Long-range correlations in measurements of the global atmospheric electric circuit

Measurements of global atmospheric electric circuit parameters have been made at different observing stations over long periods. Mountain stations are of particular interest because of their relatively low aerosol pollution environment. Some of the observations made by Reinhold Reiter in the Bavarian Alps have been made available to the SPECIAL scientific community. The observation site was on Mount Wank (1780 m, 47degrees30'N,11degrees09'E), close to Garmisch-Partenkirchen, and the data set spans 1 August 1972 to 31 December 1983. Hourly measurements of Potential Gradient obtained are analysed here, using the standard global (Carnegie) variation to select days on which local influences were small. Data selected using this approach shows that, from 1976 to 1983, and probably from 1972, there was a downward trend in the data. Furthermore, comparison between the annual data obtained in Bavaria and the UK stations of Eskdalemuir (55degrees19'N, 3degrees12'W) and Lerwick (60degrees8'N, 1degrees 11'W), at distances of 1320 and 1620 km respectively, shows similarities in December, a month in which positive daily correlations with the Carnegie curve are substantial at all three sites. The common variation in the three sites' measurements suggests a reduction in the global circuit in December 1978 and 1981, and supports the daily data selection procedure using the Carnegie curve. (C) 2004 Elsevier Ltd. All rights reserved.