Well-posed boundary conditions for limited-domain models of transient ice flow near an ice divide

作者:Koutnik Michelle R*; Waddington Edwin D
来源:Journal of Glaciology, 2012, 58(211): 1008-1020.
DOI:10.3189/2012JoG11J212

摘要

When an ice-flow model is constrained by data that exist over only a section of an ice sheet, it is computationally advantageous to limit the model domain to only that section. For example, a limited domain near an ice-core site might cross an ice divide, and have no termini. Accurately calculating ice-sheet evolution in response to spatial and temporal variations in climate and ice flow depends on accurately calculating the transient ice flux crossing the limited-domain boundaries. In the absence of information from outside the limited domain, this is an ill-posed problem. Boundary conditions based only on information from inside the limited domain can produce ice-sheet evolution incompatible with the full ice sheet within which we suppose it to exist. We use impulse-response functions to provide boundary values that are informed by the external ice sheet, without conventionally 'nesting' the limited domain in a full ice-sheet model. Evolution within a limited domain can then be consistent with evolution of the full ice sheet. Our treatment of limited-domain boundary conditions is designed for future use in an inverse problem in which external changes that affected the limited domain can be inferred from data from within the limited domain.

  • 出版日期2012