Long-Term Changes in Night Time Airglow Emission at 557.7 nm over Mid Latitude Japanese Station i.e., Kiso (35.79oN, 137.63oE)

doi:10.4236/ajcc.2012.14018

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American Journal of Climate Change, 2012, 1, 210-216

http://dx.doi.org/10.4236/ajcc.2012.14018 Published Online December 2012 (http://www.SciRP.org/journal/ajcc)

Long-Term Changes in Night Time Airglow Emission at

557.7 nm over Mid Latitude Japanese Station i.e., Kiso

(35.79˚N, 137.63˚E)

Brij Mohan Vyas1, Vimal Saraswat1,2

1Department of Physics, M. L. Sukhadia University, Udaipur, India

2Department of Basic Sciences, Pacific College of Engineering, Udaipur, India

Email: [email protected], [email protected]

Received July 21, 2012; revised August 23, 2012; accepted September 12, 2012

ABSTRACT

The present study describes the long-term changes in Pre-midnight and Midnight airglow intensities of 557.7 nm during

the period 1979-1994 over mid latitu de Japanese station i.e., Kiso, Tokyo Astronomical Observatory, University of To-

kyo (35.79˚N, 137.63˚E; 1130 m), Japan. It has observed that there is a positive increasing decadal change in Midnight

and Pre-midnight mesospheric airglow intensity of the range 25 - 88 R. This range is the order of 10% to 30% of the ob-

served MARV and average night airglow intensity of 250 R. Besides this long-term trend, inter-annual monthly varia-

tion is also seen from fluctuation of yearly variation of deviation values from MARV to particular average monthly val-

ues. The present observations about the positive decadal change in night time mesospheric airglow intensity has been

further linked to the reduction of mesospheric electron densities and temperature or shrinking and cooling of the lower

ionosphere as established from the long-term behavior of mesospheric parameters such as a negative decadal change in

thermal structure, electron density, neutral density parameters as per studies reported by other researchers.

Keywords: Airglow; Long-Term Changes; Ionosphere

1. Introduction

The ionosphere of Earth emits electromagnetic radiation

spectrum ranging from the visible to near infrared (IR)

wavelength during different hours continuously. These

radiations depend on neutral & electron density, tempe-

rature, rate of the recombination and photochemical reac-

tions between numerous chemical species occurring at

different altitudes of ionospheric layers [1,2]. It is fact

that about 40% of the light in a dark moonless night, be-

yond the city comes not from the stars or zodiacal belt or

galaxies, it scattered by atmospheric particles. The natu-

ral chemi-luminescence’s process in the presence of nu-

merous types of atmospheric atoms and molecules pre-

sent in earth’s ionosphere produce this light [3]. This weak

self-luminescence activity observed on the ground is

known as Airglow [4]. In simple way the glowing of air

is termed as airglow. The airglows are mainly of three

types like day, twilight and night airglow according to

their time of occurrences [5].

During daytime, the atmospheric atoms, molecules and

ions get excited by absorbing incidental solar energy

fluxes and subsequently they come down to the ground

state, emitting energy as light and it is termed as Day

Airglow [1,6,7]. However, in night hours, when they

come down to ground state or meta-stable lower energy

state, they emit the electromagnetic radiation light; these

transitions known as Night Airglow. In addition to this,

collision also plays a vital role for n ight airglow emission.

During twilight hours, the ions, atoms and molecules are

partly or completely getting excited not only by absorb-

ing solar energy but also by different collision pheno-

menon. The various types of airglow spectrums are such

as lines, band and continuum type of emission ranging

from ultraviolet (UV) to near IR. The primary emission

lines, accessible on the grounds are known as Oxygen

airglow (OI 557.7 nm (Green), OI 630 nm (Red)), Hy-

droxyl airglow and Sodium D-airglow lines (Na-D 589.3

nm (Yellow)) [8 ].

There are several lines of wavelengths concerned to

different ionospheric regions of night airglows. Generally

night airglow of Na-D line (589.3 nm) is found to be

linked with mesospheric-lower thermospheric (MLT)

region i.e., 90 to 100 km (peak emission altitude ~ 92km),

whereas the night airglow of deep red emission at 630

nm (peak emission altitude ~ 250 km) attributes to iono-

spheric F-region [9]. However, the nocturnal airglow in-

tensity at 557.7 nm is mainly concerned with the meso-

spheric region in different night hours [8,10,11]. Thus,

nocturnal airglow intensity of OI 557.7 nm, Na-D 589.3

B. M. VYAS, V. SARASWAT 211

nm and OI 630 nm are concerned with mesospheric, me-

sospheric-lower thermospheric and thermospheric re-

gions respectively.

