Atmospheric electricity observations at Lerwick Geophysical Observatory

Abstract. Atmospheric electricity measurements were made at Lerwick Observatory, Shetland, between 1925 and 1984. These principally provide a long series of hourly potential gradient (PG) measurements at an unpolluted site but also include air–Earth current density measurements during the late 1970s and early 1980s. An especially notable aspect was investigating the dramatic atmospheric electrical changes caused by nuclear weapon detonations in the late 1950s and early 1960s, which has parallels with the discovery of the Antarctic ozone hole. The methodology employed at Lerwick to provide the PG measurements is described. There is renewed international interest in such measurements, not least because the Lerwick PG data have been shown to be linked to Pacific Ocean temperature anomalies. The past measurements described have characterised the Lerwick site exceptionally well in atmospheric electrical terms, which also indicate its suitability for future, similar measurements.