UARS SUSIM Level 3BS: Daily Solar Ultraviolet Irradiance at 1 nm Resolution

NASA's UARS SUSIM Level 3BS dataset provides daily solar spectral irradiance measurements from 110 to 410 nm at 1 nm resolution. The data, processed with version 22 algorithm, are normalized to 1 AU and corrected for instrument degradation. It includes specific solar indices like Lyman alpha and Mg-II core-wing ratios for tracking solar variability across multiple timescales.

Use Cases

• Tracking short-term (minutes to hours) and long-term (11-year solar cycle) variations in solar ultraviolet output based on the daily spectral irradiance data.
• Modeling atmospheric photochemistry using specific solar indices like Lyman alpha and C-IV (155 nm) irradiance values.
• Calibrating other solar instruments by referencing the NIST-calibrated deuterium lamp methodology described for the instrument.
• Analyzing correlations between solar activity proxies, such as the core-wing ratios of Mg-I and Mg-II, and total spectral irradiance.

Strengths

• Provides high spectral resolution (1 nm) across a defined ultraviolet range (110-410 nm).
• Includes calibration from NIST-calibrated sources and correction for instrument degradation, suggesting high precision.
• Designed to capture solar variability across multiple timescales, from minutes to the 22-year solar magnetic cycle.

Limitations

• Key metadata like row count, file size, and specific column names are unavailable across all platforms.
• Conflicting 'last updated' dates (2005 vs. 2026) between NASA Earthdata and Data.gov create uncertainty about data currency.
• Data is stored in a binary record-oriented format, which may require specialized tools for access and analysis.

Provenance

Source

National Aeronautics and Space Administration (NASA), Upper Atmosphere Research Satellite (UARS)

Collection Method

Measurements from the Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) instrument, consisting of two double-dispersion scanning spectrometers.

Time Range

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Freshness

2026-04-09 21:24:12.977511

Geography

Full solar disk measurements (non-geospatial).