Solar EUV Irradiance Uncertainties for Planetary Studies | CU Experts

The MAVEN/EUVM solar soft x-ray (SXR) and Lyman-α measurements are; compared with analogous measurements made from Earth to characterize the; typical error introduced when phase-shifting solar EUV irradiance; measurements made from Earth to other points in the solar system; according to the 27.27 day synodic solar rotation period. The; phase-shifting error, ε, measured at SXR and Lyman-α are extrapolated to; the full EUV spectrum by assuming it is proportional to the variability; that occurs over the 27-day timescale of solar rotation. Values for ε as; a function of wavelength are reported and used to find the typical error; for estimates of photoionization frequencies of some major species found; in planetary upper atmospheres derived by phase-shifted EUV irradiance.; This study finds that the typical extrapolation error for the CO; photoionization frequency is 5.7% of the solar cycle mean value, and; 87% of the typical 27-day variability.

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