  We use time-series ultraviolet full sun images to construct limb-synoptic
maps of the Sun. On these maps, large-scale, long-lived coronal streamers
appear as repetitive sinusoid-like arcs projected over the polar regions. They
are caused by high altitude plasma produced from sunspot-rich regions at
latitudes generally far from the poles. The non-uniform longitudinal
distribution of these reveals four longitudinal zones at the surface of the sun
from which sunspots erupt preferentially over the 5-year observing interval
(2006 January to 2011 April). Spots in these zones (or "clusters") have
individual lifetimes short compared to the lifetimes of the coronal features
which they sustain, and erupt at different times. The four sunspot clusters
contain >75% of all numbered sunspots in this period. They occupy two distinct
longitudinal zones separated by ~180 degree and each spanning ~100 degree in
longitude. The rotation rates of the spot clusters are ~5% faster than the
rates at both the surface and the bottom of the convection zone. While no
convincing theoretical framework exists to interpret the sunspot clusters in
the longitude-time space, their persistent and nonuniform distribution
indicates long-lived, azimuthal structures beneath the surface, and are
compatible with the existence of previously-reported active longitudes on the
sun.
