The mean vertical velocity of solar granulation
Abstract
Direct measurements of vertical granular velocity fluctuations in spatially resolved spectrograms and the methods of their correction for the influence of atmospheric and instrumental smearing are critically discussed. An independent correction of the observations by Canfield and Mehltretter (1973) and by Keil and Canfield (1978) is reported. A vertical granular velocity component (without the oscillations) of 0.8-1.2 km/s (rms) is obtained, which is very weakly dependent on height. These values are larger than the theoretical predictions by Nelson and Musman (1977) and constitute the main component of local 'macroturbulent' broadening of unresolved line profiles.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1980
- Bibcode:
- 1980A&A....83..129M
- Keywords:
-
- Atmospheric Turbulence;
- Solar Granulation;
- Correction;
- Power Spectra;
- Spectrum Analysis;
- Vertical Motion;
- Solar Physics