1. Department of Physics, The Pennsylvania State University Lehigh Valley, Fogelsville, PA 18051, USA
2. Physics Department, Cheng Kung University, Tainan, Taiwan
3. Institute of Space Science, National Central University, Chung-Li, Taiwan
Abstract
Observations by The Imager of Sprites and Upper Atmospheric Lightning (ISUAL) broadband filter onboard the FORMOSAT-II satellite have sometimes shown a transient brightness in or below the OH airglow layer accompanied by lightning activity. The ISUAL team conducted a nine-day campaign in January 2007 with some of the observations devoted exclusively to capturing lightning-induced transient emissions (LITEs) with a narrowband filter for such investigations. The observations of lightning-induced intensity enhancements in the OH airglow layer with a narrowband filter presented here are the first and only narrowband observations currently in existence. Our analysis of the narrow-band observations shows that there is a significant intensity increase (87.5%) in the OH airglow layer when there is lightning activity and a residual intensity increase (25%) in post lightning activity. Three mechanisms are proposed to explain the airglow enhancements.
This image shows an intensity enhancement in the OH airglow induced by lightning captured by a broadband filter (623-750 nm).
This image shows an intensity enhancement in OH airglow induced by lightning captured by a narrowband filter centered at 630 nm.
We propose three mechanisms to explain the lightning-induced transient emissions (LITEs) in the OH airglow.
ISUAL’s broadband filter has also captured LITEs below the OH airglow layer like the one below.
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