Characteristics and Activity of Storms Associated with TLEs Production during Eurosprite campaigns: Statistics and Case Studies

S. Soula1, O. van der Velde2, J. Palmiéri1, J. Montanya2

1 Laboratoire d’Aérologie, UMR 5560 CNRS/UPS, Université de Toulouse, France

2 Electrical Engineering Department, Technological University of Catalonia, Terrassa, Spain

Overview of the presentation

TLEs observations during Eurosprite campaigns

Conditions of production:

Statistical study from 7 storms

Case studies

Conclusions

Localization of cameras during Eurosprite 2007

ToulouseCorsica

CRA

La Molina

Pic

du M

idi

Mon

t Aig

oual

Area with TLEs observed from July 2007 to January 2008

Observation systems during Eurosprite 2007

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 sprites385 TLEs - 42 common – 345 sprites - 40 elves

Eurosprite TLEs picture gallery

All types of sprite are observed in our storms

Elves are observed especially in winter storms

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

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+)

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

0

5

10

15

20

25

30

35

40-2

0

-15

-10 -5 0 5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

> 1

00

Delay (millisec)

%

columncarrot

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)

Case studies

Data from 21 July 2003: 27 sprites

00h00 01h00 02h00 03h15

SPRITES

21 July 2003: Integrated precipitation mass

0,0E+00

2,0E+06

4,0E+06

6,0E+06

8,0E+06

1,0E+07

1,2E+07

1,4E+07

1,6E+07

1,8E+07

2,0E+07

00:00 00:15 00:30 00:45 01:00 01:15 01:30 01:45 02:00 02:15 02:30 02:45 03:00 03:15

UT

kg s

-1

20-25 dBZ 25-30 dBZ

30-35 dBZ 35-40 dBZ

40-45 dBZ 45-50 dBZ

50-55 dBZ >55 dBZ

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

< 8 dBZ

8 – 16 dBZ

16 – 20 dBZ

20 – 24 dBZ

24 – 28 dBZ

28 – 32 dBZ

32 – 36 dBZ

36 – 40 dBZ

40 – 44 dBZ

> 64 dBZ

44 – 48 dBZ

48 – 52 dBZ

52 – 56 dBZ

56 – 60 dBZ

60 – 64 dBZ

no data

< 8 dBZ

8 – 16 dBZ

16 – 20 dBZ

20 – 24 dBZ

24 – 28 dBZ

28 – 32 dBZ

32 – 36 dBZ

36 – 40 dBZ

40 – 44 dBZ

> 64 dBZ

44 – 48 dBZ

48 – 52 dBZ

52 – 56 dBZ

56 – 60 dBZ

60 – 64 dBZ

no data

(1 h 10 min)

Z0 = 200 R1.6

Z0 in mm6 m-3 and R in mm/hr (Marshall-Palmer, 1948).

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 %)

0

20

40

60

80

100

120

140

00:00 00:30 01:00 01:30 02:00 02:30 03:00 03:30

CG

RA

TE

(/ 5

MIN

)

0

0,5

1

1,5

2

2,5

3

3,5

4

SP

RIT

E R

AT

E (

/ 5 M

IN)

CG- rateCG+ ratesprite rate

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)

0

50

100

150

200

250

300

350

400

450

500

0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2

time (hour)

CG

fla

sh n

um

be

r

CG numbersprite

Cumulative CG flash number with 12 sprites between 2000 UT and 2200 UT

0

50

100

150

200

250

300

350

400

0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5

Time (hour)

CG

fla

sh n

um

ber

spritesCG flash numberelves

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

< 8 dBZ

8 – 16 dBZ

16 – 20 dBZ

20 – 24 dBZ

24 – 28 dBZ

28 – 32 dBZ

32 – 36 dBZ

36 – 40 dBZ

40 – 44 dBZ

> 64 dBZ

44 – 48 dBZ

48 – 52 dBZ

52 – 56 dBZ

56 – 60 dBZ

60 – 64 dBZ

no data

< 8 dBZ

8 – 16 dBZ

16 – 20 dBZ

20 – 24 dBZ

24 – 28 dBZ

28 – 32 dBZ

32 – 36 dBZ

36 – 40 dBZ

40 – 44 dBZ

> 64 dBZ

44 – 48 dBZ

48 – 52 dBZ

52 – 56 dBZ

56 – 60 dBZ

60 – 64 dBZ

no data

CG lightning activity associated with 2 sprites

Spr

ite 1

Spr

ite 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) 0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6

Time (sec)

SP+CG CG+ CG+ CG- CG+ CG- CG+ CG- sprite

350 km

pare

nt 1

pare

nt 2

parent CG+ 1

parent CG+ 2

CG+ 3

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

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