Technical Report
537
J. IL Evans
R. R. Babcock, Jr.
. Millstone Hill
Thomson Scatter Results
.~ for 1973 .
J. M, Holt
22
Prepared for the National Science Foundation
under NSF Grants No. ATM75-22193 and ATM79-09189
Lincoln Laboratory
MASSACHUSETT$ INSTITUTE OF TECHNOLOGY
LEXINGTON. MASSACHUSETTS
October 1979
ABSTRACT
During
1973,
(42. 6°N,
the
71 .5°W)
temperature
and
one
times
or
two
200-900
This
vertically-directed
was employed
vertical
per
presents
to measure
ion velocity
month.
km approximately,
report
incoherent
in the
The
scatter
electron
density,
F-region
over
observations
and achieved
the
results
of
days,
the
results
at Millstone
Hil!
electron
ion
periods
spanned
a time
these
radar
the
resolution
of 24 hours
height
of about
measurements
and
interval
30 minutes.
in a set
of contour
diagrams.
For
a number
variation
of
exospheric
magnetic
of the
the
temperature
temperature)
meridian
the
pressure
variation
is
set
been
obtained
used
meridional
effect
equations
in a study
and
zonal
of magnetic
neutral
as’ the
speed
of
These
variation
in the
thermosphere
observed
to
reproduce
the
data
of the
winds.
storms
neutral
gathered
Also
on the
above
the
results
were
over
observed
winds
air.
These
and
the
.. .
Ill -
six-year
sunspot
are
thermospheric
Hill.
results,
cycle
the
winds
used
and
calculated
together
period
the
to define
whose
whose
a
E-W
N-S
by solving
with
of the
of a study
observed
(the
in
1970-1975
variation
results
diurnal
wind
Millstone
the
the
300 km
neutral
variation,
reported
-
to derive
temperature
over
seasonal
used
atmosphere
altitude.
for
using
well
the
was adjusted
momemtum
results
by
the
been
at this
plane
model for
variation
as
of
have
over
similar
have
mean
of the
Millstone
Table
of Contents
...
!1!
Abstract
1.
Introduction
Ii.
Equipment,
A.
III.
Iv.
v.
,,
1
Observing
and
Data-Analysis
Procedures
3
Equipment.
3
a.
General.
b.
New Timer.
B.
Observing
c.
Data
4
5
Procedures.
8
Reduction.
Results for Electron Density,
Electron
Temperatures
and Vertical
Velocity.
A.
General.
B.
Quiet
Winter
c.
Quiet
Equinox
Behavior.
D.
Quiet
Summer
Behavior.
E.
Disturbed
F.
H+
and
Ion
13
14
15
Behavior.
and Solar
A.
Introduction.
B.
Data
c.
Results.
D.
Discussion.
E.
Conclusions.
Analysis
17
Cycle
Introduction.
B.
Data
c.
Results.
D.
Discussion.
Analysis
Variations
in the
Thermosphere
17
17
19
Procedures.
19
21
22
Effect of Geomagnetic
Neutral Winds.
A.
11
~.,
12
Behavior.
Estimates.
Seasonal
Winds.
3
Disturbances
on Thermospheric
23
23
24
Procedures.
26
27
29
Acknowledgements
30
References
-iv-
MILLSTONE
1.
1963,
electron
This
incoherent
densities,
Millstone
Hill,
paper
results
World
The
RESULTS
FOR 1973
results
electron
the
by
and
transmitting
the
which
and
Te
a bank
returns
autocorrelation
km,
the
and
has
been
1973.
The
approximately
once
a
are
have
been
been
approximately.
The
on each
was
published
transmitted
made
of the
10).
and
to the
Ebe
determined
subtraction
described
in
of
in detail
radar
pulse
(0.5
span
were
made
or 1.0
by
msec)20.
transmitting
the
This
computer.
returns
(from
the outputs
allowing
elsewherezz.
and
information
F-regions
unwanted
Ne,
time base and
examining
varied
the
Vz
measurements
by
and
density
velocity
Spectral
of the
could
electron
of the
obtained
length
spacing
digital
sweep
computer.
to the
be
F-region
vertical
digital
were
of
and
determined)
to
1, and
Ti,
pulses
in
function
for
hilis21,
paper
Te,
whose
allowed
year
have
to
Colorado.
matched
pulses,
also
in Table
this
are
pairs
of
listed
long
measurements
the
years
200-900
Additional
presents
earlier
in
of filters
and
of 24 hours,
Boulder,
Ti
reports,
calendar
I
at
annual
periods
in
conducted
(Refs.
made for
obtained
been
F-region
71 .5°W)
were
single
integrating
of
of
t30N,
(42.
a series
have
the
ion temperature
interval
ion temperatures
during
reported
altitude
from
A,
in
measurements
program
articles
Center
and
radar
this
results
in the
Data
The
in
scatter
Massachusetts
eleventh
reported
month.
electron
Westford,
gathered
discussed
,.
SCATTER
(Thomson)
and
is the
observations
I
THOMSON
INTRODUCTION.
Since
a
HILL
approach
from
Results
echo
distant
gathered
for
1
I
I
I
E-region
ion
employed
in the
number
Other
of papers
observations
observing
( ISIS
Wallops
temperature
II
periods
and
study
(e.g.
using
of tides
, Ref.
conducted
chosen
Atmospheric
this
pulse-pair
in the
lower
method
in
thermosphere
1972
have
and
reported
here
include
been
in a
23).
in 1973 that
to coincide
Explorer)
with
or
Island.
-1-
are
the
with
not reported
overhead
the
short
pass of two satellites
launch
of
a
rocket
from
TABLE
I
PUBLICATIONS
CONCERNING
THE MILLSTONE
HILL UHF
(68-cm Wavelength)
THOMSON
SCATTER
RESULTS
I
\
‘fear
I
Months
I Publication
Covered
Ref.
Ref.
Ref.
1
11
12
Ref.
Ref.
2
13
1965
January
through
December
January,
April,
August
June
June, August,
September
Ref.
Ref.
Ref.
Ref.
3
74
15
16
1966
January
January,
December
July,
September
Ref.
Ref.
4
17
1967
January
through
February,
June,
December
October,
Ref.
Ref.
5
17
January
October
December
Ref.
Ref.
6
18
January
through
December
February,
April,
July
September,
October
Ref.
7
Ref.
19
1970
January
through
December
Ref.
8
1971
January
through
December
Ref.
9
1972
January
through
December
Ref.
10
February
1963 to January
1964
March,
July, August,
September
April,
July,
November
1963
I
I
I
1964
I
1
January
through
December
April,
July,
November
through
March,
December
I
?
I
,
i
I
1968
1969
I
through
-2-
———..
_.
I
I
Section
I I describes
During
1973,
and
described
temperature
1975
the
to
reported
in
effect
work
by
little
Results
velocity
continuation
Refs.
zonal
an
24.
in Sections
Babcock25,
reduction
employed
results
on the thermospheric
winds
student
years
Barbara
V presents
graduate
and
A.
over
principal
at
the
IV,
and
relate
This
work
Emery
of separate
the
ion
1970 through
thermosphere
by
year
In Section
circulation.
begun
V represent
previous
I I 1.
in the
in the
procedures.
electron
in Section
winds
the
density,
gathered
effort
IV and
a
those
thermospheric
Section
storms
and
electron
data
of
of
9 and
from
presented
the
and
gathering
for
are
from
meridional
of magnetic
R.
