results from vaisala’s long range lightning detection network (lldn) tropical cyclone studies
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Results from Vaisala’s long range lightning detection network (LLDN) tropical cyclone studies
Nicholas W. S. Demetriades
Applications Manager, Meteorology Business Area
Vaisala, Inc.
Monterey, CA
24 March 2009
©Vaisala | date | Ref. code | Page 2
Hurricane Rita (2005)
©Vaisala | date | Ref. code | Page 3
Demetriades and Holle (2008)Introduction - Goal
• Study inner core lightning rates throughout the full lifecycle of Atlantic tropical cyclones for a large sample size
©Vaisala | date | Ref. code | Page 4
Methodology
• Full lifecycle of tropical cyclones that occurred in Atlantic basin from 2004 through 2007
• Landfall not excluded
• Subtropical storms not studied
• Tropical cyclone position and maximum sustained wind speeds obtained from National Hurricane Center best track data
• Interpolated positions and maximum sustained wind speeds between 6-hour intervals to obtain 3-hour values
• Tropical cyclone inner core lightning defined as 3-hourly CG lightning flash rates within 100 km of center of storm position
• Day/Night detection efficiency corrections were applied
©Vaisala | date | Ref. code | Page 5
MethodologyTropical cyclone intensity categories
Tropical cyclone intensity category Maximum sustained wind speeds
Tropical depression (TD) <35 knots
Tropical storm – weak (TS-W) 35-49 knots
Tropical storm – strong (TS-S) 50-63 knots
Hurricane – weak (H-W) 64-95 knots
Hurricane – strong (H-S) >95 knots
©Vaisala | date | Ref. code | Page 6
Atlantic basin resultsDay/Night, DE-corrected cumulative lightning rate distribution table
Tropical cyclone intensity category
Sample size Percentile of first non-zero
lightning count
50th percentile 75th percentile 90th percentile
Tropical depression (TD)
480 42% 3 100 585
Tropical storm – weak (TS-W)
658 35% 18 280 1248
Tropical storm – strong (TS-S)
446 29% 24 477 1765
Hurricane – weak (H-W)
512 47% 2 43 276
Hurricane – strong (H-S)
373 29% 16 76 200
©Vaisala | date | Ref. code | Page 7
Atlantic basin resultsInner core lightning with respect to landfall
0
50
100
150
200
250
300
350
400
-24 -21 -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 21 24
Time in hours with respect to landfall (time zero)
3-h
ou
r in
ne
r c
ore
lig
htn
ing
ra
te
Median 75th percentile
©Vaisala | date | Ref. code | Page 8
Conclusions
• New finding: Atlantic tropical cyclones produce the highest inner core lightning rates during the tropical storm stage and the lowest inner core lightning rates during the hurricane stage
• High inner core (eyewall) lightning rates occur infrequently in category 3-5 hurricanes
• Appear to be related to eyewall replacement cycles (Knabb et al., 2008)
• Atlantic tropical cyclones produce more inner core lightning during the 24-hour period leading up to, and including landfall, than they do during the 24-hour period after landfall
©Vaisala | date | Ref. code | Page 9
Hurricane Katrina (2005)Eyewall replacement & Continuous eyewall lightning
0
100
200
300
400
500
600
700
800
900
1000
8/2
3/2
00
5 1
80
08
/23
/20
05
21
00
8/2
4/2
00
5 0
00
08
/24
/20
05
03
00
8/2
4/2
00
5 0
60
08
/24
/20
05
09
00
8/2
4/2
00
5 1
20
08
/24
/20
05
15
00
8/2
4/2
00
5 1
80
08
/24
/20
05
21
00
8/2
5/2
00
5 0
00
08
/25
/20
05
03
00
8/2
5/2
00
5 0
60
08
/25
/20
05
09
00
8/2
5/2
00
5 1
20
08
/25
/20
05
15
00
8/2
5/2
00
5 1
80
08
/25
/20
05
21
00
8/2
6/2
00
5 0
00
08
/26
/20
05
03
00
8/2
6/2
00
5 0
60
08
/26
/20
05
09
00
8/2
6/2
00
5 1
20
08
/26
/20
05
15
00
8/2
6/2
00
5 1
80
08
/26
/20
05
21
00
8/2
7/2
00
5 0
00
08
/27
/20
05
03
00
8/2
7/2
00
5 0
60
08
/27
/20
05
09
00
8/2
7/2
00
5 1
20
08
/27
