Second-order gravitational effects of local inhomogeneities on CMB anisotropies in nonzero-Λ flat cosmological models

Nonlinear gravitational effects of large-scale local inhomogeneities on cosmic microwave background (CMB) anisotropies are studied, based on the relativistic second-order theory of perturbations in nonzero-Λ flat cosmological models, which has been analytically derived by the present author, and on the second-order formula of CMB anisotropies derived by Mollerach and Matarrese. In this paper we derive the components of the CMB anisotropy power spectra in the range of l=1-22 which are caused by asymmetric local inhomogeneities on scales of 300 Mpc. Using our results it is found that there is a possibility to explain the small north-south asymmetry of CMB anisotropies which has recently been observed.