Inferring convective responses to El Niño with atmospheric electricity measurements at Shetland
نویسندگان
چکیده
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’.
منابع مشابه
Simulation of Two Types of El Niño from Different Convective Parameters
Many recent studies have reported the presence of two types of El Niño events in observation: Cold Tongue (CT) El Niño and Warm Pool (WP) El Niño. We investigate the sensitivity of a model simulating two types of El Niño by changing a convective triggering parameter (Tokioka parameter). When deep convections are highly suppressed with a large Tokioka parameter, the model is capable of simulatin...
متن کاملThe Termination of the 1997–98 El Niño. Part II: Mechanisms of Atmospheric Change
The mechanisms that drove zonal wind stress ( ) changes in the near-equatorial Pacific at the end of the extreme 1997–98 El Niño event are explored using a global atmospheric general circulation model. The analysis focuses on three features of the x evolution between October 1997 and May 1998 that were fundamental in driving the oceanic changes at the end of this El Niño event: (i) the southwar...
متن کاملSolar modulation in surface atmospheric electricity
The solar wind modulates the flux of galactic cosmic rays impinging on Earth inversely with solar activity. Cosmic ray ionisation is the major source of air’s electrical conductivity over the oceans and well above the continents. Differential solar modulation of the cosmic ray energy spectrum modifies the cosmic ray ionisation at different latitudes, varying the total atmospheric columnar condu...
متن کاملTwentieth century secular decrease in the atmospheric potential gradient
[1] 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. ...
متن کاملHeavy rainfall episodes in Ecuador during El Niño events and associated regional atmospheric circulation and SST patterns
To date very little is known about the relation between regional circulation patterns and sea surface temperature development in the Niño 1,2 region and the occurrence of heavy precipitation in Ecuador and northern Peru. The current study uses a comprehensive data set of 2544 Meteosat-3 imagery to investigate the dynamics of heavy precipitation during El Niño in 1991/92. Rainfall maps are retri...
متن کامل