CIRA/CSU Four-Dimensional Variational Data Assimilation System
نویسندگان
چکیده
منابع مشابه
Four-Dimensional Data Assimilation
Surface inhomogeneities, including boundaries between different types of vegetations and land use patterns, have important effects on the structure of the atmospheric boundary layer. Changes in the surface roughness, temperature and wetness make the planetary boundary layer (PBL) nonhomogeneous and produce substantial horizontal gradients of boundary layer properties. Significant differences in...
متن کاملAn ensemble-based explicit four-dimensional variational assimilation method
[1] The adjoint and tangent linear models in the traditional four-dimensional variational data assimilation (4DVAR) are difficult to obtain if the forecast model is highly nonlinear or the model physics contains parameterized discontinuities. A new method (referred to as POD-E4DVAR) is proposed in this paper by merging the Monte Carlo method and the proper orthogonal decomposition (POD) techniq...
متن کاملA reduced-order approach to four-dimensional variational data assimilation using proper orthogonal decomposition
Four dimensional variational data assimilation (4DVAR) is a powerful tool for data assimilation in meteorology and oceanography. However, a major hurdle in use of 4DVAR for realistic general circulation models is the dimension of the control space (generally equal to the size of the model state variable and typically of order 10 − 10) and the high computational cost in computing the cost functi...
متن کاملDownscaling of radio brightness measurements for soil moisture estimation: A four-dimensional variational data assimilation approach
This paper investigates the feasibility of estimating large-scale soil moisture profiles and related land surface variables from 1.4 GHz (L-band) passive microwave measurements, using variational data assimilation. Our four-dimensional assimilation algorithm takes into account both model and measurement uncertainties and provides dynamically consistent interpolation and extrapolation of remote ...
متن کاملExistence and Uniqueness for Four-Dimensional Variational Data Assimilation in Discrete Time
Variational techniques for data assimilation, i.e., estimating orbits of dynamical models from observations, are revisited. It is shown that under mild hypotheses a solution to this variational problem exists. Using ideas from optimal control theory, the problem of uniqueness is investigated and a number of results (well known from optimal control) are established in the present context. The va...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Monthly Weather Review
سال: 2005
ISSN: 0027-0644,1520-0493
DOI: 10.1175/mwr2891.1