  (Abridged) We report results of three dimensional MHD simulations of global
accretion disks threaded with weak vertical magnetic fields. We perform the
simulations in the spherical coordinates with different temperature profiles
and accordingly different rotation profiles. In the cases with a spatially
constant temperature, because the rotation frequency is vertically constant in
the equilibrium condition, general properties of the turbulence are
quantitatively similar to those obtained in local shearing box simulations. On
the other hand, in the cases with a radially variable temperature profile, the
vertical differential rotation, which is inevitable in the equilibrium
condition, winds up the magnetic field lines, in addition to the usual radial
differential rotation. As a result, the coherent wound magnetic fields
contribute to the Maxwell stress in the surface regions. We obtain
nondimensional density and velocity fluctuations ~0.1-0.2 at the midplane. The
azimuthal power spectra of the magnetic fields show shallow slopes, ~m^0-
m^{-1}, than those of velocity and density. We observe intermittent and
structured disk winds driven by the Poynting flux associated with the MHD
turbulence. The Poynting flux originating from magnetic tension is injected
from the regions above a scale height towards both the midplane and the
surfaces. Related to this, sound waves are directed to the midplane from the
surface regions. The mass accretion mainly occurs near the surfaces and the gas
near the midplane slowly moves outward, which causes large-scale meridional
circulations. The vertical magnetic fields are also dragged inward in the
surface regions, while they stochastically move outward and inward around the
midplane. We also discuss an observational implication of induced spiral
structure in the simulated turbulent disks to protoplanetary disks.
