We welcome contributions in the area of Operational Oceanography which demonstrate skill assessment, error analysis and uncertainty estimation. This might be through the use of a range of metrics comparing model simulations with data (metrics already existing in oceanography or novel methods taken from other disciplines), or through data assimilation and analysis of error covariances and error distributions. Assessment can be for hindcast, nowcast or forecast systems. Disciplines can range from physical (e.g waves, currents, the thermohaline structure and related fields) to physical-biogeochemical (e.g. inherent optical properties, chlorophyll concentration, primary production, nutrient cycling). We invite papers describing assessment of local, regional and global models and the complementary observing systems (e.g. fixed in-situ, satellite, ferries, gliders, floats) which provide the data required for assessment, from the open ocean to the nearshore. The kind of topics we would like to focus on include: forecast validity and uncertainty; observational network assessment and adaptive sampling; reconciliation of multi-model / ensemble simulations. With the move towards the routine delivery of oceanographic services we also welcome contributions reflecting the current trend in this area.