PB 151399-

j^oulder laboratories

92o. 40-4

MEAN ELECTRON DENSITY VARIATIONS

OF THE QUIET IONOSPHERE

4 -JUNE 1959

BY J.W. WRIGHT, L.R. WESCOTT AND D.J. BROWN

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
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NATIONAL BUREAU OF STANDARDS

technical ^Vtote

ko-k

May 1961

MEAN ELECTRON DENSITY VARIATIONS

OF THE QUIET IONOSPHERE k - June 1959

^7

J. W. Wright, L. R. Wescott and D. J. Brovn

Central Reidlo Propagation Laboratory

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MEAN ELECTRON DENSITY VARIATIONS OF THE QUIET IONOSPHERE

k - JUNE 1959

by

J. W. Wright, L. R. Wescott and D. J. Brown

Central Radio Propagation Laboratory

ABSTRACT

The CRPL has initiated a program for large-scale

computation of electron density profiles from ionospheric vertical soundings. Scaling is performed at

field stations, permitting computation of hourly profiles at the Central Laboratory. These profiles are combined to form hourly mean quiet profiles for each

station and month. The results of this program for

the month of June are illustrated graphically. This

report is the fourth of a series i3J.ustrating the electron density variations in the mean quiet ionosphere

between latitudes 15 °N and 50°N along the 75 w meridian,

ii

TABLE OF CONTENTS

PAGE

I Introduction 1

II Description of Basic Data 3

III Description of Graphical Representation.. 6

TV Discussion and Applications of the Data.. 7

References 10

Hourly Vertical Cross sections along 75^

Geographic Meridian _. 12

Isoionlc Maps (150, 200, 250, 300,350,400 km;

Nmax, hmax, Scat, Shniax, Shinf) 3^

Electron Density vs. Time Curves (N(t)),

(Newfoundland, Ft. Monmouth, White

Sands, Grand Bahama, Puerto Rico)... ^7

MEAN ELECTRON DENSITY VARIATIONS OF THE QUIET IONOSPHERE

k - JUNE 1959

^y

J. W. Wright, L. R. Wescott and D. J. Brovn

Central Radio Propagation Laboratory

I Introduction

Part of the "basic responsibility of the Central Radio Propagation Laboratory is to gather ionospheric, solar, or other geophysical

data necessary in the pursuit of research leading to improvements in

radio communication and knowledge of the earth's upper atmosphere.

The existing network of ionospheric vertical sounding stations is an important soxxrce of such data. Typiceilly, the radio sounding data

directly provide observations of peak electron densities (corresponding to "critical" frequencies foE, foFl, foF2), data on Sporadic E,

and certain derived propagation data such as maximum usable frequencies or MUF factors (Smith, 1939).

In fact, the vertical sounding is potentially capable of providing the complete electron density profile of the underside of the

ionosphere (i.e., belov; hmaxF2), ajid of providing a basis for extrapolation to much greater altitudes. However, becaxise a lengthy axid

difficult calculation is required, little of this work heui been done

until quite recently when techniques and conqputers have becom? available and the exigencies of the IGY and satellite programs have made

it imperative

.
2

In the coiirse of Its development of facilities for electron

density profile calculations, the CRPL has succeeded in devising

means by which basic data for this purpose may be scaled by the

individual field stations, thereby decentralizing and simplifying

the most onerous part of the vork. Through its ovn station network and those of the U. S. Army Signal Radio Propagation Agency, and

throi:igh cooperation "with closely associated stations in other countries,

the GRPL has initiated an extensive systematic data reduction program,

from which hourly electron density profiles are being computed for the

following stations:

Puerto Rico (NBS, January 1959)

Grand Bahama Island (U. S. Army Signal Corps, February 1959)

Fort Moiamouth, New Jersey (U. S. Army Signal Corps, Feb. 1959)

White Sands, New Mexico (U. S. Army Signal Corps, March 1959)

St. Johns, Newfoundland (Def. Res. Tel. Establ. Canada, June 1959)

Adak, Alaska (U. S. Army Signal Corps, June 1959)

Okinawa, Ryukus (U. S. Army Signal Corps, June 1959)

Thule, Greenland (U. S. Army Signal Corps, July 1959)

Bogota, Colombia (January I96O)

Huancayo, Peru (January I960)

Talara, Peru (Janviary I960)

Baguio, Philippines (February 1960)

Affiliation and approximate date of initial participation in this

program are given in parentheses.

