.
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
I
LINCOLN LABORATORY
x
MILLSTONE HILL THOMSON SCATTER RESULTS FOR 1966
l
J. V. EVANS
Group 21
I
t
^..
_.
I
*
I
TECHNICAL REPORT 481
19 JANUARY 1971
*
c
*
Approved for public release; distribution unlimited.
LEXINGTON
I
The work reported in this document was performed.at Lincoln Laboratory,
a center for ~esearch operated by Massachusetts Institute of Technology.
I
.,
,,!
The work is sponsored by the Office of the Chief of Research and Development, Department of the Amy; it is supported by the Advanced Ballistic
Missile Defense Agency under Air Force Contract F19620-70-C-0230.
This report may be reproduced to satisfy needs of U.S. Government agencies
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this document
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I
‘[
AEL5TRACT
This report presents F -regfon electron densities and electron temperatures
during the year 1966 at the Millstone Hill Radar Observatory
UHF Thomson (incoherent) scafrer radar.
observed
(42. 6“N, 71. 5“W) by the
The measurements were usually made for
pericds of 24 hours twice per month, and covered the altitude range 150 to 750 t-anapproximately.
Tbe time required to collect all the measurements
interval was 30 minutes, i.e., half that of previous years.
amount of random time variation than seen heretofore,
time resolution achieved and pafly
spanning this height
The results exhibit a greater
Parfly as a result of the beffer
because each day has keen analyzed individually,
i.e., we have discontinued fhe practice of computing onfy tie monthly mean behavior.
We telieve,
however, that the largest part of the random variation is real and results
from fluctuations in the solar EUV flux, which increase
number rises.
Also, we expect a growing incidence of fluctuations produced by large-
scale tmveling
ionospheric disturbances as we approach sunspot maximum.
this variability,
the characteristics
/:j
!
effects
due to Seoma@etic
Despite
“winter” and “summer” type behavior reported for
Millstone in previous years is clearly recognizable.
,
in magnimde as tbe sunspot
On four days in which pronounced
storms are evident, the layer rose to great hei@s
late affernoon and achieved an abnormally high density (and lower-than-normal
perature ).
Tbe reverse
is simila= to that first
behavior was encountered the next morning.
in tie
tern-
This sequence
seen in June 1965, and its interpretation in terms of current
ideas is summarized.
Accepted for the Air Force
Joseph R. Waterman, Lt. Col., USAF
Chief, Lincoln LabaratoW Project Office
iii
CONTENTS
Abstract
L
lNTR ODUCTION
11. EQUIPMENT,
PROCEDURES
Equipment
B.
Observing
DATA-PROCESSING
3
3
Procedures
FOR
3
ELECTRON
A.
Contour Plots
B.
Discussion
DENSITY
5
5
43
*4
ELEcTRON
TEMPERATURE
A.
Plots
i4
Temperature
2T
B.
VI.
AND
Data Reduction
111. RESULTS
V.
OBSERVING
3
A.
C.
IV.
AND
Contour
Average
SEASONAL
VARIATIONS
A.
Electron
B.
Protonospheric
SUMMARY
References
Profiles
Temperature
Beat Flux
32
32
35
37
39
MILLSTONE
1.
HILL
THOMSON
SCATTER
RESULTS
FOR
1966
INTRODUCTION
Thomson
(incoherent)
scatter
radar
temperatures
were
imately
twice
per month throughout
made at Millstone
results
obtained
and discusses
Earlier
reprts
in this series
in 1963, 4964 and 1965.
sented in a number
Hill,
of F-region
West ford,
electron
Massachusetts
t 966 for periods
of 24 hours.
densities
(42.6”N,
This rePOrt
and
71 .5”W)
approx-
summarizes
the
these in relation to the behavior observed in previous years.
4-3
have presented the results of the synoptic studies carried
Results
of journal
measurements
obtained
articles
in some of the months in these years
which are listed
in Table
have
out
pre -
been
1.
TABLE I
PUBLICATIONS
CONCERNING
THE MILLSTONE
HILL UHF
(68-cm Wavelength)
THOMSON
SCATTER RESULTS
I
Year
I
February
1963
March,
I
I
II
Section
i 966.
seasonal
from
These
in Ref. 3.
Ref. 2
November
th,o”gh
August,
January,
I
I
December
September,
April,
the equipment,
differed
little
temperature
variations
the magnetosphere.
period.
Ref. 3
average
Ref. 9
Ref. 10
and data-processing
those of the latter
the results
including
and seasonal
A summary
I
I
July
from
Ref. 6
Refs. 7, 8
and observing
In Sec. 111, we present
obtained for each 24-hour
temperature
Ref. 5
June
[
Ref. 4
September
November
July,
Juner
August,
Publicafi.n
Ref. 1
1964
through December
J.WCW
Sec. IV those for electron
ture profiles
1
/
1
April,
II summarizes
ployed during
documented
Jufy,
January
1965
1963 to January
July,
April,
1964
\
Months Covered
half of t965,
obtained
for electron
daytime
and nighttime
In Sec. V, these averages
variations
of the results
em-
which are fully
density,
and in
electron
tempera-
are employed
to derive
in the heat conducted
is provided
procedures
into the F-region’
in Sec. VI.
——---rwatz.?aam
,. .. .
TABLE II
INCOHERENT
SCATTER
OBSERVATIONS
Mean
End (1 T)
Begin
14 January
1100
15 Janmry
21 Jommry
1200
22 January
25 February
1200
26 February
11 March
1200
16 March
1200
I April
1200
2 April
-1964
P
1200
2–
D
1200
4
Q
1200
1
0
12 March
1200
2–
17 March
1200
1+
1200
3
D
K
0
Comment
Very disturbed
Quiet
Quiet
Disturbed
0
]
Quiet
28 Apri I
1700
29 Apri I
1500
1+
12 May
1300
13 May
0800
2
2B June
1600
29 June
1600
2-
11 July
0700
12 July
0900
3-
Disturbed
14 July
1500
15 July
1500
1-
Quiet
17 August
1100
18 August
1200
1+
Quiet
22 August
1200
23 August
1300
3
12 September
I 000
13 September
1000
1+
26 September
I 000
27 September
1000
4-
Disturbed
10 Octcber
1600
II
October
Q
1400
0+
Quiet
20 October
1100
21 Octc&er
Q
1100
0
1200
2
1700
3
D
D
0
Portion lost
Disturbed
0
7 November
1200
8 November
2B November
1600
29 November
5 December
1200
6 December
1200
2+
20 December
1200
20 December
1600
3
21 December
Moo
22 December
0700
2+
D
0
Disturbed
0
—
Quiet
0
II.
EQUIPMENT,
A.
AND
OBSERVING
The UHF radar
equipment
The Millstone
brought
into routine
density
has been described
Hill C-4 ionosonde
operation
of foF2 made elsewhere
PROCEDURES
previously.
during 1966, thus obviating
(Fort
No major
which had been inoperative
Belvoir,
Virginia)
changes
were
made in
during much of i965 was
the need to depend on measurements
to establish
the absolute
scale
of the electron
profiles.
B.
Observing
In i965,
accomplished
playback
required
system,
Table
obtained
in the results
analyzer
between
changes
are discussed
throughout
the
profile.
processing.
