![]() |
Spectral
Irradiance Monitor (SIM)
The Spectral Irradiance Monitor (SIM) will measure the solar spectrum in ultraviolet, visible, and near infrared wavelengths. (Image courtesy Solar Radiation and Climate Experiment Project) SIM will be the first instrument in orbit to take readings of the full spectrum of visible and near-infrared solar radiation. By reviewing data from SIM, scientists may be able to tell how the solar cycles affect both visible and near-infrared wavelengths. Combined with improved measurements by ground and by aircraft, they may be able to discern just how much of this light goes into heating up the lower layers of the Earths atmosphere and how much goes into the land and oceans. SIM may also aid in efforts to discern exactly how much of the Suns energy is reflected by industrial aerosols and clouds. A problem with prism spectrometers is that the glass in the prism can degrade over time. To account for this, the scientists will monitor how well the prism transmits light. Light exiting the first prism will be sent through a slit to create a monochrome (single wavelength) light source. The wavelength is selectable by adjusting the position of the slit. This light source is then directed through a periscope into the second spectrometer. The light is measured before and after it goes into the second prism. If the ratio between the before and after measurement changes, the scientists will know if the glass is degraded and how this degradation affects the transmission of the light at each selected wavelength. They can then take this information into account when they calibrate the data. To test the entire apparatus, the scientists will open both of the spectrometers simultaneously and compare the data between the two. next: Solar Stellar Comparison
Experiment (SOLSTICE) |
Solar Radiation and Climate Experiment (SORCE)
The SORCE Satellite Related Articles Related Datasets |