This article describes the Southern Hemisphere Additional Ozonesondes (SHADOZ) network of ozonesonde–radiosonde stations in the southern Tropics and subtropics. SHADOZ was initiated in 1998 by NASA, NOAA, and a team of international meteorological services and space agencies to remedy a paucity of ozone profile data in a region of intense natural variability and anthropogenic change. SHADOZ augments launches at selected sites and provides a public archive of ozonesonde and radiosonde data (see additional information online at