This was
The recording
this was carried
the values
about 300 and 500 km, and therefore
twi.e
both
out in a way which,
As a result,
for
are
the unwanted effects
in Ref. 3 and will not be repeated
and
i 966.
in June 4965 to permit
and means of minimizing
to make observations
tbe dates and times
and temperature
was modified
Unfortunately,
1 hour to 30 minutes
some loss of information.
are unreliable
mean Kp index over the period
C.
caused
These
density
non-real-time
in Ref. 3, was employed
to be explored.
1966, we attempted
II lists
electron
the spectrum
at the time,
in this report.
During
changed to reduce from
for later
extensively
spectrum
the ion temperature
not included
signals
the IF
discussed
of the signal
were
to obtain a complete
to this change,
though not recognized
introduced
procedures
by recording
In addition
halves
Procedures
the observing
amount of time
they
here.
Per mOnth fOr a peri Od Of 24 hOurs.
on which measurements
were
carried
out, together
with the
of observation
Data Reduction
Although
obliged
order
DATA-PROCESSING
Equipment
i 966.
were
AND
the measurements
to construct
to reduce
obtained
plots of the temperature
the scatter
eraged
to obtain the hourly
years,
were
reduced
afforded
to yield
the results
,!
temperatures.
~
day-to-day
been treated
employed
hitherto,
density
using a graphical
rected
for the variation
iation in electron-to-ion
because
Table
profiles
namely,
pulses
on consecutive
of the increased
was reduced;
111contrasts
were
by combining
overlay
method.
of the electron
temperature
was made POSsible in 4968, following
11
faced with the computer.
month.
resolution
the measurements
and electron
encountered
have
and ion
in i966,
with that for earlier
the radar measurements
the
period
measurements.
made with O.i -,
0.5- and %.O-msec
smooth
profile
section
Te/Ti.
with height resulting
Complete
the construction
machine
from
was then corthe altitude
reduction
of a new spectrum
has
in the reamer
This combined
‘1power”
av-
in previous
measurements
cross
ratio
from
in
were
for each calendar
time
we
intervals
as a rule,
each 24-hour measurement
this procedure
obtained
days were,
density,
solar activity
hence,
hourly
the measurements
the 30-minute
for each 24-hour period,
of electron
over
of 30 minutes,
like those obtained
behavior
to preserve
48 height profiles
of the behavior
separately.
because
the f965 results.
we attempted
Thus,
procedure.
Furthermore,
The electron
obtained
Thus,
here,
to yield approximately
siznilarity
Further,
plots showing the mean hourly
presented
by the observing
been reduced
results
mean profile.
a time resolution
and density averaged
of the measurements.
made only once a month for 48 hours,
fn reducing
during 1965 yielded
var-
of these data
analyzer
that is inter-
3
-—----”---.,’.
-..--..,.
I
I
TABLE Ill
OBSERVING
PROGRAM
No. of
)bserving Pericds
och @serving
Pericd
1963
OF YEAR
“ime Token to
Length of
Year
AS A FUNCTION
(hours)
per Mc.nth
30
A
Meawe
One
PrOfTle
6’=4
of Profi Ies
~o.
Obtained
pa Mcmth
80
1.5
Reduction Methcd
Employed
Mean
hourly profiles
constructed
calendar
for each
month
60
As above
0.5
96
.& .b.ve
0.5
96
Each profi Ie reduced
1964
30
2
I.o
1965
46
1
I ?66
24
2
Y
separately
—
9,.
[
Fig.
1.
Plot of fOF2 obtained
at four stdions
on 14 July 1966,
4
and assumed local variation
(solid line).
in previous
As
been established
observed
from
years,
the absolute
by normalizing
icmosonde measurements.
for the diurnal variation
Billerica,
Fort
results,
to the values
the values
lowed
except where
Wallops
Island,
obtained
from
that observed
locally,
other
- suggesting
stations
D3. RESULTS
A.
Contour
These
density
density
profiles
found a8 a function
these diagrams,
were
showing
these contour
listed
in Table
to remove
diagrams
the influence
since there
density
area
of this type.
this,
adjusted
to collect
close’0
all three
a mean profile
theresuMs
storm
hitherto
[Figs.
was constructed
the contours
effects.
inthe
intensity
3(a-u)]
out.
in Figs.
oxygen
relative
to molecular
increases
in density
5
3(a-u)
calendar
3(a-u)
nitrogen,
of the time
mOpe structure
sunspot number.
in the ionospheric
radiations,
toobThus,
sOme time Res-
irrespective
with increasing
These
averaged
of Nm=F2.
display
tbanin
by aver-
month.
~ additiOn,
for each hour,
of its ionizing
and what is nOt.
which are intro-
means constructed
mean value
rise to irregularities
a somewhat
show considerably
and less
As noted in the 1965 results,
intense magnetic
7-9
density.
The principal effect appear’s
However,
and structure
however,
their mean andthen
in the electron
the abundance of atomic
i2-i5
It is,
fOr
OperatiOn
4, 2 or 3).
monthly
in Figs.
of one of
Results
bad profiles
during a given
of the ionosphere
gives
an example
The smoothing
amount of structure
tohavethe
is to be
lines.
in the contours
(Refs.
above.
in 0.5-MHz
frequency
what is true variatiOn
all plots were
in the variability
in sunspot activity
through fluctuations
variations
of occasional
tended to be smoothed
Finally,
(u).
fluctuations
greater
outlined
smooth contours.
of measurement.
they vrere normalized
the results.
increase
The increase
tbe peak density.
observed
from
frequency
2 provides
to yield
in each of 24 hourly intervals
variations
plasma
by straight
to bave the same value of hmax F2as
Finally,
olution was lost because
fro-the
Previously,
and hour-to-hour
geomagnetic
drawn
was fol-
The variation
in the manner
3(a) through
marked
Despite
number of reasons
diagrams
taina. mean shape.
to large
curve
tO be e~remelY
given plasma
Figure
is no sure way of deciding
profile.
aging all the data obtained
directly
errors
than any that have been presented
owing to a real
tO cOm’bine the
seen at Millstone
considerably
values
of corresponding
on the diagrams
single
structure
required
fII order
plotted and a smooth
was found to differ
in Figs.
due to random
duced bya
day-to-day
were
shOtid be expeeted
were traced
11are presented
we have tended to de-emphasize
were
75-W
the variation
time was then constructed.
process
profiles
37-N,
the height at wbicha
subjective
There
74”W
at Millstone.
assigmed absolute
next given a scale
diagram
of local
were
As a rule,
earlier
the basis
stations
DENSITY
profiles
with a 30-mi. ute periodicity
more
40”N,
in which all the points have been connected
Subsequently,
is necessary
i 966 was to broaden
made at the following
of the other stations.
Millstone)
instances
has
of scaling.
