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[2] MU M, DUAN W S, WANG B. Conditional nonlinear optimal perturbation and its applications [J]. Nonlin. Processes Geophy., 2003, 10: 493-501.
[3] MU M, ZHANG Z Y. Conditional nonlinear optimal perturbation of a two-dimensional quasigeostrophic model [J]. J. Atmos. Sci., 2006, 63:1587-1604.
[4] MU M, DUAN W S. A new approach to studying ENSO predictability: Conditional nonlinear optimal perturbation [J]. Chin. Sci. Bull., 2003, 48: 1045-1047.
[5] MU M, JIANG Z N. A new approach to the generation of initial perturbations for ensemble prediction: Conditional nonlinear optimal perturbation [J]. Chin. Sci. Bull., 2007, 52: 1457-1462.
[6] DUAN W S, LIU X C, ZHU K Y, MU M. Exploring the initial error that causes a significant spring predictability barrier for El Nino events [J]. J. Geophys. Res., 2009, Accepted.
[7] MU M, XU H, DUAN W S. A kind of initial errors related to “spring predictability barrier” for El Nino event in Zebiak-Cane model [J]. Geophys. Res. Lett., 2007, 34, L03709, doi:10.1029/2006GL027 412.
[8] DUAN W S, XUE F, MU M. Investigating a nonlinear characteristic of El Nino events by conditional nonlinear optimal perturbation [J]. Atmos. Res., 2008, doi:10.1016/j.atmosres.2008.09. 003.
[9] DUAN W S, XU H, MU M. Decisive role of nonlinear temperature advection in El Nino and La Nina amplitude asymmetry [J]. J. Geophys. Res., 2008, 113, C01014, doi: 10.1029/2006JC003974.
[10] DUAN W S, MU M. Conditional nonlinear optimal perturbation: applications to stability, sensitivity and predictability [J]. Sci. in China (Ser. D), 2009, Accepted.
[11] MU M, WANG H L, ZHOU F F. A preliminary application of conditional nonlinear optimal perturbation to adaptive observation [J]. Chin. J. Atmos. Sci., 2007, 31(6):1102-1112.
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[15] MU M, WANG J F. An adjoint method for variational data assimilation with physical “on-off” processes [J]. J. Atmos. Sci., 2003, 60: 2010-2018.
[16] MU M, ZHENG Q. Zigzag oscillations in variational data assimilation with physical “on-off” processes [J]. Mon. Wea. Rev., 2005, 133: 2711-2720.
[17] ZHENG Q, MU M. The effects of the model errors generated by discretization of “on-off” processes on VDA [J]. Nonlin. Processes Geophys., 2006, 13: 309-320.
[18] ZHU J, KAMACHI M, ZHOU G Q. Nonsmooth optimization approaches to VDA of models with on/off parameterizations: Theoretical issues [J]. Adv. Atmos. Sci., 2002, 19(3): 405-424.