Since the SOHO launch in 1995, there have been seven opportunities for the Michelson Doppler Imager (MDI) to provide continuous Dopplergrams of the solar poles over extended intervals of time. Because of the nearly constant and uniform focus of the MDI images over small regions it is possible to resolve and track supergranules across the pole at these times. Seismic analysis of global modes from the MDI data has previously hinted at the possibility of a polar vortex in the upper convection zone. We report here on the first analysis of polar surface motions inferred from MDI data covering a total of about 2000 hours during five polar observing windows, including two full months around the south polar apparition of 1998. Research supported by SOI-MDI NASA grant NAG5-3077 at Stanford University.
American Astronomical Society Meeting Abstracts #194
- Pub Date:
- May 1999