HR: 10:20h
AN: SH11E-01 INVITED     [PDF]
TI: Measurement of the Solar Spectral Irradiance and its Variability
AU: * Rottman, G
EM: gary.rottman@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309-0590 United States
AB: Solar electromagnetic radiation is the dominant direct energy input to the terrestrial system. Studies of the Earth's atmosphere, land surface, and ocean require a detailed knowledge of this radiation in order to fully understand the global climate system -- and in particular to separate natural influences from possible human induced change. Irradiance measurements made today provide the time variations that are necessary input for today's climate studies. Furthermore, future global change research will rely on today's observations as an essential component of the long-term climate forcing. Measurement of solar irradiance variability can only be conducted from space. In the 1970s and 1980s space radiometers provided a first insight that total solar irradiance (TSI) varies on the order of 0.1 to 0.2%. At the same time spectrometers established that the ultraviolet spectral irradiance varies by 10% decreasing to 1% between 200 and 300 nm, and by much larger factors at shorter UV wavelengths. However, at wavelengths longer than 300 nm, in the visible and near infrared, the solar irradiance variation is much less than 1% (as constrained by the TSI observations), and with the exception of a few selected wavelengths, spectral observations had never been capable of establishing the true solar variability for this important part of the solar spectrum. In January 2003 the NASA Solar Radiation and Climate Experiment, SORCE, was launched. This satellite carries four scientific instruments including one that measures TSI and two that measure the solar ultraviolet irradiance. These observations continue the data records of UARS, ACRIMSAT, ERBE, TIMED, and SOHO. Moreover, SORCE carries a new instrument specifically developed to measure the Sun's visible and near-infrared irradiance with sufficient precision and accuracy to detect wavelength dependent variability. This talk describes the SORCE mission and provides an overview of the first nine months of SORCE observations.
DE: 1610 Atmosphere (0315, 0325)
DE: 1650 Solar variability
DE: 7536 Solar activity cycle (2162)
DE: 7538 Solar irradiance
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting