WEATHER CONTROLS.

New Zealand Herald, Volume L, Issue 15234, 22 February 1913, Page 1 (Supplement)

WEATHER CONTROLS.

■•■":;/' BY H. B. DEVEKEuX j Rbfjchexce to any hand-book of .physical geography will show a belt of high atmospheric pressure encircling "the. Southern Hemisphere and extending .from. 20deg. to QQ.deg- south. The 'old ; text books described the belt as . a fixed area of high pressure, but it remained for the late H. C. Russell, IF.R.S., of Sydney Observatory, to demonstrate* the orderly procession eastward of rapidly moving anticyclones, or high pressure systems, separate and distinct. To 'quote his words : —"Australian weather south of 20deg. south latitude is the product of a scries of rapidly moving anti-cyclones;, which follow one another with remarkable regulai-ity and are the great controlling force in determining local weather." — : . , Imagine a vast elliptical mass of air, moving from, weat to east, its winds blownig contra-clockwise Jin this hemisphere) and revolving around the central •■ maximum, ail barometers' reading 30 to 30.50. inches of mercury over the Dominion, and you have the anti-cyclone, or "weather control." In summer the anti-cyclone gives lis our ■warm, pleasant days, with alternating land and sea breezes and dews at night; in winter the clca? cool days and calm and frosty' nights, when the accumulated heat received during eummer streams away into space. , .V B'requently an anti-cyclone is 2500 miles in diameter, measured along a parallel of latitude, its forward rate of travel eastward averaging about 600 miles in the 24 hours. Some have travelled over 1000 miles in the same period of time. , The anti-cyclone is a downcast system, air flowing in from aloft, in opposition to ; the cyclone. %■/■ To the student of nature these aerial eddies are very tangible and real. By means of weather charts the daily translation eastward is demonstrated, and the :v>."quence of .weather accompanying the advent and departure of an anti-cyclone can bo anticipated. '..'By the same means the student sees the ;vidences of approaching storms on the fringes of "weather contiols." r'-: In the intervening space following the, departing and preceding the approaching anti-cyeio:>c v?;: have the "Antarctic" storm arc..., on the south side endeavouring to force its. way through, not infrequently cornbatir ? the mastery with the monsooual systems nthwards.' ' * These Antarctic . storms originate .in about 60deg. of south latitude, and are fed by the. .staA'dnary anti-cyclone about the Son'a. Pole. They usually appro? Jii from 'about west by south, moving to t'.tapposite quarter sometime.'!. These Antarctic systems extend to the latitude of NorfoL: Island, but usually their effect is most pronounced in the South Island., Occasionally a monsoonal or tropical storm lold?* sway, causing gales and floods northwards of East- Cape, Taupo, and Raglan. Such a system caused the abnormal floods it Ohinemuji and on the or:J coastal listricts in i\L.Tch, 1910. ' Thus it may be truly said that the anticyclones control our weather, performing ,he function cf a buffer, heading off the 'Antarctica" on the one := side -and the . xopical disturbances on the other. But i )ccasionally, and particularly at long intervals, the anti-cyclones are altered in size, and move in lower 'ititudes. Then he stormy westerlies prevail • unmastered, 13 in the summer of 1911 and daring,the '• present season. ; '''- : : ' , ';.v.'': ' '■:■'_ . This brings us to thm efc>rts of meteorolo- ' fists at the present time to solve the pro- '• )lems of the meteorological changes which . lave occurred and - are taking place in i nany portions of the glob*. "It is only i he girdling encircling air," says a p.h<b- < opher, * ' ; that flows above and around *. ', ' hat makes the whole world akin. .'.-.'*, *<>.. - Che ra'ji we »ec .descending was tLiw.sd'. -j or us cut 'of the -icebergs which ; bava ; witched the Polar Star for ages, and' Btus i ilies have soaked up from the Nile," nnd i xhaled as vapour, snows that rested on < he summits of the Alps.'-' ■_: . li