THE S O L A R F L A R E EFFECT A T A L I B A G ON JUNE 13th. 1 9 5 1 S . L . M A L U R K A R T h e m a g n e t i c O b s e r v a t o r y a t A l i b a g ( 1 8 " 3 8 ' / V , 72" 5 2 ' E , 1 8 m i l e SS E of C o l a b a , B o m b a y I is s i t u a t e t i a t a l o w m a g n e t i c l a t i t u d e ( 9'-.5 N). T h e v a r i o m e t e r s a r e u s u a l l y r u n o n a t i m e s c a l e of 1 5 m i n , h r . T h o u g h t h e b r o a d f e a t u r e s of a m a g n e t i c p h e n o m e n o n a r e r e c o r d e d , i h e d e t a i l e d p r o f i l e d u r i n g s u c h p e r i o d s c a n o n l y h e o b t a i n e d w h e n a n o p e n t i m e s c a l e is u s e d . F o r t h e l a s t f e w y e a r s , 011 s p e c i a l o c c a - sions, t h e i n s t r u m e n t s b a v e b e e n r u n a t 1 8 0 m m / h r . It i n a y j u s t h e p o s s i b l e t o a n t i c i p a t e a n d p u t t h e q u i c k - r u n i n a c t i o n f o r m a g n e t i c s t o r m s a n d h e f o r t u n a t e i n o b t a i n i n g d e t a i l e d r e c o r d s of t h e s a n i e . A m o n g t h e f e w p h e n o m e n a t l i a t c a n h a r d l y h e a n t i c i p a t e t i a t p r e s e n t is t h e s o l a r I l a r e e f f e c t o r t h e ' C r o c h e t s ' . A n y s u d i r e c o r d i n g of t h e s o l a r I l a r e w o u l d h e a c c i d e n t a l . W h i l e t h e m a - g n e t i c r e c o r d e r s h a d b e e n o n q u i c k - r u n , o n J u n e 1 3 t h . 1 9 5 1 , a r e m a r - k a b l e r e c o r d w a s o b t a i n e d . T h e s o l a r flare e f f e c t c o m m e n c e d o n t h e r e c o r d a t A l i b a g a t 0 5 4 6 G M T a n d t h e e f f e c t w a s o v e r a f t e r a b o u t 1 4 0 m i n u t e s . S o l a r flares w e r e v i s u a l l y r e c o r d e d a t K a n z e l h o h e , M e u - d o n , Z i i r i c h , S a l t s j o b a d e n a n d H e r s t n i o n c e u x a b o u t t h a t t i m e of t h e d a y . T h e p a r t i c u l a r o b s e r v a t i o n s c o r r e s p o n d i n g t o t h e c r o c h e t a r e : TABLE S t a t i o n T i m e G M T I m p o r t a n c e N u m b e r o f A c t i v e R e g i o n of Q u a r t e r S a l t s j o b a d e n 0 6 1 2 3 2 6 K a n z e l h o h e 0 6 4 1 - 0 9 0 5 3 2 6 0 6 4 1 - 0 7 0 0 1 — 2 4 M e u d o n 0 7 1 0 - 0 7 2 5 2 2 6 Z i i r i c h 0 7 1 3 - 1 0 0 0 2 2 6 O n d r e j o v 0 7 5 6 - 0 8 0 1 ? 2 6 0 7 5 9 - 0 9 4 8 ? 2 3 0 9 0 0 - 0 9 0 6 1 2 4 H e r s t m o n c e u x 0 9 1 0 - 0 9 2 5 1 2 6 2 1 6 S . L . M A L U R K A I t C a n b e r r a r e p o r t e d flare, r a d i o f a d e - o u t a n d i o n o s p h e r i c d i s t u r - b a n c e f r o m 0 5 5 0 G M T f o r 3 1 m i n u t e s o n a l a r g e n m n b e r of b a n d s ( 6 0 , 6 2 , 7 3 , 1 0 0 , 1 2 0 0 a n d 3 7 5 0 Mc/s). T o k y o h a d i o n o s p l i e r i c d i s t u r - b a n c e f r o m 0 6 3 5 G M T f o r 1 0 0 m i n u t e s . ( A l i t h e d a t a a b o v e a r e f r o m O u a r t . B u l l . S o l a r A c t i v i t y . N. 9 4 . 