English: Photo of a US Weather Bureau weather balloon being launched, 1944. It consists of a latex balloon filled with helium, with a 2 lb. instrument package called a "radiosonde" suspended below it that transmits temperature, air pressure, and humidity data by radio telemetry to a ground station. By tracking the balloon by radar as it is blown sideways by winds as it ascends the station can get a vertical profile of high altitude wind. The balloon rises to a high altitude, over 15 miles (72,000 feed) before it pops. Then the radiosonde package floats to Earth on the miniature parachute seen at center. The wire hanging below the radiosonde package at bottom is its antenna. By 1944 the Weather Bureau was launching weather balloons twice daily from 40 locations in the US.

Alterations to image: cropped out intruding text on page and cloned in a small amount of sky near balloon.