MAGNETIC STORM (16-18 DEC 1971)

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400

of
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MAGNETIC STORM (16-18 DEC 1971)

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MAGNETIC STORM (16-18 DEC 1971) MAGNETIC STORM (16-18 DEC 1971)

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37



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MAGNETIC STORM (16-18 DEC 1971)

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33



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é 2 é ry ny a

20



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ISO-INTENSITY CONTOURS OF GROUND MAGNETIC H PERTURBATIONS
FOR THE DECEMBER 16 - 18, 1971 GEOMAGNETIC STORM

by

Y. Kamide*
Cooperative Institute for Research in Environmental Sciences
University of Colorado, Boulder, Colorado 80302

and

Geophysical Institute
University of Alaska
Fairbanks, Alaska 99701

PART I
1. Introduction

The geomagnetic storm is one of the dramatic signatures of the solar-terrestrial phenomena which
are observable on and near the earth. Many storms seem to follow by a day or so the large solar
flares or other flurries of solar activity. Among the various kinds of space and ground manifesta-
tions of the storm, the storm's growth and decay can be most typically recognized in the H-component
magnetic depression at middle and low latitudes which is attributable to the ring current in the mag-
netosphere. For this reason the initial, main and recovery phases of the magnetic storm have conven-
tionally been identified from the mid-latitude magnetic records.

A dramatic magnetic storm which began at 1904 UT on December 16, 1971 has been very interesting
to study in detail because of the large amount of ground-based and satellite data available. The
particular sequence of processes characterizing this storm is commonly observed in many other large
storms. Some works on the interpretation of specific storm features and their physical processes have
already been published for this storm, and other studies are still being made.

To examine the progressive change of the storm in terms of ground magnetic signatures, we prepared
consecutive iso-intensity contours of the H-component ground magnetic perturbations at middle and low
latitudes. From these we estimated the intensity and the location of the symmetric and asymmetric
storm-time ring current. A total of 720 contour maps, one every 5 minutes, was produced using 52
northern hemisphere magnetic observatories for the 2 day or 60-hour interval 1200 UT December 16 to
2400 UT December 18, 1971. Then, an interpolation technique was used to obtain 30 second contours
from which a movie film was produced. This report provides exerpts from the movie film, giving the
maps and the corresponding geomagnetic activity indices for every 10 minutes.

The author provides these data as a tool for use with satellite observations to improve the
understanding of solar-terrestrial processes.

2. The December 16 - 18, 1971 Storm

Solar activity, solar radiation, ionospheric disturbances, cosmic rays, and geomagnetic and
radio propagation indices during the December 16 - 18, 1971, storm are given in SGD, Number 330,
Part I [1972].

Figure 1 shows some of the conventional representations of the time-varying characteristics of
the storm. From top to bottom it gives the auroral electrojet indices AU and AL [Allen e¢ al. 1975],
the superposed H-component records from ten mid-latitude observatories, and the Dst index for the
interval from 1200 UT December 16 to 2400 UT December 18, 1971. Two kinds of the equatorial Dst
indices are plotted: a 5-min Dst calculated from the ten observatories! data (for the method of the
calculation see the next section), and an hourly Dst [Sugiura and Poros, 1972] which was calculated
by using data from four observatories (Hermanus, Kakioka, Honolulu, and San Juan). There is a general
agreement between these two curves, except during the main phase of the storm (1700 - 2200 UT, Decem-
ber 17, 1971); the maximum depression in the 5-min Dst was -202y, but only -157y in the hourly Dst.

During the interval, there occurred two major storm sudden commencements (ssc) at 1904 UT Decem-
ber 16 and at 1418 UT December 17, which are identified by dashed lines in Figure 1. This we con-

veniently call a double magnetic storm (Cahill, 1973]. The two periods of world magnetic disturbance
following these two sudden commencements are quite different in appearance. Following the first

* Guestworker at Data Studies Division, NOAA/EDS/NGSDC, Boulder, Colorado 80302.

1



AE INDEX(7)

ee

MAGNETIC STORM (16-18 DEC 1971) MAGNETIC STORM (16-18 DEC 1971)

a
go
a
8 as
© 000}
* 1600} °
aval \ tee
8
Fo a err re 00
ia’ eb 6 8 ete eae
UT 10 0.0 18 DEC 1971 UT 11 0.0 18 DEC 1971

: | / * we J vw “* / a SI AJ \Y
Viel SL i pf (~ |

UT 10 10.0 UT 11 10.0

co) LACS

8 ia tet Eo é é ie te

ur 10400 vr i490
wo.
oo) 40-| Le
” 2.
ie et das
vo n
rr a a Boe a a
UT 10 50.0 UT 11 50.0
oo,
ane 0}
; “0 > oy \S
. yo) If
. ‘ fy ‘ ' am! c ‘ te "ea % . ‘ 6 ' ‘ wm! ‘ te 24

31



MAGNETIC STORM (16-18 DEC 1971) MAGNETIC STORM (16-18 DEC 1971)
00 00
Boo ed
Ff i - g
Eel 2
1000
a ; a
-avo0l \ oo] Det(y)
~100
a oe ‘ia a
UT 6 00 17 DEC t971 ut 7 0.0 17 DEC te71
60- 60-
al | S| re > [W)
B30 Bao, é
| %, ;
Ee. j pa * aa
10 104
é ie ie 24 é ry 1
GEOMAGNETIC LOCAL TIME GEOMAGNETIC LocAL TIME
UT 6 10.0 UT 7 10.0
50+ 60"
40, he tis o yi, ale aba
30°] ¢ 30-)*” ws
20- RA ¢ 20-]
cA cra ells
6 é te te ea o 6 12 te a
UT 6 200 ur 7200
60- \ ]
5 J} Te Th
pos 4 20- 43.5
LX \ :
o é ie te & Cc é a ie a

+—_ |

UT 6 30.0 UT 7 30.0

s0- s0-

40" 9° 40 an ahs

0. 90,

. “e,

20- AL 80

" ia ) om 7 [

ry g i a 3 ie Te a

UT 6 40.0 UT 7 40.0

60. 60,

+__|
-
a
88
a0,
|

‘ ° pe fy i : | ae ‘ a aaa w a a
TL ey
» fw i ra : 4
+ re i ‘ be o rr Z a a

7



MAGNETIC STORM (16-18 DEC 1971)
00

Boe

3 -s00]

wg ~ 009
1600

- °
-2000! ooo] Dat(r)
bie eae Oe te ag * gl t00
ow 6 6

100
fa’ te’ 6 ae
ur ie 00 17 pec 1971
om NT
5" . SA : =
ic al ole aw 4) 8 Boop ! \
Eo \ CS | “\ | J a
104 : om 10
a | a f T y 0
8 é te te
GeOMAGNETIC Local TIME
°

23



MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16-18 DEC 1971)