9.
data
understanding
presented
R.
changed
obtained
present
a
were
vertical
mean
represents
equipment,
Ref.
results
for
these
in
and
we report
the
these
the
and
study
Millstone.
results
M. I.T.
of
The
obtained
Meteorology
Department.
Il.
EQUIPMENT,
A.
UHF
antenna
(68
and
Extensive
wavelength)
This
system
hence
can
which
heights
the
described
in
and
digital
to
remedy
correlator
echo
This
scheme
of
and
20.
the
obviated
During
1972,
some incoherent
smaller
84 ft.
diameter
steerable
vertical
of the
ion drift,
spectra
to
the
were
be
an
filter
made
measured
match
for
0.5
the
measurements
procedures
bank
system
for
has
been
between
msec
of
were
filters
and
imperfect
1968
for’many
of matched
employed,
in
the
pulses),
Te
and
developed
was replaced
Ti
in an
by a
problem.
scatter
antenna
-3-
to
msec)
in the
correction
this
component
(especially
introduced
been
diameter
or 2.0
Owing
has
220-foot
made use of banks
1.0
In 1976,
equipment
procedures
power
pulses
empirical
these”g.
which
(0.5,
were
the
radar
vertically-directed
data-taking
the
Ref.
errors
some altitudes
effort
in
spectra
some systematic
over
PROCEDURES.
scatter
a fixed
only
the
lengths
detail
the
employs
to
allowed
pulse
incoherent
measure
simultaneously.
of
filters
cm
modifications
6)
each
DATA-ANALYSIS
General.
described.
(Ref.
AND
Equipment.
a.
The
OBSERVING
observations
and
were
associated
conducted
L-band
(23
using
cm
the
wavelength)
radar,
incoherent
scatter
incoherent
scatter
30 MHz
input
IF
to
of the
The
of
such
suppression
spacing
and
previous
timer
noise
gates,
during
1970
new
It
usezz.
unlikely,
The
employs
driven
by
Essentially,
developed
array
were
it
the
timer
of
was
by
the
assumed
to
and the
the
30 MHz
sampling
rearrange
IF
procedure
the
as described
follows
same
only
preset
hard-wired,
1971
elements
in Ref.
but
up to sixteen
at the
appropriate
20. )
to
It
the
all of the
pulse
length,
and
position,
line of digital
function
it
1 MHz
site
the
old
time-base
detection
in the
for
evident
which
apart
new
“and”
one,
in
pulse
Selection
panel
via
relays.
-4-
of
push
for
between
reliability
this
purpose.
two
pulse
the
In the
plug-board
which
buttons,
changes
in Ref.
(adjustable
The
are
synched
experiments.
Triggers
was included
operate
or by the
diode
the
computer
are
and
counter,
by inserting
mode shall
22.
counters)
counters
old
and
its
experiments.
modes to be established
locations.
improve
two
gates.
a matrix
developed
was described
generators
wire
continuous
further
was selected
of coincidences
diode
that
to
printed
almost
modes were
standard.
single
used
undergone
timer
logic
stepped
via
the
frequency
is employed
had
became
TTL
of
etc. ) that
two-pulse
rebuild
separate
different
can call modes through
was
controls
length
a commercial
as the
two
the front
1973
transmitter
pulse
generators,
in 1972,
decided
numbers
allows
can be made from
and
design
the
in
This
frequency,
transistors.
progressively
through
radar.
calibration
pulse
the
one
apparatus
the
using
it occupied.
essentially
the
clock
When,
space
then
together,
for
etc.
was constructed
modification
reduce
used
Laboratory)
and
to
range
the
for
length,
discrete
into
system
repetition
and
and
taking
When
was
connected
necessary
to
as pulse
construction
were
timing
was
frequency
made
timer
position,
(counters,
brought
26.
Ionosphere
data
it was
change
a new
functions
boards
the
Ref.
New Timer.
introduction
sample
radar
receiver
a wider
in
in the
so that
to span
the
(located
(Actually,
significant
receiver
of
L-band
receiver,
bank
only
timing
unit
the
unchanged.
b.
The
of
is described
control
timing
UHF
filter
system
studies,
output
the
remained
This
an
these
that
pins
radar
which
The
new timer
the
old one and
B.
1972,
method
and
or
with
As described
the
L-band
J
During
the
lists
advantage
was taken
the
a
conducted
‘3-D’
345°
4 reins.,
(Table
in
Az,
of
1973
that
(Table
and
4 reins.,
A shortened
in
used
times
of
the
L-band
C-mode
version
of this
meridian
in 1972 (Ref.
10)
-5-
to the
By
drift
The
D-mode
sequence
and once
the
UHF
radar
of the
ions
in the
information
only
employing
were
drift
and
be
F-region
to measure
the
steerable
E-W directions,
measured.
“This
Measurements
components
(D-mode)
sequence
were
then
included
in 1973 (Table
(termed
Ill).
were
conducted
was
only
were
and
16 reins. r D-mode
in which
for
between
determine
N-S
a new
computer26.
is necessary
could
between
rapidly
Since
it
three
plane
In
every
condition
To
observations
8 reins.,
long
proper
components.
El.
for
data.
rapidly
measurements
velocity
45°
single
repeated
to switch
magnetic
to secure
month
with
radar
of the
orthogonal
Az,
the
drift.
drift
pulse
computer
the
heights,
in the
the
255°
was
the
radars.
the
long
provided
C
thermosphere.
ion
drift
The
magnetic
from
the
three
the
these
single
in each mode.
from
component
attempted
Ill).
El,
observations
several
for
for
capability
E-region
of
per
reload
L-band
the
at
components
solution
the
in
winds
once
automatically
data
recover
the
B-mode
11).
to
measure
18°
that
times.
least
B,
collected
of this
(Vz)
components
additional
for
and
winds
and/or
to
times
the
employed
A,
and
transfers
vertical
possible
horizontal
termed
vertical
the
fields
pulse
was made in 1971 to switch
that
meridional
radar
provision
equipment
is
is ten
using
which
cycle
being
established
it
allows
of data
which
F-region,
two
the
transmitters
only
L-band
over
radar
measures
the
8 minutes
at
modes
altitudes
UHF
1973,
electric
the
operations,
program
the
operating
and
of
about
and
scheme
9,
operation
at
II
pair
Ref.
interface
that
in all of the
observations
in
data-taking
the
pulse
‘regular]
30 minutes
to make
newer
measurements
normal
(1 MHz)
1 ~sec adjustments
we attempted
Table
frequency
Procedures.
the
24 hours.
at a clock
provides
Observing
During
pulse
operates
A-mode
16 reins
the
L-band
2-D)
was
1
THE
Mode
TABLE
II
IICINE-PIJLSE1l EXPERIMENT
NORMAL
Pulse
Length
(psec)
Height
Resolution
(km)
A
100
15
B
500..
