Computational Infrastructure for Geodynamics (CIG)

Shijie Zhong

Department of PhysicsUniversity of Colorado at Boulder

International Workshop of Cyberinfrastructure for Geosciences

Beijing, July 2006

Outline

1) What is the CIG (mission, history and rationale)?

2) How does the CIG operate?

3) Current status and projects.

Mission

• Develop, support and disseminate community accessible software for the geophysical sciences community.

• Provide documented, validated, open-source state-of-the-art codes including pre-existing codes.

• Framework for code development and interfaces.• Form strategic partnerships with the larger world of

computational science and Geoinformatics.• Education and training.

Areas of Geophysical Sciences (at the moment)

• Mantle convection

• Seismology

• Short-term tectonics and earthquake physics

• Long-term tectonics

• Geodynamo

• Magma dynamics and melt migration

History and Rationale

In 2000, Peter Olson (JHU) and Mark Richards (Berkeley) first proposed the idea to address the following problems that they had perceived.

1. Constant need to incrementally and painfully re-engineer legacy codes.

2. Validation, documentation, maintenance of the codes.

3. Disproportional effort out of graduate students/PI’s in non-Geoscience issues (computer science, …) and often re-inventing wheels.

History

• 2002, first workshop at Lake Tahoe organized by Peter Olson and Mark Richards.

• 8, 2003, Caltech was selected by geodynamics community as the site and a proposal writing team (Gurnis, Kellogg, …) was formed to take the lead to propose to the NSF for the CIG.

• 9, 2004, funded by the NSF and established at Caltech.

More on Rationale

Through workshops and discussions, the original idea by Peter Olson and Mark Richards was expanded.

Better software engineering is also needed to enable coupling between different codes (often means different physics) and easy assembly of new codes for new scientific problems, all through a Framework.

An Earth System with Coupled Physics Demands an Integrated Approach

Coupled dynamics at different scales

Katz and Spiegelman, 2006Tan and Gurnis, 2006

How does CIG operate?

Keyword: community driven. • Input from the community on what they want. Two ways to get input: workshops (check www.geodynamics.org) and short

proposals (often only ideas with no funding involved).• The science steering committee (elected from each

individual field) prioritizes the needs and makes recommendation to the executive committee and director of the CIG.

• Decision is then made by the executive committee.• CIG staff engineers start to work with science working

group (i.e., geophysicists) to deliver the product.

A Dynamic Process

• Interaction between geoscientists and CIG staff engineers is important. It tells geoscientists what mathematical and computing techniques are out there. The interaction may improve the end product significantly.

Two different needs from community

1. Best possible existing software to solve his/her outstanding problems.

2. Software that makes it possible or easy to explore new problems (e.g., coupled dynamics).

Committees of CIG

• Director: Mike Gurnis (Caltech)

• Executive Committee: Mark Richards (Chair, Berkeley), Mike Gurnis (Caltech), Brad Hager (MIT), Marc Spiegelman (Columbia), Bill Appelbe (VPAC).

• Science Steering Committee: Peter Olson (Chair, JHU, geodynamo), Marc Parmentier (Brown Univ, magma/melt migration), Brad Aagaard (USGS, short-term tectonics), Roger Buck (Columbia, long-term tectonics), Jeroen Tromp (Caltech, seismology), Shijie Zhong (Univ of Colorado, mantle convection), Wolfgang Bangerth (Texas A&M, CS), Omar Ghattas (UT-Austin, CS).

CIG Affiliated Institutions (45 so far including foreign institutes)

Outline

1) What is the CIG (mission, history and rationale)?

2) How does the CIG operate?

3) Current status and projects.

Mantle Convection

CitcomCU (pre-existing)• 3D Cartesian/Regional

spherical finite element code.• Isochemical and

thermochemical convection.

Downloadable from www.geodynamics.org

Studies of the structure and evolution of the planetary mantles

Mantle Convection

2) CitcomS (pre-existing): A 3D Global Spherical

Convection Code. Downloadable from

www.geodynamics.org Had 75 downloads from

59 institutions in 15 countries by February of 2006.

Seismic wave propagation

Studies of propagation of seismic waves at different frequency and length scales.

SPECFEM (pre-existing): a 3D Spectral finite element code.

Downloadable at www.geodynamics.org

Short-term tectonics

Studies of earthquake physics and pre- and post-seismic crustal deformation on time scale of seconds to hundreds of years.

Pylith: A 3D finite element code with complicated meshing schemes (CIG developed).

A full version will become downloadable in December of 2006. But an early version (Lithomop) is already downloadable.

Long-term tectonics

Studies of crustal and lithospheric deformation on time scale of millions of years (e.g., mountain building)

Gale: a 3D finite element code with arbitrary Eulerian and Lagrangian mesh (CIG developed). Become

downloadable in December of 2006.

Geodynamo

Studies of convection within the outer core and generation of magnetic field. Multi-scale physics. Demand extremely high resolution to resolve the turbulent flow in the core.

Downloadable Codes (pre-existing) to be expected at the website:

MAGIC code and Kuang and Bloxham code by December of 2006.

Radial magnetic field at the CMB

Magma Migration

Studies of magma migration under various crustal and mantle conditions. Coupling physics at vastly different scales (cm to tens of km). Demand high resolution.

To be discussed at next month’s magma migration workshop at Columbia Univ.

Katz and Spiegelman

Summary of CIG

Community-driven and from the community and serve the community.

Provide the well-documented, validated, open-source codes to advance our science.

Develop software that enables us to study the coupled multi-scale dynamics and that explores at the very basic level the similarities between different geo-science subfields.

Build the community through workshops.

Check out www.geodynamics.org