ELECTRON
A contour
the periods
In general,
with all three
errors
measurements
Plots
The combined
intervals.
the C-4 ionosonde
by all four stations
but in several
FOR
Virginia
10 km from
profile
to match the value of Nmw
42 “N, 71 ‘W
New Jersey
of Fig. 1.
this disagreed
(approximately
measurements
Massachusetts
of foF2 reported
density
One change made during
Monmouth,
through as shown in the example
at Billerica
for the electron
at the peak of the layer
of foF2 by combining
1
in addition
scale
the density
storms
to bea
with a consequent
during the late afternoon
behavior
directry
through
can give
rise
lowering
of
reduction
in
have also been
{4-45 JAN {966
Fig.2.
cbtained
Plasma fmqw.cy
at 30-min.te
cOnto.r
intervals
&agmmcOnstructed
for 24-hour
6
frmelectron
pericd on 14-15
January
density pr0files
1966.
EST
(a)
I
IwO’=’
(
~””-
,
,
*wa
240.
ml
EST
(c)
b)
Smmthed contour diagrams of plasma frequency
Fig. 3(9-U).
&tai”ed
for 24-hour periods i. 1966.
7
vs height
and time
..
EST
EST
(f)
(.)
Fig. 3(a-u).
CO.tinued.
8
28-29
.,,
1966
PLASMA FREQUENCY IMHz I
Tm!EL
!s0
cam
MO.
o~
,,~
~-
EST
(9)
,2-13
w“ !966
PLASMA fREOUENCY {MHz)
I
EST
(h)
Fig. 3(a-u).
Continued.
9
‘m”
I
‘“m
,—
,,-?2
,,,,..
Ipma ‘ii
0400
J“, 1,S
FREOUE NC” {.”,1
1,-,8
,-,.s.,
mm
,200
Wm
.“.
!,66
FREO” ENC”
2W
(MHz]
7
, ST
(1)
Fig. 3(.-.).
Continued.
10
,
I
,2 -,3
,.,
s..
-L’
SEP 1966
F,,..,,.”
(MHI)
‘A
A
*:.
‘ad
EST
(n)
r
,“..,
3..
k
.-
35
Fig. 3(0-.).
Continued.
ii
~
2,-2,
.0” f,..
,LA$MA
FREQuENCY (MHz1
ma
A
CccO
c-x
.eca
-w
EsT
(s)
EST
(.)
Fig. 3(a-u).
COntin.ed.
:.0
~$..
2“””
24
found which we have attributed tO the influence of the electric field assOci*ted with the asFmet~Ic ~afl of the ring current.9 Of the days listed in Table 11, we would class only six as disturbed,
i.e.,
with an average
all the variability
scale traveling
during years
Kp value fOr the peTiOd Of greater
found here
ionospheric
of high sunspot number.
up by the heating
of the atmosphere
occurrence
of large
ionospheric
disturbances
always
properly
B.
disturbances
we dO not believe
that
produced
ionospheric
disturbances are tbougbt to he set
18-20
and, as such, the
elect rojet
by the auroral
with magnetic
activity.
have periOds “Of the order
Large-scale
Of <30 minutes,
traveling
and thus are not
Discussion
acteristic
‘<winter”
10
equinox,
This pattern
discussed
before.
increase
can be observed
diffusing
of the total electron
of the neutral
in the auroral
observed
chief characteristic
exhibit
Iusually
point.6
of the summer
Typical
near 0400 EST) cannot be
lines and thus raise
is tied to neutral
bmaxF2
can be as early
and lower
as 0200 EST
Similar variations
have been found
24
and may imply changes in the
for example,
occurred
by heat deposited
exhibiting
a winter-type
from
behavior
one type of behavior
the timing
is exhihited
of both morning
and evening
ionospheric
the loss
and 26-27 Sep-
from
winter-
of the diurnal
tO
var-
by days Of the
as seen in our data depends
in equinox.
in our data on 12-13 May,
there
is a distinct
19. iz and 14. i5 JUIY.
forenoon
peak.
The
I’bite-out”
phenomenon
peaks has given rise to the so-called
25,26
Based upon recent evident e, it would seem
workers.
is caused by the lowering
together
is the
to the other is not completed
of the transition
for observation
17-18 August and 26-27 September,
that has long fascinated
i 1-12 March
the~e am+ often days of one type followed
Thus,
This
in part by the rapid redistribution
all the days between
In ~965, we observed that the transition
3,io
In point of fact, measurements
on the days selected
summer-type
that the bite-out
~ind~ 22,23,27
While
in April.
at random.
behavior
e.g.,
unusual.
and is produced
Virtually
Near the time of tm.nsition,
On some days,
that increases
it was attrib-
Subsequently,
It would seem that tbe source
of tbe increase
brought about,
is somewhat
behavior4
at sunset.5
this type of behavior.
behavior
other type interspersed
m the actml
sunset.
a
content of the ionosphere,
on i 1-i 2 March
iation of foF2 show that the transition
all at once.
and
we have
In most cases,
the main peak on this day is shifted into the late afternoon.
above hmaxF2
summer-type
presence
UP the field
three
behavior
in Ref. 2i where
conjugate
but that the timing
winds in the thermosphere
enhancement,
of ionization
The first
zones.
The behavior
tember
at the conjugate
has a char-
the two in the
rose to a value of >7 MHz for
described
following
or as late as 0430 EST (20-22 December).
observations
predawn
frequency
rates .22S23 It may be noted that the time of the increase
(7-8 November)
between
during the late afternoon.
– a phenomenon
ionization
at Millstone
of Figs. 3(a-u).
since tbe time of the increase
to drive
observed
of the type of winter
critical
rapidly
must be the protonosphere,
winds which at night serve
pattern
diagrams
out of the protono sphere
with the time the sun is lowest
of the ionization
the loss
arid fell
density
with a rapid transition
samples
the F-1ayer
on 1300 EST,
we abandoned this explanation
reconciled
representative
On these days,
uted to ionization
electron
diurnal behavior
can be seen in the contour
are fairly
a few hours centered
predawn
that the F-region
and ‘qsummer”
the last six diagrams
from
Thus.
in our measurements.
VJe have noted earlier
small
Traveltig
is correlated
frequently
resolved
than 2+.
can be attributed to storm effects;
some may be caused hy largei6, i7
since these too occur with increasing
frequency
disturbances,
of hmax during the daytime
with a change in the composition
i4,28-31
rates.
i3
of the neutral
brought about by neutral
atmosphere
in summer
\_-
Several
tember
days show two or more
and 5-6 December)
ence of a large
traveling
was magnetically
successive
together
disturbance
density
(e. g., %2-43 Sep-
in bm= F2 that are suggestive
with fluctuations
ionospheric
disturbed,
peaks in the electron
However,
(TID).
neither
so that one cannot say with certainty
of the pres-
of the days mentioned
if indeed this is the correct
explanation.
Of the six days listed
22-23 Augmt
and 26-zI
during the major
ning increase
September)
magnetic
We believe
to drive
suggested9
exhibit
tbe layer
magnetosphere
behavior
than normal,
is conducted
into the F-1ayer
by charge
in the evening
similar
to the pattern observed
in Ref. 9.
on those days,
and was associated
separation
the eve-
with a large
of an electric
increase
field
where the loss is reduced.
along lines
of magnetic
of the electrons
Since the injecti~n
sector,
January, i‘2 April,
2i ’22
is caused by the presence
part of the ring current.
principally
that is very
via E X B drift upward into regions
where it is produced
with the asymmetric
fOur days (tiz.,
storm of June i 965 and discussed
that this phenomenon
that this field
rent occurs
II as “disturbed:’
was much more pronounced
in hmax F2.
serves
in Table
this explanation
force
readily
We have
from
and protons
of the plasma
which
the
associated
into the ring cur-
accounts for the phenomenon
being seen only in the late afternoon,
and is associated with positive increases in the total field
32
who have studied this same phenomenon via measurements
locally.