1 9 5 1 . Z u r i c h ) . I n a l e t t e r , t h e A l i I n d i a R a d i o h a s s a i d t b a t a s o b s e r v e d al T o - d a p u r ( D e l h i I , t h e r e w a s c o m p l e t e r a d i o f a d e o u t of s h o r t a n d m e d i u m w a v e b a n d s b e t w e e n 0 5 5 0 a n d 0 7 3 0 G M T a n d t b a t c o n d i t i o n s s t a r t e d i m p r o v i n g a t 0 8 4 0 G M T a n d b e c a m e n o r m a l at 0 8 5 0 G M T . F r o m d a t a of C R P L b u l l e t i n s of t h e N a t i o n a l B u r e a u of S t a n - d a r d s , W a s h i n g t o n ( U . S . A . ) t h e f o l l o w i n g t a b l e h a s b e e n e o n s t r u c t e d . TABLE R e c e i v i n g S t a t i o n T i m e G M T L o c a t i o n of T r a n s m i t t e r s H o n g k o n g ( C h i n a ) 0 5 5 5 - 0 7 2 5 C h i n a , E n g l a n d , F o r m o s a , F r e m ii I n d o - C h i - na, J a p a n , M a l a y S t a t e s , P h i l i p p i n e Ids., T h a i l a n d . C o l o m b o ( C e v l o n ) 0 5 5 5 - 0 8 0 0 C h i n a , E n g l a n d , I n d i a , J a p a n . L i n d a u ( H a r z - G e r m a n y ) 0 5 5 0 - 1 1 0 0 M u n i r l i , L i n d a u I p u l s e t r a e m i t t e r a n d re- c e i v e r ) , W i e s b a d e n . B r e n t w o o d ( E n g l a n d ) 0 6 0 0 - 0 8 0 5 A l g h a n i s t a n , A u s t r i a , B a h r e i n I d s . B e l g i a n C o n g o , B u l g a r i a , E r i t r e a , G r e e c e , I n d i a , I r a n , K e n y a , M a l t a , P a l e s t i n e , P o r t u g a l , S. R h o d e s i a , S p a i n , S w i t z e r l a n d , S y r i a , T h a i l a n d , T r a n s - J o r d a n , l i . S . R . , Y u g o s l a - S o m e r l o n ( E n g l a n d ) 0 6 0 0 - 0 8 0 0 A d e n , A u s t r a l i a , C e y l o n , C h i n a , C y p r u s , F o r m o s a , I n d i a , U n i o n of S. A f r i c a . T h e s u b - s o l a r p o i n t m o v e d j u s t s o u t b of t h e T r o p i e of C a n c e r f r o m t h e l n d o - B u r m a b o r d e r t o O m a n . A l i b a g o b s e r v a t o r v w a s f a - v o u r a b l y s i t u a t e d f o r r e c o r d i n g t h e c r o c h e t . T h e l o c a l i t i e s of t h e r a - d i o f a d e - o u t s e e m t o fit a t e x t h o o k e x a m p l e of t h e a r e a t b a t s h o u l d b e a f f e c t e d . On J u n e . 1 4 t h at 1 7 5 0 G M T a m o d e r a t e m a g n e t i e s t o r n i s t a r t e d a t A l i b a d w i t h a s. c. of 2 5 r in H a n d t h e s t o r i l i l a s t e d a b o u t 5 2 h o u r s . T H E S O L A R l-I.ARE E F F E C T A T A L I B A G ON J U N K 1 3 t l l . 