Abstract
The Total and Spectral Solar Irradiance Sensor (TSIS) Spectral Irradiance Monitor (SIM) is the next generation, space-borne SSI monitor that will fly as part of the joint agency (NASA/NOAA) Joint Polar Satellite System (JPSS) program scheduled for launch in late 2016. The instrument has been designed and calibrated to achieve unprecedented levels of measurement accuracy (less than 0.25%) and on-orbit stability required to meet the needs of establishing a complete solar spectral irradiance climate data record. The Spectral Radiometry Facility (SRF) at LASP was developed in order to validate the end-to-end performance of the SIM instrument.
This facility includes a test chamber with a 5-axis manipulator that houses the SIM instrument. The illumination source is provided by a NIST Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (SIRCUS) laser system. This laser system provides narrow tunable light from 210-2700 nm. The facility also includes a cryogenic radiometer with a precision aperture that is used to measure the absolute irradiance of the illumination light. This facility thus allows us to illuminate the instrument with a known irradiance, wavelength, and polarization. Additionally, the 5-axis manipulator permits us to test the pointing sensitivity and off-axis performance of the instrument.
A series of detailed calibrations of the SIM instrument in this facility have allowed us to fully characterize the instrument wavelength scale, spectral response functions, pointing sensitivity, and radiometric accuracy to better than 0.25%.
Calibration of the Spectral Irradiance Monitor in the LASP Spectral Radiometry Facility
The Total and Spectral Solar Irradiance Sensor (TSIS) Spectral Irradiance Monitor (SIM) is the next generation, space-borne SSI monitor that will fly as part of the joint agency (NASA/NOAA) Joint Polar Satellite System (JPSS) program scheduled for launch in late 2016. The instrument has been designed and calibrated to achieve unprecedented levels of measurement accuracy (less than 0.25%) and on-orbit stability required to meet the needs of establishing a complete solar spectral irradiance climate data record. The Spectral Radiometry Facility (SRF) at LASP was developed in order to validate the end-to-end performance of the SIM instrument.
This facility includes a test chamber with a 5-axis manipulator that houses the SIM instrument. The illumination source is provided by a NIST Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (SIRCUS) laser system. This laser system provides narrow tunable light from 210-2700 nm. The facility also includes a cryogenic radiometer with a precision aperture that is used to measure the absolute irradiance of the illumination light. This facility thus allows us to illuminate the instrument with a known irradiance, wavelength, and polarization. Additionally, the 5-axis manipulator permits us to test the pointing sensitivity and off-axis performance of the instrument.
A series of detailed calibrations of the SIM instrument in this facility have allowed us to fully characterize the instrument wavelength scale, spectral response functions, pointing sensitivity, and radiometric accuracy to better than 0.25%.