In the mesosphere OI green line emission at 557.7 nm

arising from the O (1S-1D) tran sition have one of the pro -

minent night airglow features. The production of the ex-

cited oxygen ato m O (1S) of energy 4.2 eV was first pro-

posed by Chapman in terms of a three body recombina-

tion of O atoms [12]. Later, Barth [13] proposed a two-

step mechanism involving an excited state of O2, which

favored by various measurements. These atmospheric

chemical reactions with catalyst mechanism involve the

following steps:

OOMO M



  (1)



OOOS O



 

(2)

Several researchers have described the short-term va-

riations such as nocturnal hourly variation, seasonal de-

pendence of night time airglow intensities since last de-

cades [3-5] and an excellent review works was given by

Chattopadhyay and Midya [2].

In this direction, some typical investigations were re-

ported on the Thermospheric airglow studies, concerned

with the interrelation among some of ionospheric F-re-

gion parameters such as the Maximum Electron density

of F-region (NmF2), Critical Frequency (f0F2), Virtual

Height (h’F), Total Electron Content variables as well as

precursors of Spread-F with the airglows emission at 630

nm [11,14,15]. Thus, the optical emissions of the night

airglow intensity investigation p lays a vital role in under-

standing the short as well as long-term changes in neutral

and thermal properties of different ionospheric regions

through the collision, quenching and photochemical reac-

tions in the upper an d lower ionosphere. Hence, it is v ery

useful as a proxy for monitoring of long and short-term

variations in neutral density and thermal properties of the

ionosphere during different space weather phenomena

and in normal solar geophysical environment.

In these perspectives of long-term trends, Jana &

Nandi [16-19] and Jana et al. [3,20], have performed the

analysis specifically based on computed long-term night

airglow intensity at 589.3 nm at some of Indian stations

and reported the close association of long-term change in

MLT Airglow intensities with depletion of long-term

trend in ozone. Similarly Vyas & Saraswat [21] on the

basis of observed data of Na-D airglow of the present

study site i.e., Kiso (Japan) reported a declining long-

term trend in ozone value and mesospheric temperature

or ozone depletion and mesospheric cooling phenomena.

The first critical review work on the long-term in meso-

spheric temperature trend on earlier reported observa-

tions were summarized and discussed by Beig et al. [22].

They established primary fact about the evidences of

long-term mesospheric cooling, based on ground, satel-

lite and rocket based experiments of the multi decade

period atmospheric data set. Sobral et al. [15], have in-

vestigated the ionospheric plasma bubbles climatology

based on 22 years of 630 nm airglow observations over

Brazil.

Thus, studies of long-term variation on mesospheric

airglow specifically based on experimentally observed

data and its possible causes are either rare or few [23-25].

Rajesh et al. [23], have reported the ionospheric plasma

depletion phenomenon over Kavalur i.e., Indian low lati-

tude station using the nighttime airglow intensity meas-

urements at 557.7 nm. Effect of seasonal, solar cycle va-

riation and determination of different range of periodi-

cities from a few days to less than one solar cycle on

nighttime airglow intensity of 557.7 nm over Kiso, was

also described by Das et al. [24,25]. But earlier workers

have not attempted to such rare studies on long-term

trend behavior on nighttime airglow emission intensity at

557.7 nm. Realizing these facts in mind, an attempt has

been made in the present paper to study the long-term

change on the basis of experimentally measured night-

time airglow intensities 557.7 nm, which were recorded

for the period 1979-1994 over mid latitude Japanese sta-

tions Kiso, Tokyo Astronomical Observatory (TAO),

University of Tokyo (35.79˚N, 137.63˚E; 1130 m), Japan.

Such long time series data are av ailable only on the stud y

site, so this particular station has been taken for the work.

2. Data Analysis

The basis of the present analysis is regular observations

of oxygen (OI) airglows brightness at zenith (3 degrees

diameter) on moonless clear night days. The present in-

vestigation is carried out from the analysis of data set of

hourly values of night airglow intensity at 557.7 nm re-

corded over Kiso, TAO, Japan. These daily hourly time

series have downloaded from the Solar Activity World

Data Center, Japan from the web site (http://solar www.

mtk.nao.ac.jp/wdc.html) during the period 1979-1994.

