This issue is dedicated to NEMO http://www.nemo-ocean.eu/ which is the European Modeling platform for ocean research and operational applications. NEMO (Nucleus for European Modeling of the Ocean) is a software for nu-merical simulation of the ocean. NEMO is available under free license and improves in order to stay as near as possible to technical needs and breakthroughs of research and operational projects. NEMO is in use in a wide variety of applications which main objectives are oceanographic research, operational forecasts of the ocean and seasonal weather forecasts or climate change studies. The NEMO ocean platform is for example widely used in the framework of the Myocean project. Its three main components are: the ―blue ocean‖ NEMO-OPA which simu-lates the dynamics, the ―white ocean‖ NEMO-LIM which simulates the sea-ice and the ―green ocean‖ NEMO-TOP which simulates the biogeochemistry. Some other components allow data assimilation or grid nesting. NEMO also includes interfaces for ocean-atmosphere coupled configurations using the OASIS coupler. A number of ―reference configurations‖ are also available to set up and validate implementations, so as pre- and post-processing tools. All of NEMO and its documentation are available on the NEMO website http://www.nemo-ocean.eu/.
The two first papers of the present newsletter are written by Levy et al. and are presenting the NEMO ocean code: What does NEMO produces? What are the applications? Its limitations as well as the NEMO Consortium and its organization.
Then, the next paper by Gehlen et al. is discussing the coupled physical-biogeochemical ocean modeling using NEMO components. Physical components of the NEMO system have been used with success in biogeochemical research coupled to four biogeochemical models of varying complexity: PISCES (provided with the passive tracer module TOP), MEDUSA, BFM/PELAGOS and HadOCC.
Next paper by Bouttier et al. is developing the progress toward a data assimilation system for NEMO and discuss-es the first achievement steps that have been carried out to set up a data assimilation system associated to NEMO. This data assimilation system is schematically made of three subcomponents: Interface Components, Built-in Components and External Components.
Next paper by Dombrowsky et al. is dealing with NEMO within the MyOcean Monitoring and Forecasting Centers (MFCs) context. During the MyOcean project, all the Monitoring and Forecasting Centers (MFCs) have implement-ed operational model configurations in order to cover the global ocean with a focus on the European waters. The NEMO ocean platform is used is most of the MFCs.
Ferry et al. are then dealing with the use of NEMO in the MyOcean eddy permitting Global Ocean reanalyses. They illustrate the use of NEMO ocean engine in three eddy permitting global ocean reanalyses and one reference simulation of the altimetric era (1993-2009) carried out in the framework of the MyOcean EC funded project. The ORCA025 model configuration (1/4° horizontal resolution) of the NEMO code is used both for the reanalyses and the non-assimilative reference simulation.
Beuvier et al. are then writing about MED12, i.e. the oceanic component for the modeling of the regional Mediter-ranean Sea earth system. It is the new regional configuration of the Mediterranean Sea of the ocean general circu-lation model NEMO. The development of MED12 is made in the continuity of the evolution of the French modeling of the Mediterranean Sea, following OPAMED16, OPAMED8 and NEMOMED8.
Guilyardi et al. are finally dealing with NEMO for climate modeling. Indeed, the ocean is a central component of the climate system, providing long term memory and contributing to the variability of heat and CO2 uptake on a number of time scales. NEMO global configurations are used in coupled mode by a large fraction of the climate modeling community.
We will meet again next year in January 2013. We wish you a pleasant reading,

Laurence Crosnier, Editor.
Editorial

• NEMO for dummies
• NEMO organisation
• Coupled physical-biogeochemical ocean modeling using NEMO components
• Toward a data assimilation system for NEMO
• NEMO in MyOcean Monitoring and Forecasting Centers (MFCs)
• NEMO: the modeling engine of global ocean reanalyses
• MED12, oceanic component for the modeling of the regional Mediterranean earth system
• NEMO for climate modeling