Abstract: The electromagnetic field above ground produced by an incident highaltitude electromagnetic pulse plane wave striking the ground plane was described in this paper in terms of the Fresnel reflection coefficients and the numerical FFT. The pulse reflected from the ground plane always cancel the incident field for the horizortal field component, but the reflected field adds to the incident for the vertical field component. The results of several cases for variations in the observation height, angle of incidence and lossy ground electrical parameters were also presented showing different efield components above the earth.