Mendillo,
S @.,
observed
of total electron
content,
itation of ionization
transport
from
of ionization
confirm
these findings
but attempt to explain
In the absence
the protonosphere.
during these increases,
it fails to account for the increases
always
it is difficult
occurring
them in terms
of measurements
to reject
before
sunset,
of precip-
of the vertical
this explanation,
i.e.,
although
when production
is still
taking place.
Following
these pronounced
the next morning
and exhibited
this to an increase
evening
increases,
Of Nz relative
and one is left with an F* -layer.
lieved
from the increased
F-region)
normal
Possibly
together
one,
to transport
the heating of the atmosphere
(Table
from that observed
on i4-i
er
give rise
ing produced
to more
N.
pronounced
but serves
increase
ELECTRON
TEMPERATURE
A.
Plots
Contour plots of electron
in the same manner
Like the electron
and probably
effects
temperaturevs
contours,
the same reasons
storms
it.
relative
tO N?,
altitude
density,
depletion)
andtime
apply (see Sec. 111).
storms
more
very
structure
greatly
occurring
in summ-
that the heat-
disrupt the normal
hemisphere,
the effect
is to
in the winter
hemisphere
the
appear
offset
have been constructed
and are presented
these toodisplay
14
whereas
the
for this change.
This would suggest
In the summer
from
were made during 1966
does not completely
in O and the storm-time
as those for electron
density
that magnetic
is be-
toward the equator.
on this day does not differ
in fact,
to modify
atmosphere
N2 and O in the
latitudes
zone is responsible
than those in winter.
for 0 to be depleted
(the seasonal
Contour
the behavior
It seems,
the F2
wind pattern that differs
day on which measurements
zones by magnetic
wind system,
the tendency
two effects
However,
5 January.
in the auroral
thermospheric
reinforce
II).
to increase
high and temperate
in the auroral
It may he noted that the most disturbed
was 2i -22 January
(which serves
of a thermospheric
O from
In essence,
tO O in the F-reti.0n.9
The change in the neutral
temperature
with the establishment
and appears
was formed at a very low altitude
i2-i5
we have attributed
Along with others,
a low peak density.
in the ab~dance
peak is reduced
to result
the layer
to one another.
essentially
in Figs. 4(a) through (u).
thanhs
beeri~oted
hitherto,
w
(a)
TEMPERATURE 1% I
.
04s3
om.a
I
12W
IW
2=0
-
2-
-
08CC
(c)
Smoothed conhxrd iagramso felectront
cbtcdned f0r24-hmmperiodsin
,...
,s,
EST
b)
Fig. 4(a-u).
,ZCC
1966.
i5
emperaturem
height and time
z=
J
,W
EsT
W-,,
!4..
u’
lmzzFL
TWFSRATURE
(W
COx.xcomn’w
,
,Wm
WC-3-=
,
tam
E,?
,s,
(f)
(.)
Fig. 4(a-u).
,
I
Continued.
,
7,MPEIIA,”8E
,
-2CC0,*.
r.}
EST
(9)
3
,,-2,
J“. t,66
,,?JERATuRE
[%
“lizmci_
,Xa
feca
2C.W
s-m
Es,
ES1
,,
.,..
(i)
(h)
Fig. 4(a-u).
I
Continued.
’11
2400
ES,
EST
(i)
(k)
EST
(1)
Fig. 4(0-.).
Continued.
.
EST
EST
(0)
(n)
m.
5..
.0.
,..
,00
Es>
,s,
(4
b)
Fig. 4(0-u).
Continued.
,...
—
-
XcO
!@.
28C0
P
SCa
*W
,400
f’
2400
~w
/
(m
22C0
2X.3
/
~
‘“
few
p
.,=--’
““
F-
’600
--WV
~
’400
,,.0
K.3
,Wu
,,/
, ecu
!000
feoo
!200
‘o”
p-f
!600
7-, .0”
$966
TEMPERATURE 1*K1
2000
,~o
EST
(s)
-f-=’
Fig. 4(a-.).
Ccmtin.ed.
20
F
The diurnal
reports.
rise,
variation
The most common
followed
by more
rapid fall at sunset.
behavior
5-6 December),
is a very
the temperatures
is a period
again.
following
which remains
which is almost
1“ winter
ways.
warmed
There
caused by the nocturnal
when the
into the ionosphere
that escape
of cooling
increase
This
14-i 5 January,
until midnight
by photoelectrons
a period
sunless
during the night.
(e. g.,
lasting
during
and a somewhat
this to heat conducted
follows
in previous
in temperature
tend to change little
attributed
sunlit.
certainly
rapid rise
extensively
during the daytime
sunset and u.wally
We have previously
which is continuously
hemisphere
near midnight
of behavior
has been discussed
in a number of recognizable
the protonosphere
conjugate
temperature
steady temperatures
Thereafter,
there
rises
form
or less
can be modified
temperature
from
of electron
from
the
usually beginning
in the local
density
(see Sec. III),
On a number
reached
of days (e. g.,
its peak value immediately
especially
noticeable
at altitudes
pear to be a regular
22-23 August
somewhat
of the normal
in June 1965.
before
much sooner
large
behavior
for example,
temperature
somewhat.
maximum
This is
does not ap-
recognized
on the days [20-21 January,
‘f-2 April,
earlier
pattern
a pronounced
of this,
as following
increase
value with the result
the electron
following
density
temperature
sunrise,
that the electron
a storm
in electron
Fig. 4(m) ]; no well-defined
The next morning,
the case.
below its normal
that were
Average
Temperature
began to decrease
decrease
occurred
tbe electron
temperatw-e
occurred
density
at sunwas de-
rose to unusually
encouraged
Profiles
of the temperatures
to change little
us in the past to compute
average
has been done for i 966 with results
contours,
an average
val on all the temperature
0300 EST (nighttime),
with altitude.
minimum
These
available
a“erage
temperature
was in operation
phenomenon
in Figs.
of the year,
(Table
1).
values
observed
that N ~ax
3(a-u),
the critical
A period
minimum
frequency
morning,
and the daytime
minimum
in electron
during the daytime
temperature
or above
At Millstone,
previous
hmaxF2
a temperature
when the radar
existed
this value until toward
for part of tbe afternoon
When these afternoon
an average
curve
and 2100 to
down to a fixed
atmospheres,
increase
did not begin to reach
when foF2 > 9.5 MHz.
for the following
This
obtained sin. e %966 (unpublished),
it appears that this
6
As can be
about iO el/cm3/see,
i.e., foF2 - iO MHZ.
approach
when a temperature
profiles.