The hoiirly electron density profiles are extensively used in

the research programs of CRPL and are supplied directly to certain

other agencies as part of various research and practical activities.

However, in this conrparatively early stage, broad dissemination of

the computed data is a somewhat difficult problem.

In an attempt to make at least a summary of the results of

the program widely and rapidly available, the CRPL has initiated

the present series of reports. These provide graphical representations of the monthly mean quiet hourly electron densities

from certain of the statious in the preceding list, from which

a fairly clear picture of the local ionosphere morphology may be

obtained.
These reports contain N(h) data for the stations at Newfoundland, Fort Monmouth, Grand Bahama Island, White Sands, and Puerto

Rico. Pertinent facts concerning these stations are given in the

following table:

Table 1

Geomag. Coordinates Geog. Coordinates

Station fH Lat. Dip

St. Johns, Newf. 1.38Mc/s 58.5°N 72°N i^7°33'N 52°i+o'w

Ft. Monmouth, N.J. l.kG 5l.T°N 7l.5°N i4-0°15»N 74°oi'w

White Sands, N.M. 1.30 1^1. 2°N 60% 32°2U*N io6°52'w

Grand Bahama Island 1.30 37.9°N 59.5°N 26\0»N 78°22'W

Puerto Rico 1.15 30°N 5l.5°N l8°30'N 67°l2'w

II Description of Basic Data

True heights of reflection of radio waves are calculated from

the observed or "virtual" heights by the method of Budden (I'^^h) ; this method need not be described here except to point out that

full correction for geomagnetic field effects is made and that the

usual restrictions to monotonic profiles apply.

Tabulations of the mean electron density data at 10 km intervals and certain related quantities are the bases for the graphs

and charts. A sample for the Puerto Rico June data is given on

Page II. The table on the following page identifies the quantities appearing on the tabulation.
TABLE 2

Quantity Units Remarks

Average Electron

Density (n)

NMAX

COUM'

xlO « electron/cur Body of table; given at each

10 km of height from the lowest

(lO" on maps) hmin to 950 km.

xlO = electron/cm The mean value of Nmax.

(10"'^ on maps)

Count of the number of profiles

entering the mean.

HMIN Kilometers The average height of zero or very low electron density, obtained by linear extrapolation

of the electron density of the

individual profiles.

HMAK Kilometers The average height of maximum

electron density, determined by

fitting a parabola to the upper

portion of the individual profiles .

SCAT

SHMAX

SHINF

Kilometers

ao xlO = electrons/

cm column

(10 on maps)

xlO = electrons/

cm column

(lO on maps)

One half of the half-thickness

of the parabola best fitting

the upper portion of the F- region profile . Approximates the

scale height near the true HMAK.

Obtained by averaging the integration of the individual profiles between the limits HMIN

and HMAX.

The average total number of

electrons in a column to infinity obtained by extrapolation of observed profiles into

the region above HMAK. (See

text.

)
The following particular features of the tabulated data should

be noted:

A. Averaging process . Eachhour of each day is identified with

its magnetic character figure, Kp^ For each hour, those days for

which Kp is less than k+ are included in the "quiet" average. The

other days are similarly combined to form a "disturbed" average;

however, this rarely has physical significance because the number

of distrubed periods is usually small and the behavior of the ionosphere during disturbed hours is not consistent. Thus graphs for

these latter averages are not presented here^

B. Determination of hmax . The nature of the "true height"

process is such that no direct measure of hmaxF2 is obtained, the

virtual height at Nmax being immeasurable. A useful procedure is

to fit the portion near hmaxF2 with a suitable curve and to determine hmax from this curve. A parabola is quite satisfactory for

this purpose; it is fitted to two of the highest true heights and

the measured value of Nmax(foF2).

C. Extrapolation of profiles above hmax . Before averaging,

the individual profiles are extrapolated above hmax by a Chapman

distribution of 100 km scale height. This assumed model seems to

agree well with the few published measurements dealing with the

profile of the F region above hmax (Wright, 1960)- Extrapolation

is necessary in order to calculate homogeneous averages near hmax,

and the average profiles are, in fact, given to 950 km.