Such extensive data cover almost one and half solar cy-

cle and therefore provide an opportunity to carry out

long-term trend study analysis over mid latitude airglow

emission at 557.7 nm, which primarily refers to a meso-

spheric region [2].

To ascertain the long-term trend first, it is necessary to

remove hourly, seasonal and solar cycle variation of the

airglows intensities from the available raw time series

data. In this connection, following method has adopted in

the present course of work.

3. Method of Analysis

First, average monthly airglow intensity values have

computed for three hours intervals between 20:00 to

22:00 hours as Pre-midnight period and 23:00 to 01:00

B. M. VYAS, V. SARASWAT

212

have computed and plotted as a function of years. The

average values of such deviations are also depicted as

black dotted lines to visualize the overall lon g-term trend

in Mesospheric airglow intensities or departure from the

normal level.

hours as the Midnight period from their respective daily

values of each particular month of the years (1979-1994).

The particular average monthly values of Pre-midnight

and Midnight hours have been computed to eliminate the

hourly, month-to-month as well as seasonal dependence

factors from the raw daily airglow data. Subsequently,

monthly average reference value (MARV) has also cal-

culated separately from the average monthly values of

Pre-midnight and Midnight hours for each specific month

of the entire selected study years. Such MARV value of

individual monthly value of airglow intensity is evalu-

ated to eliminate the solar cycle dependence of entire

specified period and is shown in the Table 1 and Figures

1 and 2. Therefor e, MARV ha s treat ed as refe rence v alue

for the specific month of observations of the chosen

study period.

Furthermore, such time series of deviation value of

MARV are subjected to statistical linear regression ana-

lysis to find the slope or yearly change and correlation

coefficient (R’) etc., of the linearly fitted line. The statis-

tically linearly regression fitted line as the red line is il

lustrated along with their observed trend exhibited by

dark black line in the same figures (Figures 1 and 2).

The slope, R’ and probability (P) values have also shown

in each figure, which gives the inference about the cha ng-

ing of airglow intensity per year with its statistical sig-

nificance, respectively. Figures 1 and 2 show graphical

representations of the long-term change in airglow inten-

sities 557.7 nm in each individual month of years from

The deviation of the individual average monthly val-

ues from corresponding MARV of the similar months

Figure 1. Long-term change in pre-midnight airglow intensity at 557.7 nm for different months.

B. M. VYAS, V. SARASWAT 213

Figure 2. Long-term change in midnight airglow intensity at 557.7 nm for different months.

1979-1994 for Pre-midnight and Midnight hours respec-

tively. The results obtained from the analysis have pre-

sented and discussed in the next section

4. Results

4.1. Mid Latitude Pre-Midnight Airglow

Intensities

Figure 1 represents the year to year variation in devia-

tion values from MARV to its individual particular av-

erage monthly value of Pre-midnight green airglow

emission of Oxygen on 557.7 nm. It is quite eviden t from

figures as well as calculated slope, R’ and P values that

deviation values from the MARV airglow intensity

shows the maximum positive decadal change between 32

to 80 R1 during March to June and October to December

(with a maximum value of 80 R in October) but on the

basis of the statistical significance level, the good sig-

nificance level above 95% found during April to June,

October and November month. The significance level

below 95% found in March & December and in January

& February months only ab out 75% signif icance is found

during this period 28 R per decade change occurs in de-

viation in intensity from the mean value of the airglow.

While in rest of months like July to September, there is

an insignificant statistical change (below 50%) in yearly

variation in such airglow intensity. From the close look

to the nature of red and black line in the figures and

above discussed results, it implies th at the most prob able

deviation values from the MARV to individual average

value exhibit the increasing trend and its magnitude va-

ries between 25 to 80 R per decade in most of the months

with the statistical significance level of above 90% ex-

cept in July to September. While, MARV values are

found to be chang ed between 82 to 264 R with maximu m

and minimum in October and January months, respec-

tively. Thus, the results observed in the present work

1Unit of airglow intensity, Rayleigh photons/cm2/sec.

B. M. VYAS, V. SARASWAT

214

Table 1. Monthly average reference values of the airglow

intensity of OI 577.7 nm and their standard error value in

pre-midnight and midnight hours of different months dur-

ing study period.