In constructing
at each iOO-km height inter-
and St. Santin de Maurs.
results
and at night has
i 000 to i 500 EST (daytime)
all show a monotonic
Arecibo
(u).
were then extrapolate ed smoothly
of a temperature
From
requires
imum is obscured,
between
period
temperature
5(a) through
once in i 966 and not at all in any of the years
Fig. 4(t) (5-6 December)
the results
and nighttime
in the 1965 CIFM model
profiles
at Jicamarca,
was observed
daytime
was taken of the temperatures
profiles
The appearance
has been reported
during the midday
that are shown in Figs.
of 355 “K at i20 km incorporated
The average
seen
and then decreased
is observable
As a ree”lt
ground sunset,
The tendency
“alue
sunrise
the electron
values.
B.
these
December),
300 to 400 km, but this pre-nmm
On those days,
than usual [see,
set as is normally
pressed
following
above
and 26-27 September)
observed
20-2i
occurrence.
A third variant
first
20-21 October,
in Fig.
daytime
profile
5(t) merely
results
the end
is seen in
are combined
with
is obtained in which tbe min-
exhibits
a kink near
300 km.
2i
——.
—-,.————
.,,.W.W.-..
.:..s-,
t
TEz31il
Lll)lllll
.Ce
o
,ca
!2CC
!...
*CC.I
2403
28CC
320(
TEMPERATURE [-,1
(a)
1
2,-,2
,00
JAN
,s66
N(GHT
t
I
e
,
ImEcL
(
40,
I
800
I
t
I
I
I
1
I
‘4”” “m “m 3’0
,200
;%,..,:::,.,,
b)
Fig. 5(a-u).
Average
daytime
(1000
tO 15cX3 EST) and nighttime
temperature pr.afi Ies ccmstruc ted by averaging
each 100-km altitude.
,
,
1
,1
22
.“:~
—..
I
tem~ratures
(2100 to 0300 EST) electron
cbtained
in these intervals
@
~LL-*J
...~...L..:&)...)
L
L. .,---
(c)
I
!,-,2
MAR
u—
RLA::.K) 240” “0° ’20”““’
<,66
Fig. 5(a-u).
Continued.
23
I
I
.
,6-,7
I
.00
MAR
4,6,
I
,00
4
4,00
1
,
,,
1
4600
MPER.TU.QE
!
(..)
(f)
...
fig.
5(a-u).
Continued.
24
,&...
I
I
2000
1
1
2400
$
!
z,..
,
J,.,
,t))l)l)ll,2,
.00
,..
!200
!600
,,.,,,.7
2000
”., (-K)
(h)
Fig. 5(a-u).
Continwsd.
,..
,,.
““,j
25
240.
:’::o
!0..
28-29
JUN
!966
I
!600
!,00
,,.,,,.,
”.,
I
I
2000
,..
1
2.00
mm
)
(0
7
.
I
4..
s..
,
,
!m.
d
,
,
.. . .
(
20.30
TEMPER,T”RE
,
(.,
(i)
Fig. 5(0-.).
Continued.
26
)
,
2.00
,
I
2..0
3.0.
36.
I
. .
‘~
.
.
HE,GHT
,,.
)
.:
“E,G” T (,,”1
2,-23
A“,
$,66
0
.00
:
.00
-
;
‘#
$4(.”,
..0
20.
–
TiEEIIL
.
1
0
1
1
1
.,.
I
.. .
1
1
i
I
,m.
1
1
woo
PC+.
TEMPERATURE
I
1
MO.
ZOO.
I
1
1
’200
‘G
<-K)
(m)
,.,
I
i
I
.
.0.
I
800
,
1
!2.0
1
!
I
f...
1
1
20..
,EMPER.TURE
l-K1
(n)
Hg. 5(.0-”).
Continued.
28
1
?4’39
1
1
‘“””
,
,
‘2””
.
I
26-’7“’’’”
I
t
I
4..
I
I
..0
,
,,00
,
,600
,,!4,,,,,
”,,
I
mm
J
,..
,
1
2..0
I
I
,,0,
)
(0)
~
o
,
4.0
,
,00
,,0.
,m.
,600
TEMPERATuRE
Fig. 5(a-u).
29
,-,,
Continued.
(
....
,
... .
,
,*<
I
r
,m.
20-2t
OCT 1966
,
<
..0
0
,
,
,
,
,
(
I
!200
8..
!...
T, M, ER&TURF
,
20,,
zfoo
2800
(.K)
(q)
It
‘-’ ‘“v ““
,
0
I
. . .
,
800
f...
TUAPERATURE
(-K)
(r)
fig.
5(a-.).
Continued.
30
I
#
t
$
-00
ZOoo
““”
,
,
2“0”
,
3“
28-2,
,00
,0”
4,6.
–
.
e...
–
..0
-
z
~
:
F,
r
Zoo -
;!,
?.,1.,(]
.
.. .
I
...
,20.
,,00
,...
‘-6‘EC“e’
\
Fig. 5(a-.).
I
Continued.
,4.0
,800
,,00
,.0,
20-22
OCC (966
Continued.
FicI. 5(a-u).
v.
SEASONAL
A,
VARIATIONS
Electron
Temperature
The average
temperature
plots shown in Figs.
sonal variations
of electron
and (b).
6(a) presents
Figure
temperature.
5(a-u) have been employed
The results
a contour
diagram
of average
electron
time vs height and date, and Fig. 6 [b) provides
a similar
plots,
the contour intervals
The most striking
higher
temperatures
plied from
&te
the protonosphere.
for the daytime
variation
are 500 “K apart.
at night in winter
at night,
than in summer;
Figure
these plots show the existence
with the highest values being encountered
duced for earlier
of the variation
spot cycle
years
to be of the order
since in previous
The minimum
on the basis of the variation
Fig. 9 of Ref, 10).
the layer
electron
becomes
variation
density,
storms
of a smaller
in Ref. 30.
not
so
pronounced
as observed
its seasonal
is a result
occurring
tion is the abnormally
in Figs. 6(a-b)
on several
high temperatures
and I(a-b)
encountered
de-
with the sun-
or November
(see
peak at tbe same time and
it would seem that
variation
of F-region
flux from the sun.
tO be real and associated
above.
variation,
here.
in October
of the seasonal
appears
days as reported
daytime
the variations
increases
Thus,
around 0.tober-November.6
temperature
seasonal
or January as might be expected
but rather
that Nmax F2 reaches
heat sup-
of 300 km, the amplitude
but probably
is not found in December
a minimum
of electron
7 (a) supports
At an altitude
of 300” to 500 “K,
ti both
at 500 and 300 km vs
the marked
but well-defined
Figure
for tbe day-
period.
for nocturnal
confirming
and is not brought about hy a change in the energy
Some of the structure
magnetic
it was
sea-
of these plots is the
temperature
Besides
of the sun’s zenith distance,
It is noteworthy
thickness
the seasonal
years
in the temperature
feature
this is evidence
in summer.
which are discussed
appears
temperature
plot for the nighttime
7 (a) shows the electron
and Fig. 7(b) for the nighttime.
tO inveati@e
are shown in Figs. 6(a) and (b) and 7(a)
The clearest
with the
case of this associa-
at night on 26-27 September
[Fig. 7 (b)].
32
——...,.,.,=
-.
.
OAYTIMC ,VERAGE
-
[..1
I
-IA
‘“-7’
,
Y.03
1
ELEcTRON TEMPERATURE
‘d
If
\
\
#!t
1’
/“
A
,,66
(.) ~ytirne (lOOO t. 15W EST).
