1 / 14

Coupled Model Data Assimilation:

Coupled Model Data Assimilation:. Building an idealised coupled system Polly Smith, Amos Lawless, Alison Fowler* School of Mathematical and Physical Sciences, University of Reading, UK * funded by NERC. Outline. Recap objectives tasks & progress Progress since last meeting Next steps.

fausta
Télécharger la présentation

Coupled Model Data Assimilation:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Coupled Model Data Assimilation: Building an idealised coupled system Polly Smith, Amos Lawless, Alison Fowler* School of Mathematical and Physical Sciences, University of Reading, UK * funded by NERC

  2. Outline • Recap • objectives • tasks & progress • Progress since last meeting • Next steps

  3. Objective To use an idealised system to gain a greater theoretical understanding of the coupled atmosphere-ocean data assimilation problem: • explore different approaches to coupled 4D-Var data assimilation using a single-column, coupled atmosphere-ocean model • help guide the design/ implementation of coupled DA methods within full 3D operational scale systems

  4. Building the idealised system Task 1: develop an idealised, single-column, coupled atmosphere-ocean model with a strong-constraint incremental 4D-Var assimilation scheme. The model needs to be • simple and quick to run • able to represent realistic atmosphere-ocean coupling Atmosphere: • simplified version of the ECMWF single column model (SCM) Ocean: • single column KPP (K-Profile Parameterisation) mixed-layer ocean model coupled through surface fluxes and SST

  5. Progress December 2012 • Successfully compiled and ran theSCM test-case provided by ECMWF. • Simplified the SCM code to remove physical parameterisations. • Tested the simplified atmospheric model using real data. • Coupled the KPP ocean code to the full-physics SCM and successfully ran a test case for the coupled atmosphere-ocean model. • Produced draft documentation for the models.

  6. Progress July 2013 • Revisited stripped down SCM code, now includes simplified version of the IFS turbulent diffusion scheme. • Option to run with dynamics + turbulent diffusion only dynamics + full physics (i.e. original code) • Simplified turbulent diffusion scheme computes surface fluxes to pass to ocean model. • KPP ocean code now coupled to the simplified SCM.

  7. Progress July 2013 • Produced scripts for creating coupled model input file • atmosphere data from ERA interim • ocean data from MyOcean project • Continued to update documentation for the models. • svn repository now in place. • Tangent linear and adjointmodels written and tested.

  8. Test case: 7 day run from 1stJuly 2012, (235.5oE, 24.5oN)

  9. Atmosphere

  10. ERA interim data (6 hourly)

  11. Ocean

  12. MyOcean data (daily mean)

  13. Things to think about … • Choice of suitable test-case(s) Atmosphere: • relaxation of winds Ocean: • availability of time-series data

  14. Next steps • Development of baseline 4D-Var system • minimisation algorithm • observations • error covariances • assimilation time window • Strongly coupled data assimilation experiments • aim is to have some initial results in next few months. • Exploration of different coupling strategies being implemented in the ECMWF system.

More Related