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QUASI-BIENNIAL VARIATIONS OF COSMIC-RAY INTENSITIES
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https://ntrs.nasa.gov/search.jsp?R=19660021061 2020-06-17T01:45:24+00:00Z
QUASI-BIENNIAL VARIATIONS OF COSMIC-RAY INTENSITIES"
Kaichi Maeda Gcddard Space F l ight Center
Greenbelt, Maryland
and
T. Suda Mete or ological Re search I n s t i t u t e
Tokyo, Japan
* To be submitted t o the Journal of Geophysical Research.
Quasi-Biennial Variations of Cosmic-Ray Intensities
Abstract
Owing to the atmospheric temperature effect on cosmic-rays, the
so-called quasi-biennial ( or 26-month) oscillation in the stratosphere
should be apparent in the hard component of cosmic-ray data at the
ground. As it is estimated theoretically, the cosmic-ray muon data
near the equator (Lae, 6'44 S) shows a significant biennial
variation, the period of which seems longer than 26 months, but
shorter than 30 months for 1954-1964.
analysis of Huancayo (12' S ) ion-chamber data (Maeda and Suda) is
a l s o elaborated by choosing the five highest counting days in eacn
The previous power spectrum
montn, indicating a significant peak at the period of 24 months.
similar analysis made for the ion-chamber data from Gcdhavn (69'5 N)
A
shows a very weak peak at 24 months for 1947-1959. It is concluded
from present analyses tnat biennial variations in cosmic-ray intensity
are predominantly of terrestrial origin, i.e., if the days of large
extraterrestrial modulation ( such as geomagnetic disturbed days) are
chosen no significant 26-month variation appears in cosmic-ray data.
- 2 -
Introduction
Since its discovery in the tropical stratospheric wind system
(Reed, 1960; Veryard and Ebdon, 1961), features of the biennial
variation, or the so-called 26-month oscillation in the earth's
atmosphere have been revealed t0.a great extent in the past few
years, except the theories to explain its origin and mechanisms
(Reed, 1962, 1963, 1964 and 1963; Reed and Rogers, 1962, Staley,
1963; Belmont and Dartt, 1964; Dartt and Belmont, 1964; Newell, 1964;
Kriester, 1964; Sparrow and Unthank, 1964; Wescott, 1964, etc.).
On the other hand, cosmic-ray intensities observed at the
earth' s surface are continuously modulated not only by the astro-
physical variations in outer space (particularly the magnetic field)
but also by the atmospheric variations.
of unstable components such as pions and muons, produced by incoming
primary cosmic-ray particles in the upper atmosphere, intensities
of cosmic-radiation at the ground change with variatlons of barometric
pressure and of the atmospheric temperatures (Jgnnosy, 1950;
Dauvillier, 1954; Heisenberg, 1963; Dorman, 1937). Therefore, the
cosmic-ray muon data, which are more commonly called cosmic-ray
meson data, or the hard component intensities measured at the ground
Due to the decay processes
c
- 3 -
.
and corrected fo r barametric effect , are very good indicators of
continuous atmospheric temperature var ia t ions, provided that information
about geomagnetic var ia t ions i s available.
can expect t he 26-month variations occurring i n the upper atmosphere
should be Tound a l s o i n the pressure-corrected cosmic-ray muon data.
This is already shown by means of power spectrum analysis of ion-
chamber data from Huancayo (geographic l a t . 12' s ) . s t a t ion i s not c lose enough t o the equator, t he result i s hardly
s igni f icant (as s h m i n Fig. 4 , Maeda and Suda, 1965). The purpose
of t he present paper is t o report another more s igni f icant detection
of quasi-biennial var ia t ions i n cosmic-ray data from t h e near-
equator s t a t i o n (Lae, 6'44' s) which w a s suggested i n the previous
paper, but not available a t t h a t t i m e .
