Comment on ''Radio frequency radiation beam pattern of lightning return strokes: A revisit to theoretical analysis'' by Xuan-Min Shao, Abram R. Jacobson, and T. Joseph Fitzgerald

In summary, SJF present a new approach to deriving a radiation electric field equation for the TL model when there is no current discontinuity at the return stroke front. This approach (see their equation (11)) is identical, except for the SJF sign error, to that found in the literature (e.g., equation (47) of TUR). However, their electric field equation (10), asserted to be general, is incapable of handling models with current discontinuity (intrinsic in some models) at the return stroke front, and their electric field equation (12) for the TCS model is incomplete. The correct equation for the TCS model is given by TUR (see their equation (49)). A truly general electric field equation that is valid for any model and for any distance to the field point is equation (7) of Thottappillil and Rakov [2001b]. Copyright 2005 by the American Geophysical Union.