75
“c
D*.
1000
150
10“00
‘Employed
with
50
the
L-band
Sample
Spacing
(km)
i
MODE SEQUENCE
Altitude
Coverage
(km)
7.5
Measured
Parameters
Deduced
Direct
100-1000
Power
Ne
30
150-1500
Power
Ne
75
225-675
Power...spectrum
30..
300-2000
Power
75
450-1125
Power spectrum
30
150-
75
150.- 350
‘Steerable
50.0
radar .du~ing2-D
-6-
Ti,
Vz
Ti,
Vz
Ne
:~i,
—
:Power
Power .Spectrum
and
.Te,
3-D
.Vd
experiments.
TABLE
ill
SCATTER
OBSERVATIONS
INCOHERENT
-
1973
—
I
Begin
C*
Date
flean
End
—
EST
Date
C*
EST
Comment
Ohs+
KP
—
QQ
1020
3 Jan
QQ
1230
l)+
2-D
16 Jan
Q
1500
17 Jan
QQ
1440
2-
Reg.
13 Feb
QQ
0920
14 Feb
QQ
1140
2-
Reg.
19 Mar
D
1450
20 Mar
D
2350
6+
Reg.
24 Apr
1820
25 Apr
Q
1830
3-
Reg.
22 May
0830
23 May
1040
30
Reg.
1100
19 Jul
1530
2.
3-D
2 Jan
18 JuI
Q
Az = 345°,
Magnetic
Az = 345°,
= 255°,
‘Az
.i
1430
20
3-D
D940
1+
Reg.
20 Sep
1500
20
Reg.
0800
17 Ott
1050
4+
Reg.
0900
14 Nov
1530
2+
Reg.
7 Aug
1120
8 Aug
14 Aug
1100
15 Aug
0930
19 Sep
16 Ott
QQ
!3
13 Nov
QQ
El = 15°
Storm.
El = 18°
El = 45°
As Above.
Disturbed
i
* Condition
I
QQ
Q“
D
One of the five quietest
days in the month.
One of the ten quietest
days in the month.
One of the five most disturbed
days in the month.
+ Observations
I
!
Reg
2-D
3-D)
=
Regular.
❑
L-band
and
UHF
radar
measurements.
I
1
.,
.:
,,
-7-
—--—.——
c.
Data
As described
(i. e.,
previous
as it
samples
echo
power
on magnetic
pertinent
run.
A
ly20,
as this
would
collected
as
tape at the
echo
power
vs.
of
where
R
is the
Together
each
while
it is being
The
step
in
values
are
values
obtained
stations
serve
for
on the
plots
foF2
cycle
an absolute
on
the
(N Max)t
are
the
at the
from
run
out
signal-to-noise
other
of the
-2
the
R
by
ratio
data
are
with
for
a high
at each
quality
into
power
curve
of the
is
to
be
linear
altitude
to
have
in the
local
if
are
are
the
values
from
ionograms,
and
any
half-hourly
of
these
plots
reports4’5.
curves
drawn
into the
obtain
the
the
all
“power
vs.
correct
of
The
B-
and
the
value
via
ratio
*Actually,
the time chosen = start time + 4 minutes.
?N
foF2
is expressed
= 1.24 x 104 (foF2)’2 el/cm3 when
max
points
punched
foF2
at
runs
is converted
for
the
combines
C-mode
by allowing
in
the
program
This
profile”.
variations
the
computer
value
A-,
altitude
through
the
Te/Ti
of electron
layer.
-8-
the
plots
which
Examples
interpolation*.
with
a single
the
F-region
For this,
Including
necessary
and entered
to
of the
(38”N),
reason.
smooth
density
of
Island
in scaling
any
used
a plot
Also included
that
for
made
of electron
peak
the
duration
printed
to Millstone.
errors
the
by
power
resultant
and
the
Instead,
along
of observation.
Wallops
of previous
and
of observation
profile
any
intervals
stored
days
closest
missing
scaled
echo
and
time
frequency
corrected
allows
ionograms.
interpolation
A-mode
of
the
and
operation
at half-hour
backscatter
normalizing
(45”N)
in a number
are
time
is to construct
for
Millstone
the
are
of each
data
time
reveals
guide
measurements
each
the
usually
These
mid-point
vs.
routine
included
the
Ottawa
Mil(stone
Values
cards.
at
to
from
been
from
in
stations
have
foF2
scaled
and
in real
gathered.
analysing
frequency
this
data
period
(i. e.,
of the
spectrum,
range
start
is computed
a printout
frequency
monitored
first
range)
with
of
height
the
consuming.
integration
profile
within
values
end of each
mode type,
point
can
functions
as the
printer.
these
be too time
such
speed
two
is made to analyse
information
dependence
critical
no attempt
is 9athered)
of
stored
Reduction.
in MHz.
in
to
effects
and
density
Values
for
assuming
electron
that
except
at
present
0+
night
at
near
More
J.
(private
and
the
run
It
ion
below
ratio
minimum
900 km
values
at
are
when
to
can
be
a considerable
assumption
the
obtained
which
altitude
of
the
spectra
is a good
H+
ions
due
to recover
Ill).
be
estimates
a program
attempts
one
may
temperature
using
(Section
amount
from
sufficient
render
1976)
each
recovered
This
present.
communication,
consumes
Te,
Ti
Unfortunately
computer
time
to
and
hence
from
the
this
is not
routinely.
has
been
C-mode
data
leads
to
the
night
found20
that
tend
differ
to
differences
discrepancy
of
only
accurate
H+/Ne
program
temperature
sunspot
altitudes
Massa
ion
is the
unreliable.
L.
and
in
stems from
signals
,when
for
measurement
the
less
perfectly
matched
the
that
by
comparing
height
on
four
temperatures
performed
gathered
a more
differences
using
the
in
two
Ti
years’
and
prevailing
datag.
of
extent
continuous
employed
to
scheme
was employed
electron
temperature
length
with
1969
Emery
(taken
were
(again
Ti
scheme
results
the
in the
to
assumed
reported
results
corrected
altitude8.
-9-
for
observed
to be the
from
19719
here.
for
effect
B.
and
of
the
Emery
allow
for
modes)
be applied
not
only
to
on the
C-mode)
C-mode
but
value).
A
comparison
and
The
same
197210.
the
A.
two
in the
Finally,
B-mode
(to
to
this
correction
the
heights,
depend
it
525 km nominal
correct
for
are
estimates.
an empirical
corrections
reported
the
was evident
B-mode
at
to
the
in the
pulse
derived
but
C-mode,
several
B-mode
be that
was
it also
Subsequently,
the
made
in the
to
that
are
at
those
employed
the
spectra
B-mode
gathered
of
the
in the
derived
employing
found
Te/Ti
than
19707’a.
that
particularly
ana[yser
modes
height
obtained
for
was
comparison
center
Salah
This
analysiszo,
Since
primarily
two
and
values
the
are
E.
this
correction
correct
J.
and
also on
pulse
errors
data
times.
spectrum
transmitter
in the
effective
Te/Ti
value
to a lesser
smooth
detailed
the
receiver
data
in
such
believed
attempts
in the
and
+ 1.0.
