Upward and downward lightning observed at Tokyo Skytree

Abstract

This paper describes observations of lightning current waveform at Tokyo Skytree, which stands in the eastern area of central Tokyo, located in the Kanto Plain, and is a 634-m high freestanding broadcasting tower. Direct observation of lightning current by using a pair of Rogowski coils started in the end of February 2012. From 2012 to the end of 2013, currents associated with 24 lightning flashes which hit the tower were recorded. In 2012, most of the flashes were upward as was expected; however, in 2013, most of the flashes observed in summer were downward. We have also evaluated statistical characteristics of obtained lightning current waveforms.

Meteorological Conditions and Occurrence of Upward Lightning at High Structures

“…In fact, the ratio of upward lightning of these high structures are more than 80%, which agrees with the values calculated from formula (1). According to formula (1), most of lightning to Tokyo Skytree, height of which is 634 m, should be upward lightning.…”

“…TOKYO SKYTREE R is a 634-m high freestanding broadcasting tower in Tokyo, Japan (35.71N, 139.81E). Direct observation of lightning current started in February 2012 (1) (2) , and high-speed cameras were set 6 months later (3) (4) .…”