarctic air. To determine the amount of dust and salt crystals, or the “ atmospheric pollution,” an apparatus known as a “jet dust counter " was used By its means the dust in any desired quantity of air—so cubic centimetres (about 1-10 pints) is the amount usually used in Europe—can be thrown on a microscope cover glass as a very narrow streak of dirt and can be at leisure under a high power miscroacopc, the number of particles counted and their shape and nature examined. Typical samples in other places have given up to 12,000 particles per cubic centimetre of air in London, 900 in Kew Gardens. 15 in the Bay of Biscay, yet even in 2000 cubic centimetres of Antarctic air we could find none whatsoever.

This freedom from pollution makes the atmosphere wonderfully clear. From a distance of 50 miles details of the inland mountains of Enderby Land almost invariably stood out. with crystal clearness. To all on the expedition the mildness of the temperatures throughout the entire time spent in the ice came as a pleasant surprise, as they rarely fell below 25 degrees F., and remained for the most part remarkably steady between -28 degrees and 31 degrees F. The minimum

temperature—recorded during calm weather —was only 20 degrees F., 12 degrees bSlow freezing point. Given calm weather continuous temperatures below zero cause no discomfort; in central Siberia the average for some months of the year is minus 60 degrees F., and as low as minus 94 degrees F. has been recorded; but in a blizzard even's few degrees above freezing point, there is discomfort and often danger. By reason of it being the summer season and owing to our location on ship board surrounded by sea water, the blizzards which we experienced were of a mild nature so far as temperature is concerned. In the matter of wind velocity, however, they were violent enough, in one case reaching a measured velocity of 70 miles per hour. Meteorological observations in the Antarctic, pre-eminently important as they are, lose some of their value if they are isolated. Two Antarctic stations working simultaneously are more than double the value of one alone and the closer the network of stations the greater in proportion is the value enhanced. For Innately for meterorology in so far as it has resulted in the bunching of expeditions, active interest in Antarctic exploration has recurred in waves; periods of no expeditions alternating with ones when several expeditions have been'in the’field simultaneously; 1902-4 with concurrent British, Swedish, Scottish, and German efforts; and 1912-13 with British, Australasian, Norwegian, and German expeditions are two of the wave crests. Now 1029-30 with American, Australasian, and Norwegian enterprises works a third period of intensive interest. The hope is that this last period will be doubly important not only yielding its own quota of valuable data, but acting as a good introduction to 1932, a year when international co-operation is mooted for the greatest of all Antarctic years.