Twentieth century secular decrease in the atmospheric potential gradient

Harrison, G. ORCID: https://orcid.org/0000-0003-0693-347X (2002) Twentieth century secular decrease in the atmospheric potential gradient. Geophysical Research Letters, 29 (14). 1660. ISSN 0094-8276 doi: 10.1029/2002GL014878

Abstract/Summary

Current flowing in the global atmospheric electrical circuit (AEC) substantially decreased during the twentieth century. Fair-weather potential gradient (PG) observations in Scotland and Shetland show a previously unreported annual decline from 1920 to 1980, when the measurements ceased. A 25% reduction in PG occurred in Scotland 1920–50, with the maximum decline during the winter months. This is quantitatively explained by a decrease in cosmic rays (CR) increasing the thunderstorm-electrosphere coupling resistance, reducing the ionospheric potential VI. Independent measurements of VI also suggest a reduction of 27% from 1920–50. The secular decrease will influence fair weather atmospheric electrical parameters, including ion concentrations and aerosol electrification. Between 1920–50, the PG showed a negative correlation with global temperature, despite the positive correlation found recently between surface temperature and VI. The 1980s stabilisation in VI may arise from compensation of the continuing CR-induced decline by increases in global temperature and convective electrification.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/16400
Identification Number/DOI	10.1029/2002GL014878
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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