For t h i s reason, we
Since t h i s
Meteorological Ef fec ts on Cosmic -Ray Intens it ies
The var ia t ion of cosmic-ray in t ens i ty a t t he ground due t o the
atmospneric temperature var ia t ion is an accumulated e f f e c t of the
d i f f e r e n t i a l contribution from each layer i n the atmosphere, which
i s not only a f'unction of the alt i tude of each layer i n the
atmosphere, but a l s o a function of t he cut-off energy of observed
- 4 -
cosmic rays. The l a t t e r depends on the geomagnetic and geographic
locat ion of the observing s t a t ion and on the geometric condition of
the measuring instrument, such as the thickness of shield and the
type of cosmic-ray detector . These re la t ions are well-known both
experimentally and theore t ica l ly , and can be expressed by a simple
formula :
- - 'I - J ~ ( E 0 , x ) 6T (x ) dx I O 0
where IO, 6 1 are the mean and the deviat ion of cosmic-ray in t ens i ty
a t the atmospheric depth xo due t o the temperature var ia t ion 6T a t
the depth x, respectively.
Y(Eo,x) i s cal led t h e p a r t i a l temperature coeff ic ient , which
indicates the r e l a t ive var ia t ion of cosmic-ray muon in t ens i ty with
cut-off energy Eo a t the depth xo, due t o 1' C increase i n the
- 5 -
l ayer 6x a t x. The de ta i l s of these coeff ic ients as the function
of Eo and x, as well as comparisons with the experimental data
have been discussed by many workers (Maeda and Wada, 1954; Trefall,
1955; Wada and Kudo, 1956; Dorman, 1957; French and Chasson, 1 9 6 ;
Matthews, 1959; Wada, 1961; Carmichael e t a l . , 1963 ; e tc . ) . It
should be noted t h a t the atmospheric temperature e f f ec t on the
cosmic-ray in tens i ty consists essent ia l ly of two par ts ; one i s
posi t ive and due t o the change i n production r a t e of cosmic-ray
muons with temperature var ia t ions i n the upper atmosphere, cu(Eo,x) , and the other i s negative, corresponding t o the change of decay-rate
of muons i n the atmosphere, B(Eo,x).
where cu(Eo,x) and -B(Eo,x) are plotted against x, f o r Eo = 0.3, 10
and 40 GeV.
x. A s can be seen from these figures, the temperature coeff ic ient
i s mostly negative fo r usual cosmic-ray data, the cut-off energies
of which a re l e s s than the order of 0.5 Gev. On the other hand,
the posi t ive effect dominates a t high energies (par t icu lar ly above
the ground production l e v e l of cosmic-ray mesons, i .e. , above 200 mb
l e v e l ) , because decay-rates of muons produced with energies higher
than several Gev i n the atmosphere a r e prac t ica l ly negligible.
These a re shown i n Fig. 1,
Corresponding y(Eo,x) 's a re a l so shown i n Fig. 2 against
It i s known t h a t the phase of 26-month osc i l la t ion i n the upper
atmosphere d i f f e r s with height, sh i f t ing from higher a l t i t u d e down-
wards with a r a t e roughly of the order of 1 km/month. This is shown
- 6 -
i n the upper curves i n Figure 3 , i n which var ia t ions of the s t r a t o -
spheric temperature differences between 3' S and 28' N a r e plot ted
from data obtained during the period from 1931 t o 1961 a t four
d i f fe ren t l e v e l s above 100 mb (full l i n e s ) , and zonal winds a t
Balboa, Panama (8' N ) a r e a l s o shown by a dashed l i ne , whose scale
i s indicated on the r i g h t side with u n i t s m/sec (Reed, 1965).
Since the phase of 26-month o s c i l l a t i o n and the e f f e c t of
temperature var ia t ion of cosmic-ray in tens i ty a r e d i f fe ren t with
height, t h i s kind of information i s most sui table t o see the
corresponding var ia t ions i n cosmic-ray i n t e n s i t i e s a t t he ground.
