  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.
