COSTA a Problem Solving Environment for data assimilation

Nils van Velzen Delft University of Technology Faculty of Electrical Engineering, Mathematics and Computer Science Dept. of Appl. Mathematical Analysis Mekelweg 4, 2628 CD Delft The Netherlands c.vanvelzen@ewi.tudelft.nl affiliated with VORtech Computing P.O. Box 260 2600 AG Delft www.vortech.nl Data assimilation techniques are widely used in various modeling areas like meteorology, oceanography and chemistry. Most implementations of these data assimilation methods however are custom implementations specially designed for a particular model. These custom implementations are in general very computationally efficient but they are expensive to implement and maintain and it is hard to reuse the implementation for an other model. Similarly, a lot of programming has to be done in order to try-out an alternative assimilation method in an existing system. The COSTA project offers a modular framework for data assimilation, containing methods and tools that can be easily applied for general applications. Another goal of the COSTA project is to simplify the application of data assimilation methods such that they become available to a larger group of researchers and models. The COSTA framework consists of a large number generic building blocks, called components. The interfaces of the components are chosen such that the complete system forms a flexible environment that can be used to build, incorporate and/or replace implementations of data assimilation methods and tools. A default implementation will be available for most of the building blocks but the user can easily replace them with own implementations. The software systems WAQUA and TRIWAQ for 2D and 3D shallow water simulation of the Dutch National Institute for Coastal and Marine Management (Rijkswaterstaat/RIKZ) are provided with a number of data assimilation methods. There is however a need to apply the same assimilation methods for other models and to extent the number of assimilation methods in the existing software. The COSTA framework have therefore been introduced in the system. In the development of COSTA, the team collaborates with Delft Hydraulics, where the generic data assimilation package DATools is being developed. The collaboration focuses on sharing concepts and experiences, which is expected to lead to improved design and a more efficient development cycle of both systems. The preliminary results from these applications will also be discussed in this paper.Presenters: name: van Velzen, Nils affiliation: Delft University of Technology / VORtech Computin