19

a 0
Ee a gz
i. i.
3-1 3-0
1600 ° 180 ps °
os Dst(y) -f Dat(
000 \—oowoo ts 00a! Wena ce (7)
A oe 200 PF a
a a ee ei 6 bie ie 6 6 te te ae
UT 10 0.0 17 DEC 1971 UT tt 00 17 Dec 1871
60- .
oa =\ os ~ u
Boo, ‘ 3 20. ‘
ro :
Ea. ss Ee ae ‘
i 10- 10-|
ie ry a ty 3 te ry
GEOMAGNETIC LOCAL Tue Geowacnente Local TIME
UT 10 10.0 UT 11 10.0
60. oo
a VY) 3
a0- ad 204 °
20-| aod F 20-|
wo a \e
é 2 ry 2 3 3 a
UT 10 20.0 ur 11 20.0
50+ 60-
“| TA = U
30- 3 0 a
20-| . ¥ 20- ‘
ao ahs
10- a 10-
o- r T 7 T T 0 T T 7, T v y o- T T 7 T T x, T 7 7. r T
8 é te te a 8 é 12 18
UT 10 30.0 ut 11 90.0
80 00:
40 7 0 \ ~ J
304 iy 204
20-| ‘ a Fr i | .
20. as) de * 4 *
104 10-
One T T 1 7 T + T T 7 T 7 Os T T 7 T T 7, 7 T 7 7 r
3 ry i 2 3 ie i a
UT 10 40.0 UT 11 40.0
80.
ee - ss
catog a0"
A 20- .
abs ae
i ” 10-|
abe
¢ ie ra ry 3 fe te a
‘UT 10 50.0 UT 11 50.0
80. 50
a0-| J a0.
20, - 20 ahs
1 Bs 10
ry 3 ie re ty 3 ie ry a



MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16-18 DEC 1971)

my a)
sd 3
Boo Bsa
— :-
10 ° = 00
2000) ana Dat(7) -200a! \
18
yi WO, ce Dae .
fede bea ee ie a fe ts
UT 12 0.0 18 DEC 1971 UT 13 0.0 18 DEC 1971
60 0.
z “ S
Boo. \ oO. Boo. te
10 LA A we ae
On 7 rn T * + T T + 7 T 1 O- T T 7 T T 7. 7 7 7. 7 T 3,
ie FA 3 r ie te ae
GEOMAGNETIC LOCAL ME Cozonacnenie Locate
ur 12 100
0 oo
20. s0- S
0- { a 20- -
ro 104 (
rn re 3 3 @ 7 ae
‘UT 12 20.0 ‘UT 13 20.0
60, oo.
wo \ 404 Aa
20 s0-
20, 20-
-! a a he
UT 12 30.0 UT 13 30.0
50 7 60-|
oY {\S so: :
a0 Ky es _
% e
wo.) - 2.
io a wo {)
O- v T AY T o- T r T T 7, 7 T + T 1,
3 3 ae 3 3 & i ae
UT 12 40.0 UT 13 40.0
60, 60.
40. 40- Va
20. los \ 20- ‘.
\ A U ‘
104 10- .
ee Ifa * he
3 oo a a rr er a
UT 12 50.0 ‘UT 13 60.0
00. 0.
oA WW) oe (
0: 30:
Y,
20-| me 20-
to, abe 104 4s she
ry T r $ T T @ T 7 te a oF T T ry r r @ T T ry T de

32



MAGNETIC STORM (16-18 DEC 1971)
09
E of
2-09
tg ~ 1000}
2 seo oO
“eval Poe Det(7)
er ar a a Cr rr
uro oo 17

DEC 1971 UT DEC 1971
so 0,
Pe > ~ nt eT
gu rhe L / a ae
E 20- 20. ‘
a _
ceousonente toca te erent Local rE
ur 0 100 ur
oo
J ¢ 40- [> ) we (
x0 _ wl f )
20- ° 20- a
6° “oR a “a ° rv

) Soir] WON
ACC] A zi fi

14



MAGNETIC STORM (16-18 DEC 1971) i

600, TIME BAR i

~ ie H
i

a |

2-800) |

tg ~1000 |

a |

~ 1600) ° |

-2000! Dst(y) }

-100 j

f

-200 |

12 18 O 6 12 16 O 6 12 1B 24 |

|

UT 1? 5.0 17 DEC 1971

ac ax\ ta
aA

60-

»
8 5

LATITUDE(°)
xg

6
5

24
GEOMAGNETIC LOCAL TIME

Fig. 4. Example of the iso-intensity contour and the corresponding geomagnetic
activity indices.

Acknowledgements.

It is a pleasure to acknowledge the useful suggestions given by Dr. S.-I. Akasofu of the University j
of Alaska, the assistance in computer programming by Dr. M. Kanamitsu of the National Center for Atmos-
pheric Research, and the careful digitization by Mr. C. Samora of the National Oceanic and Atmospheric
Administration. I wish to express my gratitude to Mr. A. H. Shapley and Miss J. V. Lincoln for offering
the possibility of having this report published in the World Data Center A, UAG Report series.

The computations were made using the CDC 6600 computer system of the National Oceanic and Atmos-
pheric Administration and the CDC 7600 system of the National Center for Atmospheric Research, both in
Boulder, Colorado. The National Center for Atmospheric Research is sponsored by the National Science
Foundation. This work was also supported in part by the National Science Foundation, Atmospheric
Science Section, under grant DES74-23832 to the Geophysical Institute of the University of Alaska.

REFERENCES
ALLEN, J. H., 1975 Auroral Electrojet Magnetic Activity Indices AE(11)
C. C. ABSTON and for 1971, World Data Center A for Solar-Terrestrial t
L. D. MORRIS Physics, Report UAG-39, Boulder, Colorado. {
'
CAHILL, L. J. dr. 1973 Magnetic Storm Inflation in the Evening Sector, |
J. Geophys. Res., 78, 4724. |
|
sen 1972 Solar-Geophystcal Data, 330 Part I, February 1972,
U.S. Department of Commerce, (Boulder, Colorado,
U.S.A. 80302).
SUGIURA, M. and 1972 Provisional Hourly Vi E i
D. J. POROS lourly Values of Equatorial Dst for 1971,

Greenbelt, Maryland.

f
|
I
Goddard Space Flight Center, Report X-645-72-200, |
6 |
}
i
|


AE INDEX(7)

MAGNETIC STORM (16-16 DEC 1971)

UT 6 00 18 DEC 1971

MAGNETIC STORM (16-18 DEC 1971)

600)

B 4

5

8 +00]

1000

1809 °

-2000! | Datt7)

100

a 200
a a eC a

ur 7 0.0 © 18 DEC

1971

TOS

(| <
\/ es) |
E bs
‘e .
0+ T 5 O-- 7 . T v NS T ro y
o ‘ Ey ° 12 a4
UT 6 10.0 UT 7 10.0
so. oo.
o ~ “ a J a
o| _ w .
20-| ia 20- .
a ( ° UI SN
0. CAS o--— 7
67 ‘ ar a ar 0 6
ur 6200 ur 7209
om oo.
40- wa 40- \.
al OA. — oN —- . ) ~
20 > 20- so 0
ow i i
" N
% ' ‘ 6 ' 2! “ip ‘da y ‘ ‘ 6 ' te | ar vga
ur 6200 ur 7200
30-) . ‘30- a s as k
ol om ; '
FQ | He Ar
TM ‘ "6 ' ar a ar) 0 ‘ 6 te" ‘ te ar
ur e400 ur 7400
oo, 0.
30- ¢ ao) "
®. ®. a’ “e,
20/ 204 ae 1
‘e ‘e "
re rr cs 3 ze B de
ur 6500 vt 7609
0. oo,
a ‘ J — a / “,
» . wo
ff atl Hen
% ‘ ‘ an ve °% ' ‘ . "da

29



ie
GEOMAGNETIC LOCAL TIME,

Noe

(Si

ie ie 4,

UT 1 30.0

hora

UT 140.0

26



sudden commencement, the ground records in auroral latitudes show successive substorm activity; the
maximum AE index (AE = AU - AL) was greater than 1400y (at about 0445 UT on December 17). However,
the corresponding worldwide depression at middle and low latitudes was not very large; the minimum
Dst was only -50y. On the other hand, a rapidly growing main phase (the minimum Dst was -202y)
followed the second sudden commencement. During the early main phase AL reached -2000y, although
the simultaneous AU was quite small. This is one of the characteristics of the auroral electrojet
activity during the maximum phase of a great magnetic storm. Throughout the two periods, the main
phase decrease in the H component at mid and low latitudes was asymmetric, as indicated by the large
differences in value among the observatories plotted.

