Adjoint CISM

An adjoint of the Glimmer-CISM model

A National Science Foundation - Collaboration in Mathematics and Geoscience (NSF-CMG) project:
Enabling ice sheet sensitivity and stability analysis with a large-scale higher-order ice sheet model's adjoint to support sea level change assessment

The Glimmer-CISM model Glimmer-CISM is the the community developed ice sheet model. The model web site is: http://glimmer-cism.berlios.de/ The model source code repository: Glimmer-CISM on berliOS The Glimmer-CISM adjoint Our goal is to enable applications of powerful mathematical concepts and computational tools for rigorous sensitivity analysis and formal state estimation in the context of large-scale ice sheet modeling. At the center of the proposal is the generation and application of adjoint model (ADM) and tangent linear model (TLM) components of the new Community Ice Sheet Model (CISM). The goal will be achieved through rigorous use of automatic differentiation (AD). Read the project summary here. Adjoint methods and automatic differentiation in ice sheet modeling were also taught at a recent Summer School on Ice Sheet Modeling in Portland, OR.

Gallery Images of project related results can be viewed here. Code Review To begin, we are looking at the Glimmer-CISM HO velocity code and identifying portions that may need to be altered for openAD to preform the automatic the differentiation. Use of pointers Allocation of memory Calling the solver Use of NaN Module Organization Test Suite A suite of tests, ranging from the simplest to the most complex applications of Glimmer/CISM is being developed. Temperature test Shallow ice flow test Temperature and flow test Higher order ice flow test Meetings One or more project members will be attending the following meetings. 16 December 2009, AGU Fall Meeting, San Francisco 9/10 September 2009, University of Chicago