Solar extreme ultraviolet irradiance measurements from sounding rockets during solar cycle 22

Abstract

Our sounding rocket measurements during solar cycle 22 include solar extreme ultraviolet (EUV) irradiances below 12 nm with 0.2 nm spectral resolution, far ultraviolet (FUV) airglow spectra below 160 nm, and solar soft x-ray (XUV) images at 17.5 nm. Compared to the earlier observations, these rocket experiments provide a more accurate absolute measurement of the solar EUV irradiance because these instruments are calibrated at the National Institute of Standards and Technology (NIST) with a radiometric uncertainty of about 8%. These more accurate sounding rocket measurements suggest revisions of the previous reference AE-E spectra by as much as a factor of 2 at some wavelengths. Our sounding rocket flights during the past several years (1988–1994) also provide information about solar EUV variability during solar cycle 22.