MARV during

Month Pre-midnight Midnight

January

February

March

April

May

June

July

August

September

October

November

December

82.41 ± 10.09

108.05 ± 11.65

136.68 ± 13.44

185.45 ± 27.14

168.51 ± 10.97

175.84 ± 9.09

133.38 ± 13.84

141.47 ± 15.28

222.57 ± 15.44

264.25 ± 18.84

150.93 ± 10.91

103.48 ± 13.34

116.67 ± 13.80

129.52 ± 12.57

151.78 ± 16.62

190.35 ± 25.91

186.43 ± 12.52

213.27 ± 10.23

156.69 ± 11.56

171.08 ± 18.04

195.01 ± 16.42

236.98 ± 19.39

168.51 ± 12.75

137.24 ± 14.95

like the variation of MARV follows the same trend as

well as comparable values to monthly airglow intensity

magnitude with the highest value of airg low intensity ob-

served in October and lowest in January retrieved from

several year observations over mid latitude sites by

Carovillano and Forbe [26]. They also reported the aver-

age value of night airglow of OI 557.7 nm of order 250 R

which are also in the same order as observed in the pre-

sent investigation of the average value of the MARV

value of all months.

With consideration of above reported average nominal

value of night time airglow intensity of 557.7 nm order

of 250 R, observed change in MARV of individ ual mon-

th and decadal fluctuation rang e of 25 to 80 R, it is impe-

rative that increasing decadal change in the Pre-midnight

airglow intensity is seen up to 30% of the average refe-

rence nominal value. Furthermore, the year to year fluc-

tuations in the deviation value of the airglow intensity is

also attributed the inter-annual month ly nature as evident

from the black dotted line.

4.2. Mid Latitude Midnight Airglow

Intensities

The Midnight yearly behavior of departure values from

the MARV to each specific monthly average value are

plotted with years in Figure 2. The positive deviation v a-

lues per decade are found to be lying in the range be-

tween 30 to 88 R (statistically significant at least 90% or

above significance level), which is in the same order as

observed for the Pre-midnight period. However, the li-

near regression trend line (shown by red colour) and av er-

age deviation line (shown by dotted black line) exhibit

enhancement trend in the highest range of 60 to 88 R per

decade during March, October and November and the

lowest range of 30 to 40 R per decade in Feb ruary, April

to July. However, in remaining months there is no sig-

nificant long-term variation in the same night airglow

intensity. The MARV of the different months are also

found to be varied from 116 to 236 R with a peak value

of 236 R in October and the least value in January as

shown in Table 1 and Figure 2. Similar monthly varia-

tion in airglow intensity is also observed in Pre-midnight

hour case in the present investigation and also reported

by several researche rs on ot her stations [3-5,10 ,11] .

On the basis of the above discussed results, it is obvi-

ous that there is a remarkable inclination of long-term

increasing trend in Pre-midnight as well as Midnight

mesospheric airglow intensity of 25 to 80 R in some of

months with good statistical significance level above

90%. This rate of increase the airglow of OI 557.7 nm

line intensity per decade is in the magnitude of 10% to

30% with the observed MARV as well as average nomi-

nal of 250 R. Furthermore, the yearly fluctuations in the

difference values of specified month are also illustrating

the nature of inter-annual monthly behavior in the air-

glow intensity.

5. Summary and Discussions

The long-term behavior of Pre-midnight and Midnight

airglow intensities concerning to mesospheric layers are

described in the present work. The present results reveal

that there is positive increasing decadal change in Mid-

night and Pre-midnight mesospheric airglow intensity of

the magnitude in the range of 25 to 88 R, which is the

order of 10% to 30% of the observed MARV and aver-

age night airglow intens ity values of OI 557.7 nm of 250

R as reported by Carovillano & Forbes [26]. It has been

well recognized and well established fact that each air-

glow emission intensity and its width primarily depends

on the large number of ionospheric parameters like elec-

tron density, temperature profile, the nature of chemical

species of the concerned height range of airglow emis-

sion lines, where it takes p lace. On the basis of the above

argument, it may be stated that consequence of the in-

creasing of mesospheric airglow intensities may be re-

sponsible to alter the mesospheric thermal structure, wh ich

further seems the cause of reduction of mesospheric

electron density. Therefore, such long-term trend in air-

glow mesosphere intensity can be further linked to the

observed reduction of electron density, shrinking of the

ionosphere or in term of negative varying nature of its

decadal change in temperature and electron density etc.,

of concerned ionospheric D-region [23-25].

