Simulation of effects of atmospheric seeing on the observation of high-degree solar oscillations

Abstract

view Abstract Citations (3) References (45) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Simulation of Effects of Atmospheric Seeing on the Observation of High-Degree Solar Oscillations Hill, Frank ; Gough, Douglas ; Merryfield, William J. ; Toomre, Juri Abstract Numerical simulations of the effects of atmospheric seeing distortions on observations of solar oscillations of intermediate and high degree are performed. The simulations involve a representation of about 100 p-modes of oscillation, with degrees l = 50-150 (intermediate-degree) and 150-450 (high-degree), formed from the complement of a sexated mode set. These modes are superposed on a steady large-scale convective background, and projected onto the plane of the sky. Image motion is modeled by displacement maps generated from two-dimensional turbulence power spectra; the maps are scaled so that the rms amplitude of the displacements has values of 2-5 arcsec. The distorted velocity field is then Fourier analyzed to produce simulated (l, nu) power diagrams, where nu is the temporal cyclic frequency. The results show that power in the mode ridges is diminished as atmospheric seeing worsens, particularly at high degrees. Redistribution of power produces an apparent decrease in the frequencies of the oscillations as measured by the centroids of the ridges in the power spectra. It is found that time-averaging the observations is quite effective in reducing the noise. Publication: The Astrophysical Journal Pub Date: March 1991 DOI: 10.1086/169754 Bibcode: 1991ApJ...369..237H Keywords: Digital Simulation; Earth Atmosphere; Seeing (Astronomy); Solar Oscillations; Fourier Analysis; Power Spectra; Solar Granulation; Solar Interior; Solar Physics; EARTH: ATMOSPHERE; SUN: OSCILLATIONS full text sources ADS |