Radio Tracking of Meteorological Balloons

There is a need for upper air meteorological observation at night as well as in the daytime, in cloudy and in foggy weather as well as in clear. This need has given rise to a number of interesting methods of obtaining these data, among them radio tracking of meteorological balloons. A free balloon moves in the air current prevailing at the level it occupies. A small rubber balloon, six inches or less in diameter, when inflated with hydrogen to a given excess lift will rise at a given ascensional rate to great heights. Successive determinations of the position of one of these pilot balloons provides ready means for computing the mean direction and speed of the wind in the layer of air through which the balloon has risen during the interval between determinations of position. On clear days these balloons have been followed by visual methods to heights of 20 miles. This paper deals with a radio method of determining successive balloon positions. A light transmitter, weighing about a pound, is carried up by the balloon at a known ascensional rate. Loop receivers are employed in ranging for this transmitter. The whole project involves the determination of air temperature aloft as well as air movement but the work on it so far has been limited to the development of equipment needed for the observation of wind, direction, and speed. Positions are usually determined at minute intervals.