Persistent North-South Alignment of the Solar Supergranulation

Abstract

We have found evidence of an alignment of the solar supergranulation in the direction parallel to the Sun's rotation axis. Signatures of the alignment are apparent in both time-averaged images and in three-dimensional power spectra. The north-south organization is persistent in time, extending over many supergranular lifetimes. It occurs over a wide latitudinal extent, to +/-60°, and shows variation on a 10°-30° scale. These properties, as well as the rotation rate of the pattern, suggest a underlying larger scale dynamical cause. We examine a mechanism by which giant cell motions may contribute to such alignment.