(B-mode)
principle,
at
is correct,
days7,
In
is
B-
of the frequency
pulses
suffer
in the
the
msec
Te/Ti
It
of smearing
employed
systematic
scheme
0.5
when
Ti .
for
amount
obtained
summer
method
to the
C-mode
in
narrow.
must
employed
that
Assuming
large
the
Te/Ti
etimates
are
by
of
night
using
spectra
this
filters
is believed
the
the
accuracy
that
at
introduced
the
compensate
estimates
the
values
changing
for
Debye
Beginning
in 1976,
a digital
correlator
error.
The
ANALYSIS
influence
on the
of
The
in
electron
and
height
and
of
ion
and
has
been
distortion
that
at
the
shifted
This
A
effective
center
echoes
owing
to
profiles,
for
sampled
variation
is
was
of
not
the
INSCON
the
the
into
Te
a truly
only
electron
a
B-mode
fitting,
account
in
routinely
a
best
as INSCON,
simply
delay
fact
by the
time
within
the
plots
for
by the
height),
constructing
for
in
that
introduced
“nominal”
with
of
can compensate
is not given
so-called
as functions
is known
altitude
density,
surface
program
power
included
017 the
in the
by
this
INSCON
echo
the
polynomial
pulse
the
in
errors
performed
vs.
for
represents
estimates
performs
Ti
(i. e.,
taken
but
velocity
The
and
bias
which
but
the
is
pulse.
the
electron
of
Te,
Ti
to 1970.
Calcomp
of
plotter
Vz.
provides
the
are
coefficients
The
which
recovery
is
as a function
recovered.
a listing
which
These
parameter
tape
8.
Te
height
are
the
Ref.
of
automatically
subroutine
and
in
and
the
seems unwarranted.
two-dimensional
that
written
correction),
ANA LYSl S20
is
with
allowing
Te/Ti
smoothing
vertical
program
of
approach
operation
a
The
described
the
density
prior
data.
profiles
effect
and
been
of height,
by
systematic
analysed
has
possible
involves
be
length
in
of the
analysis
sense,
in the
which
Debye
employed
in view
This
( INSCAL)
variations
the
was replaced
to introduce
cannot
as functions
height
(via
temperature
time.
the
device
a more elaborate
the
least-mean-squares
represents
Ne
but
at some times,
part
of
analyser
less likely
program
Ti
That
correction,
next
new
spectrum
be
this
Te,
fashion.
first-order
results
a
profile
variations
to
with
Ne,
N
bank
is believed
and
recover
self-consistent
filter
gathered
program
to
analog
that
data
attempts
profile
the
sets
used
here
machine-readable
polynomial
of
of
the
height
or
coefficients
to the
)
by other
World
A.
allow
users8.
-1o-
next
from
Data
day
Center
These,
numerical
of
In
which
(within
each
tape
diagrams
section.
fit
time
for
a plotting
contour
of the
(RCVR
form
obtain
in
as Appendix
program
to
produces
given
is transmitted
given
program
to
Ne,
Te,
addition,
variation
the
period
fitted)
are
combined
together
values
Boulder)
with
to
Ti
of any
can
be
on a single
together
a simple
be
a
INSCON
the
(in
drive
with
FORTRAN
obtained
in
Ill.
RESULTS
FOR ELECTRON
TEMPERATURES
A.
drawn
altitude
and
described
where,
These
of
h
set
At
higher
(shown
the
echoes
are
ION
that
measurement
accuracy
of
in
the
are
labeled
from
the
but
is greatest
the
experimental
foF2
uncertainty
in
in units
of
encountered
in any
the
with
case are
in the
vicinity
uncertainty
(typically
in
listed
to be increasing
plots,
uncertainty
(and
wherever
are
pfots
where
days
Ne = 0.2
appears
of
above
for
sometimes
determining
the
as functions
outlined
Ioglo
F2
of these
line)
Ne
of
density
edited
Vz
manner
presented
hmax
to the overall
the
scheme
but
Disturbances
the
and
fO.2
MHz).
incoherent
- especially
is
scatter
at night
when
weakest.
is believed
adequately,
Ti
steps
the
been
however,
contributes
in
error,
uncertainty
in
are
above
as a broken
altitudes,
Te,
Contours
drawn
have
The
these
12.
well
usually
real.
max ‘2
chiefly
by
smoothed
1 through
are
Ne,
generated
8);
to experimental
measurements
,i
Ref.
Regions
owing
considered
It
AND
VELOCITY.
of
been
and
> 3.0.
not
the
in
Figures
(eI/ems)
altitude.
plots
have
detail
in
logloNe
contour
time
in
Ill
logloNe
VERTICAL
ELECTRON
General.
Computer
Table
AND
DENSITY,
30 minute
allows
the
fluctuations
(TIDs)
with
time
resolution
normal
caused,
periods
of
provided
diurnal.
for
variations
example,
less than
by
by
about
the
to
be
Traveling
2 hours,
“regular”
followed
Ionospheric
are
effectively
out.
1
The
results
at 200”K
I
plotted
“chirp”
for
and
at
the
electron
IOO” K,
intervals
introduced
dWatiOn
of
88°
measured
is
not
and
ion temperatures
respectively.
of
5 m/see
by
the
due
and
contours
have
transmitter7.
south,
precisely
The
the
been
but
corrected
the
component
for
presented
of vertical
Since
drift
vertical,
are
most
velocity
for
beam
of
Vz
the
is
the
purposes
as isotherms
are
frequency
directed
plasma
at
an
that
is
the
distinction
usually
were
is
unimportant.
I
Values
scattered
of
the
at
drift
night
observed
and
quite
with
the
unreliable.
-11-
L-band
radar
Accordingly,
these
very
measurements
have
not
been
employed
the
by
included
Kirchhoff
ionospheric
magnetic
activity
that
spectra
the
employed
R.
must
that
could
Early
to
the
Quiet
is
a
Ti
as
Te
however,
diurnal
and
been
variation
of
its dependence
on
intervals
of
assuming
these
program
is
far
Ti.
The
using
spectra
0+
is the
a
are
only
to yield
estimates
computer
program
subsequently
slow,
owing
to
has
limited
the
this
75 km
that
spectra
interval
these
Massa 28 and modified
L.
thus
altitude
the
Normally,
and
are
variation
with
densities
by
sunspot
13a-h.
the
large
by
search
number
of days
winter,
In
atmosphere
trends
the
in 1969,
program
sunspot
since
obtained
used
close
to
reduce
minimuml”’so.
they
between
method
was
i.e.,
allow
the
for
conclusions
ionosphere
the
outlined
We
H+
in
Ref.
to
and
percentage
10 for
some
Behavior.
quiet-time
Millstone
that
the
daytime
minimum
gathered
nearer
results
given
in Figure
the
fluxes
by
a factor
pronounced.
proton
The
data
interest
800 km altitude
the
for
i.e. ,
of great
Millstone.
Winter
In
1973,
the
characteristic
reports s-g.
were
Subsequently,
results
over
ionosphere
of these
and
program
and
over
in 1973 are
neutral
at
of 150 km.
by J.
and
1972
725 or
B.
