Issue |
J. Space Weather Space Clim.
Volume 14, 2024
Topical Issue - Space Climate: Long-term effects of solar variability on the Earth’s environment
|
|
---|---|---|
Article Number | 10 | |
Number of page(s) | 25 | |
DOI | https://doi.org/10.1051/swsc/2024008 | |
Published online | 12 April 2024 |
Research Article
Advancements in solar spectral irradiance measurements by the TSIS-1 spectral irradiance monitor and its role for long-term data continuity
1
Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Boulder, CO 80309, USA
2
Department for Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USA
* Corresponding author: erik.richard@lasp.colorado.edu
Received:
29
August
2023
Accepted:
19
March
2024
The first implementation of NASA’s Total and Spectral Solar Irradiance Sensor (TSIS-1) launched on December 15th, 2017, and was integrated into the International Space Station (ISS) to measure both the total solar irradiance (TSI) and the solar spectral irradiance (SSI). The direct measurement of the SSI is made by the LASP Spectral Irradiance Monitor (SIM) and provides data essential to interpreting how the Earth system responds to solar spectral variability. Extensive advances in TSIS-1 SIM instrument design and new SI-traceable spectral irradiance calibration techniques have resulted in improved absolute accuracy with uncertainties of less than 0.5% over the continuous 200–2400 nm spectral range. Furthermore, improvements in the long-term spectral stability corrections provide lower trend uncertainties in SSI variability measurements. Here we present the early results of the TSIS-1 SIM measurements covering the first 5 years of operations. This time period includes the descending phase of solar cycle 24, the last solar minimum, and the ascending phase of solar cycle 25. The TSIS-1 SIM SSI results are compared to previous measurements both in the absolute scale of the solar spectrum and the time dependence of the SSI variability. The TSIS-1 SIM SSI spectrum shows lower IR irradiance (up to 6% at 2400 nm) and small visible increases (~0.5%) from some previous reference solar spectra. Finally, initial comparisons are made to current NRLSSI2 and SATIRE-S SSI model results and offer opportunities to validate model details both for short-term (solar rotation) spectral variability and, for the first time, the longer-term (near half solar cycle) spectral variability across the solar spectrum from the UV to the IR.
Key words: Spectral irradiance / Solar variability / Solar spectrum / Solar cycle
© E. Richard et al., Published by EDP Sciences 2024
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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