Reversal Of Wind Direction Research Articles

Some notes on the stratospheric winds at Canton Island and Christmas Island

AbstractStratospheric wind data for Canton and Christmas Islands show a fluctuation with a period of about 24 to 28 months in the zonal component. Christmas Island data also show that the fluctuation exists from below 60 mb to 10 mb (the highest level for which data are available) and that the amplitude of the fluctuation increases with height. The change in wind direction from W to E, or vice versa, is evident first at the higher levels and appears to work gradually downwards; at 60 mb the reversal of wind direction is evident about six months after that at 25 mb, and about twelve months after that at 10 mb.Attempts to connect events in the equatorial stratosphere with events in the equatorial troposphere were not successful.

Results of IGY rocket-grenade experiments to measure temperatures and winds above the island of Guam

Temperature and wind measurements up to an altitude of 80 km resulting from 9 rocket-grenade firings during November 1958 on the Island of Guam are presented and discussed. Densities and pressures were calculated from the temperature data. The temperature results agree with previous grenade measurements at White Sands, New Mexico. They show a peak temperature of approximately 270°K at 47 km. Weak westerly circulation prevails between 35 and 70 km. An abrupt reversal in wind direction from east to west between 25 and 35 km was observed. The weak westerlies sometimes are subjected to major disturbances near the 55-km level. Toward 70 km, the westerlies generally seem to diminish.

Aircraft Applications of Insecticides in East Africa. II.—An experimental Attempt to Produce a Fly-free Corridor through a Belt of Tsetse-infested Woodland

An experimental attempt was made to produce a fly-free corridor through a belt of savannah woodland containing the tsetse fly G. swynnertoni.An area two miles wide and four miles long was treated with a coarse spray of a 4·6 per cent, w/v solution of DDT in Shell Diesoline. The dosage per application was 0·5 gallons per acre, and seven applications were made, at intervals of approximately two weeks, so that the treatment covered two pupal periods.The fly density had fallen to a very low level by the end of the experiment, and the area remained virtually free from flies for the subsequent two months. An examination of the data suggests, however, that the fly population was maintained largely by immigrant flies, and was certainly subject to wide variations, and it seems certain that the effect of the applications would have been considerably less upon a stable, self-supporting population.The drop spectrum of the ground deposit had a mass median diameter of 0·35 mm., and the recovery of insecticide in the area was approximately 60 per cent. Leeward and under sides of obstacles did not receive a dose although in some cases dosages were obtained on apparently leeward sides, probably because of local reversals of wind direction.