Ecmwfs 4dvar data assimilation system the genesis and. Assimilation of observations, an introduction gtspecial. Since we will have the maximum probability when x minimises. A sequential variational algorithm for data assimilation. Recent research and development activities in data. A strategy for data assimilation technical memorandum no. Assimilation of meteorological or oceanographical observations can be described as the process through which all the available information is used in order to estimate as accurately as possible the state of the atmospheric or oceanic flow. This approach has become known as data assimilation, whose purpose is defined by talagrand 1997 as using all the available information, to determine as accurately as possible the state of the atmospheric or oceanic flow. Philippe courtier and olivier talagrand quickly set out to demonstrate these capabilities of 4dvar with a vorticity equation model in 1986 and a shallow water model in 1987 published in 1987 and 1990, respectively. It then describes ecmwfs current overall strategy for data assimilation.
This is considered to be a crucial element of weather fore. Common software for land data assimilation is urgently needed to implement a wide variety of assimilation applications. Data assimilation is a mathematical discipline that seeks to optimally combine theory usually in the form of a numerical model with observations. Therefore, general software for land data assimilation and its corresponding applications are still urgently needed. Dart, developed and maintained at the national center for atmospheric research, provides welldocumented software tools for data assimilation education, research, and development. Data assimilation chapter 5 atmospheric modeling, data. There may be a number of different goals sought, for exampleto determine the optimal state estimate of a system, to determine initial conditions for a numerical forecast model, to interpolate sparse observation data using e. In this paper, we introduce common software for nonlinear and nongaussian land data assimilation system comda, which we developed to meet the above demands of a general software platform of data assimilation. Abstract this study theoretically establishes a sequential variational svar method for the data assimilation in oceanography and meteorology defined on. System development and preliminary testing hongli wang,juanzhen sun,xin zhang,xiangyu huang, and thomas auligne national center for atmospheric research, boulder, colorado. Variational data assimilation the idea in variational data assimilation we seek the solution that maximises the a posterior probability pxy.