The Solar Radiation and Climate Experiment (SORCE) : Mission Description and Early Results

The Solar Radiation and Climate Experiment (SORCE) is a small, free-flying satellite carrying four scientific instruments to measure the solar radiation incident at the top of the Earth’s atmosphere. SORCE was successfully launched from NASA’s Kennedy Space Center on 25 January 2003. As one element of NASA’s Earth Science Enterprise, the SORCE mission is a joint effort between NASA and the Laboratory for Atmospheric and Space Physics (LASP). The primary objectives of SORCE are to make daily measurements of Total Solar Irradiance, TSI, and spectral irradiance over almost the entire spectral range from soft X-rays, through the visible, and into the infrared. The SORCE instruments – the Total Irradiance Monitor (TIM), the Spectral Irradiance Monitor (SIM), two Solar Stellar Irradiance Comparison Experiments (SOLSTICE), and the XUV Photometer System (XPS) – are currently measuring the Sun’s total and spectral irradiance with unprecedented accuracy and precision capable of establishing solar variability. In addition to securing a reliable long-term database with which to characterize solar radiative forcing of climate and global change, the SORCE program seeks to foster new understanding of the origins of the solar variations and the physical pathways by which the Earth’s atmosphere, oceans, and land respond on multiple time scales. This collection of papers describes the SORCE mission, goals, spacecraft, instrument development and calibration, planning software, ground operations, data processing, early science results, and science implications on how the Sun influences Earth’s environment.

The Solar Radiation and Climate Experiment (SORCE) is a small, free-flying satellite carrying four scientific instruments to measure the solar radiation incident at the top of the Earth’s atmosphere. SORCE was successfully launched from NASA’s Kennedy Space Center on 25 January 2003. As one element of NASA’s Earth Science Enterprise, the SORCE mission is a joint effort between NASA and the Laboratory for Atmospheric and Space Physics (LASP).

The primary objectives of SORCE are to make daily measurements of Total Solar Irradiance, TSI, and spectral irradiance over almost the entire spectral range from soft X-rays, through the visible, and into the infrared. The SORCE instruments – the Total Irradiance Monitor (TIM), the Spectral Irradiance Monitor (SIM), two Solar Stellar Irradiance Comparison Experiments (SOLSTICE), and the XUV Photometer System (XPS) – are currently measuring the Sun’s total and spectral irradiance with unprecedented accuracy and precision capable of establishing solar variability. In addition to securing a reliable long-term database with which to characterize solar radiative forcing of climate and global change, the SORCE program seeks to foster new understanding of the origins of the solar variations and the physical pathways by which the Earth’s atmosphere, oceans, and land respond on multiple time scales.

This collection of papers describes the SORCE mission, goals, spacecraft, instrument development and calibration, planning software, ground operations, data processing, early science results, and science implications on how the Sun influences Earth’s environment.

The Solar Radiation and Climate Experiment (SORCE) Mission for the NASA Earth Observing System (EOS)....Pages 3-6 The SORCE Mission....Pages 7-25 SORCE Contributions to New Understanding of Global Change and Solar Variability....Pages 27-53 An Overview of the Disposition of Solar Radiation in the Lower Atmosphere: Connections to the SORCE Mission and Climate Change....Pages 55-69 The SORCE Spacecraft and Operations....Pages 71-89 The Total Irradiance Monitor (TIM): Instrument Design....Pages 91-109 The Total Irradiance Monitor (TIM): Instrument Calibration....Pages 111-127 The Total Irradiance Monitor (TIM): Science Results....Pages 129-139 The Spectral Irradiance Monitor: Scientific Requirements, Instrument Design, and Operation Modes....Pages 141-167 The Spectral Irradiance Monitor: Measurement Equations and Calibration....Pages 169-204 The Spectral Irradiance Monitor (SIM): Early Observations....Pages 205-224 Solar-Stellar Irradiance Comparison Experiment II (SOLSTICE II ): Instrument Concept and Design....Pages 225-258 Solar-Stellar Irradiance Comparison Experiment II (SOLSTICE II): Pre-Launch and On-Orbit Calibrations....Pages 259-294 Solar-Stellar Irradiance Comparison Experiment II (SOLSTICE II): Examination of the Solar-Stellar Comparison Technique....Pages 295-324 The Mg II Index from SORCE....Pages 325-344 XUV Photometer System (XPS): Overview and Calibrations....Pages 345-374 XUV Photometer System (XPS): Solar Variations During the SORCE Mission....Pages 375-387 The SORCE Science Data System....Pages 389-413 This book describes the state-of-the art instruments for measuring the solar irradiance from soft x-ray to the near infrared and the total solar irradiance. Furthermore, the SORCE mission and early results on solar variability are presented along with papers that provide an overview of solar influences on Earth. This collection of papers provides the only detailed description of the SORCE mission and its instruments. The Solar Radiation and Climate Experiment (SORCE) is a small satellite, carrying four scientific instruments to measure the solar radiation incident. This collection of papers describes the SORCE mission, goals, spacecraft, instrument development and calibration, science implications on how the Sun influences Earth's environment, and others One and only detailed description of the SORCE mission and its instruments Description of state-of-the-art instruments and calibration techniques Latest information on knowledge of solar irradiance variability