Extreme Events and Climate Variability
X. William Proenza, Director
National Weather Service Southern Region
Fort Worth, Texas
Issues:
Scientists are telling us that global warming means more extreme weather.
Every year we seem to experience weather extremes.
What is the origin of extreme events?
A Major Issue for All Countries Is Global Warming and Its Regional Impacts
- 0 . 6 - 0 . 3 0 . 0 0 . 3 0 . 6 0 . 9
L a n d a n d O c e a n
Anomaly (°C)
a
1 8 8 0 1 9 0 0 1 9 2 0 1 9 4 0 1 9 6 0 1 9 8 0 2 0 0 0
1 8 8 0 1 9 0 0 1 9 2 0 1 9 4 0 1 9 6 0 1 9 8 0 2 0 0 0
- 1 . 2 - 0 . 9 - 0 . 6 - 0 . 3 0 . 0 0 . 3 0 . 6 0 . 9 1 . 2
L a n d
Anomaly (°C)
c
- 0 . 4 - 0 . 1 0 . 2 0 . 5 0 . 8
Anomaly (°C)
O c e a n
b
1 8 8 0 1 9 0 0 1 9 2 0 1 9 4 0 1 9 6 0 1 9 8 0 2 0 0 0
S e a s o n a l C l i m a t e I m p a c t s D e p e n d o n t h e S i m u l t a n e o u s I n f l u e n c e s o f :
E x t r e m e E v e n t s a r e M o s t l y R e l a t e d t o C i r c u l a t i o n C h a n g e s , i . e . t o V a r i a b i l i t y
N a t u r a l C l i m a t e V a r i a b i l i t y E l N i n o / L a N i n a
P a c i f i c D e c a d a l O s c i l l a t i o n
A r c t i c O s c i l l a t i o n ( w e a k i m p a c t i n T r o p i c s ) C l i m a t e C h a n g e
A t m o s p h e r i c N o i s e
( P D O )
The El Nino/Southern Oscillation (ENSO) is a major factor in
global climate variability.
T h e P a c i f i c D e c a d a l O s c i l l a t i o n ( P D O )
t y p i c a l w i n t e r t i m e S e a S u r f a c e T e m p e r a t u r e ( c o l o r s ) , S e a L e v e l P r e s s u r e ( c o n t o u r s ) a n d s u r f a c e w i n d s t r e s s ( a r r o w s ) a n o m a l y p a t t e r n s d u r i n g w a r m a n d c o o l p h a s e s o f P D O
w a r m p h a s e c o o l p h a s e
L a N i n a ( J u l y 1 9 9 8 - J u n e 1 9 9 9 )~
D e p a r t u r e f r o m N o r m a l ( m m ) E l N i n o ( J u l y 1 9 9 7 - J u n e 1 9 9 8 )~
R a i n f a l l C h a n g e s A s s o c i a t e d w i t h E N S O a r e t h e L a r g e s t S o u r c e o f V a r i a b i l i t y i n t h e T r o p i c s
E N S O A l s o I m p a c t s H u r r i c a n e A c t i v i t y
S o c i e t a l I m p a c t s f r o m 1 9 9 7 /9 8 E l N i n o
1 . C r o p / S t o c k D a m a g e 2 . E n e r g y S a v i n g s 3 . F a m i n e
4 . F i r e s
5 . F i s h e r i e s D i s r u p t i o n 6 . H e a l t h R i s k s
7 . H u m a n F a t a l i t i e s
8 . P e s t s I n c r e a s e d 9 . P r o p e r t y D a m a g e 1 0 . T o u r i s m D e c r e a s e d 1 1 . T r a n s p o r t a t i o n P r o b l e m s 1 2 . S o c i a l D i s r u p t i o n s
1 3 . W i l d l i f e F a t a l i t i e s 1 4 . W a t e r R a t i o n i n g
1
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1 1
1 4 3
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1 1 1 2
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1 1 1
1 4 4 3 6 8 9
9 9
1 0 1 3 1 2
5 1
1 4
6 9
9
1 1
7 8 9 1 9
4 7
8 9 1 3 1 1
5 2
Colombia Gets Less Rain During El Nino
Major Weather-Related Natural Disasters (1999 La Nina)
6 0 N 5 0 N 4 0 N 3 0 N 2 0 N 1 0 N E Q 1 0 S 2 0 S 3 0 S 4 0 S 5 0 S 6 0 S
0 6 0 E 1 2 0 E 1 8 0 1 2 0 W 6 0 W 0
S S
S S S
S S
F F F F F F
F
F F F
F F F F
F F
F F F F F F
F
F F F F
F
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H H
D D
S S t o r m s , H a i l , T o r n a d o e s
F F l o o d s , L a n d s l i d e s
H H u r r i c a n e s , T y p h o o n s
D D r o u g h t
F l o o d 5 5 , 3 6 0 $ 1 . 3 B S t o r m s 1 6 , 8 6 3 $ 1 7 . 0 B D r o u g h t s 4 0 4 - C o l d W a v e s 4 0 9 $ 1 . 3 B
