1. Characteristics and Activity of Storms Associated with TLEs Production during Eurosprite campaigns: Statistics and Case Studies S. Soula 1, O. van der Velde 2, J. Palmiéri 1, J. Montanya 2 1 Laboratoire d’Aérologie, UMR 5560 CNRS/UPS, Université de Toulouse, France 2 Electrical Engineering Department, Technological University of Catalonia, Terrassa, Spain

2. Overview of the presentation  TLEs observations during Eurosprite campaigns  Conditions of production: Statistical study from 7 storms Case studies  Conclusions

3. Localization of cameras during Eurosprite 2007 Toulouse Corsica CRA La Molina Pic du Midi Mont Aigoual Area with TLEs observed from July 2007 to January 2008 Observation systems during Eurosprite 2007

4. Eurosprite Observations 2000 (July – August) 1 camera (Pic du Midi) 40 sprites 2003 (CAL) (July – August) 1 camera (Pic du Midi) ~ 102 sprites 2004 (July – August) 1 camera (Pic du midi) - 2005 (July – November) 1 camera Pic du Midi 1 camera Puy Dôme 54 sprites 10 sprites 2006 (July – November) 1 camera Pic du Midi 1 camera Mont- Aigoual / Toulouse 32 sprites 54 sprites (2 common) 2007 (July – January) October-January 89% of TLEs 1 camera Pic du Midi 1 camera CRA 1 camera La Molina 1 camera Toulouse ~ 130 TLEs ~ 250 TLEs ~ 26 sprites ~ 22 sprites 385 TLEs - 42 common – 345 sprites - 40 elves

6. Eurosprite TLEs picture gallery All types of sprite are observed in our storms Elves are observed especially in winter storms

7. 15/11/2007 311,9 kA 0-20 ms 16/01/2008 -472,3 kA 0-2 ms 17/12/2007 77,9 kA 3-23 ms 17/10/2007 108,4 kA 0-19 ms

8. Statistical study Data from 2003-2006 sprite storms with radar covering: 7 storms, 145 sprites CG parent The CGs with large peak current tend to be located in low rain rate areas The CG parent are located in low rain rate cloud areas The CG parent have higher peak currents (average 60 kA / 30 kA for other CG+)

9. Statistical study Data from 2003-2006 sprite storms with radar covering: 7 storms, 145 sprites CG parent The CGs with large peak currents are located in areas with uniform rain rate The CG parent are located in cloud areas with uniform rain rate STRATIFORM AREA

10. Statistical study Data from 2007 sprite storms : 8 storms, 120 columns et 64 carrots Shorter delay in average for column sprites Average value : column 14 ms ; carrot 29,6 ms Time delay between CG parent and sprite (column and carrot) (+/- 20 ms)

11. Case studies Data from 21 July 2003: 27 sprites The sprites are produced in a well identified and short period During this period: increase of the rain mass from regions 30- 40 dBZ radar reflectivity (1 h 10 min) Z 0 = 200 R 1.6 Z 0 in mm 6 m -3 and R in mm/hr (Marshall-Palmer, 1948).

12. Case studies Data from 21 July 2003: 27 sprites The sprites are produced after a decrease of the CG- rate and when the CG+ proportion is high (about 50 %)

13. Case studies Data from 11 September 2006 : 27 sprites in two storm periods The sprites are often associated with CG flash « jumps » (sequences of several CGs in about 1 sec) Cumulative CG flash number with 12 sprites between 2000 UT and 2200 UT

14. Analysis of the the case of 15/11/2007 15 sprites and 2 elves observed in one convective system Radar reflectivity < 45 dBZ Evolution of the CG flash number 21h00 - 02h00 UT 350 km 2 sprites at 22h 38min 38 sec 2 periods of TLE production Several CG jumps associated with a sprite

15. CG lightning activity associated with 2 sprites Sprite 1 Sprite 2 15 CG flashes (10 CG+ and 5 CG-) associated with sprite event within 1.2 sec The CG flash sequence covers a big region of the storm Spider flash ? The sprites from CRA (Easterly direction) 350 km parent 1 parent 2

16. From Pic du midi (2 frames) From CRA (integrated) Sprites Location – 15/11/2007 at 22:27:38 The sprite event is located by using triangulation 2 CG+ triggering 2 sprites 2 different locations (50 km) The sprites are close to the parent CG+ 350 km

17. Conclusion  Better conditions for observation in Autumn and Winter  All types of sprite in our thunderstorms and more elves in winter storms (over Sea and CG flashes with bigger peak currents)  Carrot sprites more delayed than column sprites  Sprites are produced within a short period of the storm activity during the development of the stratiform region of the storm  Sprites are produced after the high CG flash rate, when the +CG flash proportion is high  Sprites often associated with a CG flash sequence (up to 15 CGs) covering a large area of the storm – Spider flash ?  Cases of multiple sprites located in different areas of the storm