/20
05
15
00
8/2
7/2
00
5 1
80
08
/27
/20
05
21
00
8/2
8/2
00
5 0
00
08
/28
/20
05
03
00
8/2
8/2
00
5 0
60
08
/28
/20
05
09
00
8/2
8/2
00
5 1
20
08
/28
/20
05
15
00
8/2
8/2
00
5 1
80
08
/28
/20
05
21
00
8/2
9/2
00
5 0
00
08
/29
/20
05
03
00
8/2
9/2
00
5 0
60
08
/29
/20
05
09
00
8/2
9/2
00
5 1
20
08
/29
/20
05
15
00
8/2
9/2
00
5 1
80
08
/29
/20
05
21
00
8/3
0/2
00
5 0
00
08
/30
/20
05
03
00
8/3
0/2
00
5 0
60
08
/30
/20
05
09
00
8/3
0/2
00
5 1
20
08
/30
/20
05
15
00
8/3
0/2
00
5 1
80
0
Date and Time (M/D/YYYY HHmm) UTC
3-h
ou
r e
ye
wa
ll lig
htn
ing
ra
te
0
20
40
60
80
100
120
140
160
Ma
xim
um
su
sta
ine
d w
ind
sp
ee
d (
kn
ots
)
Uncorrected Day/Night DE Corrected Maximum Sustained Wind Speed
©Vaisala | date | Ref. code | Page 10
Hurricane Wilma (2005)Eyewall replacement
0
100
200
300
400
500
600
700
800
900
1000
10
/15
/20
05
18
00
10
/15
/20
05
21
00
10
/16
/20
05
00
00
10
/16
/20
05
03
00
10
/16
/20
05
06
00
10
/16
/20
05
09
00
10
/16
/20
05
12
00
10
/16
/20
05
15
00
10
/16
/20
05
18
00
10
/16
/20
05
21
00
10
/17
/20
05
00
00
10
/17
/20
05
03
00
10
/17
/20
05
06
00
10
/17
/20
05
09
00
10
/17
/20
05
12
00
10
/17
/20
05
15
00
10
/17
/20
05
18
00
10
/17
/20
05
21
00
10
/18
/20
05
00
00
10
/18
/20
05
03
00
10
/18
/20
05
06
00
10
/18
/20
05
09
00
10
/18
/20
05
12
00
10
/18
/20
05
15
00
10
/18
/20
05
18
00
10
/18
/20
05
21
00
10
/19
/20
05
00
00
10
/19
/20
05
03
00
10
/19
/20
05
06
00
10
/19
/20
05
09
00
10
/19
/20
05
12
00
10
/19
/20
05
15
00
10
/19
/20
05
18
00
10
/19
/20
05
21
00
10
/20
/20
05
00
00
10
/20
/20
05
03
00
10
/20
/20
05
06
00
10
/20
/20
05
09
00
10
/20
/20
05
12
00
10
/20
/20
05
15
00
10
/20
/20
05
18
00
10
/20
/20
05
21
00
10
/21
/20
05
00
00
10
/21
/20
05
03
00
10
/21
/20
05
06
00
10
/21
/20
05
09
00
10
/21
/20
05
12
00
10
/21
/20
05
15
00
10
/21
/20
05
18
00
10
/21
/20
05
21
00
10
/22
/20
05
00
00
10
/22
/20
05
03
00
10
/22
/20
05
06
00
10
/22
/20
05
09
00
10
/22
/20
05
12
00
10
/22
/20
05
15
00
10
/22
/20
05
18
00
10
/22
/20
05
21
00
10
/23
/20
05
00
00
10
/23
/20
05
03
00
10
/23
/20
05
06
00
10
/23
/20
05
09
00
10
/23
/20
05
12
00
10
/23
/20
05
15
00
10
/23
/20
05
18
00
10
/23
/20
05
21
00
10
/24
/20
05
00
00
10
/24
/20
05
03
00
10
/24
/20
05
06
00
10
/24
/20
05
09
00
10
/24
/20
05
12
00
10
/24
/20
05
15
00
10
/24
/20
05
18
00
10
/24
/20
05
21
00
10
/25
/20
05
00
00
10
/25
/20
05
03
00
10
/25
/20
05
06
00
10
/25
/20
05
09
00
10
/25
/20
05
12
00
10
/25
/20
05
15
00
10
/25
/20
05
18
00
Date and Time (M/D/YYYY HHmm) UTC
3-h
ou
r e
ye
wa
ll lig
htn
ing
ra
te
0
20
40
60
80
100
120
140
160
180
Ma
xim
um
su
sta
ine
d w
ind
sp
ee
d (
kn
ots
)
Uncorrected Day/Night DE Corrected Maximum Sustained Wind Speed
©Vaisala | date | Ref. code | Page 11
Hurricane Felix (2007)Eyewall replacement
0
100
200
300
400
500
600
700
800
900
1000
8/3
1/2
00
7 1
20
08
/31
/20
07
15
00
8/3
1/2
00
7 1
80
08
/31
/20
07
21
00
9/1
/20
07
00
00
9/1
/20
07
03
00
9/1
/20
07
06
00
9/1
/20
07
09
00
9/1
/20
07
12
00
9/1
/20
07
15
00
9/1
/20
07
18
00
9/1
/20
07
21
00
9/2
/20
07
00
00
9/2
/20
07
03
00
9/2
/20
07
06
00
9/2
/20
07
09
00
9/2
/20
07
12
00
9/2
/20
07
15
00
9/2
/20
07
18
00
9/2
/20
07
21
00
9/3
/20
07
00
00
9/3
/20
07
03
00
9/3
/20
07
06
00
9/3
/20
07
09
00
9/3
/20
07
12
00
9/3
/20
07
15
00
9/3
/20
07
18
00
9/3
/20
07
21
00
9/4
/20
07
00
00
9/4
/20
07
03
00
9/4
/20
07
06
00
9/4
/20
07
09
00
9/4
/20
07
12
00
9/4
/20
07
15
00
9/4
/20
07
18
00
9/4
/20
07
21
00
9/5
/20
07
00
00
9/5
/20
07
03
00
9/5
/20
07
06
00
Date and Time (M/D/YYYY HHmm) UTC
3-h
ou
r e
ye
wa
ll lig
htn
ing
ra
te
0
20
40
60
80
100
120
140
160
Ma
xim
um
su
sta
ine
d w
ind
sp
ee
d (
kn
ots
)
Uncorrected Day/Night DE Corrected Maximum Sustained Wind Speed
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