A number of ozonesonde stations are operating in the tropics, subtropics, and the southern hemisphere in general, but with differing frequency and reporting procedures. SHADOZ (Southern Hemisphere ADditional OZonesondes) is designed to remedy this data discrepancy, by coordinating launches, supplying additional sondes in some cases, and by providing a central archive location. Since 1998, ozonesonde data have been collected and made available through this website.