  We investigated Lorentz violation through anisotropy of gravity using a
worldwide array of 12 superconducting gravimeters. The Lorentz-violating signal
is extracted from the difference between measured gravity and a tidal model. At
the level of sensitivity we reach, ocean tides start to play an important role.
However, most models available that include ocean tides are empirically based
on measured gravity data, which may contain Lorentz-violating signal. In this
work we used an ocean tides included tidal model derived from first principles
to extract Lorentz-violating signal for the first time. We have bounded
space-space components of gravitational Lorentz violation in the minimal
standard model extension (SME) up to the order of $10^{-10}$, one order of
magnitude improved relative to previous atom-interferometer tests.

General Relativity and Quantum Cosmology