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Marko Scholze

Senior lecturer

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Testing variational estimation of process parameters and initial conditions of an earth system model

Author

  • Simon Blessing
  • Thomas Kaminski
  • Frank Lunkeit
  • Ion Matei
  • Ralf Giering
  • Armin Koehl
  • Marko Scholze
  • P. Herrmann
  • Klaus Fraedrich
  • Detlef Stammer

Summary, in English

We present a variational assimilation system around a coarse resolution Earth System Model (ESM) and apply it for estimating initial conditions and parameters of the model. The system is based on derivative information that is efficiently provided by the ESM's adjoint, which has been generated through automatic differentiation of the model's source code. In our variational approach, the length of the feasible assimilation window is limited by the size of the domain in control space over which the approximation by the derivative is valid. This validity domain is reduced by non-smooth process representations. We show that in this respect the ocean component is less critical than the atmospheric component. We demonstrate how the feasible assimilation window can be extended to several weeks by modifying the implementation of specific process representations and by switching off processes such as precipitation.

Department/s

  • Dept of Physical Geography and Ecosystem Science
  • eSSENCE: The e-Science Collaboration
  • MERGE: ModElling the Regional and Global Earth system

Publishing year

2014

Language

English

Publication/Series

Tellus. Series A: Dynamic Meteorology and Oceanography

Volume

66

Document type

Journal article

Publisher

Wiley-Blackwell

Topic

  • Physical Geography

Keywords

  • data assimilation
  • climate modelling
  • coupled ocean-atmosphere model
  • earth system model
  • automatic differentiation
  • adjoint model

Status

Published

ISBN/ISSN/Other

  • ISSN: 1600-0870