Total Solar Irradiance Data Available for Studying Trends

The Atmospheric Science Data Center (ASDC) at NASA Langley Research Center archives total solar irradiance (TSI) data from the Active Cavity Radiometer Irradiance Monitor (ACRIM) II and III, Nimbus-7 Earth Radiation Budget (ERB), and Earth Radiation Budget Experiment (ERBE) projects. These data span approximately 27 years and can be used to study trends in solar activity. Some of the goals of ACRIM are to monitor variability of TSI including solar cycles and sunspots and to analyze relationships between TSI and climate change. ACRIM II data are available for October 1991 through August 1997. ACRIM III data are available from April 2000 through the present. Some of the objectives of Nimbus-7 ERB are to obtain accurate measurements of solar irradiance, monitor its variation in time, and to observe the temporal variation of the solar spectrum. The data are available for November 1978 through December 1993. Measurements of the total solar irradiance provide one of the important elements of Earth's radiation budget. These measurements also provide possibilities for "climate experiments" by allowing the sensitivity of the radiation budget to various forcings to be studied empirically. One of those forcings is the variation in the Sun's total energy output which drives our climate system. The ERBE data are available for October 1984 through March 2003. These data along with documentation and read software may be obtained from the NASA Langley ASDC at http://eosweb.larc.nasa.gov.