As
of the
over
to reanalyse
the
concerning
either
There
was written
in
that
drawn
days
have,
Millstone
measured
Te
well
maximum ]9’29.
magnetosphere
at
as
to use this
gathered
be
data
be examined.
sunspot
believe
are
is possible
undertaken,
attempts
data
over
reflections
of
Unfortunately,
be
field
the
estimates
this
Julian.
These
in a study
resolution
percentage
for
that
of
It also
H+
electric
a height
to yield
ion present.
of
Carpenter
approximately,
yields
analysed
and
report.
27.
450 to 1125 km,
pulse
this
polarization
signal
The
in
of
is
addition,
density
winter
has
electron
densities
10 and
near
F-layer
in the
-12-
exhibits
the
this
is
in
many
exceeding
density
seasonal
lower
presented
the
in
diurnal
nighttime
becomes
altitude
is reduced.
here.
the
previous
in summer
variation
of the thermosphere
results
of
a pronounced
midday
formed
behavior
summer
discussed
hmax F2
exceeding
at all levels
can be detected
been
density
approached,
the
and
as
also.
less
the
Both
One
interesting
reviewed
in
during
and
Ref.
many
26a.
hours
pea k
after
indicating
for
when
addition,
the
seen
at
scale
at these
O+/H+
believe
its
atomic
times
charge
c.
the
1),
Quiet
Equinox
separate
no very
Equinox
results
may
remain
on
Figures
and
reaches
and
13-14
for
reach
from
obtained
layer
is
flux
-
not
of
the
H+
ions
reaction
variation
thermosphere
This
from
is just
H+
thereby
to
ensuring
for
result
a minimum,
the
condition
O
large
to
proceed
that
the
H+/Ne
In
is seen
a lowering
to
of the
flux.
exospheric
the
show
view1°’30.
can be explained
with
is at
the
which
h > 600 km
downward
of the
L.T.
13,
this
evidence
the
event
by
support
at altitudes
with
Figure
identified
provides
of the
0300
be
of
altitude,
associated
quite
simply
This
temperature.
that
the
while
abundance
that
necessary
as
of
neutral
to cause
most rapidly
protonospheric
of
(i.e.
the
, to
flux
is
Behavior.
obvious
seasonal
a
in electron
particles
via the
a
November
a decrease
a downward
7a
constant
increase
energetic
results
can
also
timing
reaction
Eq.
flux
this
at about
large1°’30.
three
or
may
(as
exchange
The
the
diurnal
and
seems
in the
the
in
in
There
around
of
and
the
minimum
exchange
downward
that
800 km
is at a maximum.
right
earlier31
H+
altitude
of
oxygen
hydrogen
of
charge
evening
is invariably
precipitation
725 or
that
a consequence
reaches
3a)
sunrise
increase
increase.
height
transitional
We now
Figure
in
Millstone
(1)
a downward
the
increase
then
over
and
+O~H+O+
responsible
percentages
density
this
which
evident
The
argued
protonosphere
H+
the
we
agent.
is
feature
the
before
that
occurs
during
-
papers3’6’31
that
declines
February
and
of previous
Nmax
This
midnight.
2-4
in
nights.
Accompanying
responsible
periods
on
in a number
increase
Nmax
0200 L. T.
12a).
the
the
winter
after
(as
temperature
is
is
quiet
a little
many
Figure
7,
discussed
Typically,
minimum
from
feature,
separation
dependencies.
Summer
to Winter.
in 1973,
in large
of the
Rather,
This
part,
behavior
there
transition
because
over
Millstone
is a rapid
is not clearly
the days
into
transition
evident
obtained
near
i
-13-
.—.
—.....,..
.. ...
.-. . ..,..._-. _.,”_r_,_r, =_,=_,
Equinox
that
To
tended
magnetic
the
to
disturbances
extent
that
is represented
10).
N
reaching
of the
On
The
night
in
some equinoct.al.
temperature
the
time
of
we
have
ionospheric:
tends
N ~ax
(as
quite
short.
it
is
a consequence
Equinox.
13-14
the
thisis
follow
of
of
sufficieti’t~.y
no si.gnificantTe
pattern,
winter
At
The
length
increase
in
production
conjugate
at
point32’33.
is controlled
increaswis
with
however,
night,
a predawn
.Iarge.(as
it.
pattern
photoelectron
effect
fact
on 19-20. September
the
observe
at the
this
equinox
Nov. ) seem absent.
onset
(X=1050)
quiet
noon.
possible’ .to
magnitude
When
to
of the
)
observed
after
on
with
aunrise
the
September),
near
behavio~
the
shortly
associated.
density.
on 19-20
by
variation
nights.,
shown 32,
electron.
results
is of course
electron
to maximize
maximum
increases
is partly
can be said to be a typical
daytime
a
(This
tend
there
in these
(Figure
max
significant
be disturbed.
by
apparently
As
the
local
wasthe
case
detectable
nearthe..!ayer
peak.
D.
Quiet .Summer
In summer
time,
in
during
winter
the
electron
the
It
now
of the
neutral
air
oxygen
from
maximum.
Behavior.
density..
daytime
is recognized
at these
at +evelsnear
by
an
that
this
levels
amountthat
reflects
introduced
the summer-to-winter
hmax
by
F2
is lower
increases
a change
at
in the
horizontal
than
sunspot.
composition
transport
of atomic
hemisphere7~9.
1
The
diurnal
variation
encountered
near
exhibits
a much
as then
conjugate
pattern
can
(Figures
The
sunset
larger
and
diurnal
heating
be seen
also
in
not
near
variation
is absent
on 22-23
that
May,
the
largest
midday.
The
at Millstone
18-19
July,
7-8
density
electron
of this
August
and
is
temperature
in summer than
Examples
at night.
electron
winter,
characteristic
14-15
August
6-9).
cause
produced
wind
differs
from
of the
by
the
evening
reversal
equatorwards
increase
of
(i. e.,
the
was
reviewed
meridional
tending
to
in Ref.
component
drive
the
10;
of
it appears
the
layer
to be
thermospheric
into
regions
of
-14-
——________
.- -.,>.,<.
“,..==
,,,<
..=-
higher
are
recombination
lower).
The
contraction
than
in
night
winter,
the
variation
then
largest.
while
in
winter
T
Disturbed
days
(Figure
24-25
April
seen during
(Figure
5)
with
upward
vertical
this
behavior
to the
place.
electric
Following
day,
Both
As
evening
the
the
summer
Ti
by
point
very
causes
much
a
heat
+ 1.0
winter
which
day
at
conducted
in
shorter
between
Te/Ti
protonosphere
conjugate
19-20
March
remains
(Figure
magnetically.