D. Integrated Electron Densities . The total number of electrons in a unit column of the ionosphere between the effective

bottom (hmin) and hmax is called Shmax; it is obtained by num- erical integration of the observed profiles between these

limits. An estimate of the total electron content to Infinity,

based upon the Chapman model, is called Shinf. It is obtained by

adding to Shmax the quantity N = 2.82 HNmax where H is an (assumed

constant) scale height for the region above hmax. Current evidence
(Wright, i960) indicates H = 100 km, is an acceptable choice.

Ill Description of Graphical Representation

The relative smoothness of mean quiet ionosphere data lends

itself to various kinds of graphical presentation which offer con- venient aids to the visualization of the height, geographic, and

temporal variability of the ionosphere. Three such graphical forms

are included here, prepared from the tabulations described in Section II.

A. Vertical cross sections of the ionosphere along the 73 W

meridian. Pages 12 through 35 give for each hour, a vertical cross section of the mean quiet ionosphere along a meridian section,

nominally the 75 W geographic meridian, for the month of June 1959-

Contours are parametric in "plasma" frequency (f^) related to electron density N by

12,il-00 f (Mc/s) = N(electrons/cm^)o

The height of maximum electron density is represented by a dashed

line„ Note that the vertical scale is expanded about ^.^ times.

With the exception of White Sands, each of these stations is

reasonably close to the 75 W meridian (see Table l). There is the

possibility that some of the anomolies imposed by White Sands on these contours are the result of the well-known longitudinal

asymmetry of the ionosphere.

Bo Local time vs Latitude Maps . Another form of presentation,

useful for indicating the two-dimensional geographic variations of

the ionosphere, is that illustrated by the maps of pages 36 through

45. Here, for fixed levels in the ionosphere (150,200,250,300,350,

i^-00 km), contours of electron density are drawn in the latitude

vs. local time plane. To the extent to which longitude anomalies

are negligible, these maps give also the longitude vs. latitude
7

distribution of electron densities at the indicated heights when it is noon over the 75 w meridian. Similar maps for the peak density, NmELx; its height, hmax; its characteristic thickness, Scat; the total electron content to Nmax, Shmax; and the estimated total electron content,

Shinf, are also shown.

C. Electron density vs. time curves (N(t) curves) . The meein

quiet diurnal variation of electron density between 150 and UOO km

heights above the sounding stations is illustrated by these curves. Dashed lines are used wherever the electron density at any height falls

below the peak density (i.e. when the height hinaxF2 falls below the

height for the curve in question.) Such electron densities are the re- sult of the extrapolations by the Chapman model discussed in Section

II C.

IV Discussion and Applications of the Data

Mean quiet electron density data over wide geographic areas are essential for application to numerous problems of both practical and

scientific interest. For example, the assessment of the radio refraction errors and Faraday rotation effects in satellite tracking require

a knowledge of the electron density profile in the direction of the

satellite or an estimate of the electron density at the satellite itself. Alternatively these properties of the ionosphere, or estimates

of the total electron content in a column, may be measured by observations from rockets and satellites, or from radar moon-echoes, and com- pared with ground-based observations of the kind shown here.

Frequently it will be necessary to use instantaneous density data

because of the considerable variability of the ionosphere about the

quiet itean. In such cases, the maan data are of value as a "reference

level" in the design of the experiment; for example, in the choice of

radio frequencies, satellite heights, antennas, etc.
8

Since electron density data represent virtually our only source

of continuous, widespread data on the earth's upper atmosphere, such

data also are essential to geophysical problems involving the electrical, neutral, and magnetic properties of the atmosphere.

For example, data on the vertical cross sections may be compared

with theoretical expectations for the meridional height dependence

of the quiet ionosphere. Several workers, (Hirono, 1955), ^^^ Martyn (I956), have investigated the equilibrium height (of hmax)

for an ionosphere controlled by diffusion, height-varying electron

loss rate, and uniform (or zero) vertical electron drift. The

results are qualitatively in agreement with these observations in

predicting a rise of hmax towards the equator in daytime and a reversal of this tendency at night.