By 0000 UT December 18, the electrojet activity ceased, and there was no appreciable substorm
activity until an intense substorm took place at about 1030 UT. During the interval from the main
phase (1900 UT December 17) to the onset of the substorm during the recovery phase (1030 UT December
18), the world depression showed a rapid recovery from about -200y to -50y in the Dst index. After
1200 UT December 18, all mid- and low-latitude observatories showed a slowly decreasing ring current
effect. Not until the end of December 21 (not shown in Figure 1) did the depression recover completely.

All these ground magnetic signatures are commonly observed in many other large storms, e.g.,
April 1965, February 1967, March 1970, and August 1972. There have been a number of published works
on these magnetic storms. Some unsolved topics of interest are:

1. Why are there two sudden commencements?

2. Why does a large main-phase depression occur only after the second sudden commencement?
3. Why is there no AU activity during the main phase?

4. What is the main constituent of the storm-time ring current?

5. Why does the main-phase depression show an asymmetric growth with respect to local time?

6. Why is the recovery of the main-phase depression two-fold (rapid recovery and subsequent
slow recovery)?

2. Practical Procedure and Examples

To examine the growth and decay of the storm-time magnetic disturbances in these dimensions
(time and geographical locations), we made iso-intensity contours of the ground magnetic perturbations
at middle and low latitudes for a 2 day period of the magnetic storm 1200 UT December 16 - 2400 UT
December 18, 1971. The quiet interval, which was used as the baseline, was 1200 UT December 15 -
1200 UT December 16, 1971, when EKp = 4+,

The first step was digitizing the H-component traces from 52 northern hemisphere magnetic obser-
vatories (see Table 1) for both disturbed and quiet intervals. These 52 observatories were all the
data available through the World Data Center A for Solar-Terrestrial Physics at the time of the study.
Figure 2 shows the location of these observatories in geomagnetic "latitude - local time" coordinates
for 1200 UT. Observatories are identified by observatory numbers which are also given in Table 1.

A value was taken every 5 minutes during the storm period and every one hour during the quiet periods.
The 5-min disturbed values were then subtracted from 5-min quiet-time values, interpolated linearly
from the hourly values, to obtain H-perturbation values at each observatory.

~
5 e 2, &
~ 3
uw 504 oe e e
E 404 % é ° 7
§ 5 e27

304
re) % 20
im e ° 40
Ge} ¢ co 2 21
2 & % 024

104 o!
m7 oe oe gis
So 5 - ez 830

se
° 6 0 2 46 18 er 24

GEOMAGNETIC LOCAL TIME

Fig. 2. Distribution of the 52 magnetic observatories whose data are
used in this report (see Table 1).

3



~2000

| |
500 | |
| AU (I!)
|
; peppers
|
‘500 |
ae | |
| | AL (ID
~1000 + |
|
| | AE=AU-AL
1500 | |
| |
| |
|

-100

UT 16-18 DECEMBER 197!

The auroral electrojet indices, the superposed H-component records from
ten mid-latitude observatories, and the Dst index. The 5-min Dst (solid
line) are calculated from data at ten mid-latitude observatories.

The hourly Dst (circles) are from data at four observatories [Sugiura and
Poros, 1972].



MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16-18 DEC 1971)

- TM% ~
Bo eR 3
5 a
2 2
g i a
~1600 © 0
-sooa! a Det(7) oo
100 -
eee ah ge WT 200 eee
[a er rn i SO Te 2' ie" 6
uT 2 0.0 17 DEC 1971 UT 3 0.0 17 DEC 1971
50- 50+
nto »)) XY a ) fijy aha
Bao. H # s0- é
Ex ‘ 2
10+) 10-| a
on 7 Ce a er ee
é e ty b te 24
GEOMAGNETIC LocaL TIME GEOMAGNETIC LOCAL TIME
UT 2 10.0 UT 3 10.0
60- bu
AAS) \\
30- 3 a0- ‘
‘ i : : &
20, 20,
* / | ( ( .
O- T T T r 7 T T T ry o-, T T ry 7 Y 7, T T 7 T 7 iy
6 te 24 6 te 18 a
ur 2200 UT 3 20.0
60+ 60-
«|| 0 \ 0
a0 ( 20- ae
20-| “ . Pf 20-|
* cf} 3
ti) 6 ae ea } é [| ca)
ur 2.20.0 UT 3.30.0
50+ 50-
40-| \ [ | she f “0 Me
30, \ 30-|
: Y ¢ %
wf) \ \ a
10 | 10,
o- T T T T T , T T + + T ij o T 7 7 7 T *. T T 7 T 7 ,
3 2 Ry za ° é rs te 24
ur 2400 ur 3400
60+ 60-
a 7 I °
30- d \. 30-
20- t ‘ 20-|
wo, | os to
oy T T 1 T T +, T T 7. 7 7 or 7 T 7 A 7 . Y T 7. T 7 i
é é ib ie 4 é $ i te 24
ur 2500 ur 350.0
60+ 60-
: ; / ai °
30- , oy a0.
20-| 7 ‘ 20-1 abe
ry 2 é 3 ny te a

15



As a by-product, we calculated the equatorial Dst index for every 5 minutes from ten mid-latitude
observatories’ H perturbation values (denoted by AH). The observatories used are Dallas, Ebro,
Honolulu, M'Bour, Memambetsu, Odessa, Sakhalinsk, San Juan, Tashkent, Vladivostok. The equatorial
Dst is given by

L 10
Dst = to > AH, sec o mi>
i=l
where @ is the geomagnetic latitude of the i-th observatory. These are the Dst values given by
the solid curve in Figure 1.

The iso-intensity contour is drawn in geomagnetic “latitude - local time” coordinates. — Figure 3
shows a schematic illustration. The letter H or L in the center of each vortex expresses high or low
intensity, respectively, of the magnetic H-component perturbation as compared with the values surround-
ing the region. Iso-intensity contour lines are drawn for every 20y intervals. In the actual diagram,
contour lines are labelled at every 40y interval.

Re SS

60-

ao +
e 6

LATITUDE(*)
is

23 3

1
GEOMAGNETIC LOCAL ‘TIME

o-

24

Fig. 3. Schematic iso-intensity contour plot of ground magnetic H perturbations
which appear during magnetic substorms and storms.

Because features similar to Figure 3 appear repeatedly in the consecutive patterns of the contour
maps, we will briefly discuss some aspects of the currents which produce such characteristic features.
There are essentially two different vortices, H and L: H in the early morning and L in the evening
sectors. The high vortex is centered in high latitudes, whereas the low vortex is in low latitudes,
suggesting that the current sources are different for these two disturbances. If the magnetic dis-
turbances are larger in higher latitudes, field-aligned currents or return currents from the auroral
electrojet or a combination of the two could be the source currents, That is, either the field-aligned
currents flowing into the morning part and out from the evening part of the ionosphere or eastward

the earth's surface. If the magnetic disturbances a
with an increase of the latitude, the ring current in the magnetosphere may be responsible for such a
magnetic signature. In this way, the negative H perturbations could be explained by the partial
(westward) ring current in the evening sector. Note, however, that actual patterns observed during

the storm period are not as simple as this, but there often appear several complicated vortices which
require detailed examination for each pattern of these cases.

