TSIS_SSI_L3_12HR: Solar Spectral Irradiance 12-Hour Means

TSIS-1 SIM instrument measures solar spectra from 200 to 2400 nm with an absolute uncertainty of about 0.2%. The Level 3 data product averages these measurements over 12-hour periods, reporting irradiance at 1 AU. Data is appended daily to a single tabular ASCII file, with rows containing values for each wavelength across the mission's duration.

Use Cases

• Tracking solar spectral variability over time based on daily appended wavelength-specific irradiance data.
• Calibrating atmospheric and climate models using irradiance values reported at a standard 1 AU distance.
• Assessing instrument performance and data quality trends using the provided data quality column.
• Analyzing the relationship between solar activity and spectral resolution, which ranges from 2 nm to 45 nm.

Strengths

• Provides high-resolution spectral data across a broad range from 200 to 2400 nm.
• Offers a low reported absolute uncertainty of about 0.2% for the irradiance measurements.
• Data is updated daily, providing a continuous time-series from the mission start in December 2017.
• Data is structured in a simple tabular ASCII format, facilitating use in spreadsheet applications.

Limitations

• Sources conflict on the current version number: nasa_earthdata lists Version 14, while datagov lists Version 13.
• Key metadata such as row count, file size, and author are consistently listed as unknown or None across platforms.
• The dataset description is duplicated across platforms, suggesting potential stale or copied metadata.

Provenance

Source

GES_DISC (Goddard Earth Sciences Data and Information Services Center)

Collection Method

Measurements from the Spectral Irradiance Monitor (SIM) instrument on the TSIS-1 mission, mounted on the International Space Station.

Time Range

From the mission start date (December 15, 2017 launch, December 30, 2017 mounting on ISS) onwards, with daily updates.

Freshness

Last updated date reported as 2026-04-09 on nasa_earthdata and datagov platforms.

Geography

Solar measurements from the International Space Station, reported for a mean solar distance of 1 AU.