The N(t) curves are perhaps the most physically significant

representation of electron density data. The strong solar control

at all levels and the important perturbations of this solar control

in the upper F region may be easily seen.
Acknovledgment s

We are Indebted to Mr. A. H. Shapley for guidance In the

initiation of this work, and to Dr. H. H. Hove for the development of the computer programs upon vhich the whole system

heavily depends. This series of reports resiilts from the com- hlned efforts of the NBS Electron Density Profile Group, including at various times L. R. Wescott, L. Hayden, D. J. Brown,

F. J. Burmont, I. Ford, N. Moore, M. Durham, G. Lira, under the

direct supervision of G. H. Stonehocker. The cooperation of the

U. S. Army Signal Radio Propagation Agency, in particular the

assistance of Mr. F. H. Dickson (Chief ), is gratefully acknowledged.
10

References

Budden, K. G. , "A method for determining the variation of Electron

Density with height (n(z) curves) from curves of

equivalent height against frequency (h'(f) curves).

Proc. Cambridge Conf. on the Physics of the Ionosphere, pp 332-339, September l^^k. Pub. by the

Physical Society (1955).

Martyn, D. F., "Processes controlling ionization distribution in the

ionosphere," Austo Jo Phys, 2> PP l6l-l65> March

19560

Hirono, M.

Smith, N.

,

Wright, Jo W.

"Effect of gravity and pressure gradient on vertical

drift in the F2 region," Rpt. on Iono„ Res. in

Japan, 2> NOo 2, p 95-10i^» (1955).

"The relation of Radio Skyvave Transmission to Ionosphere measurements," Proc, IRE, _22, No. 5, pp 332-

3hl, (1939)0

"A model of the F region above hmaxF2," Journal of

Geophysical Research, 6^ I85-I9I, January I960.
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25* 20« I5«
800

13 JUNE 1959

0100 75" W TIME

1

TOO

600

CO

tc

»-

l»J _ 2 500

o

400

X

(9

UJX

300

200

100

CONTOURS OF fN

h -MAXIMUM

NEWFOUNDLAND FORT MONMOUTH

\ I \ 50* 46' 40*

VERTICAL SCALE 5 5 X HORIZONTAL SCALE

WHITE SANDS GRAND BAHAMA PUERTO RICO

J \ I \ I L_J

35' 30* 25" L-TiTUOZ IN DECREES N

20* •6«
Ik

JUNE 1959

0200 75** W TIME

800

700

600

CO

o:

bJH

UJz

o

-J

500

400

X

X

300

200

100 CONTOURS OF fN

h-MAXIMUM

50"

VERTICAL SCALE 5.5 X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH WHITE SANDS GRAND BAHAMA PUERTO RICO

X -J I I I . L_J

45* 40" 35" 30"

LATITUDE IN DEGREES N

25* 20«
800

15 JUNE 1959

0300 75° W TIME

r

TOO

600

«>K

lit UJ2 500 O

X

o

uJX

400

300

200

100

CON'TOURS OF fN

h-f.;AXIMUM VERTICAL SCALE 5 5 X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH WHITE SANOS GRAND BAHAMA

I I I

I

I i

PUERTO RICO

50* 45* 40* 35« 30»

L'.TITUCE IN DEGREES N

25' 20« I5*
16

JUNE 1959

0400 75^ W TIME

800

700

600

CO

q:UJ

iUJs

o

_l

z

X

o

lUX

500

400

300

200

100

CONTOURS OF fN

h-MAXIMUM

NEWFOUNDLAND FORT MONMOUTH

VERTICAL SCALE 5.5 X HORIZONTAL SCALE

WHITE SANDS GRAND BAHAMA PUERTO RICO

J L__J I L_J

50" 45' 40" 15" 30*

lat;tude in degrees n

25' 20«
800

17 JUNE 1959

0^00 75" W TIME

TT"

\

700

600

v>

cc

UJ

»-UJ9 500

I 400

o

UJI

300

200 —

100

CC.'VOUaS CF fN

h-;.'.AXi.v,u.v; VCnriCAL SCALE 5.5X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH

[ \ I

WHITE SANOS GRAND BAHAMA

L_ I I I

PUERTO RICO

50* 45' 40« 35* 30°

LAV;TUOE IN DEGREES N

25' 20' 15'
18

JUNE 1959

0600 75* W TIME

800 T

700

600

a:

UJ

UJ2 500

O

t-X

«>UJI

400

300

200

100 CONTOURS OF fN

h -MAXIMUM

NEWFOUNDLAND FORT MONMOUTH WHITE SANDS GRAND BAHAMA

i ^ I I I.I.

