Accessibility navigation

Twentieth century secular decrease in the atmospheric potential gradient


Downloads per month over past year

Harrison, G. (2002) Twentieth century secular decrease in the atmospheric potential gradient. Geophysical Research Letters, 29 (14). 1660. ISSN 0094-8276

[img] Text - Published Version
· Please see our End User Agreement before downloading.


To link to this article DOI: 10.1029/2002GL014878


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
Divisions:Faculty of Science > School of Mathematical and Physical Sciences > Department of Meteorology
ID Code:16400
Publisher:American Geophysical Union

Download Statistics for this item.

University Staff: Request a correction | Centaur Editors: Update this record

Page navigation