NCAR
The National Center for Atmospheric
Research
is operated
by
the University
Corporation
for Atmospheric
Research
under sponsorship
of the National Science
F o u n d a tio n
Information Release
O c t o b e r 6, 1979
For I m m e d i a t e R e l e a s e
1979-18
C l e a r A i r T u r b u l e n c e Stirs P o l l u t i o n i n t o S t r a t o s p h e r e
Sofia, B u l g a r i a --- C l e a r a i r t u r b u l e n c e does m o r e t h a n c r e a t e d i s c o m f o r t
for a i r l i n e p a s s e n g e r s .
It m a y also b e a m a j o r f o r c e in m i x i n g a t m o s p h e r i c
p o l l u t a n t s f r o m the l o w e r a t m o s p h e r e i n t o the r e l a t i v e l y c l e a n s t r a t o s p h e r e ,
a c c o r d i n g to Dr. M e l v y n Shapiro.
Sh a p iro, a s c i e n t i s t w i t h the N a t i o n a l C e n t e r for A t m o s p h e r i c R e s e a r c h
(NCAR) in Bould e r , C o l o r a d o p r e s e n t e d his f i n d i n g s at an i n t e r n a t i o n a l
s y m p o s i u m e x a m i n i n g the e x c h a n g e p r o c e s s e s b e t w e e n the t r o p o s p h e r e
of the a t m o s p h e r e c l o s e s t to the earth) and the s t r a t o s p h e r e .
(the la yer
The t r o p o s p h e r e
is w h e r e w e live and w h e r e m a n k i n d d umps p o l l u t i n g c h e m i c a l s i n t o the a i r —
c h l o r o f l u o r o m e t h a n e s , c a r b o n m o n o x i d e , and o x i d e s of n i t r o g e n , to n a m e a few.
T h e s e c h e m i c a l s , e v e n in small, t r a c e amoun t s , can h a v e a s i g n i f i c a n t i m p a c t
on the g l o b a l a t m o s p h e r e once they r e a c h the s t r a t o s p h e r e , b y r e d u c i n g our
p r o t e c t i v e o z one l a y e r and c h a n g i n g the a m o u n t of s o l a r r a d i a t i o n w h i c h r e a c h e s
the e a r t h ' s surface.
S h a p i r o s h o w e d that u n d e r c e r t a i n c o n d i t i o n s t h ese c h e m i c a l s can r e a c h the
s t r a t o s p h e r e in a m a t t e r of hours.
The t u r b u l e n t p r o c e s s e s w h i c h m i x p o l l u t e d
t r o p o s p h e r i c air w i t h the s t r a t o s p h e r e are most c o m m o n a c r o s s the m i d - l a t i t u d e s
of the g l o b e — N o r t h A m e r i c a , E u r o p e , S o v i e t U n ion, C h i n a and J a p a n — w h e r e m o s t
of the w o r l d ' s p e o p l e live and w h e r e m o s t p o l l u t i o n is r e l e a s e d into the
atmosphere.
T h e c o n d i t i o n s w h i c h b r i n g a b o u t this m i x i n g are c r e a t e d b y c l e a r air
t u r b u l e n c e n e a r the h i g h - s p e e d jet stream.
W h e n the j e t s t r e a m in the a t m o s ­
p h e r e m o v e s d o w n t o w a r d the t r o p o s p h e r e , it can c ause a f o l d i n g of the
troposphere.
The t r o p o s p h e r i c f o l d i n g i n c o r p o r a t e s p o l l u t a n t s i n t o the
-more-
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s t r a t o s p h e r e , m u c h like f o l d i n g e g g w h i t e s i n t o a souf f l e , a l b e i t on a
l a r g e r scale.
S h a p i r o and his c o l l e a g u e s m e a s u r e d the v e l o c i t y , t e m p e r a ­
t u r e and t u r b u l e n c e a s s o c i a t e d w i t h this f o l d i n g and some of its
chemical consequences using a specially instrumented N C A R Sabreliner,
g a t h e r i n g case s t u d i e s in d i f f e r e n t m i d - l a t i t u d e r e g i o n s o v e r N o r t h
America.
" M e t e o r o l o g i s t s h a v e k n o w n for some t i m e that o c c a s i o n a l s t o r m s c oul d
c a r r y a i r f r o m the t r o p o s p h e r e to the s t r a t o s p h e r e , " S h a p i r o e x p l a i n s ,
"Yet it h a s b e e n a s s u m e d that the p r i m a r y m e c h a n i s m for e x c h a n g i n g air
b e t w e e n the t r o p o s p h e r e and the s t r a t o s p h e r e w a s the g e n e r a l c i r c u l a t i o n
p a t t e r n a r o u n d the globe.
T h e s e l arge c i r c u l a t i o n p a t t e r n s take s e v e r a l
w e e k s to e x c h a n g e the air, a l l o w i n g time for r a i n f a l l to w a s h out m u c h of
the p o l l u t i o n .
W h a t our m e a s u r e m e n t s s h o w is that t h e r e is a m u c h faster,
a l t h o u g h i n t e r m i t t e n t , p r o c e s s w h i c h r e s u l t s in i n c o r p o r a t i n g m u c h m o r e
c h e m i c a l l y r e a c t i v e p o l l u t a n t s into the s t r a t o s p h e r e . "
T o e v a l u a t e w h a t e f f e c t s this m a y h a v e on the d e l i c a t e c h e m i c a l
b a l a n c e of the s t r a t o s p h e r e w i l l r e q u i r e m e a s u r e m e n t s to d e t e r m i n e m o r e
e x a c t l y the time it takes for r e a c t i v e c h e m i c a l s to m o v e f r o m g r o u n d - b a s e d
s o u r c e s like p o w e r plants, f a c t o r i e s a n d c i t i e s i n t o the s t r a t o s p h e r e .
U n d e r s t a n d i n g the c h e m i c a l and d y n a m i c p r o c e s s e s of the t r o p o s p h e r e and the
s t r a t o s p h e r e are a m o n g the long t e r m r e s e a r c h g oals of NCAR, w h i c h is
s p o n s o r e d b y the N a t i o n a l S c i e n c e Foun d a t i o n .
Yet, S h a p i r o told the group
of r e s e a r c h e r s f r o m a r o u n d the w o r l d , i n t e r n a t i o n a l c o o p e r a t i v e p r o g r a m s are
n e e d e d to d e t e r m i n e the e x t e n t to w h i c h h u m a n a c t i v i t y is a l t e r i n g our
atmospheric environment.
-EndDiane Johnson
H ead/Information Office
N a t i o n a l C e n t e r for A t m o s p h e r i c R e s e a r c h
P o s t O f f i c e B o x 3000
Boulder, Colorado
80307
(303)
4 9 4 - 5 1 5 1 , E x t e n s i o n 260