Professor Emeritus of Earth and Planetary Sciences
University of California, Santa Cruz
glatz@es.ucsc.edu
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Gary develops global three-dimensional time-dependent computer models to study
the structure and dynamics of the interiors of planets and stars.
The first in this series of models was written in the 1980s to study the
solar dynamo. A modified version of this model was used for
pre-flight studies and post-flight analyses of a
rotating fluid dynamics experiment
flown aboard NASA Space Shuttles in 1985 and 1995. In his
studies of geodynamics he has simulated global circulation and convection
in the Earth's atmosphere, mantle and core.
He has also simulated convection and magnetic field generation
in the deep interiors of giant gas planets like Jupiter and Saturn.
Gary and colleagues, Paul Roberts (UCLA) and Rob Coe (UCSC),
study the internal magnetohydrodynamics of the Earth's core, i.e., the
geodynamo.
This is the mechanism in the Earth's fluid outer core that maintains the
geomagnetic field.
Their computer simulations span millions of years,
using an average numerical time step of 15 days. At the surface of the
model Earth, the simulated magnetic field has an intensity, an axial dipole
dominated structure, and a westward drift of the non-dipolar structure that
are all similar to the Earth's. The model's solid inner core rotates slightly
faster than the surface of the model Earth; this computer modeling result in
1995 served as a prediction for the Earth that several seismic analyses now support.
Several spontaneous reversals of the magnetic dipole polarity also occur in
the simulations, similar to those seen in the Earth's paleomagnetic record.
Gary and his former graduate student
Tami Rogers
(now at the University of Newcastle upon Tyne, UK)
studied the internal magnetohydrodynamics of the
sun using her spectral computer codes.
Their simulations illustrate how gravity waves in the sun's deep
radiative interior may be excited by turbulence in the outer
convection zone.
Gary and his former graduate student
Martha Evonuk studied the internal magnetohydrodynamics of
giant planets using her finite volume codes.
A recent dynamo simulation of the deep interior dynamics of a giant planet
maintains a latitudinally banded surface zonal wind profile similar to those seen on the surfaces
of Jupiter and Saturn. The simulation also displays banded patterns of the resulting
magnetic field and gravity field at the surface,
which serve as predictions for the Juno and Cassini observations at
Jupiter and Saturn, respectively.
Gary and his former graduate student
Darcy Ogden studied the supersonic multiphase dynamics of
explosive volcanic eruptions
using a library of computer codes, CFDLib, from the Los Alamos
National Laboratory. When a standing shock wave (Mach disk)
forms above the vent their simulations predict a
flow profile within the erupting column that is very different
than that which has been assumed in simple parameterized models.
Gary, Francis Nimmo and their former graduate student
Erinna Chen studied circulations and induced magnetic fields in the subsurface oceans of
Europa and Titan driven by tidal potentials using 3D MHD simulations.
Gary, Nic Brummell and their former graduate student
Katelyn White studied magnetic field generation in laboratory dynamo experiments using
3D dynamo simulations.