Status of Canadian Regional and Global Coupled Modelling Systems

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Wednesday, 5 February 2014: 12:00 AM
Room C202 (The Georgia World Congress Center )
Harold Ritchie, EC, Dartmouth, NS, Canada; and G. Smith, J. F. Lemieux, J. M. Bélanger, C. Beaudoin, Z. He, F. Roy, F. Dupont, M. Reszka, F. Davidson, G. Garric, and C. E. Testut

The Canadian Operational Network of Coupled Environmental PredicTion Systems (CONCEPTS) including Mercator-Océan participation (France) is providing a framework for research and operations on coupled atmosphere-ice-ocean (AIO) prediction. Operational activity is based on coupling the Canadian atmospheric Global Environmental Multi-scale (GEM) model with the Mercator system based on the Nucleus for European Modelling of the Ocean (NEMO), together with the CICE sea ice model. Within CONCEPTS two main systems are under development: a short-range regional coupled prediction system and a global coupled prediction system for medium- to long-range applications. A fully coupled AIO forecasting system for the Gulf of St. Lawrence has been developed and has been running operationally at the Canadian Meteorological Centre (CMC) since June 2011. This system demonstrated the strong impact that dynamic sea ice cover can have on 48hr atmospheric forecasts leading to large changes in surface air temperature (up to 10 deg. C), low-level cloud cover, and precipitation. The original Saucier et al. ocean-ice component of this system is currently being replaced by NEMO and CICE, with generally comparable performance. This system is the basis for the development of an integrated marine Arctic prediction system in support of Canadian METAREA monitoring and warnings. Specifically, a multi-component (atmosphere, land, snow, ice, ocean, wave) regional high resolution marine data assimilation and forecast system is being developed for short-term predictions of near surface atmospheric conditions, sea ice (concentration, pressure, drift, ice edge), freezing spray, waves and ocean conditions (temperature and currents). More recently a fully coupled global AIO system is under development. The first step was the Global Ice-Ocean Prediction System (GIOPS). A 33 km resolution global version of the GEM model has been interactively coupled with GIOPS on a ¼ degree resolution grid. Coupled and uncoupled medium-range (16-day) forecasts have been made and evaluated over the period Jan.-Mar. 2011. In the tropical atmosphere the coupled forecasts show robust improvements compared to both tropical moored buoys and analyses produced by the European Centre for Medium Range Weather Forecasts. Evaluation against CMC ice analyses in the northern hemisphere marginal ice zone shows the strong impact that a changing ice cover can have on coupled forecasts. In the Arctic, however, the coupled system is very sensitive to the ice lead fraction in pack ice which is predicted rather than being held steady at 3% as in the uncoupled runs. This sensitivity is under further investigation. This talk will provide an overview of these activities, summarize results to date, and discuss plans for new and future operational systems.