Antarctic Balloon Reaches Height Of Nearly 23 Miles

Press, Volume XCIX, Issue 29398, 28 December 1960, Page 8

Antarctic Balloon Reaches Height Of Nearly 23 Miles

A 15ft scientific balloon has been launched from McMurdo Sound to a height of almost 23 miles, believed higher than that achieved by any other such large balloon’released in the Antarctic. The rubber balloon, carrying an BJib instrument package for the measurement and transmission of water vapour data from the stratosphere, attained a height of 120,000 ft., or nearly 23 miles, on December 21. This is the first time a balloonlaunched instrument intended to measure stratospheric water vapour has been sent up in the Southern Hemisphere, according to its launchers, Dr. J. A. Brown and Mr E. J. Pybus, of the United States Army Ballistic Research Laboratories, Aberdeen proving grounds, Maryland. Dr. Brown and Mr Pybus have made about 18 previous balloon launches to measure the amount of water vapour in the stratosphere—six in the Arctic at Thule, Greenland, and Fort Churchill, Canada, and 12 in mid-latitude zones. These two men are now in the Antarctic on an 8500-dollar grant from the National Science Foundation, through its United States Antarctic research programme, for a study of the vertical profile of water vapour in the Antarctic. Series of Launches They have been several weeks preparing for a series of balloon launches, starting with this record launch, which is expected to continue to the end of January The 61b, helium-filled balloon rose at an average rate of 1000 ft a minute, and reached a height of 120,000 ft shortly before it burst, about two hours after being sent up.

The instrument package is estimated to have plummeted to earth about 20 miles from McMurdo Sound, indicating very light winds aloft.

The radiosonde payload contained a semi-transistorised hygrometer—an instrument for measuring the degree of moisture of the atmosphere—which measured the dew point, or temperature at which a vapour begins to condense as a liquid. The study of stratospheric water vapour at McMurdo Sound is expected to contribute to glaciological and geophysical data being gathered on the extent and rate of growth or ablation of the Antarctic ice cap.. Measurements from the research balloon were transmitted back to McMurdo Sound and tracked by United States Navy meteorological ground equipment. These measurements indicate a rather dry atmosphere. Preliminary data obtained by

this first Antarctic launching indicate that the water vapour profile at McMurdo Sound at the outset of the austral summer is similar to that of early summer in the Arctic —that is, quite dry. It is suspected that Arctic stratospheric water vapour is at a minimum in spring and early summer, and at a maximum in late summer and early autumn. How closely the Antarctic pattern will follow the Arctic pattern may be revealed by the subsequent measurements Dr. Brown and Mr Pybus will make at McMurdo Sound.

They plan to send up 16 radiosonde balloons by the end of January, the data from which will be reduced by the Ballistic Research Laboratories, using data-reduction techniques developed for previous moistureprofile flights made during the International Geophysical Year and the current Northern Hemisphere research programme.