B. M. VYAS, V. SARASWAT 215

6. Acknowledgements

We the authors are grateful to Dr. G. Beig, IITM, Pune,

India for scientific advice and suggesting the views for

the present carried research work. The authors are also

thankful to Head, Department of Physics, M. L. Sukhadia

University, Udaipur, India for providing necessary en-

couragements during investigation.

REFERENCES

[1] M. H. Rees, “Physics and Chemistry of the Upper Atmo-

sphere,” Cambridge University Press, Cambridge, 1989.

doi:10.1017/CBO9780511573118

[2] R. Chattopadhyay and S. K. Midya, “Airglow Emissions:

Fundamentals of Theory and Experiments,” Indian Jour-

nal of Physics, Vol. 80, No. 2, 2006, pp. 115-166.

[3] P. K. Jana, I. Saha and S. Mukhopadhyay, “Long-Term

Ozone Decline and Its Effect on Night Airglow Intensity

of Li 6708 Å at Varanasi (25˚N, 83˚E) and Halley Bay

(76S, 27W),” Journal of Earth System Science, Vol.

120, No. 2, 2011, pp. 291-300.

doi:10.1007/s12040-011-0047-8

[4] S. K. Midya and D. Midya, “The Effect of Antarctic O3

Decline on Night Airglow Inten sity of Na5893Å, O55 77Å,

OH Emission and Its Correlation with Solar Flare Num-

bers,” Earth, Moon & Planets (The Netherlands), Vol. 61,

No. 2, 1993, pp. 175-182.

doi:10.1007/BF00572412

[5] S. K. Midya and R. Chattopadhyay, “Evening Twilight-

Glow of Sodium 5893 Å Line Emission at Calcutta and

Its Typical Relation with Astronomical Parameters,” In-

dian Journal of Radio & Space Physics, Vol. 35, No. 2,

2006, pp. 77-83.

[6] J. W. Chamberlain, “Physics of the Aurora and Airglow,”

Academic Press, New York, 1961.

[7] D. M. Hunten, “Airglow Introduction and Review,” In: B.

M. McCormac, Ed., The Radiating Atmosphere, D. Reidel

Publishing Company, Dordrecht, 1970, pp. 1-16.

[8] T. N. Davis, “The Night Airglow,” 1979, Article #293.

http://www.gi.alaska.edu/ScienceForum/ASF2/293.html

[9] A. Taori, A. Jayaraman, K. Raghunath and V. Kamalakar,

“A New Method to Derive Middle Atmospheric Tempe-

rature Profiles Using a Combination of Rayleigh Lidar

and O2 Airglow Temperatures Measurements,” Annals of

Geophysics, Vol. 30, No. 1, 2012, pp. 27-32.

doi:10.5194/angeo-30-27-2012

[10] H. Gao, J.-B. Nee and J. Xu, “The Emission of Oxygen

Green Line and Density of O Atom Determined by Using

ISUAL and SABER Measurements,” Annals of Geophy-

sics, Vol. 30, No. 4, 2012, pp. 695-701.

doi:10.5194/angeo-30-695-2012

[11] T. Bangia, S. Bhattacharjee, A. Guharay, A. Taori and W.

Uddin, “Study of Upper Atmospheric Emissions Using

Mesosphere Lower Thermosphere Photometer (MLTP)

Designed at ARIES,” Indian Journal of Radio & Space

Physics, Vol. 39, No. 5, 2010, pp. 325-329.

[12] D. R. Bates, “Excitation of 557.7 nm OI Line in Night-

Glow,” Planetary and Space Science, Vol. 36, No. 9,

1988, pp. 883-889. doi:10.1016/0032-0633(88)90094-3

[13] C. A. Barth and A. F. Hildebrandt, “The 5577 Å Airglow

Emission Mechanism,” Journal of Geophysical Research,

Vol. 66, No. 3, 1961, pp. 985-986.

[14] T. Ogawa, N. Balan, Y. Otsuka, K. Shiokawa, C. Ihara, T.

Shimomai and A. Saito, “Observations and Modeling of

630 nm Airglow and Total Electron Content Associated

with Traveling Ionospheric Disturbances over Shigaraki,

Japan,” Earth, Planet Space (Japan), Vol. 54, No. 1,

2002, pp. 45-56.