By using the above-mentioned formula, we can see the amplitude
and phase of 26-month cosmic-ray var ia t ion f o r the corresponding
periods of years. The calculations a r e nade f o r three d i f fe ren t
cut-off energies, Eo = 0.3, 10 and 40 Gev, using y ( E o , x ) ' s , as shown
i n Fig. 3 (Maeda and Suda, 1965).
It i s found from previous calzidations t h a t the phase r e l a t i o n
between 26-month osc i l la t ion i n the upper atmospheric temperature
and t h a t of cosmic-ray in tens i ty a t the ground i s not simple, but
ra ther reversed a t low energies (Eo < 3.5 Gev) and a t high energies
(Eo >> 1 Gev). This r e s u l t s from the d i f fe ren t temperature e f f ec t s
a t low energies (negative) and a t high energies ( p o s i t i v e ) . The
former corresponds t o the usual hard component data such as those
observed by a n ion-chamber or by the so-called cubical meson telescope,
- 7 -
while the l a t t e r corresponds t o the underground cosmic-ray in t ens i t i e s .
These are shown by two dash-dot l ines i n the bottom of Fig. 3 f o r
Eo = 0.3 Gev (heavy l i n e ) and 10 Gev ( t h i n l i n e ) , respectively. It
should be noted t h a t although the posi t ive temperature e f f ec t
increases with increasing cut-off energy, there i s an upper l i m i t
(Maeda, 1960) and tha t because of i t s energy spectrum, cosmic-ray
in t ens i ty decreases rapidly with increasing cut-off energy, i . e . ,
with depth underground.*
A t any ra te , it is concluded t h a t i f continuous measurements
of cosmic-ray in tens i ty had been made a t the geographic equator f o r
more than one decade, the 26-month var ia t ion with amplitude of the
order of 0.0% or the maximum deviation of the order of 0.1% can
be detected even by ion-chamber data. I f the underground cosmic-
ray measurements had been made continuously fo r more than several
years near the geographic equator, the 26-month var ia t ion with
amplitude of more than 0.2% (which i s the order of magnitude observed
i n the diurnal var ia t ions of cosmic-ray in tens i ty) can a l so be found
i n these data with an anti-phase t o those of low energies (Maeda
and Sub , 1965).
* For example, r e l a t ive in tens i t ies with cut-off energies Eo = 0.3, 10 and 40 Gev are roughly 1 : 0.l : 0..005, respectively.
- 8 -
Quasi-Biennial Variations of Cosmic-Ray Intensities
By means of the power spectrum analysis applied for the ion-
chamber data from Huancayo, Peru (12' s, geographic) and from Cheltenham, Maryland (39' N, geographic) for the period of more than
20 years since 1937, the 26-month variations of cosmic-ray intensities
have been hardly shown, if only geomagnetically quiet days (5-Q
days in each month) are used (Maeda and Suda, 1965).
is somewhat elaborated by choosing 5-H days in each month as
shown in Fig. 4, where 5-H days means the five highest cosmic-ray
intensity (counting) days in each month.
rays are modulated by the change in solar emissions, their intensities
in general decrease. In other words, the highest counting days
correspond to the period when the effects of solar disturbances,
such as the Forbush effect, are eliminated, or at least minimum.
A similar analysis is also applied for the identical ion-chamber data
from Godhavn, Greenland (69'23' N geographic) for the period
extending from January 1947 to July 1959.
Fig. 5, where the scale of the ordinate is taken arbitrarily, but
is identical for all three curves. 5-Q and 5-H mean five quiet days
and five highest counting days in each month, respectively. Comparing
Figs. 4 and 3 , one can see that the biennial variation of cosmic-ray
intensity at high latitude is very small as compared with those
near the equator.
This result
When the galactic cosmic
The results are shown in
- 10 -
and zonal wind analysis (shown in the upper portion of Fig. 3) , are
shown by a full line in the bottom of Fig. 3, where a heavy dashed
line and dots represent the first and the second harmonics of this
curve.
