To explore lightning-generated electromagnetic wave behavior and lightning-related ionospheric phenomena, a fullwave two-dimensional cylindrical finite-difference time-domain (FDTD) model was developed to simulate lightning-generated electromagnetic wave propagation in the ionosphere with high altitude and long distance capabilities. This FDTD model removes the approximations made in other similar models to extend its applicability, and incorporates a variety of existing methods and new techniques. A dispersive and anisotropic realization of the nearly perfectly matched layer (NPML) absorbing boundary condition is adopted in this numerical model for ease of implementation. Earth curvature is included in the model through the modified refractive
index method. The surface impedance boundary condition is adopted to treat arbitrary but homogeneous ground parameters. We quantify the errors through dispersion relations, and
the solution convergence is analyzed. Comparisons between our simulation, numerica