What is variational data assimilation?
Variational data assimilation optimizes for an initial state of a dynamical system such that its evolution fits observational data. The physical model can subsequently be evolved into the future to make predictions.
What is data assimilation system?
Data assimilation is the science of combining different sources of information to estimate possible states of a system as it evolves in time. Often only one state is estimated at a time, e.g. the most likely state, or the mean state. The information used comes from observations and a numerical model.
What is 3D VAR?
1. Three-dimensional variational assimilation (3D-Var) In the derivation of Optimal Interpolation, we found the optimal weight matrix W that minimizes the total analysis error variance. Lorenc (1986) showed that this solution is equivalent to a specific variational assimilation.
Why does 4D VAR beat 3D VAR?
One of the main advantages of 4D-Var over 3D-Var is its ability to make better synergetic use of sequential observations. An example is presented here to show how 4D-Var is able to accurately reproduce variability in the data occurring on time-scales comparable to or less than the width of the assimilation window.
What is the most important part of the data assimilation cycle?
One of the most important aspects of a variational assimilation is the specification of background errors.
Which is the process by which observations of a system are incorporated into the model state of a numerical model of that system?
Assessing instantaneous variability and providing accurate initial conditions for model forecasts require scientifically incorporating instrumental data into numerical model systems. This process is data assimilation.
What is 4d VAR data assimilation?
Four dimensional variational data assimilation, or “4d-Var”, is a method of estimating this set of parameters by optimizing the fit between the solution of the model and a set of observations which the model is meant to predict.
What is similar to assimilation?
acclimation,
How does 4D-VAR work?
How does it work? 4D-Var adjusts a short-range forecast, called the background, in space and time to bring it into closer agreement with meteorological observations. The model state xb at the initial time is modified to achieve a statistically and dynamically based good compromise xa by minimizing a penalty function.
What is assimilation in science?
Assimilation is the movement of digested food molecules into the cells of the body where they are used. For example: glucose is used in respiration to provide energy. amino acids are used to build new proteins.
What is assimilation in geography?
Assimilation is defined as the complete integration of someone of minority status into a dominant culture. As geographers, we can observe how assimilation impacts these migration patterns.