Discussion
The results shown in the previars section, particularly those
shown in Figures 3, 4, 5 and 6, indicate consistently that the
26-month variations in cosmic ray intensities are predominantly
of atmospheric origin. In other words, 26-month periodicity is
clearer in the geomagnetically quiet period than in geomagnetically
disturbed days.
the amplitude of the 26-month variation in the stratospheric
temperature field is largest at the geographic equator above the
100 mb level, which is of the order of 2' Cy and decreases with
latitude, but increases again slightly beyond 20 degrees of latitude,
indicating a minimum around 17 degrees in each hemisphere. It is
also indicated that the phase of 26-month oscillation is reversed
between these two regions, i.e., tropics and subtropics.
According to the latest investigation (Reed, 1963),
From the viewpoint of this present status of 26-month oscillations,
the location of Huancayo is rather close to the region of minimum
- 9 -
A s it w a s suggested i n the previous paper (Maeda and Suda, 19651,
t h e cosmic-ray data from Lae, New Guinea (6'44' S ) i s most promising
t o see the 26-month var ia t ion, because t h i s i s the data from the
s t a t i o n s c losest t o t h e geographic equator, where the var ia t ion i s
known t o be maximum.
The analysis is made as fo l lows: (i) a l l avai lable data, being
corrected by a coef f ic ien t -0.14%/mb obtained by the standard
s t a t i s t i c a l method, a r e folded by d i f f e ren t lengths of month
extending from 20 t o 30 months.
then divided by the number of folding, where the t o t a l avai lable
data consist of two periods, one from Ju ly 1957 t o October 1960,
and the other from September 1962 t o December 1964.
shown in Fig. 6, where 5-Q and 3 - H correspond t o t he data chosen
from f ive quiet (geomagnetically) days and f i v e high counting days
i n each month, respect ively. The bottom l i n e s stand fo r normalization
i n t o the same scale, taking the average value as 10%.
curves, one can see t h a t the period of b iennia l var ia t ion appearing
i n the cosmic-ray data from Lae i s somewhat longer than 26 months,
but l e s s than 30 months, f o r 1960-1964.
standard deviations (dispersions of each point i n v e r t i c a l s ca l e )
a re of the order of 0.1%.
(ii) The folded sum of the data i s
The result i s
From these
It should be noted t h a t t he
Finally, the r e s u l t s of 26-month folding of the 5 - H cosmic-ray
data from Huancayo, corresponding t o Reed' s s t ra tospher ic temperature
- 11 -
temperature var ia t ion, bu t within the region of t rop ic osc i l l a t ion
(not i n the subtropic) . I n t h i s respect, cosmic-ray data from
Makerere i n Kampala, E a s t Africa (0.33' N geographic, near sea l e v e l )
are more useful f o r the present analysis, though the da ta from Lae
have shown already a s igni f icant quasi-biennial var ia t ion as shown
i n Fig. 6. The difference between the theo re t i ca l ly estimated
cosmic-ray in t ens i ty var ia t ion and those obtained from data, as
shown a t the bottom of Fig. 3 , i s possibly due t o t h e following two
reasons:
Reed's and t h e present analysis, cosmic ray data a r e taken far from
Reed's w y s i s . (ii) Huancayo i s rather close t o the subtropic
boundary, while t heo re t i ca l estimations a re made f o r near-equator.
I n t h i s respect, fur ther analysis o f cosmic-ray data near t he equator
i s desirable .
(i) Though t he period of analysis i s the same f o r both
A s indicated by recent aerological observations, the quasi-
b i enn ia l var ia t ions a re pers i s ten t even i n the high la t i tudes ,
espec ia l ly i n the southern hemisphere, including the Antarctic (Funk
and Garnham, 1962; Angell and Korshover, 1964; Sparrow and Unthank,
1964 ; Reed, 1963). Since high energy cosmic-ray data, pa r t i cu la r ly
those measured underground, should be avai lable a t several places
i n t h e world, quasi-biennial var ia t ions i n cosmic-ray phenomena
s t i l l seem worthy of investigation.