V i c t i m s I n s u r e d L o s s e s
Regional 1999 Floods Possibly Linked to La Nina Date Event
April 9-16 Mudslides & heavy rains Columbia:
Cauca, Argelia
May 5-15 High water in Amazonas, Peru August 15-22 Flooding in eastern Venezuela Aug 30-Sept 11 Flooding in Columbia: Antioquia, Cordoba, Choco
Sept 12-29 Persistent rains, floods, mudslides in Columbia, Honduras, Nicaragua,
Guatamala
Dec 12-19 Major flooding and mudslides in Venezuela (50,000+ victims)
Impacts of December 1999 Floods
in Venezuela
E x t e n d e d P a c i f i c J e t S t r e a m
& A m p l i f i e d S t o r m T r a c k
L
L o w P r e s s u r e
P o l a r J e t S t r e a m W a r m
C o l d D r y
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E l N i n o~
H
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H i g h P r e s s u r e P o l a r
J e t S t r e a m
C o l d
D r y
D r y W e t
W a r m W e t
V a r i a b l e
L a N i n a~
Typical Winter Weather Anomalies And Atmospheric Circulation Changes
During El Nino & La Nina
L o c a t i o n s F o r M a j o r S t o r m s ( D a y s P e r W i n t e r S e a s o n ) E x t e n s iv e S t o r m s
D e c 9 7 - M a r 9 8
M a s s i v e I c e S t o r m J a n 9 8 S t r o n g
“ N o r t h e a s t e r ” S t o r m s J a n - F e b 9 8 T o r n a d o O u t b r e a k
F e b 9 8
F r e q u e n t S t o r m s N o v 9 7 - M a r 9 8
E x a m p l e s o f C l i m a t e C o n t r o l O v e r W e a t h e r P a t t e r n s . T h e B a s i s o f L i n k i n g C l i m a t e a n d W e a t h e r
L A N i n a 1 9 9 8 - 1 9 9 9~
A b o v e A v e r a g e S t o r m s , H u r r i c a n e
F o r c e W i n d s N o v 9 8 - F e b 9 9
A c t i v e H u r r i c a n e S e a s o n A u g - N o v 9 8
T o r n a d o e s J a n 1 9 9 9
N o M a jo r “ N o r t h e a s t e r s ”
B e lo w N o r m a l S t o r m i n e s s D e c 9 8 - F e b 9 9
M a jo r I c e S t o r m J a n 9 9 M a j o r
S n o w S t o r m J a n 9 9
E x t e n s i v e I c e S t o r m D e c 9 8 D r o u g h t
S p r i n g 1 9 9 9
D i m i n i s h e d H u r r i c a n e
T h r e a t
J e t S t r e a m S h i f t s A s s o c i a t e d w i t h C l i m a t e V a r i a b i l i t y P r o d u c e R e g i o n a l C h a n g e s I n E x t r e m e W e a t h e r E v e n t s
T h e P a c i f i c D e c a d a l O s c i l l a t i o n ( P D O )
t y p i c a l w i n t e r t i m e S e a S u r f a c e T e m p e r a t u r e ( c o l o r s ) , S e a L e v e l P r e s s u r e ( c o n t o u r s ) a n d s u r f a c e w i n d s t r e s s ( a r r o w s ) a n o m a l y p a t t e r n s d u r i n g w a r m a n d c o o l p h a s e s o f P D O
w a r m p h a s e c o o l p h a s e
R e f e r e n c e : N a t h a n M a n t u a U n i v e r s i t y o f W a s h i n g t o n
T o t a l T r e n d P a c i f i c D e c a d e l O s c i l l a t i o n
A r c t i c O s c i l l a t i o n G l o b a l W a r m i n g
Contributions to Surface Temperature Trend from 1950-1999
S U M M A R Y
E x t r e m e s r e s u l t f r o m :
- m a j o r c l i m a t e a n o m a l i e s ( e . g . e s p e c i a l l y E l N i n o a n d L a N i n a i n T r o p i c s )
- u n u s u a l a t m o s p h e r i c c i r c u l a t i o n p a t t e r n s ( m o s t l y r e l a t e d t o c l i m a t e v a r i a b i l i t y )
- f a c t o r s a c t i n g t o g e t h e r f o r a i r t e m p e r a t u r e ( e . g . E N S O , P D O , A O , g l o b a l w a r m i n g )
T h e i m p a c t s o f t h e w a r m i n g t r e n d o n c i r c u l a t i o n c h a n g e s , i . e . a l s o e x t r e m e s , i s s t i l l a r e s e a r c h i s s u e .
