The SOCCOM OSSE program uses the HYCOM model (at 1/12°) and CM2.6 (at 1/10°):

- to assist in interpretation of data and development of new analysis techniques
- to provide guidance on the optimal design of an observing system
- We sample model-simulated fields in the same way the real observational array samples the real ocean, and reconstruct gridded model fields
- We use the reconstruction errors (RErr) – the difference between the reconstructed and actual model fields – as a quantitative metric for the reconstruction skill

RErr (rms of monthly values) of upper ocean heat content (UOHC). Values are non-dimensional – scaled by the vertical temperature contrast, for years 2007-2014.

## Trajectory Ensembles

- 40 ARGO floats are deployed along the 40 stations of the Polarstern cruise
- The start date is varied, with a maximum deviation of 32 days
- The ensemble is compared with the 12 deployed floats as of March 2015