http://www.greenhorsesociety.com/Station_Research/tropospheric_ozone.htm

Satellites have allowed researchers to create estimates of ozone on a global scale. However, limitations of satellite data include a lag between data collection at each location and the uncertainty associated with methodology for deriving ozone concentrations. For over 20 years, detailed maps of tropospheric ozone concentrations have been created using the Total Ozone Mapping Spectrometer (TOMS) and stratospheric ozone profiles derived from Solar Backscattered Ultraviolet (SBUV) instruments. The SBUV instruments have been launched on several NOAA satellites and the TOMS instrument was aboard the Earth Probe satellite. The relatively small proportion of ozone in the atmosphere has made it difficult to separate the tropospheric ozone component and compare it to existing datasets (Fishman et al. 2003). Today, NOAA's Aura satellite carries sensors to track the movement of ozone across oceans and continents (Allen 2002).

The existing dataset are usually created from ozonesonde measurements. Ozonesonde measurements are taken by attaching an ozone sensor to a radiosonde. The radiosonde measures pressure, temperature, humidity, and wind. The ozonesonde is sent into the atmosphere using a hydrogen gas filled balloon. Each time a balloon is sent up the ozone sensor collects data on O3 concentration and allows researchers to create a vertical distribution profile (Allen 2002). The image on the left shows how the ozonesonde instrument is released into the atmosphere.