DOI: 10.5194/tc-8-721-2014
Scopus记录号: 2-s2.0-84899094815
论文题名: Adjoint accuracy for the full Stokes ice flow model: Limits to the transmission of basal friction variability to the surface
作者: Martin N ; , Monnier J
刊名: Cryosphere
ISSN: 19940416
出版年: 2014
卷: 8, 期: 2 起始页码: 721
结束页码: 741
语种: 英语
英文关键词: adjoint method
; algorithm
; friction
; glaciology
; ice flow
; ice thickness
; Stokes formula
; wavelength
英文摘要: This work focuses on the numerical assessment of the accuracy of an adjoint-based gradient in the perspective of variational data assimilation and parameter identification in glaciology. Using noisy synthetic data, we quantify the ability to identify the friction coefficient for such methods with a non-linear friction law. The exact adjoint problem is solved, based on second-order numerical schemes, and a comparison with the so-called "self-adjoint" approximation, neglecting the viscosity dependence on the velocity (leading to an incorrect gradient), common in glaciology, is carried out. For data with a noise of 1%, a lower bound of identifiable wavelengths of 10 ice thicknesses in the friction coefficient is established, when using the exact adjoint method, while the "self-adjoint" method is limited, even for lower noise, to a minimum of 20 ice thickness wavelengths. The second-order exact gradient method therefore provides robustness and reliability for the parameter identification process. In another respect, the derivation of the adjoint model using algorithmic differentiation leads to the formulation of a generalization of the "self-adjoint" approximation towards anincomplete adjoint method, adjustable in precision and computational burden. © Author(s) 2014. CC Attribution 3.0 License. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/74858
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: INSA and Institut de Mathématiques de Toulouse, 135 Avenue de Rangueil, 31400, Toulouse, France
Recommended Citation:
Martin N,, Monnier J. Adjoint accuracy for the full Stokes ice flow model: Limits to the transmission of basal friction variability to the surface[J]. Cryosphere,2014-01-01,8(2)