Long-term changes in atmospheric electrical parameters observed at Nagycenk (Hungary) and the UK observatories at Eskdalemuir and Kew

Abstract. The Nagycenk Geophysical Observatory in Hungary (47° 38 ' N, 16° 43 ' E) has made continuous measurements of the vertical atmospheric electric Potential Gradient (PG) since 1962. Global signals have previously been identified in the Nagycenk PG data. A long-term (1920–1981) decrease has been discovered in the PG measured at the Eskdalemuir Observatory, Scotland (55° 19 ' N, 3° 12 ' W), suggesting that this represents a global change in the atmospheric electricity related to a decline in cosmic rays. A 40% decline in PG is shown here to have occurred at Nagycenk between 1962 and 2001, also consistent with changes in the air-Earth current measured at Kew (51° 28 ' N, 0° 19 ' W), London, 1966–1978. Comparison of the long-term PG measurements at both Eskdalemuir and Nagycenk gives further evidence to support the hypothesis of a global atmospheric electrical decline from the early twentieth century to the present time, as it is shown that local effects at Nagycenk are unlikely to have dominated the changes there.

Key words. Meteorology and atmospheric dynamics (atmospheric electricity)