BibTeX
@ARTICLE{
         Losch2007ASo,
       author = "M. Losch and P. Heimbach",
       title = "Adjoint Sensitivity of an Ocean General Circulation Model to Bottom Topography",
       journal = "Journal of Physical Oceanography",
       pdf = "http://hdl.handle.net/10013/epic.23381.d001",
       ad_tools = "TAF",
       ad_area = "Oceanography",
       ad_theotech = "Adjoint",
       volume = "37",
       number = "2",
       pages = "377--393",
       year = "2007",
       doi = "10.1175/JPO3017.1",
       abstract = "Bottom topography, or more generally the geometry of the ocean basins, is an
         important ingredient in numerical ocean modeling. With the help of an adjoint model, it is shown
         that scalar diagnostics or objective functions in a coarse-resolution model, such as the transport
         through Drake Passage, the strength of the Atlantic Ocean meridional overturning circulation, the
         Deacon cell, and the meridional heat transport across 32$^\circ$ S, are sensitive to bottom
         topography as much as they are to surface boundary conditions. For example, adjoint topography
         sensitivities of the transport through Drake Passage are large in choke-point areas such as the
         Crozet-Kergu{\'e}len Plateau and south of New Zealand; the Atlantic meridional overturning
         circulation is sensitive to topography in the western boundary region of the North Atlantic Ocean
         and along the Scotland-Iceland Ridge. Many sensitivities are connected to steep topography and can
         be interpreted in terms of bottom form stress, that is, the product of bottom pressure and
         topography gradient. The adjoint sensitivities are found to agree with direct perturbation methods
         with deviations smaller than 30\% for significant perturbations on time scales of 100 yr, so
         that the assumption of quasi linearity that is implicit in the adjoint method holds. The horizontal
         resolution of the numerical model affects the sensitivities to bottom topography, but large-scale
         patterns and the overall impact of changes in topography appear to be robust. The relative impact of
         changes in topography and surface boundary conditions on the model circulation is estimated by
         multiplying the adjoint sensitivities with assumed uncertainties. If the uncertainties are
         correlated in space, changing the surface boundary conditions has a larger impact on the scalar
         diagnostics than topography does, but the effects can locally be on the same order of magnitude if
         uncorrelated uncertainties are assumed. In either case, bottom topography variations within their
         prior uncertainties affect the solution of an ocean circulation model. To this extent, including
         topography in the control vector can be expected to compensate for identifiable model errors and,
         thus, to improve the solutions of estimation problems."
}