Model sheds light
on lightning protection of WSR-88D sites

by Vlad Mazur

Lightning is a serious threat to WSR-88D sites around the United States. NSSL is working to improve lightning protection of WSR-88D sites through a Memorandum of Understanding (MOU) between NSSL and OSF. Part of the MOU includes the development of a 3-dimensional model of lightning interaction with a ground structure protected by a vertical rod. The following figures illustrate an example of the results. The model was created to help evaluate present and proposed lightning protection systems.

Results of the modeling suggest that the idea of an universal definition of a zone of lightning protection is unrealistic, because the dimension of the region where a vertical rod of a given height serves as a lightning protector depends heavily upon the potential of the lightning leader. In particular, it would be very difficult to protect a ground structure with a vertical rod against lightning leaders with a low potential.

For more information contact Vlad Mazur at: mazur@nssl.noaa.gov

Upper right: The same as in upper left, except leader's tip is 125m above ground, and the positive leader from the vertical rod is 37.5m long.

Lower left: The same as in upper left, except leader's tip is 95m above ground and the positive leader from the vertical rod is 52.5m long.

Lower right: The same as the upper left, except two leaders contact when the downward leader tip is 80m above ground.