1,,,,,1,1~’1’’’’’l’~
NWITTIME
NERAGE
ELECTRON
TEMPERATURE
(-K>
lmm
!666
(b) Nighttime
Fig. 6(a-b).
derived
COntcur plots with 50&K
frmn average
temperature
(2100 to 0300 EST).
intewals
of el ectro.
profi 1.s of Figs. 5(.-u).
33
temperature
vs height and season
4
,.+
i
lam
JiN
!0?3
ma
,Om
MAR
,o~
A,,
,o~
MAY
l,(l!lllllklml~
;“;
‘m
wL
‘:”:
,Om
SE,
!020
~,
*.0”
g
,,66
~)
,!
Nighttime
(210il
tO 0300 EST).
“1
‘1
Fig. 7(cI-b).
seasonal
from overage
ternper.at.re
variation
of electron
tempemture
profi Ies of Figs. 5(a-.).
.i
34
at 300-
and 500-km
altitude
~tained
.-—.”-
-----
Above-normal
.--T.
temperatures
storms,
to he limited
creases
in the total magnetic
to the period
by heat introduced
by Cole33
tures
the phenomenon
of nocturnal
observed
locally.
into the magnetosphere
to explain the stable
conducted
Thus,
satellite
and is accom~nied
via the injection
observations
related
The occurrence
by de.
we have argued that the phenomenon
of ring current
This idea was first
into the ionosphere.
red arc seen at midlatitudes
support from
i -2 April
heating
in all storms.
of the main phase of the storm,
field
and that this heat is subsequently
and has received
on the nights of 2t -22 January,
and showed that it is not seen at Millstone
appears
is caused
also encountered
In Refs. 7 and 8, we discussed
and 22-23 August.
to geomagnetic
were
particles,
proposed
during some geomagnetic
of the exi8tence
storms,
of high electron
tempera-
in such arcs?4,35
By contrast,
sometimes
the average
appear
the late .afterrmcm.
served
electron
10
peratures
This type of behavior
in tbe average
for the afternoon
the next morning
The reason
Figs. 5(a-u)
because,
day of a magnetic
density
to tbe low average
in se”er-al
temperatures
The daytime
cases,
with abnormally
storm
encountered
abnormally
in
ob-
effects
are
low tern -
high ones en.o.ntered
was low).
Heat Flux
lies in the existence
of this heating,
electron
and 26-27 September.
have been combined
for the monotonic
the protonosphere
has contributed
density
on the first
due to the large
1-2 April
temperatures
period
(when the F-layer
Protonospheric
B.
temperatures
than normal,
in Fig. 7(a) on 21-22 January,
less pronmmced
increase
under normal
deposition
“ia encounters
with ambient
on the total escaping
in electron
temperature
of a flux of heat conducted
into the ionosphere.
the subsequent
limit
daytime
t. be lower
is the escape
fraction
electrons.
along the magnetic field lines from
36-38
that the most likely source
of photoelectrons
of the photoelectron
As such, the observed
that the energy
in the photoelectron
in tbe escape
flux.
energy
from
the ionosphere
and
in the magnetosphere
heat flux should place a lower
tbe observations
made in i964,
36,37 This is in
40
accord with calculations
of the escape energy performed
by Fmtheim,
et
al. ,39 Duboi”, ~ ~.,
——
41
42
and Nagy, et
al,,
Nisbet,
among others.
Experimental
estimates of the escape flux have been
——
44
and
made from temperature
profile measurements
by %natani and Hanson, 43 Bauer, et al.,
45,46
from direct satellite observations
by Rao and Maier,
which are as large or larger than our
we deduced
energy
seen in
We have shown elsewhere
conditions,
of a large
with altitude
flux must exceed
From
5 X 109 eV/cm2/sec.
estimate.
Despite
energy
early
this large
extracted
workers
Experimentally,
direct
satellite
of particles
arriving
at the conjugate
the energy
g
some uncertainty
.–{,95XI0
It has recently
-i2
energy,
to be scattered
in the magnetosphere.
in the magnetosphere
E is the photoelectron
electrons.
hemisphere
deposited
has it heen fully included.
unit path length
ds
where
remains
in the fraction
In part,
flux in the magnetosphere.
this arises
of the
because
the backscattering
of photoelectrons
arriving at the conjugate ionosphere.
47
and in
this has been observed through plasma -line observations
at Millstone
45
This phenomenon may cause as much as 50 percent of the flux
measurements.
(Nagy and Banks49)
per
there
neglected
thus tends to increase
energy
amount of effort,
from the photoelectron
In most papers,
back along tbe field line, and
48
Only in one recent paper
the rate of loss
has been taken as
of photoelectron
50
N
~ eV/cm
(i)
s is the path length,
been suggested
and N is the density
that this equation underestimates
35
of the ambient
the loss
rate for
5$
photoelectrons.
flu% is deposited
Thus,
We have attempted
sphere
at high latitudes,
to calculate
along the lines of force
temperature
the heat flux
from
7.7 X 105 T~/2
~
heat flux,
it is necessary
dTe/dh was estimated
above
from
via Eq, (Z) employing
estimates
and nighttime
daytime
for
a variation
is not clear
observed
shown in Figs.
The values
profiles
observed
above the
38,44
each t 00-km
The heat flux was
and an average
of Q obtained in this way from
in 1965 (Ref. 10).
of the daytime
Figure
i.e.,
Results
8(a) shows
somewhat
obtained
flux with a minimum
larger
during
in local
fmmmer.
The exact source
of a seasonal
variation,
at present.
flux [Fig. 8(h) ] shows a marked
seasonal
at tbe conjugate
the flux falls to an extremely
small
appear
that the high values
value
variation
expected
as a consequence
point at night in local winter,
set by the cooling
to be real and associated
wYT,ME
In local
disturbances.
23 August and 29 November
WE61 f..,
lzzza
m —wllbld!l,
!020
JAN
l<t,
<,18,
,,,
,.20
,02.3
(!
,020
mm
,,,
MAR
.,.
MA”
l,,
$1,
l,,
*a
,“.
,rrl,,,
,083
Jo,
((lt(~
ma
ma
.“.
SE,
@m
mm
ma
cc,
.0”
.,.
,%6
(.)
wgt
flux carried
of Figs. 5(.-u)
Daytime
into icmxphere
(1000 to 1500 EST).
via electron
sum-
of the protonosphere.
with the magnetic
seen in Fig. 8(a) on 22 January,
AvER&2E
s,. -
Fig. 8(a-b).
of
the mean
here [Fig. 8(a)] seem to support this but do
(2:1) as found in i 964.
Some peaks in Figs. 8(a-b)
profiles
the
important.
over
5(a-u).
are shown in Figs. 8(a) and (b).
variation
of the sun being above the horizon
we believe
differences
profiles
substantially
to the ions has become
the temperature
1965 (Ref. 10) and those presented
The nighttime
at an altitude
heat tlux was about 4 X 409 eV/cm2/see,
to show a seasonal
not exhibit as large
Thus,
dTe/dh and
Eq. (2) to estimate
to employ
the mean value of Te for &at internal,
than the value of 2 to 3 X i 09 eV/cm2/sec
i 964 appemwd
In order
the electrons
of Q was then taken.
temperature
that in f966 the average
mer,
from tbe magneto-
gradient
(z)
field.
