SOLAR IRRADIANCES AND RADIANCES OF UV AND EUV LINES DURING THE MINIMUM OF SUNSPOT ACTIVITY IN 1996

Full Sun observations in UV and EUV emission lines were performed by S UMER (Solar Ultraviolet Measurements of Emitted Radiation) on SOHO (So lar and Heliospheric Observatory) in 1996. The radiometric pre-flight calibration of SUMER is traceable to a primary radiometric source stan dard - the electron storage ring BESSY. Based on this calibration, the irradiance values at SOHO and at 1 AU have been obtained for the line s He I (X 584.33 Angstrom), O V ( 629.74 Angstrom), Ne VIII (lambda 77 0.41 Angstrom), S V (lambda 786.47 Angstrom), O IV (lambda 787.72 Angs trom), S VI (lambda lambda 933.39, 944.52 Angstrom), HI Ly epsilon (la mbda 937.80 Angstrom), C III (lambda 977.04 Angstrom), N V (lambda 123 8.81 Angstrom), Si I(lambda 1256.52 Angstrom), and C IV (lambda 1548.2 0 Angstrom). The spatially resolved measurements allowed good estimate s to be made of the active region contributions to the irradiance of t he quiet Sun. The centre-to-limb radiance variations of these lines ha ve also been obtained from these measurements. For quiet solar conditi ons, a radiance spectrum was determined for wavelengths from 800 Angst rom to 1500 Angstrom near the centre of the solar disk.