Computational Math Seminar: Hari Rajaram

Glaicer and Ice Sheet Modeling - governing equations and numerical methods  

Hari Rajaram

Civil, Environmental, and Architectural Engineering; University of Colorado Boulder

Date and time: 

Tuesday, March 4, 2014 - 10:30am

Location: 

Grandview Conference Room, 1320 Grandview Avenue

Abstract: 

I will present an overview of the governing equations of mass, momentum and energy conservation for glacier and ice sheets.  The momentum equation takes the form of a nonlinear Stokes flow problem due to the non-Newtonian ice rheology, and two common approximate forms will also be discussed.  Ice viscosity depends strongly on temperature, necessitating thermo-mechanically coupled models that implement coupled solutions of mass momentum and energy balance equations.  I will also present results from implementation and initial testing of an enthalpy-based thermodynamic module in the Community Ice Sheet Model (within the Community Earth System Model) being developed at Los Alamos National Laboratory and NCAR.  The advantage of the enthalpy-based formulation lies in its ability to handle both cold and temperate ice efficiently by exploiting semi-implicit time-stepping to retain linearity, which is justified by the slow rate of variation of thermal properties.