ozonsondes

An ozonesonde is a balloon-borne instrument package that measures atmospheric ozone concentration as a function of altitude. Launched from ground stations, it ascends with a weather balloon and transmits a continuous vertical profile of ozone from near the surface to the stratosphere before the balloon bursts.

Most commonly, ozonesondes use an electrochemical concentration cell (ECC) sensor. A small pump draws ambient air through the sensor, where ozone generates a current proportional to its concentration. The current is converted to ozone mixing ratio using calibration, with temperature and pressure from the radiosonde applied to yield vertical profiles in ppbv or ppmv. Some networks also operate UV photometric ozonesondes that measure ozone by UV absorption at 253.7 nm.

During operation, the sondes are integrated into standard radiosondes and transmit data by radio. Balloons typically reach 25–35 km before bursting; the payload may descend by parachute and continue transmitting for some time.

Applications include monitoring ozone distribution for climate studies, validating satellite products, and long-term trend analysis. Data are collected globally by networks such as SHADOZ and WOUDC and archived for access by researchers.

Limitations include sensor drift and the need for regular calibration, as well as dependence on balloon launches, which constrain coverage in time and space. Despite these, ozonesondes provide high vertical resolution measurements and remain a widely used method for profiling atmospheric ozone.