Inferring convective responses to El Niño with atmospheric electricity measurements at Shetland
Harrison, G., Joshi, M. and Pascoe, K. (2011) Inferring convective responses to El Niño with atmospheric electricity measurements at Shetland. Environmental Research Letters, 6 (4). 044028 . ISSN 1748-9326
To link to this item DOI: 10.1088/1748-9326/6/4/044028
Pacific ocean temperature anomalies associated with the El Niño–Southern Oscillation (ENSO) modulate atmospheric convection and hence thunderstorm electrification. The generated current flows globally via the atmospheric electric circuit, which can be monitored anywhere on Earth. Atmospheric electricity measurements made at Shetland (in Scotland) display a mean global circuit response to ENSO that is characterized by strengthening during 'El Niño' conditions, and weakening during 'La Niña' conditions. Examining the hourly varying response indicates that a potential gradient (PG) increase around noon UT is likely to be associated with a change in atmospheric convection and resultant lightning activity over equatorial Africa and Eastern Asia. A secondary increase in PG just after midnight UT can be attributed to more shower clouds in the central Pacific ocean during an 'El Niño'.