In Figure 4, we show an actual example of the obtained iso-intensity contours, the one for 1705
UT on December 17, 1971. This particular example was taken from the early main phase of the magnetic
storm when auroral electrojet activity reached nearly its maximum value. The AU(11) and AL(11) in-
dices and the Dst indices are plotted for every 5 minutes for the entire 60-hr interval. Time is
identified along the bottom of the index plots, 3 hours per tick mark. The time, for which the iso-
intensity contour is illustrated in the lower half of the Figure, is marked by the vertical timing bar
which in the movie film and the excerpts given in this report moves from left to right as time progresses.
Universal time and date are identified at the top right of the contour plot.

4. Availability of Detailed Data

The full data set is available on a 16-mm movie film 575 feet in length. Each frame on the movie
shows a frame like Figure 4 every 30 seconds, and is repeated two times to allow the viewers to follow
the progression of the storm disturbances. Film copies may be obtained from the Data Studies Division,
NOAA/EDS/NGSDC, Boulder, Colorado 80302, U.S.A., at a cost of $60.00 per film.

5



MAGNETIC STORM (16-18 DEC 1971) MAGNETIC STORM (16-18 DEC 1971)

z 600
z of = of
Td Ba
3 0 3%
0 16 °
2000! Vo] Detty) 2000! a4 peor
pee ah We -200 Fae oe
iz’ te fa ie’ te ee ee A
UT 14 0.0 17 DEC 1971 UT 15 0.0 17 DEC 1971
60. 60.
aM Ao:
Boo, Le E oo.
Ea $ Em
a 3 . °
f ie ie ae ry i ie &
GeoWAGNETIC LOCAL THE GEOMAGNETIC Local THE
UT 14 10.0 UT 15 10.0
60- 60.
= Y
%- aby so
a 4 @ 2,
10. a 10- ia ‘S
oO 6 12 18 24 oO 6 12 18 eA
UT 14 20.0 ‘UT 15 20.0
60. 0+
aia |e ds 1
204 . 0-
20, } (al } y 20 ae U
10-| E j 10-
oN, CA sal i Zo
$ rr rr, ee) $ 3 rr re)
ut 14.300 ur 15 30.0
s0- 80+
o he + te ae 4
wo. a0- | :
20 ve Fy ia as) du ‘
io C iN n ie
O-5 T r T T r 7. r 7 + T T iy 0: T r 7 T T o 7 x T T 7
8 é te te 24 o é te te a
UT 14 40.0 ‘UT 15 40.0
60- o0-
cal B 40" abs hey
30. 304
" ° ‘ (Al a
10, 104 7
SS a 1 oo (i En)
o 6 te 18 a4 6 é te 18 24
UT 14 50.0 UT 15 50.0
80 60
304 ve a0, ?
20+ 20+ te
104 vA \ 10} (K vy
Hy 3 rs te a é 3 2 7 i

21



- 56

WORLD DATA CENTER A

for
Solar-Terrestrial Physics

REPORT UAG

ISO-INTENSITY CONTOURS OF |
GROUND MAGNETIC H PERTURBATIONS

FOR THE DECEMBER 16-18,1971 j
GEOMAGNETIC STORM

Sy
C

April 1976



‘00, MAGNETIC STORM (16-18 DEC 1971) MAGNETIC STORM (16-18 DEC 1971)
z 0
z 4 = o4
Baa Eso
pe 3-1
- oo 1000 p 0
-2000 ba : bat
Vo hee ooo \o 8 )
Ce ee A a a Ae
UT 12 0.0 16 Dec 1971 UT 19 0.0 18 DEC 1971
80. 004
nite / ‘nfs 40- " » Q 5
ie 0 E» A [
aa 10- i “4
Te i a 3 A ib ea
GEOMAGNETIC LOCAL TIME GeouAGNETIE Local Ta
UT 12 10.0 UT 13 10.0
60-
. WI / "
20
2
104 fa
3 7 u fe ie zu
ut 12 20.0 ur 13 20.0
00,
w a \
%- obs ae.
204
10- 7
0. r T 7 T 7 0 T T . 7 T ry a, T T 7. T 7 1
$ 3 ie ie a ie ie ue
ur 12 90.0
20, . 50-
40- , 40+
30 <<) f/f Q
204 ( 20
10, 10,
is
a 5, oF A
é 3 ie ry ea a te te ey
ut 12 40.0 Ur 13 40.0
60: 1 04
4 \\ NS a 40. a
20- 30- _
# aa
nl ( eK
10. . 10,
3 3 i 7 a 3 i te a
ur 12 50.0 Ur 13 60.0
60: .
a & he a L
20+ i) rs) .
20 C\ - / | 20-
10, . 104 '
4 é a ie 2 é 6 a nr
8



PART II
The 10-minute Plots

The iso-intensity contours are shown for every 10 minutes, with plots covering two hours on each
page. At the top of each page the AU(11) and AL(11) indices and the equatorial Dst index are plotted
for the entire 60-hr period with the timing bar corresponding to the Universal Time of the first
contour map of each hour.

Universal Time and date are identified for each contour plot. Geomagnetic noon is fixed at
the center of each contour plot, so that the earth's rotation effect is eliminated in seeing the
Progressive change of the contour pattern.



UAG-53 “Description and Catalog of Ionospheric F-Region Data, Jicamarca Radar Observatory (November
1966 - April 1969)", by W. L. Clark and T. E. Van Zandt, Aeronomy Laboratory, NOAA, Boulder,
Colorado 80302 and J. P.McClure, University of Texas at Dallas, Dallas, Texas 75230, April
1976, 10 pages.

UAG-54 “Catalog of Ionosphere Vertical Soundings Data", prepared by Environmental Data Service, NOAA,
Boulder, Colorado 80302, April 1976, 130 pages.

UAG-55 “Equivalent Ionospheric Current Representations by a New Method, Illustrated for 8-9 November
1969 Magnetic Disturbances", by Y. Kamide, Cooperative Institute for Research in Environmental
Sciences, University of Colorado, Boulder, Colorado 80302 and Geophysical Institute, University
of Alaska, Fairbanks, Alaska 99701, H. W. Kroehl, Data Studies Division, NOAA/EDS/NGSDC,
Boulder, Colorado 80302, M. Kanamitsu, Advanced Study Program, National Center for Atmospheric
Research, Boulder, Colorado 80303, J. H. Allen, Data Studies Division, NOAA/EDS/NGSDC, Boulder,
Colorado 80302, and S.-I. Akasofu, Geophysical Institute, University of Alaska, Fairbanks,
Maska 99701, April 1976, 91 pages.

UAG-56 "Iso-intensity Contours of Ground Magnetic H Perturbations for the December 16-18, 1971 Geo-
magnetic Storm", by Y. Kamide, Cooperative Institute for Research in Environmental Sciences,
University of Colorado, Boulder, Colorado 80302 and Geophysical Institute, University of
Alaska, Fairbanks, Alaska 99701 (currently Guest worker at Data Studies Division, NOAA/EDS/
NGSDC, Boulder, Colorado 80302), April 1976, 37 pages.