[15] J. Sobral, M. Abdu, H. Takahashi, M. Taylor, E. de Paula,

C. Zamlutti, M. de Aquino and G. Borba, “Ionospheric

Plasma Bubble Climatology over Brazil Base d on 22 Year s

(1977-1998) of 630 nm Airglow Observatio ns,” Journal of

Atmospheric and Solar-Terrestrial Physics (UK), Vol. 64,

No. 1214, 2002, pp. 1517-1524.

doi:10.1016/S1364-6826(02)00089-5

[16] P. K. Jana and S. C. Nandi, “Effect of Solar Parameters

on Antarctic, Arctic and Tropical Ozone during the Last

Solar Cycle,” Indian Journal of Radio & Space Physics,

Vol. 34, No. 2, 2005, pp. 114-118.

[17] P. K. Jana and S. C. Nandi, “Depletion of Ozone and Its

Effect on Night Airglow Intensity of Na 5893 Å at New

Delhi (29˚N, 77˚E) and Halley Bay (76˚S, 27 ˚W),” Indian

Journal of Physics, Vol. 79, No. 11, 2005, pp. 1113-1317.

[18] P. K. Jana and S. C. Nandi, “Depletion of Ozone and Its

Effect on Night Airglow Intensity of Na 5893 Å at

Trivandrum (8.25˚N, 76.9˚E) and Halley Bay (76˚S,

27˚W),” Mausam, Vol. 57, No. 2, 2005, pp. 350-354.

[19] P. K. Jana and S. C. Nandi, “Ozone Decline and Its Effect

on Night Airglow Intensity of Na 5893 Å at Dumdum

(22.5˚N, 88.5˚E) and Halley Bay (76˚S, 27˚W),” Journal

of Earth System Science, Vol. 115, No. 5, 2006, pp. 607-

613. doi:10.1007/BF02702913

[20] P. K. Jana, I. Saha, P. Das, D. Sarkar and S. K. Midya,

“Long-Term Ozone Trend and Its Effect on Night Air-

glow Intensity of Li 6708 Å at Ahmedaba d (23˚N, 72.5˚E),

India and Halley Bay (76˚S, 27˚W), British Antarctic

Service Station,” Indian Journal of Physics, Vol. 84, No.

1, 2010, pp. 41-53. doi:10.1007/s12648-010-0003-5

[21] B. M. Vyas and V. Saraswat, “Long Term Trend in Noc-

turnal Airglow Emission of 589.3 nm over Mid Latitude

Japanese Station i.e., Kiso (35.79˚N, 137.63˚E),” 2012.

http://www.nipne.ro/rjp/accpaps/Saraswat_V_8FB31B.pd

f).

[22] G. Beig, P. Keckhut, R. P. Lowe, R. G. Roble, M. G.

Mlyczak, J. Scheer, V. I. Fomichev, D. Offerman, W. J. R.

French, M. G. Shepherd, A. I. Semenov, E. E. Remsberg,

C. Y. She, F. J. Lubken, J. Bremer, B. R. Clemesha, J.

Stegman, F. Sigerne s and S. Fadnavis, “Revie w of Meso-

spheric Temperature Trends,” Reviews of Geophysics,

Vol. 41, No. 4, 2003, pp. 1-41.

doi:10.1029/2002RG000121

[23] P. K. Rajesh, J. Y. Li u, H. S. S. Sinha, S. B. Banerjee , R.

N. Misra, N. Dutt and M. B. Dadhania, “Observations of

Plasma Depletions in 557.7 nm Images over Kavalur,”

Journal of Geophysical Research, Vol. 112, 2007.

doi:10.1029/2006JA012055

B. M. VYAS, V. SARASWAT

216

[24] U. Das and H. S. S. Sinha, “Long Term Variations in

Oxygen Green Line Emission over Kiso, Japan from

Ground Photometric Observations Using Continuous

Wavelet Transform,” Journal of Geophysical Research,

Vol. 113, 2008. doi:10.1029/2007JD009516

[25] U. Das, C. J. Pan and H. S. S. Sinha, “Effects of Solar

Cycle Variations on Oxygen Green Line Emission Rate

over Kiso, Japan,” Earth Planets Space, Vol. 63, No. 8,

2011, pp. 941-948.

[26] R. L. Carovillano and J. M. Forbes, “Solar Terrestrial

Physics, Principles and Theoretical Foundations,” D.

Reidel Publishing Company, Dordrecht, 1983.