VERTICAL SCALE 5.5 X HORIZONTAL SCALE

PUERTO RICO

50" 45* 40" 35» 30«

LAViTUDZ IN DEGREES N

25' 20«
1' JUNE 1959

0700 75" W TIME

800

TOO

600

COK

bJH

UJO 500

X

o

lUX

400

300

200

100 —2-

CC flTGi.J'^S OF fN

n-.V.AXuV.CM VERTICAL SCALE 5 5X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH WHiTE SANOS GRAND BAHAMA

\ I 1 J 1 .. ^ I ^

PUERTO RICO

50" 45' 3«' 30* 25' 20* 15' L-.V.VJDE li\D£3SZcS N
800

20

JUNE 1959

0800 75" W TIME

,

CONTOURS OF fN

h-MAXIWUM

NEWFOUNDLAND FORT MONMOUTH WHITE SANDS GRAND BAHAMA

\ 1 I I

1 ,

VERTICAL SCALE 5.5 X HORIZONTAL SCALE

PUERTO RICO

50* 45* 40" 35 ^ 30"

L^T'TUDZ IN DEGREES N

ZS* 20" I5«
JUNE 19 59

0900 75" W TIME

800

700

600

ac

ui2 500

o

l_ 400 —

X

o

UI

iOO

200

100

CCi.' iOLi.\3 Or iii

h-.'.'Ai'!..'.L..'.i VIRTICAL SCALE 55 X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUThi vVHiTE SANOS GRAi\C aAHAMft

I I I I I I I .

PUERTO RiCO

J_J

50' 45' 40» ^5* rO'

^^iTjzz i\ ::j:g.rees n

25' 20' 15*
JUNE 19 59

1000 75* W TIME

800

700

600

m

K

111 I-bJo

H

X

UlX

500 -

400

300

200

100

CONTOURS OF fN

h-MAXIMUM

NEWFOUNDLAND FORT MONMOUTH

\ I I

VERTICAL SCALE 5.5 X HORIZONTAL SCALE

WHITE SANDS GRAND BAHAMA PUERTO RICO

J. 50' 45" 40" 35" 30«

LATITUDE IN DEGREES N

ZS" 20* 15'
23 JUNE 1959

100 75° W TIME

800

TOO

600

CO

q:

iLl o 500 —

•- 400 —

X

o

HiX

300

200

100

-iNi CONTOURS OF fN

h-MAXI.ViUM

3 :

VERTICAL SCALE 5.5 X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH WHITE SANDS GRAND BAHAMA

_L _L I PUERTO RICO

_L_J

50* 45' 40* 35"=" 30'

LATITUDE irj DEGREES N

25' 20' 15*
2k

JUNE 1959

1200 75* W TIME

800

3 —

700

600

m

u>

IUJz

o

500

1-400 —

X

o

LJX

300

200

100 3-

CONTOURS OF fN

h-MAXIMUM

NEWFOUNDLAND FORT MONMOUTH

\ ^ \ 50«

VERTICAL SCALE 5.5 X HORIZONTAL SCALE

WHITE SANDS GRAND BAHAMA PUERTO RICO

J 1 I

i ' L_J

45* 40» 35 « 30°

LATITUDE IN DEGREES N

25 » 20* i5"
800

25

JUNE 1959

1300 75" W TIME

1

TOO

600

UJ

iii O 500

I 400

o

UJX

300

200 —

100

L

CONTOURS OF TN h-MAXIMUM

NEWFOUNDLAND FORT MONMOUTH

\ I I

VERTICAL SCALE 55 X HORIZONTAL SCALE

WHITE SANDS GRAND BAHAMA

\ ^ \ .

PUERTO RICO

_l_J

50' 45' 40* 35* 30*

LATITUDE IN DEGREES N

25' 20* 15*
26

JUNE 1959

1400 75" W TIME

800

700

600

llJ I-UJo

_J 500

X

o

X

400 —

300

200

100 CONTOURS OF fN

h-MAXlMUM VERTICAL SCALE 5.5 X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH

1 i I WHITE SANDS GRAND BAHAMA

J I I

1 . 50*

PUERTO RICO

» i 45« 40» 35" 30"

LATITUDE IN DEGREES N

25« 20« i5«
800

JUNE 1959

1500 75° W TIME —I

700 — 4

600

in

tr. Ui

\-UJz

o

iC

X

o

liJ X

500 —

400

300

200

—3 too

L

CONTOURS OF fN

h-i.^AXi:.'.UM VERTICAL SCALE 5 5 X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH

I I I WHITE SANDS GRAND BAHAMA

A \ ^ I ^

PUERTO RICO

50* 45' 40» 35' 30«

LATITUOE l.-<! DEGREES N

25' 20* 15'
28

JUNE 1959

1600 75** W TIME

800

700

600

m

a:UJ

UJO 500

z

X 400

111

300

200

3 —

100

L

CONTOURS OF fN

h-MAXIMUM

NEWFOUNDLAND FORT MONMOUTH

I I

I

VERTICAL SCALE 5.5 X HORIZONTAL SCALE

WHITE SANDS GRAND BAHAMA PUERTO RICO

I I \ i L_l

50« 45* 40" 25" 30*

LATITUDE IN DEGREES N

25«' 20« 15'
800

JUNE 1959

1700 75° W TIME

1

TOO

600

m

K

Ul

h-UJ2

o 500

^ 400

UJX

300

200

100

CONTOURS OF fN

h -MAX I MUM VERTICAL SCALE 5 5 X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH

I i \

WHITE SANDS GRAND BAHAMA

J L___^ \ ^

PUERTO RICO

_L_J

50* -45« 40* 35* 30*

LATITUDE IN DEGREES N

25* 20*
r

800

30

JUNE 1959

1800 75* W TIME

1 ?—

TOO

600

o>

Q!UJ

»-

tiJ 3 500

I 400

UJX

300

200

100 CONTOURS OF fN

h -MA XI,MUM

NEWFOUNDLAND FORT MONMOUTH

I I I 50*

VERTICAL SCALE 5.5X HORIZONTAL SCALE

WHITE SANDS GRAND BAHAMA PUERTO RICO

J 1 1 1 I L__i

45* 40« 55" 30"

LATITUDZ IN DEGREES N

25' 20« I5«
31

1900

JUNE 1959

75* W TIME

800

700

600

(A

UJ

»-Ul

500

I 400

o

UJX

300

200

100

—•4 .

— 5.

CONTOURS OF fN

h-r.Axir/.uM VERTICAL SCALE 5 5X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH WHITE SANDS GRAND BAHAMA

I I I I \ I \ .

PUERTO RICO

_L_J

50" 45' 40* 35* 30*

LATITUDE IN DEGREES N

25* 20* 15*
800

32

JUNE 1959

2000 75* W TIME

1 T — 4.

"4 —

700

600

V)K

bJUJs

O 500

o

UJ

3:

400

300 _

200

100

N CONTOURS OF fN

h-MAXIMUM VERTICAL SCALE 5.5 X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH

\ I \

WHITEI.I. SANDS GRAND BAHAMA PUERTO RICO

J_J

50* 45« 40« 35» 30"

LATITUDE IN DEGREES N

25* 20« I5«
33

JUNE 1959

2100 75" W TIME

800

—4

700

600

CO

a:U)

h-UJO 500

X

(DUJI

400

300

200

100 CONTOURS OF fN

h -MAX I MUM

VERTICAL SCALE 5 5 X HORIZONTAL SCALE

NEWFOUNDLAND FORT MONMOUTH WHITE SANDS GRAND BAHAMA PUERTO RICO

\ i I I L__J \ . L_J

50* 45* 40* 35 • 30*

LATITUDE IN DEGREES N

25' 20*
3^

800

JUNE 1959

2200 75* W TIME

1 1 T~\

-4

700

600

500

CO

o:

lij IUJo

-J

z

•- 400 —

X

CJ) UJX

300

200

100

CONTOURS OF fN

h-MAXIMUM

NEWFOUNDLAND FORT MONMOUTH WHITE SANDS GRAND BAHAMA

1 ^ I I I.I.

VERTICAL SCALE 5.5X HORIZONTAL SCALE

PUERTO RICO

50« 45* 40» 35» 30"

LATITUDE IN DEGREES N

25 < 20« 15'
35

JUNE 1959

2300 75° W TIME

800

TOO

600

a:u

»-UJ 500

^ 400

o

UJI

300 _

200 —

100

N CONTOURS OF fN

h -MAXIMUM

NEWFOUNDLAND FORT MONMOUTH

I I \

VERTICAL SCALE 55 X HORIZONTAL SCALE

WHITE SANDS GRAND BAHAMA

_L _L _L

PUERTO RICO

_L_J

50* 45* 40* 35* 30*

LATiTUDZ IN DEGREES N

25« 20* 15*
36

ELECTRON DENSITY AT 150 KIUOMETERS

JUNE 1959

GBI

75'* W TIME

CONTOURS 'T*|i X

10"'
37

N*50

NF45-

f^f^-T^-

35

ITS30

GBh

25

20

PR1500

ELECTRON DENSITY AT 200 KIUDMETERS

JUNE 1959

J L 1 I L. 75' W TIME

18 00

CONTOURS' ^ X 10"*
38

ELECTRON DENSITY AT 250 KIUOMETERS

JUNE 1959

GBI

75** W TIME

CONTOURS*;:^ X

10"'
39

N*50r

NF45-

^A'-TO35

WS30

ELECTRON DENSITY AT 300 KIUOMETERS

JUNE 1959

GBI25

20

PR 1

1500

L_Li—I—Jb^ i. L^ 1 ii 1 1 1 I L

TS*' W TIME

18 00

CONTOURS' j*^ X 10"*
ko

N 50

^^-KUELECTRON DENSITY AT 350 KILOMETERS

JUNE 1959

75* W TIME L » .«-9 CONTOURS'^ X 10
hi

ELECTRON DENSITY AT 400 KILOMETERS

JUNE 1959

00

CONTOURS'^ X

10"'
k2

MAXIMUM ELECTRON DENSITY

NMAX

JUNE 1959

N" 50

6B/

PR

75** W TIME

CONTOURS = -^x 10
^3

HEIGHT OF MAXIMUM ELECTRON DENSITY

HMAX

JUNE 1959

FM

**'5-

60/-

75" W TIME

CONTOURS =Km
kh

QUARTER THICKNESS OF F -REGION PEAK

SCAT

JUNE 1959

75° W TIME

CONTOURS=Km
^5

N" 50

NFELECTRON DENSITY INTEGRATED TO HEIGHT OF MAXIMUM

ELECTRON DENSITY

SHMAX

JUNE 1959

45

^^^m

35-

WSI

I

I \

i \ 5

\

30-

CB/-

\

20

\

PR \ ^\

\

15 J il I \1 L

21 19 \ \ 'ill i__Li II lLL

00 06 12 IB 75* W TIME

el CONTOURS--^ col KlO

cm'

00

-12
46

ELECTRON DENSITY INTEGRATED TO INFINITY

SHINF

JUNE 1959

GBI

75° W TIME

CONTOURS = -^ col. xlO-'3
hi

25

N(t) NEWFOUNDLAND JUNE 1959

FIXED HEIGHTS IN Km

20

E

•5^ 15 O

to

UJo

o

a:& 10

UJ

_jUJ 400
r

25

20

E

S^ 15

II mO

UJo

o

t 10

Ul

-IUJ

N(t)

k&

FT. MONMOUTH JUNE 1959

FIXED HEIGHTS IN Km
25

20

ITE

UJo

h9

N(t) WHITE SANDS JUNE 1959

FIXED HEIGHTS IN Km

o

B 10 "a

UJ
50

25

N(t) GRAND BAHAMAS JUNE 1959

FIXED HEIGHTS IN Km

20
51

25

N(t) PUERTO RICO JUNE 1959

FIXED HEIGHTS IN Km

20

u s^ 15 O

z

UJQ

Z

o

cr»-o

UJ

_lUJ

10

400

00 06 12 LMT16 00

USCOMM - NBS • BL

U. S. DEPARTMENT OF COMMERCE

Luther H. Hodges, Secretary

NATIONAL BURI;AU OF STANDARDS

A. V. Attin, Dirtclor THE NATIONAL BUREAU OF STANDARDS

The Bcopp of aclivilios of ilir National niironii of Slan<Jards al its major lalioraloriryi in VCiwIiington, D.(;.. and lt<iiililrr Colorado, is sngfr*"''*''' '" 'f"" rf>IIo%\ins! lislinc of llif <livisions and scclion* on<ja2f>d in ,lr>rliniral work, (n "rncral

parli srrtion parries onf spcrializcd rcscareli. develof>nienl. and encini-erinfj in llie fu-Ul indiraled l»v ilx lillr. A lirief depcriplion of the artivilies, and of llic resullanl pnblicutions, apftears on llie inside of llie front rover. WASHINGTON, D.C.

Elpolririly. Resistance and Reactance. Electrochemistry. Electrical Tnstrnmcnts. Magnetic NfruKnremrnis.

nicjeclrics.

Melrology. Photometry and Colorimetry. Refiactometry. Photografjhic Rescarcli. I^ength. Engineering

Mctiolopy. Mass and Scale. Vohunelry and Densimetry.

Ilent. Temperatnre Physics. Heat Measurements. Cryogenic Physics. Equation of Slate. Statistical Phvoict. Radiation Pliysics. X-ray. Radioactivity. Radiation Theory. High Energy Radiation. Radiological Equipment.

Nucleonic rnstrumentation. Nenlron Physics.

Analylirnl an<l Inorgnnic Chemistry. Pure Substances. Spectrochemistry. Solution Chemistry. Analytical

Chemistry. Fnorganic Chemistry.

IMechnnicR. Sound. Pressure and Vacuum. Fluid Mechanics. EnKincorinE ATechanics. Rlicolorrv. C<iiiiliii>iiiiin Controls. OrRnnic and Fibrous Mntorinls. Rubber. Textiles. Paper. Lcaiiicr. Icsiing and .^i><-iili<;iit">im. i'lilvnirr Structure. Plastics. Dental Research. iMelalhirpy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion. Metal Phytics"

Mineral Products. Engineering Ceramics. Class. Refractories. Enameled Metuls. Crystal (rroidli. Pbyeicai Properties. Constitution and Microstructure.

Riiildinfi Research. Structural Engineering. Fire Researcli. Vfechanical Systems. Organic Ruilding Materials,

Codes an«l Safety Stan«lards. Heat Tran.*fer. Inorganic Huililing Materials. Applied Malhomalics. Numerical Analysis. Computation. Statistical Engineering. Mathematical PhyHicA.

Data Processinp Systems. Comi>onents and Techni<iucs. Digital Circuitry. Digital Systems, .\ualog Syttenis.

.Applications Engineering.

.\tomic Physics. Spectroscopy. Radiomelry. Solid Slate Physics. Electron Physics. .Vtomic Ph).-*!! Inslriimentalion. Engineering Electroni<-s. Klcj-iron l)e\ici->:. l-'lectrunic Instriinicntntion. MccliiiKu i. in-numenls. Rasic Instrumentation.

Pliyaioal Chemistry. Thermochemistry. -Surface f!lieuiislry. Organic ("licniislry. iNfolecular S|»ectro«c«ipy. Moleculiir Kim-lics. Ma.ss Sjiectrometry. Molecular Structure and Radiation (Jicmistry.

• < KFice of Weights and Measures. BOULDER, COLO.

t ry<t((cniv Kngincvriiip. Cryogenic Equifuncnt. ("ryogeni*- IVtK-esses. Properties of MatrriuU. (.ax Liquefaction.

Ionos|>hcre Research and PmpuKMtii>n. l,o\v Frequency and \ cry l-o*v I'Vcqiicucy Hi-»cdrcli. loiiiMpherr Research. Prediction Services. Siui-Karth Relationships. Field Engineering. Radio \K arnmg Scrv ice*. Ruilio Propagation En^jineerinft. Data Reduction Inslrumeniation. Radio Nuioe. Tlo|Miftplicric Menaurrnienl*.

Tro(M)spheric Analysis. Propagation -Terrain E(Tc<-tH. Radio-Meteorology. Ixjwer AtmosiiliPle Physic*. Ruflio Standards. High l''rc(picncy Iillcclrical .Standards. Radio liroadcahl .Sit\ icr. Ruilio and Mict' Materials. Atomic l-'requi-ncy and Time Interval .Standards. Electronic Culibrution (!i-iiler. Millnnplrr-W an

Research. Miciowave Circuit Standards. Radio .Systems. High Frequency and Very High Frequency RcHearcli. MiMlulation Resraicli. .Anirnn* Rwearrli. Navigation Systems. Space Telecommunications.

I pp«'r Atmitsphere and -Space PhysirH. I pper Atmosplieie and Plasma i'li>Nic». loiioKplirn- itinl KMwphrre

flatter. Airglow and Aurora. Ionospheric Radio Astronomy.