” USCOMM-NOAA~ASHEVILIE=-5~7~76--1150



MAGNETIC STORM (16 (8 DEC i971)

8 NDE)
88.8

MAGNETIC STORM (16-18 DEC 1971)

~ Net ono

ut 400 18 pec 1971 uT 5 00 18 DEC 1971
wT y ane
10-| ‘a J
o-. 7 Y T T m . 7 x T T 1 On r T
° F en 3 Te ey
CGeoMAONETIC LOCAL TE GEOMAGNETIC LOCAL TIME
ur 4 100 ut 5 100
60: 60-
CZ CU ‘
00: wo, ° ‘
304 304 :
20" fa hy a sha 9
ww} a, ie * Bs a
O, T 7 r T T * T =. T T i o-5 T 7 7 r 7 7 * 7 7
d 1 te a $ 3 7s a
ut 4200 ur 6200
_ : 60+;
\ a Y..
aoe] oo ee
20- Q
aN .
T 7 7, T 7 os T 7 iy O- 7 T y 7 T 7 T 7 + T T y
% ca 3 te te ue
ut 430.0 ur 6300
60+ 50- U
40 404 aN
oy
oo, 1 wo) ~ / °
|. | Qa
wo, ae oly,
O- 7 + 7 O- T T T T 7 x [XN 7 + T T y
é i u Hy 3 fe ie a
UT 4 40.0 UT 5 40.0
804 20,
a ¥/ KJ] 404 ao J
20 20
204 As 20 ao ©
10, f 10, IX “
Or T r 7 T 7 , + T 7 7 T o- r r + 7 7 x. T r 7 7 7 a
3 te i a 3 i ie ey
ut 4500 ur 5 500
504 504 7,
WT, = |
\ (\ Ys 40+
0-| |e
a0-} a
2 o q 20 oa
10- 10-|
NM |
v T 7 7 7 + T 7 7 7 o- 7 r rn 7 T 7. T 7 i
3 1 a é é a

28



MAGNETIC STORM (16 18 DEC 1971) MAGNETIC STORM (16-18 DEC 1971)
_« _ '
i | gz 4
4 Fey
8 ae 5
a “oo \ a
2000! z Varo be
Wz" eo Bw oOo 6 i te 6 6 te a
ut 200 16 p6c 1971 ut 3 00 18 pec 1971
s0- 60, g :
a: . V #04 / Lad
Bo YS “| Er Oo
‘ : Be a, ‘e
E . he \ ( £ of ] K “y ~
10} Y fF
a rr ar 3 a er
rouse Local TE crowAGNSM Local Te
UT 2 100 ut 3 10.0
so, 7
40-| % \/ 40-| ws
wf \ Tan me
wa) a y A, On
10. 1. :
LN [ ‘ “ _|
a a a rr a ee)
ut 2200 ut 3200
° [NV ° T_yra
* fy aa °
10,
A [ ‘ (CS aN
a re a a er
ut 2300 ur 3.300
50, g 60 - :
ty PLAS : AV
ol), /
ae AG tae
10. 10.
rr er i,
UT 2 40.0 UT 3 40.0
—— 0, =
o ; Lo | Waid
aol fy 0
‘ | Bb
" CS Ie = 3 CD (
i a a i a a |
UT 250.0 UT 3 50.0
a , $0 _
40-// | 40-[ we “ A ra
| yy a so :
a % Q wm) 2s .
a) OS Ste RN
i a a rr a
27



Table 1.
Observatories used for the plot of the iso-intensity
contours of ground magnetic H perturbations
Geographic Geomagnetic*
No. Observatory Latitude Longitude Latitude Longitude
(north) (east) (north) (east)
1 ALIBAG 18.63° 72,87° 9.43°  144.34°
2 ANNAMALATNAGAR 11.40 79.68 1.51 150.10
3 BAGUIO 16.42 120.60 5.16 189.98
4 BOULDER 40.13 254.77 49.04 317.40
5 CHAMBON-LA-FORET 48.02 2.27 50.31 85.07
6 DALLAS 32.98 263.25 42.98 328.64
7 DAVAO 7.08 125.58 73.95 195.26
8 DOURBES 50.10 4.60 51.83 88.39
9 EBRO 40.82 0.50 43.74 86.37
10 ESKDALEMUIR 55.32 356.80 58.31 83.57
11 FREDERICKSBURG. 38.20 282.63 49.51 350.78
12 FUQUENE 5.47 286.27 16.88 355.87
13 FURSTENFELDBRUCK 48.17 11.28 48.67 93.99
14 GUAM 13.58 144.87 4.10 213.63
15 HARTLAND 50.98 355.52 54.48 79.70
16 HONOLULU 21.32 202.00 21.23 267.29
17 HUANCAYO -12.05 284.67 ~0.67 354.55
18 HYDERABAD 17.42 78.55 7.61 149.62
19 IRKUTSK 52.17 104.45 40.78 175.31
20 KAKIOKA 36.23 140.18 26.15 206.65
21 KANOYA 31.42 130.88 20.65 198.75
22 KAZAN 55.83 48.85 49.26 130.94
23 KIEV 50.72 30.30 47.46 112.79
24 LUNPING 25.00 121.17 13.76 190.19
25 LVOV 49.90 23.75 47.89 106.49
26 M'BOUR 14.40 343.02 21.07 55.77
27 MEMAMBETSU 43.90 144.20 34.14 209.10
28 MINSK 54.10 26.52 51.37 110.98
29 MOSCOW 55.48 37.32 50.77 121.08
30 MUNTINLUPA 14.37 121.02 3.13 190.46
31 NEWPORT 48.26 243.01 55.18 301.13
32 NIEMEGK 52.07 12.68 52.10 97.21
33 ODESSA 46.78 30.88 43.57 111.74
34 OTTAWA 45.40 284.40 56.76 352.51
35 PARAMARIBO 5.82 304.78 16.88 15.13
36 RUDE SKOV 55.85 12.45 55.74 99.16
37 SAKHALINSK 46.95 142.72 37.02 207.33
38 SAN FERNANDO 36.47 353.80 40.81 72.06
39 SAN JUAN 18.12 293.85 29.79 3.98
40 SIMOSATO 33.57 135.93 23.15 203.13
41 ST. JOHN'S 47.60 307.30 58.39 22.17
42 SVERDLOVSK 56.73 61.07 48.45 141.26
43 TASHKENT 41.33 69.62 32.30 144.07
44 TBILISI 42.08 44.70 36.58 122.72
45 TOLEDO 39.88 355.93 43.71 75.39
46 TRIVANDRUM 8.48 76.95 -1.11 147.11
47 TUCSON 32.25 249.17 40.50 313.06
48 VALENTIA 51.93 349.75 56.48 74.18
49 VICTORIA 48.52 236.58 54.27 293.51
50 VLADIVOSTOK 43.68 132.17 32.38 198.60
51 WINGST 53.75 9.07 54.27 95.32
52 WITTEVEEN 52.82 6.67 54.00 91.85
* These coordinates based on different model than that used in Report UAG-38.
4



ied COU
mL] PL
fi ie lity

18



MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16-18 DEC 1971)

a om 8
3 — gq Loe
8 sod B tod
é z
3 te eo
: na °
2000! 2000 4 Pa)
J] 00
a
UT 18 0.0 18 DEC 1971 UT 19 0.0 18 DEC 1971
04
04 : y .
3 3 Be s a
Koo. \ y \ ‘e
E ao. Be OG ‘
5 fa f
vo (* a
$ $ ie 7 zs fs a
GEOMAGNENC LOCAL Tae CGeOUAGNETIC LOCAL TE
Ut 18 10.0 UT 19 10.0
804 60+
40-| \ | ata 40" J f
20+ 20,
2 \ f {| 20 V
10- . q 10-| gg
a (4s * K\ | f
; ptt, a
UT 18 20.0 UT 19 20.0
04 so.
T
40- \ 40- J %, Fond
-
304 0.
Kw
oo | oo VV
10 fas io
O- 7 T z 7 7 . 7 T T ay 7 T r T 7 7, 7 T 7 3,
é ie ae ay é te a
Ur 18 90.0 UT 19 90.0
04 604
0 ‘4 SO o f \ we
0+ . " a0] \
20, *, } Be 20, ‘
10 Fas io
$ 3 i 7 a 3 3 mo i ze
Ut 18 40.0 ut 19 40.0
60: 20,
a 5 she “S 0
30, a \,
20,
10 4X Fsbo ‘0 oN
5 1 _1 op - lh ahd
é 7 ie te 2 3 ie au
UT 18 50.0 UT 19 50.0
0, 804
F
40-' 0 al wy ae
30-hu, S 30-- ‘e
2 (| 20 oe
10, : 104
-! L 0-) #
0 $ 7 T $ > T fe T 7 e T T a "s T T $ T T te 7 . te T 7 a