500 km for the mean temperature
then calculated
the separate
if real,
the ionosphere
temperature
to make measurements
Accordingly,
The results
electron
magnetic
the rate of local beat loss from
daytime
in tbe escaping
sin2 1 eV/cm2
height where
interval
Q entering
the observed
I is the dip angle of the earth!s
arriving
all the energy
To through
Q.
where
be that almost
it may
in the magnetosphere.
gas as deduced from average
w season.
36
—..
temperature
ma
1,111,,,111
,vE.QAw
N !GHTT, ME HE4T FLUX
,s z
q
“s
‘2 :
:
>
.,
-
i
.4 -
m
,.0 ~1
(mm
,AN
1,,1,
~
mm
1111111
,Oza
,Om
0,0
Oa
FEB
MAR
@.PR
MAY
mm
WN
mm
JUL
!Oa
AU.
0s0
SW
mm
OCT
Om
NO”
DEC
,366
(b) Nighttime
(2100 to 0300 EST).
Fig. 8(a-b).
are manifestations
those days.
of additional
Similarly,
and 28-29 November
discussed
above,
VI.
heat being supplied
to the ionosphere
from
the protozmsphere
the peaks in Fig. 8(b) on the nights of 2f -22 January,
probably
represent
this heating appears
is caused by heat deposition
tons (possibly
Continued.
nocturnal
to coincide
heating events associated
with storms.
with the main phase of the storm
in the magnetosphere
through ion-cyclotron
through the loss of energy
damping by ambient
cm
26-27 September
As
and probably
of ring current
pro-
electrons).
SfJMMARY
The Millstone
sities
Hill Thomson
and t emperat”res
during
month.
The measurements
interval
roughly
construct
scatter
yielded
contour
diagrams
structure
an electron
believe
ospheric
this,
i 965 (Ref. 3).
fluctuation
first
was lifted
the results
i -2 April,
witnessed
electron
follow
trends
per
over the height
as a function of
These
time
variability
plot S show
resolution
have not been presented.
of
We also
of the ionosphere
EIJV output and the presence
recognized
of traveling
for the data collected
22-23 August and 26-27 September)
in June 9965 (Ref. 9).
to an abnormal
The great height of the layer
normal
of the improved
in the hour-to-hour
of the solar
profile
den-
twice
data have been used to
3(a-u) and 4(a-u) ].
A number of daye appear to have been magnetically
(2i -22 January,
layer
partly as a result
These
and temperature
[Figs.
electron
re-
ion-
disturbances.
Despite
behavior
of density
and the fact that mean monthly averages
increased
F-region
approximately
and temperature
of 30 minutes.
of observation
that there has been a real increase
sulting from
density
showing tbe variation
than found heretofore,
the measurements
to measure
of 24 hours at a time,
f 50 to 750 km in a time interval
height and time for each of the periods
greater
radar was employed
f 966 for periods
temperature.
a6@eS intO the ionosphere
density
We attribute
along magnetic
achieved
of the first
to an east-west
four
storm
day, the
densities.
for lower-than-
electric
lines from the magnetosphere.
37
storm
higher-than-normal
appear to have been responsible
this behavior
field
and at least
exhibit a characteristic
Late in the afternoon
height and simultaneously
and large
in i 964 (Ref. 2) and
distm-bed,
field
that prop-
The electric
field
is produced
by charge
for the asymmetric
rected
separation
portion
north and upward,
and neutral
low and the electron
(principally
a large
The results
ture profiles
increase
can be examined.
in the daytime
exceeding
morning,
the reverse
temperature
into the evening
The electric
the downward
sector
field produces
diffusion
shows a slight
summer
to construct
di-
due to gravity
– the peak density
this is caused by composition
average
increase
ones that is probably
heat flux conducted
seasonal
variation
A large
of the Opposite$ind
variation
variation
point which remains
(winter > summer),
is evident
sunlit
(winter
in winter.
ACKNOWLEDGMENTS
The author would like to acknowledge the efforfs of W. Abel,
W. A. Reid and J. H. McNally in collecting these data; atso,
R. Julian, J.K. Upbam, Mm. A. Freeman, Miss D. Tourigny
and Miss L. Zak in various p+rtions of tie data reduction.
The continued support of P. B. Sebring is also gratetily
ac!-mowledged.
,“/
,...
I
,,,
J
38
day-
of
from the protonosphere
but no
temperatures
to be caused by the heating of the protonosphere
from the conjugate
into tbe
(300” to 400 “K) in the summer
caused by tbe seasonal
nighttime
tempera-
and heat flux conducted
into the ionosphere
is
changes
regiOns.$5’3i
daytime and nighttime
in the temperature
We find s significant
ones) and is believed
escaping
is often encountered
We believe
variations
for this has been offered.
photoelectrons
L
and responsible
an E X B drift
of ionization
in NZ) brought ahout by the heating of the aurOral
over the winter
The average
behavior
is high.
have also been employed
density.
explanation
of the ring current.
and hence opposes
from which seasonal
time temperatures
electron
injected
winds,
On the following
ionosphere
of the plasma
by
___
..
..
REFERENCES
1. J.V. Evans, “Ionospheric Backscatter Observations at Millstone Hill,” Technical ReptJrt 374,
Lincoln Laboratory, M.LT. (22 January 1965), DDC AD-616607.
2. _,
“MiJlstone Hill Thomson Staffer Results for 1964: Tecbnicat Report 43o,
Lincoln Laboratory, M.I.T. (15 November 1967), DDC AD-66 B436.
3.
“Mfflstone Hill Thomson Stiffer Results for 1965Y Technical Rep.a
Lincoln L&oratory,
M.1.T. (8 December 1969), DDC AD-707501.
4. _,
FJanet. Space Scf. @
5, —,
6
—
103i (1%5), DDC AD-616607.
J. Geophys. Res. ~,
1175(1965), DDCAD-51431O.
, Flanet. Space Sci. Z&, 1387(1967).
7,
,J. Geopbys. Res. 7&, 4803(1970), DDC AD-714447.
8, —
, J. Geophys. Res. ~,
9,
,].
10. —>
11,
474,
4815(1970), DDC AD-714446.
Atmos. Terr. Fbys. ~,
Planet. Space Sci. ~,
1629(1970), DDC AD-716057.
1225(1970), DDC AD-716056.
R. F. Julia,nand W.A. Reid, “incoherent Scatter Measurememsof F-Region
Density, Temperamres, mdVeflicaS Velocity at Millstone Hill; Technical Report 477,
Lincoln Laboratory, M.I.T. (6 February 1970), DDC AD-706863.
12, G. A.M.
King, planet. Space Sci. ~, 95 (1962).
13.
,J. Atmos. Terr. Phys. 3LJ,1733(1968).
14. R. A. Duncan, Flanet. Space Sci. ~,
15. R. B. Norton, Proc. IEEE~,
16. G. Theme, J. Geophys. Res. z,
17. J. Testudand G. Vasse.r,
6319(1968).
Ann. Geophys. Z&, 525(1969).
18, M. J. Davis and A. V.daRosa,
19. W. BlumemandR.Hendl,
841 (1969).
1147(1969).
