Effects of certain analysis procedures on solar global velocity signals

Abstract

view Abstract Citations (4) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Effects of certain analysis procedures on solar global velocity signals Gilman, P. A. ; Glatzmaier, G. A. Abstract The effects of data reduction procedures on the signals obtained for global solar velocities from the Doppler magnetograph at Mount Wilson are examined. The data reduction procedure used by Howard (Howard et al., 1980; LaBonte and Howard, 1979; Howard and LaBonte, 1980) is applied to idealized global velocity data, and it is shown that the effects of removing daily rotation, ears and zero offset signals and the construction of synoptic maps can easily reduce an original periodic east-west flow velocity of peak amplitude 100 m/sec to 10 m/sec or less for any wavenumber. Furthermore, it is shown that a velocity spectrum obtained from a nonlinear spherical convection model is attenuated to rms residual velocities close to or within the upper limits of Howard and LaBonte. It is concluded that there could be a substantially larger global velocity signal present in the Mount Wilson magnetograph data than has so far been demonstrated, and data reduction and observational techniques for obtaining these signals are suggested. Publication: The Astrophysical Journal Pub Date: October 1980 DOI: 10.1086/158390 Bibcode: 1980ApJ...241..793G Keywords: Atmospheric Circulation; Flow Velocity; Signal Analysis; Solar Atmosphere; Amplitudes; Data Reduction; Phase Velocity; Solar Rotation; Solar Physics full text sources ADS |