Domain Decomposition in space-time of 4D-VAR Data Assimilation problem: a case study on the ROMS software

Domain Decomposition of 4D-VAR Data Assimilation (DD-4DVAR) is made up of decomposition of the spate-time domain, solution of reduced forecast model and minimization of local 4D-VAR functionals. Relying on the existing software implementation of ROMS software, we describe main components of DD-4D VAR DA method, highlighting the topics that we will should address both on the mathematical problem underlying ROMS and the MPI-based code implementation of the ROMS-IS4DVAR formulation.