To all who are or have been involved in the development, evaluation and maintenance of the ICON modeling framework,

   The development of ICON stands as a remarkable success story. Since the beginning of the joint development of a new global weather and climate model by DWD and MPI-M nearly 20 years ago, ICON has evolved into a world-class modeling system for weather forecasting, climate simulation, environmental prediction, process studies, data assimilation and reanalysis. More recently, DKRZ and KIT have joined the ICON partnership, and C2SM is included as a development partner. The ICON partners are committed to develop and maintain a comprehensive, seamless, flexible, globally as well as regionally applicable modeling system, requiring continuous improvements in the dynamical, physical and chemical processes along with an increasing effort in the areas of software design and optimal use of high-performance computers.

   All this has only been possible thanks to the formidable expertise, effort and dedication of countless individuals. The five ICON partner institutions and all scientists and software engineers contributing to code development, evaluation and maintenance, bring in complementary ideas, knowledge, and skills. Bringing them together has not always been easy, but has resulted in a model that none of the institutions would have been capable of developing alone. We as the ICON board offer our heartfelt thanks to everybody involved for the countless hours of discussion and coding, careful evaluations and constant improvements, and for making the development of ICON also their own project.

   A new chapter will open when ICON is published as open-source code in January 2024. The preparations of the open-source release required a lot of work by many people, an effort we greatly appreciate. We are looking forward to the increased involvement of the German and international communities and are proud to present the ICON modeling system with its outstanding capabilities. This is only possible thanks to the ideas and efforts from all of you.


For the ICON board,

Sarah Jones, DWD
Jochem Marotzke, MPI-M
Thomas Ludwig, DKRZ
Corinna Hoose, KIT
Nicolas Gruber, C2SM