THE FAR SOUTH

Evening Post, Volume CX, Issue 36, 11 August 1930, Page 11

THE FAR SOUTH

ANTARCTIC WEATHER

DISCOVERY'S OBSERVATIONS

GALES AND CALMS

Meteorology was one of the scientific subjects in which Sir Douglas Mawson's recent Antarctic Expedition was interested, and tho assistant meteorologist on board was Mr. E. G. Simmers, of the Dominion's Meteorological Office. Describing the meteorological achievements of the expedition, Mr. Simmers

says: —: ' "Meteorology during the last hund- . red years has been lifted from the state of. merely being 'weather lore' to the status of a science, aad, as such, has claimed the earnest attention of numbers of notable physicists. 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 beforo the scientific meteorologist of to-day is not so much 'what weather is there to bo?' 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 Bcsoareh Expedition. "The Discovery proceeded south from Cape Town as a fully equipped floating observatory. The ship's officers in their respective watches co-operat-ed with the expedition meteorologist in carrying out a comprehensive observational programme. This undertaking involved two main classes of meteorological work—routing 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-hour-ly 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 fourhourly; observations of barometric pressure, air temperature, state and temperature of the sea, and, when in the higher latitudes, ice conditions. To supplement these readings autographic instruments provided continuous records of atmosphoric 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 climatplogical ' 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 40deg 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), insolation (or the total amount of heat imported by tho rays ■of the sun), the motion of the air in ■ the up"per atmosphere, and the type and amount of impurity in the air.'' 'JHB "SOARING PORTIES." The '.'Bearing Forties" lived up to their, reputation as far as wind %vas concerned, and a galo drove the Discovery far off its course and kept the ship battling for days. The island of Eerguelen belied its reputation for wind when the Discovery first called there, and for the most part during the first fortnight spent there in November the days were line and calm. "Not so in February, however, when on our return from tho Antarctic we sojourned there again," writes Mr. Simmers. "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 caliu 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 re- . marks of one chronicler, who states that he1 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 w^ite spray fifty feet iv the air.

"December treated us badly. This is midsummer in the Antarctic, yet there ■were only lour days without snow and • out of a possible of seven hundred -hours of sunshine we were favoured "with only seventy-five; or only an average of two and a half hours a day out of a possible twenty-three. Even this two and a half hours does not give an /exact indication of the monotonous amount of cloud, as, of the seventy-five hours' sunshine, sixty occurred on five days, leaving only fifteen to be spread over the remaining twenty-six diys. 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." A CLEAR AIR. Advantage was taken of 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 ft • a minute and on release watched with a special theodolite ■which damps out tho motion of the vessel, the direction of motion of the air up to 53,200ft — ten miles—was determined.

Tho transparency of the air was also measured, and it was found to bo singularly free from pollution. This freedom from pollution made the atmosphere wonderfully clear. From a distance of 30 miles details of tho inland mountains of Enderby Land almost invariably stood out with crystal clearness. The air, too, was found to be free from bacteria. NO DISCOMFORT PROM COLD. "To all on the Expedition," says Mr. Simmers, "the mildness of the tempera- ■■ tures throughout the entire time spent in the ice came as a pleasant surprise, as they rarely fell below 25deg F., and remained for the most part remarkably steady between 28deg and 31deg F. The minimum temperature—recorded during calm- weather—was only 20deg F., 12deg below freezing point. Given calm weather continuous temperatures below zero causes no discomfort; in een- ' tral Siberia the average for some •months of the year is minus SOdeg F., and as low as minus 94deg F. has been recorded; but in a blizzard even a few degrees abovo freezing point there is discomfort and often danger. By reason of it being tlm summer season, and owing to our location on shipboard, surrounded by sea. water, the blizzards • which we experienced were of a mild nature so far as temperature is coneern<B,tL In the matter of wind velocity,! how-way ifcejf; were violent enough, iai

I 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 tho network of stations the greater in proportion is tho value enhanced. Fortunately for meteorology insofar as it has resulted in the bunching of expeditions, active interest in Antarctic exploration lias recurred in waves; periods of no expeditions alternating with ones whci.i. several expeditions have been in tho i':»\\ simultaneously. 1902-04, with concurrent British, Swedish, Scottish, and Gorman efforts, and 1912-13, with British, Australasian, Norwegian, and German expeditions, are two of the wave crests. Now 1929-30, with American, Australasian, and' Norwegian enterprises, marks a third period of intensive interest. . The hope is that this last period will be doublj- important, not oniy yielding its own-quota1 of valuable data, but acting as a good introduction to 1932, a year when international cooperation is mooted for tho greatest of all Antarctic years.