气候变化领域集成服务门户(CCPortal): Sensitivity of ice sheet surface velocity and elevation to variations in basal friction and topography in the full Stokes and shallow-shelf approximation frameworks using adjoint equations

CCPortal

DOI	10.5194/tc-15-715-2021
	Sensitivity of ice sheet surface velocity and elevation to variations in basal friction and topography in the full Stokes and shallow-shelf approximation frameworks using adjoint equations
	Cheng G.; Kirchner N.; Lötstedt P.
发表日期	2021
ISSN	19940416
起始页码	715
结束页码	742
卷号	15 期号:2
英文摘要	Predictions of future mass loss from ice sheets are afflicted with uncertainty, caused, among others, by insufficient understanding of spatiotemporally variable processes at the inaccessible base of ice sheets for which few direct observations exist and of which basal friction is a prime example. Here, we present a general numerical framework for studying the relationship between bed and surface properties of ice sheets and glaciers. Specifically, we use an inverse modeling approach and the associated time-dependent adjoint equations, derived in the framework of a full Stokes model and a shallow-shelf/shelfy-stream approximation model, respectively, to determine the sensitivity of grounded ice sheet surface velocities and elevation to time-dependent perturbations in basal friction and basal topography. Analytical and numerical examples are presented showing the importance of including the time-dependent kinematic free surface equation for the elevation and its adjoint, in particular for observations of the elevation. A closed form of the analytical solutions to the adjoint equations is given for a two-dimensional vertical ice in steady state under the shallow-shelf approximation. There is a delay in time between a seasonal perturbation at the ice base and the observation of the change in elevation. A perturbation at the base in the topography has a direct effect in space at the surface above the perturbation, and a perturbation in the friction is propagated directly to the surface in time. © 2021 Copernicus GmbH. All rights reserved.
英文关键词	analytical method; elevation; ice sheet; kinematics; numerical model; steady-state equilibrium; topography
语种	英语
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202290
作者单位	Department of Information Technology, Uppsala University, P.O. Box 337, Uppsala, 751 05, Sweden; Department of Physical Geography, Stockholm University, Stockholm, 106 91, Sweden; Bolin Centre for Climate Research, Stockholm University, Stockholm, 106 91, Sweden
推荐引用方式 GB/T 7714	Cheng G.,Kirchner N.,Lötstedt P.. Sensitivity of ice sheet surface velocity and elevation to variations in basal friction and topography in the full Stokes and shallow-shelf approximation frameworks using adjoint equations[J],2021,15(2).
APA	Cheng G.,Kirchner N.,&Lötstedt P..(2021).Sensitivity of ice sheet surface velocity and elevation to variations in basal friction and topography in the full Stokes and shallow-shelf approximation frameworks using adjoint equations.Cryosphere,15(2).
MLA	Cheng G.,et al."Sensitivity of ice sheet surface velocity and elevation to variations in basal friction and topography in the full Stokes and shallow-shelf approximation frameworks using adjoint equations".Cryosphere 15.2(2021).