The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology Bluelink – an integrator of the Integrated Marine Observing System David Griffin and Peter Oke CSIRO Wealth from Oceans Flagship May

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology What is Bluelink? Goal: An ocean forecasting system to meet the needs of the entire marine sector for timely and detailed information on the physical state of the ocean sub-systems: Assembly and processing of observations Global ocean model Limited-area model Relocatable model Littoral-zone model Product delivery A partnership: RAN, BoM and CSIRO. A sustained effort: , , ~$5M/yr

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology Bluelink is a modelling project. Why is it in this session? Consider the situation with meteorology: Where would we be without meteorological modeling? No forecasts, no re-analyses, just lots of scattered observations of ‘unwanted’ quantities (eg pressure) Bluelink is an important means by which Australia will benefit from the global ocean observing system, and IMOS Think of it as part of the delivery system

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology Data assimilating models: principles observations beats physics if the model state and obs disagree, change the model state physics beats statistics (interpolation or extrapolation) use model physics to fill data gaps (space, time, variables) statistics beats ignorance technique of last resort Think of a data assimilating model as a fancy way of gridding data.

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology Multivariate Ensemble Optimal Interpolation 1.run model for ~15 years → large database of realistic ocean states (u,v,t,s,eta), a.k.a ‘the Ensemble’ 2.commence run of model with data assimilation: 3.every few days: 1.compute model difference from available observations (u,v,t,s,eta) 2.use the ensemble as a set of (multivariate) basis functions to project a sparse array of model-data misfits onto the full state space of the model 3.apply the corrections to the model in a way that minimises shocks 4.integrate model forwards to the end of the forecast → Observed sea level (altimetry), SST (IR imagery) and T,S (Argo) correct all model variables in a realistic way

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

Finding AHS Centaur

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology What really happened

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology which was very different to:

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology How rare is an eddy like that?

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology Sydney Morning Herald, last Saturday

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

Summary Observing systems (eg IMOS) and modelling systems (eg Bluelink) have a lot to offer each other. Neither have achieved their end-goals yet but both have already radically changed the oceanographic landscape in Australia In Bluelink3 ( ) we will make fuller use of Australia’s IMOS. Some data types are suited for assimilation, more types are valuable for validation heed the lessons from meteorology: researchers, as well as end users, want gridded products as well as more-precise, but location-specific data sets.

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology David Griffin Team Leader: Ocean Hindcasting and Remote Sensing Phone: Web: Thank you