In
some of the
evening
velocities.
lifting
4)
and
night
from
the
is caused
by
sunlit.
and
characteristics
16-17
the
addition,
that
is
increase
that
around
Based
upon
a prior
layer
while
it still
of the
plasma
the
lifting
(in
an
presumably
the
main
October
results
commonly
caused
sunset,
study 18,
is sunlit
is caused
? x ~
density
trough
density
for
are
we attribute
and
production
by an eastward
direction)
by
associated
the
electric
northwards
penetration
of
and
substorm
dropped
now was over
was below
normal
to
extremely
During
Millstone.
until
late afternoon
kIw
values
the
second
when
a second
occurred.
increases
which
density
decreasing
again
appear
have
to
in
above
a large
the
the
increase
temperature
exhibit
increase,
electron
evening
sunspot
losses
to midlatitudesle.
that
the
the
periods.
field
this
suggesting
temperature
because
active
was
drives
fields
electron
is
namely,
We believe
The
with
heights)
the
the
quite
there
upwards.
associated
to where
ionospheric
of
from
disturbed
which
(at
of
were
19 March,
field
to Iift’it
Behavior
On
is taking
is
heating
of observation,
11)
layer
is maintained
e
The
(tending
also may contribute.
This
of photoelectrons
E.
the
which
summer
is
Two
of
the
protonosphere.
I
layer
night
escape
to polewards
cooling
of the
Although
rate)
appear
reached
been
have
a minimum
decayed,
during
to
the
obtained
somewhat
rose
Te
hours
at
caused
of
night,
again
before
to
darkness.
the
large
its
decreases
the
electron
density
daytime
While
in
few
electron
maximum.
values
before
reliable
temperature
results
does
not
-15-
--==.
. .—
. .
aPPear
to
distance
The
have
from
the
that
equator
24 hour
period
disturbed
radar
began
and
that
pronounced
evening
in
temperature
They
heat
caused
usually
find
signature
A
similar
24-25
April.
began
to
increase.
the
During
decrease
with
a
6 hours
of
(Section
the
when
By
V).
nor
feature
incoherent
observations
intense
a
most
contrast,
fall
19 EST
of
was
to
of this
the
period
There
previous.
around
oxygen
been one of the
less
density
storms
of atomic
day.
during
storm
composition
winds
to have
anomalous
of
of the
a decrease
it
the
is the
no
very
day
that
low
was the
persisted
increase
winter
01 EST
in density
night
Te
began
and
may
be
the
during
when
causes,
the
viz. :
deposited
current
in
by
particles,
latter
and
case,
we
This
E-region.
October,
suggesting
that
mechanism.
appears
to
to increase
as the
have
described
an increase
in the
occurred
at about
electron
commencing
increases
winter
In the
densities
heating
Millstone
separate
particles.
responsible
Te
in
ring
in the case of 16-17
after
in
and
electron
at
to be two
where
low energy
night,
little
previously
detectable
appear
nocturnal
nocturnal
readily
plasma
high
this
seen
magnetosphere,
ambient
of
been
There
conduction
at
chemical
was in progress
taken
most
to be missing
instance
characteristics
associated
the
the
heat
The
are
long.
abnormally
magnetospheric
some
of the
of summertime
operations
commencing
have
precipitation
appears
lay
Ilb).
Te
are
from
by
were
day
transport
following
most obviously
periods.
between
the
electron
disturbed
interaction
storm
in
of
conducted
The
increase
increases
second
thermospheric
during
about
Nocturnal
heat
Millstone
in the
the
1973 appears
only
(Figure
of darkness
normal
March
Hill.
01 EST
hours
from
begun
The
electron
about
than
October
had
values.
results
throughout
16-17
on the
to a change
encountered
at Millstone
disturbance
increase
,
ever
of
that
is a common feature
that
larger
continued
density
attributed
of 19-20
observation
nocturnal
,,
by
intervals
scatter
until
been
atmosphere
the
electron
midafternoon
has
suggesting
high,
minimum34’35.
of the
until
neutral
towards
The
value
persisted
at Millstone
abnormally
the trough
depressed
which
of
been
22 EST
density
near
downward
——.-—.
and
began
to
02 EST has all
above,
-16-
on
i.e. ,
flux.
it
is
It
may,
therefore,
have
protonospheric
complete
study
(Section
appears
13a-h
are
night
not
though
seen
utilizing
this
increases
late
estimates
in
of
the
due
to
a
year.
A more
+
H
abundance
the
warranted.
presents
at either
we believe
that
the
flux
ionospheric
sunrise.
in
usually
(e. g.,
H+
percentage
(of
Based
previous
Figure
is approached
the
upon
flux
As
can
midnight
there
may
Such
be
seen,
when
CYCLE
VARIATIONS
studies l”,
725 km > 10%).
be no time
becomes
ion
noting
end
this
total
by
and
though
the
is downwards
20% (at
13a-h.
around
In summer,
13c),
when
800 km exceeds
begin
Figure
SEASONAL
the
periods
at
indicated
downward
minimum
of
725 or 800 km altitude.
percentage
are
escaping
plots
we can identify
H+
intervals
Iv.
this
explanation
H+ Estimates,
abundance)
when
same
normally
of
III-F)
F.
Figure
flux
the
less
periods
of
a
little
after
the
flux
is not
frequent
as sunspot
1°’30.
AND
SOLAR
IN
THE
THERMOSPHERIC
WINDS.
A.
A
i
Introduction.
summer-to-winter
circulation
inferred
from
neutral
thermospheric
i
i
provided
I
thermosphere
by
seasonal
airglow
in
and
the
weeks)
meridional
a14s
the
42,
and
depict
eastward
the
structure
patterns
global
equinox
Figure
pattern
-77-
results
and
relatively
14 from
and
the
as
been
in
the
the
rapid
from
6300 A
the
zonally
indicate
winds
is a short-lived
is
and
made at Millstone
such
poleward
been
has
winds
winds
meridional
weak
circulation
in
neutral
models
and
there
shown
notion
observations
All available
with
equinox,
this
the
has
ionospheres’36
of thermospheric
zonal
in summer
of the
of
from
theoretical
the
thermosphere
for
variation
derived
by
of
the
symmetric
Support
et a143-45.
Near
which
mass flow
in the
measurements
values
winter.
in
mid-latitude
diurnal
seasons
nighttime
averaged
equatorward
(3-4
of
model of Dickinson
diurnally
winds
by
the
composition 37.
in different
observations
averaged
differences
estimates
Hi119’24’3s-4i,
of
that
are
strong
strongly
westward
transition
period
symmetric.
model
of
transition
the
The
Roble
to
et
the
asymmetric
from
solstice
the
heating
cell
inclusion
in the
in
which
winter
winter
hemisphere
It
been
has
as the
acts
solar
the
observed
To
decrease
heating
the
examine
this
wind
neutral
winds
and
made
at
over
the
Roble
et
alqs
model
to simulate
observations
to
set
small
the
to
heating
conditions,
The
with
rates,
the
the
in
flow
in
that
in
the
hemisphere.
heat
sources
models
as
in order
The
reverse
winds
driven
by
the
and
results
in
an
used
to
at mid-latitudes.
wind
presented
measurements
by
from
period
Emery 9’26’41.
ionospheric
1970-1971
the
and
latitude
in
have
Using
measurements
as
persistence
input
to
a
of this
pattern
rates
in their
presented
the
of
the
solar
data
from
to
and temperature
minimum,
latitude
averaged
declining
in this
solar
high
at
added
wind
hemisphere
zonally
than
heating
Using
near
winter
been
covers
cycle.