- 12 -
Finally, it s h m l d be e~~phaoizzd. that si:izz the G S G ~ C ~ G ~f
cosmic-ray variations are terrestrial as well as extraterrestrial,
they are separable, as shown in Figures 5 and 6.
the present analysis show, however, the quasi-biennial variations
in cosmic-ray data are predominantly of terrestrial origin. This
conclusion seems to be consistent with the results of spectrum
analysis of the quiet day geomagnetic variations at Huancayo (12' S
geographic), Alibag (19' N geographic) and Apia (14' S geographic)
given by Stacey and Wescott (1962).
however, to check the consistency with other phenomena which have
been discussed recently by many authors (Shapiro and Ward, 1962;
Hope, 1963; Wescott, 1964; Newell, 1964 a.b; Linden, 1964; Reed,
1965, etc.).
Investigations of
Further analysis seems necessary,
._
- 13 -
Acknowledgement
The cosmic-ray data used in the present analysis are obtained
through the courtesy of Dr. S. E. Forbush at the Carnegie
Institution of Washington, D. C., to whom we are very gratefUl. We
wish also to express our appreciation to Prof. R. T. Reed at the
University of Washington, who has kindly advised us to use a part
of his latest results as well as his early findings.
- 14 -
Figure Captions
Figure 1
Figure 2
Figure 3
Coefficients of the partial temperature e f f e c t
( i n Lg/g cm-' O C ) for cosmic-ray in t ens i ty a t sea
l e v e l with cut-off energies, Eo = 0.3, 10 and 40
Gev, p lo t ted against atmospheric depth x ( i n
g an-*).
pos i t ive (production) e f f ec t , cr(E0,x) and negative
(decay) effect , -fl(Eo,x), respect ively.
Nl l ines and dashed l i n e s stand f o r
Composite coeff ic ient of t he partial temperature
e f fec ts i n l i n e a r scale, y(E0,x) i n '%/g 'C,
derived from Fig. 1.
The 26-month var ia t ions of t rop ica l s t ra tospher ic
temperatures (AT)* a t Canton Island (3' S) and
zonal wind at Balboa (8' N) given by Reed (1965)
fo r the period from 191 t o 1961. The full l i n e
~~ ~~
* The temperature difference between Canton Island and f i v e subtropical Since the var ia t ion a t the la t te r s t a t i o n s (average l a t i t u d e 27' N ) .
i s very small as compared t o the one at the equator, AT can be regarded as the va r i a t ion a t Canton Island.
- 13 -
Figure 4
Figure 5
in the lower portion is a similar expression of
the ion-chamber data from Huancayo (12' S) based
on 5-Q days in each month. Dashed line and dots
are the first and the second harmonics of the
full-line.
Dashed lines are theoretical estimations correspond-
ing to AT-curves in the upper portion of the
figure computed by coefficients Shawn in Fig. 2,
where heavy dash-dot and thin dash-dot lines
correspond to the cut-off energies, Eo = 0.3 Gev
and 10 Gev, respectively.
Power spectrum (Periodogram) of Huancayo (12' S )
ion-chamber data based on 5-H days in each month
for the period from 1937 to 1961.
scale is arbitrary and T in the horizontal scale
is in months.
The vertical
Power spectrum of Godhavn (69O23' N) ion-chamber
data for the period from 1947 to 1939.
3-H stand for the data of five quiet days and
five high counting days in each month.
5-Q and
Figure 6
- 16 -
The folded-average curves of cosmic-ray muon data
from Lae (6'44' S), where horizontal scale
indicates the length of folding and v e r t i c a l scale
is r e l a t ive cosmic-ray in t ens i ty corrected fo r
barametric e f fec t . The meaning of 5-Q and 5-H
m e the same as Fig. 5 . The bottom curves
correspond t o the r e l a t ive var ia t ion with a mean
value normalized t o lo@.
\
1. Vergard, R.G., and R. A. Ebdon, Fluctuations i n t rop ica l Stratospheric winds, Meteorol. Mag., 90, 125 - 143, 1961.