1 9 5 1 2 1 7 T l i e p r o f i l e of t h e flare f o r t h e h o r i z o n t a l a n d v e r t i c a l m a g n e t i c c o m p o n e n t s a n d d e c l i n a t i o n is g i v e n a f t e r t a k i n g o u t t h e e f f e c t of d i u r n a l v a r i a t i o n ( T a h l e a n d D i a g r a m ) . TABLE T i m e R e l a t i v e d i s p l a c e m e n t f r o m v a l u e s ( c o r r e c t e d f o r d i u r n a l v a r i at 0 5 4 6 G M T a t i o n ) T i m e H i r ) v ( r ) D ( m i n u t e s l o w a r d s E a s t ) 0 5 4 6 0.0 0.0 0.0 0 5 5 1 4.75 0.0 0 5 5 6 10.55 — 2 . 2 8 — 0 . 3 0 6 0 1 1 8 . 1 0 — 2 . 9 5 0 6 0 6 3 0 . 9 0 — 6 . 4 3 — 0 . 9 0 6 1 1 4 7 . 6 5 — 8 . 9 3 0 6 1 6 5 8 . 4 0 — 1 0 . 5 3 — 1 . 1 0 6 2 1 6 3 . 2 0 — 1 1 . 9 0 0 6 2 6 6 6 . 4 0 — 1 1 . 7 5 — 1 . 6 0 6 3 1 7 1 . 6 0 — 1 3 . 5 5 0 6 3 6 6 9 . 5 5 — 1 2 . 0 5 — 2 . 0 0 6 4 1 6 3 . 2 — 9 . 3 0 0 6 4 6 5 2 . 1 5 — 3 . 6 5 — 1 . 7 0 6 5 1 4 3 . 6 5 1 . 0 7 0 6 5 6 3 6 . 4 0 3 . 4 7 — 1 . 0 0 7 0 1 3 0 . 5 0 7 . 0 1 0 7 0 6 2 6 . 6 0 8 . 1 5 — 0 . 6 0 7 1 1 2 4 . 8 0 8 . 8 5 0 7 1 6 2 2 . 4 0 11.71) — 0 . 3 0 7 2 1 1 9 . 7 5 UiO 0 7 2 6 1 6 . 1 0 1 1 . 5 5 0.0 0 7 3 1 1 0 . 9 0 1 2 . 2 5 0 7 3 6 8 . 6 0 1 2 . 3 0 0 . 4 0 7 4 1 4 . 8 0 1 3 . 4 5 0 7 1 6 — 1 4 . 9 5 0 . 7 0 8 0 6 0.00 T h e v a r i a t i o n i n D is v c r v s n i a l l 011 m o s t o c c a s i o n s , at A l i b a g . T h e d e c i m a i p o i n t fignres a r e g i v e n t o h e l p t o d r a w t h e r e s u l t a n t c u r v e . T h e i n a i l i f e a t u r e t o n o t i c e is t h e f a c t t l i a t t h e r i s e t o t h e m a x i - m u m h a s b e e n i n t w o s t a g e s , w i t l i a n i n f l e c t i o n b e t w e e n 0 6 2 1 a n d 0 6 2 6 G M T . T h e m a x i m u m w a s a t t a i n e d a t 0 6 3 2 G M T . T h e a c t i v e r e - g i o n s of flares t l i a t w e r e o b s e r v e d 1 n o s . 2 3 , 2 4 a n d 2 6 of t h e q u a r t e r ) c r o s s e d t h e c e n t r a i m e r i d i a n of t h e s u n 011 J u n e . 7 . 9 , 1 1 . 8 a n d 1 8 . 3 . A s t h e flare c o r r e s p o n d i n g t o a c t i v e r e g i o n n. 2 3 w a s o b s e r v e d a t O n - d r e j o v b e t w e e n 0 7 5 9 a n d 0 9 4 8 G M T , t h e c r o c h e t r e c o r d e d a t A l i b a g is d u e t o flares of t h e a c t i v e r e g i o n s n. 2 4 a n d n. 2 6 a n d t h e t w o s t a g e s 2 1 8 S . L . M A L l ' R K A R 0 6 1 1 0 6 3 6 0 7 0 1 0 7 2 6 0 7 5 1 T I M E IN C . M . T . F i g . 