that
the
years
high
Roble47
found
winter
four
period
solar
mid-latitude
in
1975
are
flow
deposited
latitude
confirmed
and
they
cell
additional
results
solar
Hernandez
poleward
an
the
a reverse
from
1972 through
Emery 9,24,41;
this
cycle.
by
Emery
to the
directed
patterns43’46.
winds
a Hadley
summer
in. that
hemisphere,
two-year
zone
directed
poleward
derived
auroral
1970-1971.
varied
In addition,
strongly
been
data
the
model,
heat
high
thermospheric
temperature
changes
made
drive
minimum.
more
have
summer
has
the
in self-consistent
hemisphere
of
from
deposited
these
arise
EUV to drive
oppositely
heat
equinox
the
an oppositely
and temperature
the
pattern
period
an
mean meridional
over
two year
by
solar
auroral
absorption
winter
sample
dynamic
the
at
solstice,
equator
by
auroral
UV
in
the
include
wind
of the
Millstone
semi-empirical
the
to
and
the
largest
by
winds
At
with
resisted
resisted
by
centered
behavior
date,
is
necessary
EUV
to
asymmetric
driven
in situ
reproduce
heating.
combines
driven
is
equatorward
across
flow
flow
found
latitude
transported
This
This
net
hemisphere
hemisphere
winter
cell
is
The
high
summer
air
hemisphere.
to
of
hemisphere.
the
well
pattern.
heating
(Figure
Millstone
To
two
portion
Hill
years
of
the
was too
15)
meridional
maximum.
the
as a guide
at
solar
winds
test
these
(42°N)
taken
analyzed
last
are
by
sunspot
Section.
-18-
,,.-.*,~;,,
Data
B.
Measurements
ion
drift
Analysis
of
respect
electron
have
approximately
height
made
Per
month
and
temperature,
Tm,
the
magnetic
meridian,
v
and
are
U
eastward,
model assumes
distribution
is
set
temperature
the
A detailed
anal yzed
these,
we have
85 days,
index
model will
needed
c.
Figure
considered
and
in
their
the
Scatter
from
disturbed
behavior
calculations
.24U,
where
northward
and
employed
as
the
from
equilibrium
E-W
of
the
pressure
exospheric
model is adjusted
solving
the
until
momentum
in a least squares
‘Hn
not be presented
here.
of
1969
48 days
-
through
December
1972 through
1975.
days
(daily
is
discussed
were
taken
1971.
Of the
average
in Section
from
the
of
total
aurorai
V.
Mass
To
Neutral
Spectro-
(MS IS) mode148.
Results.
16
presents
300 km obtained
data
of
amplitudes
is given
another
were
meter/1 ncoherent
the
of the
that
in the
computed
description
added
at 300 km in
were
variation
variation
December
with
exospheric
in hydrostatic
so
time
variation
from
the
wind
then
are
km)
diurnal
37 days
21
local
~ 24 hours
smoothing
to derive
neutral
vertical
local thermosphere24’40.
constituents
300 km
After
parameters
(120
and
of
= .97V
‘Hn
winds,
positive
observed
AE > 300y),
densities
at
I).
used
model of the
pressure
periods
horizontal
neutral
observed
V
been
zonal
boundary
N-S
over
Millstone,
and
neutral
lower
The
have
(For
ion temperature
(Section
of the
These
the
1963
these
the
and
give
Emery
of
a
by
U
equations
sense.
that
Tm.
winds
)
and
Millstone
since
semi-empirical
above
variation
at
‘Hn’
meridional
respectively.
This
electron
a measure
the
to a dynamic
the
time,
and
input
density,
been
once
to
Procedures.
an
are
from
results
for
the
analysis.
analytical
linear
the
function
functions
diurnally
averaged
The
line
with
of the
solid
12,
meridional
is a least
6 and 4 month
10 cm solar
radio
flux
wind
squares
fit
harmonics,
‘10,7”
at
to
whose
The
by
-19-
..— - “
fit
~
=
[18.2
centered
fitted
is
r = 1).84
mean
cos [4n/365
(day
+ 15 t 12)]
cos [6n/365
(day
-
11 t 5)]
where
FT0,7
annual
has
the
wind
period
of
solar
squares
about
fit
to the
=
[-0.8t
the
f 8.4)–F]*
= 160),
the
diurnally
averaged
of the
same form
is
minimum
(~lo.7
zero).
coefficient
statistically
~
about
75 m/see
with
a seasonal
the
average
winds
as in Eq.
at
2,
of
to
the
solar
at equinox,
300 km,
given
average
duration
compared
mean
winter
the
to be equatorward
zonal
of
an annual
solstice,
reduced
is that
= 70),
however,
aid
gives
The
Near
~10 1
points
are
fit
wind
be
the
with
poleward,
tend
to be poleward.
all
30 m/see
to
of
correlation
variation
equatorward;
winds
between
terms
poleward.
appears
average
linear
summer
tend
data
t 14.9) ~]*
i 10.5)F~*
(3.7
81 day
approximately
70 m/see
the
-
rms error
solar
40 m/see
maximum,
the
,
winds
they
17 shows
At
(i.e.
t 7.8
an
(~lo.7
is about
m/see.
+ (17.4
semiannual
The
wind
f 7.8
a significant
m/see,
is about
at minimum,
Figure
to
is
and
and
+ (4.2
(2)
m/see
having
t 19.3
+ [5.3
The
maximum
O. 7 m/see
equatorward
At
one
winter
f50
still
i31
annual
25.2
increased
maximum.
I
of
is
is
solar
about
summer
while
only
For
and
wind
Z)
+ [52.2
+ [-31.9
analyzed.
mean,
the
velocity
of
being
(Eq.
wind.
equatorward
wind
day
The
but
variation
t 5,6)F~
+ 5 t 4)]
curve
significant
(27.1
(day
on the
mean
-
~o.7/7oo,
the
the
11.7
cos [2x/365
~=~
with
i
with
a least
by
i
U
There
general[y
summer
+ [27.9
+ 29 t 74)]
+ [-14.7
cos [4n/365
(day
+ 36 t 78)]
+ [2.7
cos [6rI/365
(day
+ 8 t 48)]
is the
and
t 18.8)F3
(day
deal
to
of scatter
r = 0.60
since
seems
(1.7
cos [2n/365
is a great
significant,
there
23.9-
and
same order
be
a
an eastward
wind
—
t 30.7
-
(4.3
and the fit
the
standard
deviation
as the
seasonal
in winter
t 24.2)H*
+ (12.3
points,
-20-
—... ,. ..—
___
t 32.9
in the
i
I
+ (1.6
f 25)F~*
* 24.5)F7*
(3)
of magnitude
recognizable
I 31.0
and
pattern
is not statistically
in
coefficients.
with
no obvious
the
Nevertheless,
a westward
solar
amplitudes
cycle
wind
variation.
in
Discussion.
D.
From
the
winds
results
seen
by
variations,
temperature
solar
EUV
force
as the
In their
and
UV
sunspot
flux
a
by
by
a
reverse
cell
in
in the
poleward.
