PROGRAM TITLE: Total Ozone Mapping Spectrometer (TOMS) ACTIVITY STREAM: Data and Observations SCIENCE ELEMENT:Climate and Hydrologic Systems Global Observing Systems NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SCIENTIFIC MERIT: The TOMS Program goal is to monitor the seasonal and long term variations in the stratospheric ozone concentration of the Earth, and provide the basic input to atmospheric chemistry and dynamics models. The Nimbus 7 spacecraft monitored ozone continuously from it's launch in 1978 until its failure in May, 1993. A TOMS instrument is currently flying on a Russian Meteor 3 spacecraft, and has provided a nearly continuos set of measurements since August, 1991. In May, 1994 an Earth Probes TOMS instrument will be launched to continue the critical ozone trend measurements from space. Complementing data from the TOMS instruments are the SBUV-2 (Solar Backscatter Ultraviolet) measurements. These data provide less frequent maps of ozone concentration than TOMS, but can be used to more closely examine vertical distribution of ozone. Operational SBUV-2 instruments fly on the NOAA platforms. NOAA 11 was launched in September, 1988. NOAA 13 was launched in August, 1993 and the SBUV-2 instrument should become operational in September, 1993. The Shuttle Solar Backscattered Ultraviolet (SSBUV) instrument flies at regular intervals on the Space Shuttle. It makes very precise measurements of the atmosphere and is used to calibrate the other UV instruments in orbit. Rough ozone measurements from the TOMS instruments are reduced in near real time, and made available to the scientific community via electronic network. Precision ozone trend data are produced some time later when calibration and ancillary data are validated. STAKEHOLDERS: The NASA ozone program is conducted in close association with researchers at NOAA and the USEPA. POLICY RELEVANCE: Stratospheric Ozone and UV-B Radiation TOMS ozone measurements have played a key role in providing information to decision makers regarding the International Ozone Assessments and the Montreal Protocol as well as the later revisions. PROGRAM CONTACT:Mr. Stanley Schneider Chief, Mission Operations and Data Analysis Branch NASA Headquarters, Code YD Washington, DC 20546 202-358-0255 sschneider@se.hq.nasa.gov