Open AccessA new data assimilation method using complex-variable differentiation
Author(s) -
Xiaoqun Cao,
Junqiang Song,
Weimin Zhang,
Yue Zhao,
Bainian Liu
Publication year - 2013
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.62.170504
Subject(s) - data assimilation , computation , mathematics , nonlinear system , computer science , initial value problem , chaotic , variable (mathematics) , complex system , function (biology) , numerical differentiation , algorithm , mathematical optimization , mathematical analysis , physics , artificial intelligence , meteorology , quantum mechanics , evolutionary biology , biology
A new method for data assimilation is proposed using complex-variable differentiation (CVD), which can be used to estimate the initial conditions of the nonlinear physical system governed by the following equation:. Firstly, the gradient analysis of cost function in variational data assimilation is transformed into function numerical computation in complex domain, and the value of gradient is computed more efficiently and exactly. Secondly, the new algorithm of data assimilation is developed by combining an accurate gradient information from CVD with the classical optimization method. Finally, numerical simulations of typical chaotic systems and a humidity evolution equation with physical on-off process show that the new data assimilation method can reconstruct initial conditions of the nonlinear dynamical system very conveniently and accurately.