Application of the adjoint approach to optimise the initial conditions of a turbidity current with the AdjointTurbidity 1.0 model
File(s)
Published version
Author(s)
parkinson, SD
Funke, SW
Hill, J
Piggott, MD
Allison, PA
Type
Journal Article
Abstract
Turbidity currents are one of the main drivers of
sediment transport from the continental shelf to the deep
ocean. The resulting sediment deposits can reach hundreds
of kilometres into the ocean. Computer models that simulate
turbidity currents and the resulting sediment deposit can help
us to understand their general behaviour. However, in order
to recreate real-world scenarios, the challenge is to find the
turbidity current parameters that reproduce the observations
of sediment deposits.
This paper demonstrates a solution to the inverse sediment
transportation problem: for a known sedimentary deposit, the
developed model reconstructs details about the turbidity cur-
rent that produced the deposit. The reconstruction is con-
strained here by a shallow water sediment-laden density cur-
rent model, which is discretised by the finite-element method
and an adaptive time-stepping scheme. The model is differ-
entiated using the adjoint approach, and an efficient gradient-
based optimisation method is applied to identify the turbidity
parameters which minimise the misfit between the modelled
and the observed field sediment deposits. The capabilities of
this approach are demonstrated using measurements taken in
the Miocene Marnoso-arenacea Formation (Italy). We find
that whilst the model cannot match the deposit exactly due
to limitations in the physical processes simulated, it provides
valuable insights into the depositional processes and repre-
sents a significant advance in our toolset for interpreting tur-
bidity current deposits.
sediment transport from the continental shelf to the deep
ocean. The resulting sediment deposits can reach hundreds
of kilometres into the ocean. Computer models that simulate
turbidity currents and the resulting sediment deposit can help
us to understand their general behaviour. However, in order
to recreate real-world scenarios, the challenge is to find the
turbidity current parameters that reproduce the observations
of sediment deposits.
This paper demonstrates a solution to the inverse sediment
transportation problem: for a known sedimentary deposit, the
developed model reconstructs details about the turbidity cur-
rent that produced the deposit. The reconstruction is con-
strained here by a shallow water sediment-laden density cur-
rent model, which is discretised by the finite-element method
and an adaptive time-stepping scheme. The model is differ-
entiated using the adjoint approach, and an efficient gradient-
based optimisation method is applied to identify the turbidity
parameters which minimise the misfit between the modelled
and the observed field sediment deposits. The capabilities of
this approach are demonstrated using measurements taken in
the Miocene Marnoso-arenacea Formation (Italy). We find
that whilst the model cannot match the deposit exactly due
to limitations in the physical processes simulated, it provides
valuable insights into the depositional processes and repre-
sents a significant advance in our toolset for interpreting tur-
bidity current deposits.
Date Issued
2017-03-07
Date Acceptance
2017-02-08
Citation
Geoscientific Model Development, 2017, 10, pp.1051-1068
ISSN
1991-9603
Publisher
European Geosciences Union (EGU)
Start Page
1051
End Page
1068
Journal / Book Title
Geoscientific Model Development
Volume
10
Copyright Statement
© Author(s) 2017. CC-BY Attribution 3.0 License (https://creativecommons.org/licenses/by/3.0/)
Sponsor
Natural Environment Research Council (NERC)
Grant Number
NE/K000047/1
Subjects
04 Earth Sciences
Publication Status
Published