Adjoint approach to VDA of "on-off" processes based on nonlinear perturbation equation  

作　　者：WANG Jiafeng, MU Mu and ZHENG Qin(LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China) 

出　　处：《Progress in Natural Science:Materials International》2002年第11期869-873,共5页自然科学进展·国际材料（英文版）

基　　金：the CAS Key Innovation Direction Project (Grant No. KZCX2-208); the National Natural Science Foundation of China (Grant Nos. 40023001 and 40075015); Innovation Foundation of Institute of Atmospheric Physics, CAS (Grant No. 8-1315), and LLAMA Project 98

摘　　要：A new adjoint approach is applied to variational data assimilation of a general 'on-off' switch model. The accurate gradient expression is obtained in analytical case. In discrete case, the existence of gradient is discussed in three types of difference schemes, and the corresponding adjoint equations are derived. The advantage of the new approach in real application is shown by numerical experiment: not only it can lead optimization to converge to global minimum, but also the assimilation system built by conventional approach can still be used.A new adjoint approach is applied to variational data assimilation of a general on-off switch model. The accurate gradient expression is obtained in analytical case. In discrete case, the existence of gradient is discussed in three types of difference schemes, and the corresponding adjoint equations are derived. The following advantage of the new approach in real application is shown by numerical experiments: it can not only lead the optimization to converge to global minimum, but also the assimilation system built by conventional approach can still be used.

关 键 词：'on-off' switch  ADJOINT approach  NONLINEAR PERTURBATION equation. 

分 类 号：O151.21[理学—数学]