SSI Composite Data File Summary
The SORCE Solar Spectral Irradiance (SSI) composite data product is constructed using measurements from the SOLSTICE, SIM, and XPS instruments, which are combined into merged daily solar spectra over the spectral intervals shown in the table below. The SORCE SSI data products are provided on a fixed wavelength scale, which varies in spectral resolution from 1-34 nm over the entire spectral range. Irradiances are reported at a mean solar distance of 1 AU and zero relative line-of-sight velocity with respect to the Sun.
Learn more about SORCE SSI data products.
| Measuring Instrument | XPS | SOLSTICE (A&B) | SIM |
| Temporal Cadence | Daily | Daily | Daily |
| Detector | Photodiodes | Photomultiplier Tubes | Photodiodes, ESR |
| Spectral Range | 0.1 – 40 nm | 115 – 310 nm | 310 – 2416 nm |
| Spectral Resolution | 7 – 10 nm | 1 nm | 1 – 34 nm |
| Accuracy | 12 – 30% | 2 – 6% | 2% |
| Long-Term Repeatability | 1%/yr | 0.2 – 0.5%/yr | < 0.1%/yr |
| Data Level | 4 | 3 | 3 |
Solar Spectral Irradiance (SSI) Measurement Summary. The SORCE SSI data product is constructed using measurements from the SIM, SOLSTICE, and XPS instruments.
Data Product Release Notes per Instrument:
