Seminars

Lecturer: Carl-Fredrik Enell (SGO)
Date: 2007-05-24 10:00
Place: Aniara

Transient luminous events in the middle atmosphere: Observations and modelling

Carl-Fredrik Enell
Sodankylä Geophysical Observatory
University of Oulu
and the CAL, Tohoku University and IRF-Umeå collaborators

Many details of transient luminous events (TLEs) above thunderstorms, such as sprites, jets and elves, are still unknown. The European research network CAL (Coupling of Atmospheric Layers) is one of the groups addressing these phenomena (Cnf. Enell et al, 33AM, Kiruna, oral presentation; IRF Technical report by the CAL team, in review).

One unanswered question is whether TLEs may affect the chemistry of the middle atmosphere. Tropospheric lightning is a significant source of NOx. Schumann & Huntrieser (2007) is a recent review. Modelling with the Sodankylä coupled Ion-neutral Chemistry (SIC) model (Enell et al, to be submitted to Annales Geophysicae), as well as satellite observations (Arnone et al, submitted for IUGG General Assembly, 2007), suggest that this source is of only little global importance.

The CAL collaboration has also confirmed (Farges et al, 2005) a correlation between infrasound signatures and sprites suggested by Ludwik Liszka (see Liszka and Hobara, 2006). Recent findings will be discussed.


References
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E. Arnone et al. (ed. C-F Enell), The Eurosprite 2005 campaign, IRF Technical report, in review

Carl-Fredrik Enell, Enrico Arnone, Olivier Chanrion, Toru Adachi, Pekka T. Verronen, Annika Seppälä, Torsten Neubert, Thomas Ulich, and Esa Turunen. Parameterisation of the chemical impact of transient luminous events in the middle atmosphere. In preparation for submission to Annales Geophysicae, 2007.

T. Farges, E. Blanc, A. Le Pichon, T. Neubert, and T. H. Allin. Identification of infrasound produced by sprites during the Sprite2003 campaign. GRL, 32:L01813, 2005.

L. Liszka and Y. Hobara. Sprite-attributed infrasonic chirps - their detection, occurrence and properties between 1994 and 2004. JASTP, 68:1179-1188, 2006.

U. Schumann, H. Huntrieser, The global lightning-induced nitrogen oxides source, Atmos. Chem. Phys. Discuss., 7, 2623-2818, 2007

Created 2007-04-24 10:36:55 by Mats Holmström
Last changed 2007-05-17 14:35:03 by Mats Holmström