2. Reed, R.J., Some features of the annual temperature regime i n the t rop ica l stratosphere, Monthly Weather Rev., 90, 211 - 215, 1962.
3. Reed, R.J., and D. G. Rogers, The circulation of the t rop ica l stratosphere in the years, 1954 - 1960, J. Atmospheric Sci., & 127 135, 1962.
4. Dartt, D. B. and A. D. Belmont, Periodic features of the 50- milliband zonal winds i n the tropics, J. Geophys. Res., 2887 - 2893, 1964.
5 . Belmont, A.D., and D. G. Dartt, Double quasi-biennial cycles i n observed winds i n the t ropical stratosphere, J. Atmospheric Sci., 21, 354 - 360, 1964.
6. Vergard, R.G., and R. A. Ebdon, The 26-month t ropica l stratospheric wind osc i l la t ion and possible causes, Proceedings of International Symposium on Strato-Mesospheric Circulation, Aug., 1962. ,Berlin, Meteorol. Abhand., 36, 225 - 244, 1963.
7. Reed, R.J., On the cause of the 26-months periodicity in the Equatorial atratospheric winds, Meteorol. Abhand., Berlin, 36, 245 - 257, 1963-
Kriester, Barbara, Die ann'&ernd zwei j ' h i g e schwingung des zonalen windes i n der tropischers stratosphzre, Meteorol. Abhand., (Berlin), 3 1 - 38, 1964.
Sparrow, J.G. , and E. L. Unthank, Bienial stratospheric osci l la- t ions i n the Southern Hemisphere, J. Atmospheric Sci., 21, 292 -
8.
9.
596,1964. 10. Reed, R.J., A tentat ive model of the 26-month osci l la t ion i n t rop ica l
la t i tudes, @ut. J. Roy. Bkt. SOC., 90, 4-41 - 466, 1964.
11. Heisenberg, W., Kosmische strahlung, Springer-Verlag, Berlin, 1953.
12. Jbossy, L., Cosmic rays, Oxford-Clarendon Press, 1950.
13. Dorman, L.I., Cosmic ray vuia t ions , State Publishing House, Moscow, 197, (Englihs translation, Air Force Office of Scient i f ic n- ----.-I.. 1 newccw LU).
14.
15.
16.
17-
18.
19
20.
21.
22.
23
24
25
Maeda, K., and M. Wada, Atmospheric temperature e f fec t upon the Cosmic-ray intensi ty a t sea level., J. Sic., Res. Ins t . (Tokyo), 48, 71 - 79, 1954. Wada, M., Atmopsheric e f fec ts on the intensi ty of Cosmic-ray mesons, (111, the temperature effect . , Sci. Paper, Ins t . Phys. Chem. Res., (Tekyo) z, 7 - 23, 1961. Maeda, K., Directional dependence of atmospheric temperature effects on Cosmic-ray muons a t sea-level, J. Atmos. Terr. Phys., 245, 1960.
184 -
French, W.R., and R. L. Chasson, Atmospheric e f fec ts on the hard component of cosmic radiation near sea level, J. Atmos. Terr. Phys. I& 1 - 18, 1959. Carmichael, H., M. Bersovitch and J. F. S te l jes , A comparison of several methods of correcting cosmic-ray muon in tens i ty f o r at- mospheric temperature variations, Proceedings of International Conference on Cosmic Rays, Dec. 2 - 14, 1963, Jaipur, India.
Beardsley, N.F., Correlation between Cosmic-ray intensi ty and upper air pressures and temperatures, Phys. Rev. 1940 ( l e t t e r )
336 - 337,
Rossi, Bruno, High energy par t ic les , Prentice-Hall, Inc., N.Y., 1952, P* 95.
