Ocean Data Assimilation Working Group

February 8, 2005

February 15, 2005

Topics of Interest
- Multiresolution/Multiscale statistics
- Differences between atmosphere and ocean data assimilation
  - Dynamical Differences
  - Observation differences, amount of data
  - Different goals
- Coupled Atmosphere/Ocean models - Assimilation?
- New numerical approaches to assimilation
Goals of Ocean DA
- State estimation - climate scales
- Prediction (coastal)
  - biological questions
  - dynamical questions
  - 3-4 day time-scale for forecasts
  - mostly wind-driven (sources of data?)
  - boundary conditions
  - tides
For 3/1:
Big picture questions:
- What are the goals of ocean data assimilation?
- What is the current state-of-the-art for ocean DA?
- What is the current state-of-the-art for coupled atmosphere/ocean (ENSO) DA?

March 1, 2005

Long-term goal for the working group:

What is the state of the art in ocean data assimilation?
Provocative Questions:
- Is (ocean) data assimilation nudging or fudging?
  
  Nudging - Pushing the model slightly towards reality
  
  Fudging - Making the model give you desirable results
- If our models are structurally unstable, why should we use them?
  
  Structurally unstable - If a small change in system parameters or structure makes a large change in system outputs
For 3/8:
Resources on current projects in ocean DA:
- Coupled Data Assimilation Workshop (2003) Report
- GODAE, the Global Ocean Data Assimilation Experiment
  http://www.bom.gov.au/bmrc/ocean/GODAE/
- An introduction to GODAE
  http://www.bom.gov.au/bmrc/ocean/GODAE/Presentations/2004-06.COI.Bahurel.ppt
- Mercator, an operational ocean forecasting group
  http://www.mercator-ocean.fr/html/mod_actu/public/welcome_en.php3
- A short article on the data assimilation scheme used by Mercator
  http://www.mercator-ocean.fr/documents/lettre/lettre_13_art1_en.pdf
- Mersea, the european operational ocean forecasting consortium (2004-2008 timeframe)
  http://www.ifremer.fr/merseaip/
- ECCO, a collaborative ocean state estimation project
  http://www.ecco-group.org/
- HYCOM, a data-assimilative hybrid coordinate ocean model
  http://hycom.rsmas.miami.edu/
- An Australian bureau of metorology monthly analysis system
  http://www.bom.gov.au/bmrc/ocean/results/climocan.htm

March 8, 2005

For 3/22:
Please read this paper on "Data Assimilation for a Coupled Ocean-Atmosphere Model" by Chaojiao Sun, Zheng Hao, Michael Ghil and J. David Neelin. Come with questions and curiosities on the contents.

March 15, 2005

March 22, 2005

For 3/29, read the Sun et al. paper on data assimilation in a coupled ocean-atmosphere model.

March 29, 2005

Discussed the Sun et al. paper on data assimilation in a coupled ocean-atmosphere model.
For 4/5, a discussion of GODAE.

April 5, 2005

Discussed global ocean data prediction as described in the following documents:
- Ocean observing systems and prediction - the next ten years by D.E. Harrison and Neville Smith
- Basin-scale Ocean Prediction with the Hybrid Coordinate Ocean Model by Eric P. Chassignet, Patrick J. Hogan, Harley E. Hurlburt, E. Joseph Metzger and Alan J. Wallcraft
- U.S. GODAE: Global Ocean Prediction with the Hybrid Coordinate Ocean Model (HYCOM)
For 4/19: a guest speaker

April 12, 2005

April 19, 2005

Questions to consider:
1. After the workshop, have you changed your ideas as to what are the main issues in ocean DA?
2. Should we use particle filters? Kalman filters? Should we be smoothing or just filtering?
3. Is feature-tracking, as discussed by Greg Lawson an important new element? This can be viewed as a multi-scale approach. Is that a good direction for the ocean?
4. Are search and rescue efforts as described by Arthur Mariano a good motivator? Can we really help these efforts?

April 26, 2005

May 2, 2005

May 9, 2005

Summary
- Ocean DA is both state estimation and prediction
- Global ocean DA uses basic DA algorithms
Coastal Ocean DA presentation