Browsing by Author "Snow, Martin"

Now showing 1 - 4 of 4
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    Calibration of the solar position sensor on GOES-R as a proxy for total solar irradiance I: Modeling the SPS bandpass
    (EDP Sciences, 2025) Snow, Martin; Penton, Steven Victor; Woodraska, Donald L.
    Context: The Geostationary Environmental Operational Satellites R series (GOES-R) includes an instrument that measures visible light from the Sun at high cadence: the Solar Position Sensor (SPS). SPS is part of the Extreme ultraviolet and X-ray Irradiance Sensors (EXIS) instrument package. The visible wavelength range observed by SPS includes the peak power of the solar spectrum. Tracking the solar input to the climate system is important at all timescales. Aims: This article is the first in a series that will describe using the SPS data as a high-cadence proxy for Total Solar Irradiance (TSI), and as an input to the spectral model used in the NOAA Climate Data Record for solar irradiance. Methods: We describe the design of the SPS instrument and create a model of its output using the solar spectrum measured by the Total and Spectral Irradiance Sensor-1 (TSIS-1) on the International Space Station. We apply the bandpasses of the SPS components to the daily TSIS-1 Solar Irradiance Monitor (SIM) spectrum and integrate over wavelength to simulate the SPS measurement. Results: After applying the appropriate SPS filter transmittances and diode responsivity to the TSIS-1/SIM spectrum, we compare the integrated irradiances from the full SIM spectrum and the SPS model to the TSI measurement from TSIS-1. These comparisons of daily averages show that the integrated SPS model reproduces TSI with an uncertainty of 53 parts per million. We also show a preliminary comparison of the SPS data to the high-cadence TSI measurements from the Digital Absolute RAdiometer (DARA) on the FY-3E satellite. Conclusions: The modeled SPS spectrum shows excellent agreement with TSI on a daily cadence. Once all the instrument calibrations have been established, the SPS data will be a viable operational high-cadence proxy for TSI.
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    How open data and interdisciplinary collaboration improve our understanding of space weather: A risk and resiliency perspective
    (Frontiers Media, 2022) Ledvina, Vincent E.; Palmerio, Erika; Snow, Martin
    Space weather refers to conditions around a star, like our Sun, and its interplanetary space that may affect space- and ground-based assets as well as human life. Space weather can manifest as many different phenomena, often simultaneously, and can create complex and sometimes dangerous conditions. The study of space weather is inherently trans-disciplinary, including subfields of solar, magnetospheric, ionospheric, and atmospheric research communities, but benefiting from collaborations with policymakers, industry, astrophysics, software engineering, and many more.
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    Solar irradiance spectra from the compact SOLSTICE (CSOL) experiment: Instrument design, FUV calibration, measurements, and comparison of the 2018 rocket flight
    (Springer, 2023) Snow, Martin; Furst, Mitchell; Harder, Jerald
    The Compact SOLSTICE, a compact far and mid ultraviolet (FUV and MUV) spectrograph, flew on a sounding rocket on 18 June 2018 to validate and potentially calibrate the SOLar STellar Irradiance Comparison Experiment (SOLSTICE) onboard the Solar Radiation Climate Experiment (SORCE) spacecraft. This article reports the instrument design, the calibration of the FUV channel, and the FUV irradiance measurements. Irradiance measurements are compared to SOLSTICE showing agreement within the combined instrumental uncertainties at most wavelengths, including the H Lyman-α emission at 121.6 nm. Some unexplained differences in line ratios between 130.5 nm and 147.5 nm are observed.
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    Solar irradiance spectra from the compact SOLSTICE (CSOL) experiment: instrument design, FUV calibration, measurements, and comparison of the 2018 rocket flight
    (Solar Physics, 2023) Snow, Martin; Furst, Mitchell; Harder, Jerald
    The Compact SOLSTICE, a compact far and mid ultraviolet (FUV and MUV) spectrograph, flew on a sounding rocket on 18 June 2018 to validate and potentially calibrate the SOLar STellar Irradiance Comparison Experiment (SOLSTICE) onboard the Solar Radiation Climate Experiment (SORCE) spacecraft. This article reports the instrument design, the calibration of the FUV channel, and the FUV irradiance measurements. Irradiance measurements are compared to SOLSTICE showing agreement within the combined instrumental uncertainties at most wavelengths, including the H Lyman-α emission at 121.6 nm. Some unexplained differences in line ratios between 130.5 nm and 147.5 nm are observed.