Maeda, K., and T. Suda, The annual and diurnal variations of Cosmic-ray intensi ty and temperature effect , J. Geomag. Geoelect. 1, 18 - 21, 1950. Maeda, K., Remarks on annual and dimma1 variat ion of Cosmic-ray intensi ty ( l e t t e r ) , J. Geomag. Geoelect., z( lo5 - 108, 1953. Mathew, P.M., Atmospheric e f fec ts on Cosmic-ray in tens i ty at sea- level, Can. J. Phys. = 85 - 101, 1959. Dorman, L.I. , 0 temperaturnom effeckte zdstkoi komponenty kosmicheskich luchei, Dok., Akad., Nauk, SSSR, a 49 - 52, 1954.
Dorman, L.I . , Kteorii meteoroloricheskih effecktov kosmicheskich luckei, Dok. Adak., Nauk., SSSR, 94, 433 - 436, 1954 Forbush, S.E . , Cosmic-ray in tens i ty var ia t ions during two so lar cyclee, J. Geophys. Res., 6-3, 651 - 669, 1958.
26.
27
28.
29.
30.
31
32
33
34
35
36.
37.
38.
39 9
Reed, R.J., The present s ta tus of the 26-month osci l la t ion, Paper delivered at 45th annual meting of the Am. Met. SOC., New York, Januar~, 1965.
Staley, D.O., A pa r t i a l theory of the 26-month osci l la t ion of
P . t . L ; m J g r ~ . T. k +I;&J ;fr& of kA*.)G)..&e.
the zonal wind i n the equatorial stratosphere, J. Atmos. Sic., 20, 506 - 515, 1963.
Hewell, R.E., A note on the 26-month oscil lation, J. Atms. Sic., 21, 320 - 321, 1964.
Westcott, P., The 25 - 26 month periodic tendency i n sunspots, J. Atms. Sic., 21, 572 - 573, 1964.
Black=, R.B. and J . W . Tukey, !!%e Measurement of power spectra, Dore publications, Inc., N.Y., 136.
Ne*, N.F., J . C . Harrison and L. B. Slichter, Observation of f ree osci l la t ions of the Earth, J. Geophys. Res., 66, 621 - 629, 1961.
Stern, D., The low-frequency power spectrum of Cosmic-ray variations during IGY, J. Geophys. Res. a 2133 - 2144, 1962.
Maeda, K., and J. M. Young, Propagation of pressure harcs pro- duced by auroras, Proceedings for the Second Benedum Earth Symposium, Pittsburgh, Novernber, 1964. ( i n press)
Pierson, W . J . and W. Marks, The power spectrum analysis of ocean harc records, T m s . Amer. Geophys. Union, a 834 - 844, 1952.
Funk, J.F., a n d J . L. -ham, Australia 's ozone observations and a suggested 24-month cycle, Tellus, 14, 378 - 382, 1962.
Angell, J.K., and J. KorshoYet Quasi-biennial variations i n tem- perature, t o t a l ozone, and tropopanse height, J. Atmos. Sci., 479 - 4 2 , 1964. Shapiro, R., and F. Ward, A neglected cycle i n sunspot nuuibers, J. Atms. Sci.,
Stacey, F.D., and P. Westcott, Possibi l i ty of a 26 o r 27 month periodicity i n the equatorial geomagnetic f i e l d and i ts correla- t i on with stratospheric winds, Nature, 196, 730 - 732, 1962.
Hope, E.R., Geomdgnetic analog of 26 month meteorological sunspot cycle, J. Atmos. Sci., 20, 342, 343, 1963.
506 - 508, 1962.
40. Linqen, R.S., Radiative and photochemical processes in strato- and mesopheric dynamics, Ph.D., Thesis, Harvard University.
41; Wada, M.> a.nd s. Kum, 4. statistical i2vestigatior- f o r the atmospheric temperature effect on Cosmic-ray intensity, J. Sci. Res. Inst., (Tokyo), 50, 1 - 9, 1956.
42. Trefall, H., On the positive temperature effect in the Cosmic radiation and the Mu - e decay, Proc. Phys. SOC. 68A, 893 - 904, 1955 '
43. Danvillier, A * , Les Rayons Cosmignes, Dunod, Paris, 1954.
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