J. Geophys. Res. ~,
J. Atmos. Sci. ~,
210(1969).
20. G. Cbimonasand C.O. Hines, Planet. Space Sci. ~,
21. J.V. Evans, J. Geophys. Res. ~,
5721 (1969).
565 (1970).
4331 (1965), DDC AD-623606.
22. H. Risbbeth, J. Atmos. Terr. Pbys. 3Q, 63 (1968).
23. G. Vasseur, J. Atmos. Terr. Fbys. ~,
775 (1970).
24. J. A. Klobuchar, J. Aarom and H. Hejeb Hosseinieh, J. Geophys. Res. ~,
25. J. A. Ratcliffe,
J. Geophys. Res. &
463 (1951).
26. B. Chatterjee,
J. Geophys. Res. ~,
353 (1953).
7530 (1968).
2-1. H. Kohl, J. W. King and D. Eccles, J. Afmos. Terr. Ybys. 3Q, 1733 (1968).
28. H. Rishbefb and C. S. G.K. Setty, J. Atmos. Terr. Phys. Q,
29. J.V. Evans, J. Geophys. Res. ~,
30.
3343 (1967), DDC AD-658912.
and L. P. Cox, J. Geophys. Res. ~,
31. L. P. Cox and J.V. Evans, J. Geophys. Res. ~,
32. M. Mendillo,
263 (1961).
159 (1970), DDC AD-703492.
6271 (1970).
M.D. Papagiamis and J.A. Klobuchar, Radio Sci. ~, 895 (1970).
33. K. D. Cole, J. Geopbys. Res. ~,
1689 (1965).
34. R.B. Norfon and J.A. Findlay, Planet. Space Sci. ~,
1867 0969).
35. J.A. Findlay, P.L. Dyson, L. H. Brace, A.J. Zmuda and W. E. Radford, J. Geopbys.
Res. ~,
3705 (1969).
36. J.V. Evans, Planet. Space Sci. l&, 1557 (1967).
37. —
p. 717.
, Space Research VIII (North Holland Publishing Co., Amsterdam, 1968),
38.
and G. P. Mantas, J. Afmos. Terr. Phys. ~,
39
563 (1968).
!
39.
E.G. Fontheim, A. E. Beutler and A. F. Nagy, Ann. G60phYs. z,
489 (1968).
40. M. L. Duboin, G. Lejeune, M. Petit and G. Weill, J. Atmos. Terr. Phys. 30, 299 (1968).
41. J.S. Nisb-et, J. Afmos. Terr. Fhys. 3A, 1257 (1968).
4.2. A. F. Nagy, E.G. FontheIm, R. S. Stolarski and A. E. Beutler, J. Geophys. Res. ~,
(1969).
43. S. Sanatani and W. B. Hanson, J. Geophys. Res. E,
469 (1970).
44. P. Bauer, G. Lejeune and M. Petit, planet. Space Sci. E,
45. B. C.N. Rao and E.J. R. Maier, J. Geophys. Res. ~,
4667
1447 (1970).
816 (1970).
46. E.J. R. Maier and B.C. N. Rae, ,%Geophys. Res. 7J, 7168 (1970).
47. J.V. Evans and I.J. Gastman, J. Geophys. Res. ~,
48. P.M. Banks and A. F. Nagy, J. Geophys. Res.
807 (1970), DDC AD-704626.
7&, 1902 (1970).
49. A. F. Nagy and P.M. Banks, paper presented at the XIII Planetary Meeting of COSPAR,
Leningrad, 20-29 May 1970.
50. A. Dalgarno, M. B. McElroy and R. J. Moffett,
Planet. Space Xi.
~,
463 (1963).
51. A. F. NasY, private communication (1970).
40
. “=...
—
UNCLASSIFIED
Securitv Classification
00CUMENT
(secu,lIYcla,.#ftoellm
,,
ORIGINATING
ACTIVITY
of ,{,1.,
body of .b.,,ac,
(C-F----
CONTROL
&
Ind.xi%!
OATA
mn.,..,lon
-
m“ei
R&D
be entered
2*.
..”lhor)
when tha 0“.,.11
REPORT
mP.rt
SECURITY
is .Ia.d{led)
CL& S,, FtCATt
ON
Unclassified
Lincoln Laborato~,
3.
REPORT
M.I.T.
2b. G,OU?
None
TITLE
Mitlstone HiU Thomson Scatter Restdts for 1966
..
DESCRIPTIVE
(%.
NOTES
of rnmrt .ndincl. sive date.)
Technical Report
5.
AU THOR{S1
Evans
6.
.!s,0,,
<Lam
“a”ze,
, John
V.
1,,s,
.-.,
in ft?d>
7..
DATE
19
..
CO. T.AC7
PROJECT
0.
NO.
GRANT .0.
0.,.,
F19628.70<-oz30
7X263304DZ15
,,.
76.
PAGES
NO.
0,.,,
OF
REFS
51
.EPO.
? NUMBER(S1
Report 481
R.,..,
ed t.,.
.0(s}
(.4.,
.th.r””,mb.r.
(ha, “,.,
b.
report)
ESD-TR-71-7
.,
NOTICES
AVAILABILITY/Limitation
Approved for pubtic release;
,.
N.,0.,,
Technica3
a.eig.
,0,
OF
48
,..
6..
NO.
,0,..
1971
January
SUPPLEMENTARY
distrihmion unlimited.
,2.
NOTES
SPONSO
R,..
MILITARY
AC T, VITY
of the Chief of Research
Department of tie Army
Office
None
and Oevelopnent,
i
,,
.,s,...,
This report presents F-region electron densities and electron temperatures observed during
the year 1966 at the Mitlstone Hill Radar Observatory (42.6-N, 71.5” W) by fbe UHF Thomson (incoherent) scatter radar. The measurements were usually made for periods of 24 hours twice per
month, and covered the akitude range 150 to 750km approximately.
The time required to collect
all the measurements spanning fhis hei@ interval was 30 minutes, i.e., ha2f that of previous years.
The results exhibit a greater amount of random time variation than seen heretofore, partly as a
resutt of the ~tter time resolution achieved and partly because each day bas been amtyzed individually, i.e., we have discontinued the practice of computing onty the monthly mean behavior. We
believe, however, that the largest patt of the random variation is real and results from fluctuations
in the solar EUV flux, which increase in magnitude as the sunspot numkr rises. Also, we expect a
growing incidence of fluctuations prcduced by large-scale fraveling ionospheric distm+ances as we
apprOach sunspot m~mum.
Despite fbis v=iabili~,
tie ch=acteristic
“winter” md” summer”
type behavior reported for Millstone in previous years is clearly recognizable.
On four days in
which pronounced effects due to geomagnetic storms are evident, the layer rose to great heights in
the late afternoon and achieved an abncmmdly hi$ densify (and lower-than-norma3 temperature).
The reverse behavior was encountered fbe next morning. This sequence is similar to fbat first
seen in June 1965, and its interpretation in terms of current ideas is summarized.
,,
KEY
WORDS
Millstone radar
F-region
diurnal variations
electron demify
ionospheric scatter
seasomd variations
41
temperahme effects
spectrum analyzers
UNCLASSIFIED
—
Security Classification
..—
.—