1 steji to t h e m a x i m u m , w h i c h is e q u i v a l e n t t o t w o s u p e r p o s e d m a x i m a , is d u e t o t w o d i s t i n c t flares. M o s t of t h e r a d i o f a d e - o u t s h a v e b e e n r e p o r t e d 4 m i n u t e s a f t e r t h e c r o c h e t a t A l i b a g c o m m e n c e d . T h e i o n o s p h e r i c d i s t u r b a n c e a t T o k y o h a s b e e n r e p o r t e d a b o u t t h r e e t o f o u r m i n u t e s a f t e r t h e abso- l u t e m a x i m u m of t h e c r o c h e t w a s r e a c h e d a t A l i b a g . T l i o u g h o n e s h o u l d b e r e l u c t a n t t o u s e t h e V r e c o r d s i n t l i e s e l a t i t u d e s , i t m a y b e p o i n t e d o u t t b a t f r o m 0 5 4 6 t o 0 5 5 1 G M T t h e r e h a s b e e n l i t t l e c h a n g e a n d t l i a t f r o m 0 7 2 0 t o 0 7 3 0 G M T t h e r e h a s b e e n a flattenins I | S O L A R F L A R E . 1 3 " J U N E 1 9 5 1 . ( C 0 R R E C T E D F O R D I U R N A L V A T U A T 1 0 N ) Y • ^ 6 0 < 2 0 in t h e s m o o t h e d V c u r v e s . W h e t l i e r t l i i s h a s a n y t h i n g to d o w i t h t h e p e r i o d of c o m p l e t e f a d e - o u t of s t a t i o n s as r e c e i v e t l a t D e l h i ( 0 5 5 0 t o 0 7 3 0 G M T ) c a n n o t b e d e f i n i t e l y s a i d . T h e d e t a i l e d c o r r e l a t i o n of t h e p r o f ì l e c a n o n l y b e d o n e if a n y o t h e r i n s t i t u t i o n h a s c o l l e c t e d c o g n a t e d a t a o n a c o m p a r a b l e t i m e s c a l e . F r o m t h e p u b l i c a t i o n s of t h e N o r s k e I n s t i t u t t f o r K o s m i s k F y s i k ( N r . 3 4 . o b s e r v a t i o n s of 1 9 5 1 ) , i t is n o t i c e d t l i a t t h e d a i l y r a n g e of T H F . S O L A R F L A R E E F F E C T AT A L I B A G ON J U N E 1 3 l l l . 1 9 5 1 2 1 9 O z o n e a t T r o n i s p w e r e m u d i l a r g e r o n t h e 1 3 t h a n d ] 4 t h J u n e . 1 9 5 1 (1.19 i n n i a n d 0 . 3 6 n i n i r e s p e c t i v e l y w h i l e t h e a v e r a g e d i u r n a ] r a n g e f o r l h e i n o n t h w a s o n l v 0 . 0 8 i n n i . T l i e r e c o r d i n g w a s d o n e b y M r . A . S . C h a u b a l a n d M r . D . K . D e s h m u k h a n d h e l p w a s r e n d e r e d i n c a l c u l a t i o n s b y ÌVIr. M . P a n d u - r a n g a R a o a n d M r . K . S . R a j a R a o . Colobii Observatory. — Bombay. 5. Jan. 21st. 1953. SUMMARY A detailed study oj the quick-run magnetograms oj tlie Solar Flare oj Jane 13, l'J51. Alibag tv as favourably situated. Corresponding to different flares on tliat day the profili' oj tlie solar flare effect has a tteo-stagi' maximum. The time oj the onset oj the radio fade-out in relation to the fiori• has been pointed out. In the vertical force, effect corresponding to the onset and end of radio fade-out tliere has been a temporary no-variation-ivith-time stage or a sort oj inflexion. The diurnal rang oj ozone at Ironisti also ivus abnormally large ivithin the next 24 hours.