Dropsonde (left) and Radiosonde on Balloon

Credit: UCAR

Sondes are instrument packages used by atmospheric scientists to gather data at various altitudes. On the left, a sonde (brown tube at bottom) descends beneath a small parachute. Dropsondes such as this are often deployed from aircraft. The photo on the right shows a scientist attaching a sonde to a weather balloon, which will carry the instruments aloft.