To more thoroughly reveal the characteristics of lightning channel base current and its radiated electric fields in the atmospheric boundary layer

six attenuation models of lightning channel base current are employed to analyze the attenuation characteristics of the current versus altitude

and the two-dimensional FDTD method is adopted to simulate the variations of the horizontal and vertical el

ectric fields radiated by the lightning channel at four distances from the channel with time. The results indicate that: 1)The six attenuation models are listed descendingly as follows according to their attenuation differences at different altitudes: MTLTQ

MTLE

MTLT

MTLCOS

MTLL

and TL;2)The horizontal radiated electric fields at four horizontal distances from the lightning channel and the altitude of 0 m are almost negative

and the ones at two farther horizontal distances and the altitude of 15 m have both positive and negative maxima

while the ones at other horizontal distances and altitudes are all positive with the absolute values within 0

1

04V/m; and 3)The vertical radiated electric fields at the altitudes of 200 and 500 m and the horizontal distances of 20 and 50 m from the channel

as well as at the altitude of 500 m and the horizontal distance of 200 m

are rather complicated

but the ones at the altitude of 2 500 m and different horizontal distances are very simple

which exhibit negative increase after 8.6 or 8.9 μs

while the fields in other conditions exhibit positive variation with one maximum. It is concluded that of all six models the MTLL gains moderate attenuation difference at all altitudes

so it is a representative model

and the FDTD methods can effectively simulate the horizontal and vertical radiated electric field components of CG（cloud-to-ground）lightning channel in the atmospheric boundary layer.