35



MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16-18 DEC 1971)

Pei |
2 oO oo = oO}
io i.
3 ie =e
oa ° = 00
“000 aan attr) “ooo Vor atin)
188 108
hee a rn coo
& fete 6 6 a ie se
UT 20 0.0 18 DEC 1971 UT 21 0.0 18 DEC 1971
s0-
a0. *,
. Fo, Q ws
cory 3
a a ;
F ze 3 te ie as
GEOMAGNETIC LOCAL EME couacnenic toca nie
Ur 20 100 ur 2t 10.0
60,
” ate
: 20:
i a, 2 a,
ry 0. y
) 10, = #
T 7 O- A {
re 2 3 rr a ey
ut 20 20.0 ur et 200
s0- 50.
o Ly ©. .
ao “a, s wo wo .
YN" VG 1, “ ye
20° ba | 20° 0" ab
. 2 } * a A
rr a re re) ot a a ae)
ut 20 80.0 ut 21 300
s0- 60.
0. U «0:
i -
30- J % 30- —N
af ~ ta eNO. ' *
Le IN } if _ \
O- T T 7 T + 7 + 7 iy T 7 T 7, T T r T 7 i
3 3 te i a 3 re & a
ut 20 40.0 ur et 400
so 0.
20 — 40
20, wn f \t . ol] re on,
20 ‘ \ to NL
tof 10
“ls ae ee dun
: ae a 3 a. ——Fz et
ut 20 50.0 ut et 500
60. 50,
w0- oo
30-] 0 90- \
mG Si i :
wo) (5, S wo )
who Nop |e . a
3 7 fe ie ra ee tO

36



TVA

a a a rr

ary 7 oF TM J yn | a

a a

NY

a rr)

a er)



TABLE OF CONTENTS

Page.
PART I
1. Introduction 1
2. The December 16-18, 1971 Storm 1
3. Practical Procedure and Examples 3
4. Availability of Detailed Data 5
Acknowledgements 6
References 6
PART IT

The 10-minute Plots 7-37

ii



MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16-18 DEC 1971)

00 Pe
2 tae eq
g rw
8 ted 8 200
: 5
160 ° “1
2000 ood Datt7) -200a! Dat(y)
100 -100
A a ee 200 wa 200
fn a a a Bote
UT 18 0.0 16 DEC 1971 UT 19 0.0 16 DEC 1971
60 50+
et] ads Wh a we
Foo. E oo.
Eaol ' E20,
a 5
10- we 10-
0.) T T 7 T 7 7 7 T 7 y 0 7 T T T 7 ro 7 T . 7 T 1,
$ 6 tz ti 24 6 t2 Ea
GEOMAGNETIC LOCAL TIME GEOMAGNETIC LocaL TIME
ut 18 100 ur 19 10.0
80 60.
1 ty ss o a
aw] 204 le
0. . a)
10. we d 10-
ox t o-—— A —4
Sc a A poe 4
UT 18 20.0 UT 19 20.0
[TM ; al shi
( e a
0-, T T T 7, T 7 T T q O-, T T T T 7 . 7 T - T T y
6 é 12 te 24 8 é te 18 24
UT 18 20.0 UT 19 90.0
0+ 80+ >
“( wo} yy << tbs
al) 0.
20-4 a. 7 20- a
10. .
3 3 fe ie ee 3 re &
UT 18 40.0 UT 19 40.0
60. 0.
“ ' wr gs
: a. | ft 0
20-| 0, 20
0-, T 7, T T 7 T T ry O-p 7 T 7 T T 7. T 7 T T T ,
6 te te a é te te aa
UT 18 50.0 UT 19 50.0
50 60
40°) . a 40) aha
a0 he a0
20) as
to ch ds
° i ie a 3 ie ny a

11



MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16~18 DEC 1971)

7 a)
S 3
E 5 v iy
5 to 5 so
pe 3-109
= oo ° =o ps °
-2000! Vou] Dot(7) 2000 Vo] Det(7)
100 100
ie’ te fe’ ie 6 6 ae ae ae ie’ 6 lie’ 6° 6 ie te ae
‘UT 22 0.0 16 DEC 1971 UT 23 0.0 16 DEC 1971
04 : 60+
M
40°) ab 2 aa
20, an E ao.
5 tm 5
10. 10
o-) 7 T T T 7, T T r T T , 0- T T > 7 r, T T 7 7 T ,
8 12 18 ea é é t2 18 ae
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UT 22 10.0 UT 23 10.0
a
ima a UV
204 a0:
30- ° 30-| " IN
a an as 20
10 \ 104
0. 7 T 7 T 7 +, T T - 7 T 7 oF T T T r 7 r + 7 ro T
6 12 18 24 6 é te 18 ea
UT 22 20.0 UT 23 20.0
90+ 60:
yw UL = \
30-| w 5 ne 80-
te
20 a 20,
10, 104
6 é te ry as 6 é 12 18 2a
UT 22 30.0 UT 23 30.0
50. J 60:
40+ 40-
20, A | y
20 to 20- abe
10, ran 10}
3 te i By % 3 fe i a
ur 22 40.0 UT 23 40.0
60: 20.
aol | 0:
20" 28.0 20" 30.2
10, 0
on T T T T 7 x. 7 7 7 7 7 O-, r 7 z 7 7 7. T 7 rm 7 r 3
8 é 12 18 24 é 6 te te a
ur 2 50.0 ut 29 50.0
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“ “ we
afl /\ oo. r
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O-r 7 T ry T T 7. T T T 7 7 Or 7 T T Dm —
é ie te 24 8 é te te 24

13



WORLD DATA CENTER A
for
Solar-Terrestrial Physics

t
if

REPORT UAG - 56

ISO-INTENSITY CONTOURS OF
GROUND MAGNETIC H PERTURBATIONS
FOR THE DECEMBER 16-18,1971
GEOMAGNETIC STORM

by

Y. Kamide
Cooperative Institute for Research in Environmental Sciences

University of Colorado, Boulder, Colorado 80302 U.S.A.

and
Geophysical Institute, University of Alaska,

Fairbanks, Alaska 99701 U.S.A.

April 1976

Solar-Terrestrial Physics, NOAA, Boulder, Colorado
and printed by BZ
U.S, DEPARTMENT OF COMMERCE G
NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION TNIWS
ENVIRONMENTAL DATA SERVICE |
Asheville, North Carolina, USA 28801 |

|
|
Published by World Data Center A for Si , |

SUBSCRIPTION PRICE: $25.20 a year; $12.00 additional for foreign mailing; single copy price
varies." Checks and money orders should be made payable to the Department of Commerce, NOAA.
Remittance and correspondence regarding subscriptions should be sent to the National Climatic
Center, Federal Building, Asheville, NC 28801, Attn: Publications.

|
*PRICE THIS ISSUE $0.70 |
|
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|


AE INDEX(7)

MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16-18 DEC 1971)

UT 17 0.0

18 DEC 1971

60 s0-
milf c >
E ao. ¢ a0. y .
8 ¢ she & ye wy aa Ao
eon ‘. (© (a
Jig, . 9 ho, he
0.) z 7 + o 7 + 7 T OF T T T 7 7 + T r . T T
3 te 7 3 i
CEOUAGNETI LOCAL Tae Cceowacnete Local rae
UT 16 10.0 UT 17 10.0
60. 60,
+o. Ss { +o
oo: é . sa 0:
ie
“| “\Qi : Mt
% oe a)
ut 16 200 ut 17 200
0. 60,
of Ss ff of \ eS
304 . ! “ ‘0.0 30- se H
20 : 0 . bs
i. wo ‘ [ he
" bo SS ne
Ut 16 300 ur 17 300
s0- 0.
“pu onl
=| aM Od ,
20-| . 20- .
104 10.
"5 pO — rr a
UT 16 40.0 UT 17 40.0
60, 0.
~ C7 qo ‘
w) boa % a a0 » re) ‘: oN
20- 7 é 20-| -
0-5 rn T T 7, T T 7 7 T o-r T 7 r T T o 7 T rs 7 T
$ 3 ze i $ 7 & a
‘UT 16 50.0 UT 17 50.0
20. 60.
“ ‘. CO “ \ (
a0 * § aha % e 0 % = g 5 a
° NY) ° :
“| Lf = f\ a
o-, 7 T T r T T , T r O-5 T + t T 7 os T 7 7 T
3 3 @ te ae $ 3 @ 8 a

34



on Aee 2 So ee ee

TET

i re in

: h A = at ae



WORLD DATA CENTER A

National Academy of Sciences

2101 Constitution Avenue, N. W.
Washington, D. C., U.S.A., 20418

World Data Center A consists of the Coordination Office

and seven Subcenters:

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Coordination Office

National Academy of Sciences
2101 Constitution Avenue, N. W.
Washington, D. C., U.S.A. 20418

[Telephone:

Glaciology:

World Data Center A:
Glaciology

U.S. Geological Survey

1305 Tacoma Avenue South

Tacoma, Washington, U.S.A. 98402

[Telephone: (206) 593-6506]

Meteorology (and Nuclear Radiation):

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Federal Building
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[Telephone: (704) 258-2850]

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World Data Center A:
Oceanography

National Oceanic and Atmospheric
Administration

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[Telephone: (202) 634-7249]

Rockets and Satellites:

World Data Center A:
Rockets and Satellites
Goddard Space Flight Center
Code 601
Greenbelt, Maryland, U.S.A. 20771
[Telephone: (301) 982-6695]

Notes:

(1)

(2)
(3)

(202) 389-6478]

Rotation of the Earth:

World Data Center A:

Rotation of the Earth
U.S. Naval Observatory
Washington, D. C., U.S.A. 20390
[Telephone: (202) 254-4023]

Solar-Terrestrial Physics (Solar and

Interplanetary Phenomena, Ionospheric
Phenomena, Flare-Associated Events,
Geomagnetic Variations, Magnetospheric
and Interplanetary Magnetic Phenomena,
Aurora, Cosmic Rays, Airglow):

World Data Center A
for Solar-Terrestrial Physics
Environmental Data Service, NOAA
Boulder, Colorado, U.S.A. 80302
[Telephone: (303) 499-1000, Ext. 6467]

Solid-Earth Geophysics (Seismology,

Tsunamis, Gravimetry, Earth Tides,
Recent Movements of the Earth's
Crust, Magnetic Measurements,
Paleomagnetism and Archeomagnetism,
Volcanology, Geothermics):

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for Solid-Earth Geophysics
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[Telephone: (303) 499-1000, Ext. 6521]

World Data Centers conduct international exchange of geophysical observations in accordance
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Communications regarding data interchange matters in general and World Data Center A as a
whole should be addressed to: World Data Center A, Coordination Office (see address above).
Inquiries and communications concerning data in specific disciplines should be addressed to

the appropriate subcenter listed above.



MAGNETIC STORM (16-18 DEC 1971) MAGNETIC STORM (16-18 DEC 1971)

‘AE INDEX(y)

$i5e.8

UT 8 0.0 18 DEC 1971 UT 9 00 18 DEC 1971

Se, po a ae,
CGeOWAGNENI LOCAL Ta oMAGNENI LOCAL Tame
ur 8 100 ur 9 100
04 804
40-| an { 40-] 9 y
20- \ .
‘ “e 30 rm} .
.| 8
7 ° 20. be
10, 10 {
o- T T ry 7 T . T T 7, T 7 T T r 7. 7 7 + T T 1,
8 é t2 18 aa é te 18 24
UT 8 20.0 UT 9 20.0

ut 9 40.0
ol AN
of \
as \ J |

a0 8 0.
20" he
10
On T T 1 T T io T T 7 T T y 7 . T 7 r. 7 7 iy

3 ie ry ze ie 1b 2

UT 8 50.0 UT 9 50.0

30



UAG-35

UAG-36

UAG-37

UAG-38

UAG-39

UAG-40

UAG-41

UAG-42

“Catalogue of Digital Geomagnetic Variation Data at World Data Center A for Solar-Terrestrial
Physics", prepared by Environmental Data Service, NOAA, Boulder, Colorado, July 1974, 20 pages,
price 20 cents.

"An Atlas of Extreme Ultraviolet Flashes of Solar Flares Observed Via Sudden Frequency Devia-
tions During the ATM-SKYLAB Missions", by R. F. Donnelly and E. L. Berger, NOAA Space Environ-
ment Laboratory, Lt. J. D. Busman, NOAA Conmissioned Corps, 8. Henson, NASA Marshall Space _
Flight Center, T. B. Jones, University of Leicester, UK, G. M. Lerfald, NOAA Wave Propagation
Laboratory, kK. Najita, University of Hawaii, W. M. Retallack, NOAA Space Environment Laboratory,
and W. J. Wagner, Sacramento Peak Observatory, October 1974, 95 pages, price 55 cents.

“Auroral Electrojet Magnetic Activity Indices AE(10) for 1966", by Joe Haskell Allen, Carl C.
Abston and Leslie D. Morris, National Geophysical and Solar-Terrestrial Data Center, Environ~
mental Data Service, December 1974, 142 pages, price 75 cents.

"Master Station List for Solar-Terrestrial Physics Data at WDC-A for Solar-Terrestrial Physics",
by R. W. Buhmann, World Data Center A for Solar-Terrestrial Physics, Juan D. Roederer, Univer-
sity of Denver, Denver, Colorado, M. A. Shea and D. F. Smart, A.F.C.R.L., Hanscom AFB, Massa~-
chusetts, December 1974, 110 pages, price $1.60.

“Auroral Electrojet Magnetic Activity Indices AE(11) for 1971", by Joe Haskell Allen, Carl C.
Abston and Leslie D. Morris, National Geophysical and Solar-Terrestrial Data Center, Environ-
mental Data Service, February 1975, 144 pages, price $2.05.

VH-Alpha Synoptic Charts of Solar Activity For the Period of Skylab Observations, May, 1973-
March, 1974", by Patrick S. McIntosh, NOAA Environmental Research Laboratory, February 1975,
32 pages, price 56 cents.

"H-Alpha Synoptic Charts of Solar Activity During the First Year of Solar Cycle 20 October,
1964 - August, 1965", by Patrick S. McIntosh, NOAA Environmental Research Laboratory, and
Jerome T. Nolte, American Science and Engineering, Cambridge, Massachusetts, March 1975,
25 pages, price 48 cents.

“Observations of Jupiter's Sporadic Radio Emission in the Range 7.6-80 NHz 10 December 1971
through 21 March 1975", by James W. Warwick, George A. Dulk, and Anthony C. Riddle, Depart-
ment of Astro-Geophysics, University of Colorado, Boulder, Colorado 80302, April 1975,

49 pages, price $1.15.

UAG-43 "Catalog of Observation Times of Ground-Based Skylab-Coordinated Solar Observing Programs",

UAG-44

UAG-45

UAG-46

UAG-47

compiled by Helen E. Coffey, World Data Center A for Solar-Terrestrial Physics, May 1975,
159 pages, price $3.00.

tSynoptic Maps of Solar 9.1 cm Microwave Emission from June 1962 to August 1973", by Werner
Graf and Ronald N. Bracewell, Radio Astronomy Institute, Stanford University, Stanford,
California 94305, May 1975, 183 pages, price $2.55.

“Auroral Electrojet Magnetic Activity Indices AE(11) for 1972", by Joe Haskell Allen, Carl C.
Abston and Leslie D. Morris, National Geophysical and Solar-Terrestrial Data Center, Environ-
mental Data Service, May 1975, 144 pages, price $2.10.

"Interplanetary Magnetic Field Data 1963-1974", by Joseph H. King, National Space Science
Data Center, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, June 1975, 382
pages, price $2.95.

"Auroral Electrojet Magnetic Activity Indices AE(11) for 1973", by Joe Haskell Allen, Carl Cc,
Abston and Leslie D. Morris, National Geophysical and Solar-Terrestrial Data Center, Environ-
mental Data Service, June 1975, 144 pages, price $2.10.

UAG-48A "Synoptic Observations of the Solar Corona during Carrington Rotations 1580-1596 (11 October

UAG-49

UAG-50

UAG-51

UAG~52

1971 - 15 January 1973)", [Reissue with quality images] by R. A. Howard, M. J. Koomen, D. J.
Michels, R. Tousey, C. R. Detwiler, D. E. Roberts, R. T. Seal and J. D. Whitney, E. 0. Hulbert
Center for Space Research, NRL, Washington, D. C. 20375 and R. T. and S. F. Hansen, C. J.

Garcia and E. Yasukawa, High Altitude Observatory, NCAR, Boulder, Colorado 80303, February 1976,
200 pages.

“Catalog of Standard Geomagnetic Variation Data", prepared by Environmental Datia Service, NOAA,
Boulder, Colorado, August 1975, 125 pages, price $1.85.

“"High-Latitude Supplement to the URSI Handbook on Ionogram Interpretation and Reduction", by
W. R. Piggott, British Antarctic Survey, c/o SRC, Appleton Laboratory, Ditton Park, Slough,
England, October 1975, 292 pages, price $4.00.

isynoptic Maps of Solar Coronal Hole Boundaries Derived from He II 304A Spectroheliograms from
the Manned Skylab Missions", by J. D. Bohlin and D. M. Rubenstein, E. 0. Hulbert Center for
Space Research, Naval Research Laboratory, Washington, D. C. 20375 U.S.A., November 1975,

30 pages, price 54 cents.

"Experimental Comprehensive Solar Flare Indices for Certain Flares, 1970-1974", compiled by
Helen W. Dodson and E. Ruth Hedeman, McMath-Hulbert Observatory, The University of Michigan,
895 Lake Angelus Road North, Pontiac, Michigan 48055 U.S.A., November 1975, 27 pages, price
60 cents.

i]
t
f



GEOMAGNETIC LOCAL TIME

GEOMAGNETIC LocAL TIME

WO) LYDIA SI

ee

a a



MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16-18 DEC 1971)

1004 = 800
gts z Of a
8 -+00 8 oo]
tg - 009 Pe
1609 t ° 1600} ] °
7 eae Dat) “ Det(7)
2000 Fe 2000 be
an a er ey Ca a a rr
UT 14 00 16 DEC 1971 UT 15 0.0 16 DEC 1971
50- 50+
2 ° als L a NN
Eo. 4 B ao L&
E 20 @ E20.
6 é 2 2 6 12
GEOMAGNETIC LOCAL THE GEOMAGNETIC LocAL TiKE
UT 14 10.0 UT 15 10.0
om
oi “ *
a “
20- é
10. |
r 7. 7 T 3, o- T T 7 T r 7, T r 7 r T ry
te 3a 8 ny ny a
Ut 14 200 UT ts 20.0
50+
wh o fe
A, 30- Re) ate
20- ®
10-| 7}
7 7 T 7 ,, o-; 7 T 7 7 T 7, T T + 7 T y
te 2a é ie ie 24
UT 14 30.0 UP 15 30.0
60+ 50-
UN se vied “ be
20-] : 80 a Qs wl
20. 20-| ,
I * aa
7 T 7 T r 7 7 * T T , 0, T 7 7 T 7 x. 7 7 7 7 7
$ 2 fe a é é ® ny 4
UT 14 40.0 UT 15 40.0
| ‘
ee
ny te da é ie i Ea
UT 14 50.0 UP 15 50.0
60+ - 50- -
30. 20-
20- 20- » pe
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MAGNETIC STORM (16-18 DEC 1971)

MAGNETIC STORM (16-18 DEC 1971)

= mM 5 800)
Soot go
§ v ie
B tod Bs
ty ~ 1009} ty 71000)
1600} * 1600 °
2000 2000 Voor Dat(7)
“108
fe’ ie 6 fee 6 te is bie’ ia a
ut 20 0.0 16 bec 1971 ur 2t 00 16 pec 1971
so: 204
et] os a 2% @ tbe
Bao, Bao,
E 20. E 2. 3
3 ie a
CEOUAGNETIC LOCAL TMs GEOMAGNETIC LOCAL TIME
ut 20 10.0 ut 2t 100
0- 0: -
ols “| @ \? nN
a0. a4
20- Is 20-| ® f
10, 10, XM te
0. r 7 T 7 .. T 7 7 T oF T T 7 7 7 7, 7 7 > T T 2,
% ie te cy é ta ie 24
ut 20 20.0 ur at 20.0
60- 04
of\ 2 os “ V7]
a0} 3 a | ae o
20- ) 20- aha
10, en 10
On T T 7 7 T 7. T 7 7 7 o- 7 7 7 + T * 7 7 m T T
$ 3 ie % a 3 3 i ie Ea
ur 20 90.0
60: oe
l/s, | © }
30- 90+ a
a} 20. ahs
wo rc 1 A
$ 3 i te a $ ie i au
UT 20 40.0 ur 21 40.0
20, s0-
vw
40, a 40"
30 a0 fake
20-| 20-| f
10+ (~ 10-
O- T 7 T T 7, T T v T T 7 7 T 7 T T 7 9
3 A Te 7 a te uh
ut 20 60.0 ur 21 50.0
ong eo.
0, hs U tee o =
20. a4 Log oe
20- é 20-
10, 1 line
O- T 7 r T o 7 7 os T r o- T 7 r 7 T x. T 7 7 7 +
$ 3 ie te a 3 fe ie

12