In
factor
the
The
through
the
solar
cycle
diurnally
same,
averaged
suggesting
which
pattern
with
the
in the
only
winds
that
minor
and
of
decrease
accompanies
by an equivalent
to
the
decrease
et a145 reduced
simulate
to
Roble47,
4.5.
With
the
in the
decrease
in the
the
in
ion drag
winds
not
also shows
the
and
at
temperatures
latitude
present
winds
activity
heating
high
at mid-latitudes
averaged
solar
and
latitude
reduced
globally
in
winds
high
was
the
decline
the
the
hemisphere
analysis
the
reproduce
and
hemisphere
present
seasonal
Roble
two
winter
winter,
the
gradient
order
of
that
decreases.
of
Hernandez
reduced
the
model,
factor
appears
the
is balanced
density
minimum.
observed
about
averaged
by
of
(pressure)
electron
zonally
flux
that,
remain
it
persists
magnitudes
variation
day-night
here,
Emery 24’41
The
seasonal
EUV
presented
had
to
heating,
with
the
be
the
result
tended
to become more
becoming
more poleward
in winter.
The
change
in the equinox
to poleward
latitude
at minimum
heating
so optically
is very
small.
latitudinal
quite
at
the
high
minimum,
solar
the
region
this
analysis
that
there
EUV
in going
solar
a
between
latitude
extent
heating
of the
by
reverse
for
region
an equator-to-pole
The
generally
for
1974
1975
support
the
in the
high
is a larger
from
decrease
sunspot
maximum
equinoxes,
Figure
-21-
level
latitudes.
to
by the
equatorward
view,
latitude
to minimum.
14(a)
of
heating
circulation
expand.
at equinox
then
relative
controlled
rate
is
the
latitude
decreases
thermosphere
in a narrow
average
400 km at all
the
in high
is concentrated
near
an
maximum
a decrease
heating
circulation.
will
and
solar
at solar
of
Because
which
high
150 and
in terms
in the
to maximize
The
equatorward
flux.
heating,
circulation
maximum.
from
EUV
variation
tends
equinox
dominated
heating
also
wind
be explained
latitude
driving
solar
flow
to the
high
in
can
latitudinal
and
averaged
equatorward
the
The
region
activity
of
the
effective
zonally
also
relative
thin,
meridional
the
drives
an
magnitude
heating
at
cell shrinks,
pattern
driven
equinox
heating
the
geomagnetic
As the
reverse
advanced
shows
then
solar
can be
winds
by
Roble
relative
and
by the
found
in
et a145,
to
solar
The
net
plays
flow
from
a major
summer
role
in the
and
the
mid latitudes.
The
almost
imply
in
the
that
the
However,
not
present
support
such
thermospheric
that
the
significantly
Von
Zahn
0/N2
ratio.
not
processes
such
when
the
reduced,
v Hn,
(where
winds
closely
winds
are
observed
more
the
.j
calculated
computed
the
non-linear
zonal
and
wind
and
at
where
the
and
Roble47,
global
peak
neutral
does
model
also
for
suggests
does
in
lower
electron
but
not
the
production,
is
on
dynamical
At
solar
minimum,
lower
altitudes.
density
also
winds.
thermosphere
Presumably
loss and
model are constrained
As
.24 U).
values
the
(pressure)
terms
to
also decreases.
thermosphere
balance,
atmosphere
observed
to assumptions
lower
taken
the
diffusion
is
winter
balance
is less pronounced.
-
from
temperature
in the
then
= .97V
represent
sensitive
scatter
by
VHn
the
level
peak)
of
photochemical
is formed
at the
be
Christopher*G
in the
magnitude
transport
of
ionosphere
enrichment
winds
the
height
(i.e., the F-region
The
on
and
seasonal
Furthermore,
satellite
‘10.7”
-= 90)
by Maurersberger
et also and
(F10,7
showed a definite
S&3SOflal
variation
in the
and
as diffusive
scale
the
oxygen
only
Straus
at
reduced
both
height
of Hernandez
three-dimensional
bulge
minimum
Frickesl
The
dependent
oxygen
with
solar
and
by
might
winds
oxygen
F-region
anomalous
minimum
levels
seasonal
the
the
thermos pheric
also that
A
transport
of the
near
and
of
of
sunspot
in the
conclusion.
oxygen
observations
by
a
magnitude
decrease
analysis,
at
of the
behavior
disappearance
foF2
variation
at mid-thermospheric
explanation
seasonal
complete
ionospheric
hemisphere
diffusion”
anomalous
seasonal
the
winter
“wind
anomaly37’49
variation
to
linearized
gradient,
made
electric
in the
fields.
to reproduce
a result,
of
the
‘Hn”
momentum
and
calculated
By
the
equations
these
analysis,
especially
This
explain
observed
meridional
contrast,
accordingly,
may
the
zonal
using
the
results
are
the
neglect
partly
of
the
large
zonal
winds
values.
I
E.
Analysis
,
computed
Hill
Conclusions.
of results
using
incoherent
for
the
the
dynamic
scatter
data
diurnal
model
gathered
variation
of
i
I
Emery Z4,40
over
-22-
of the
1970-75
meridional
adjusted
shows:
and
to
match
Millstone
The
1.
seasonal
*5O m/see
solar
variation
seen by
cycle
to
observations
diurnally
2.
The
at
mean
at
Both
the
et a145,
heating
The
detailed
v.
in
found
that
The
during
(for
the
equatorward
constituents)
of the
and
data
The
equatorward
solar
minimum,
strongly
poleward.
conclusions
reached
of the
than
the
annual
high
solar
by
latitude
EUV
and
minimum.
is
too
pattern
and
westward
through
the
large
solar
to
permit
of eastward
winds
DISTURBANCES
by
review,
could
seasonal
winds
ionospheric
geomagnetic
(e. g.,
caused
transport
causes
factor
a general
winter
persisted
depression
attributed
structure
the
but
at
magnitude
of the
equatorward
25 m/see
more
the
results
in
the
any
average
summer
is
cycle.
ON THE RMOSPHERIC
WINDS.
mid-latitudes
heating
zonal
be
with
I ntoduction.
marked
been
maximum
OF GEOMAGNETIC
NEUTRAL
A.
the
the
a larger
the
analysis,
winds
EFFECT
in
to
the
et a14s.
O m/see
with
that
by
between
scatter
winter
namely,
the
minimum.
was about
about
through
generally
solar
of about
is consistent
and
from
at
consistent
decreases
UV heating
changed
which
in
result
model of Roble
became
winds
winds
persists
Roble47
to poleward
wind,
are
meridional
This
and
winds
maximum,
effects
Roble
3.
period
meridional
solar
minimum.
circulation
maximum
causing
I
solar
by Hernandez
equinox
mean
Emery 24’ 4] in 1970-77
averaged
solar
in the
by
strong
equatorward
explained
oxygen
result
equatorward
Mayr
as
anomaly.
the
high
and
same
and
Section
global
forced
Voliand53’54
“wind
over
I I i-E)
neutral
by
high
have
diffusion”
the
globe,
of atomic oxygen
mid-latitudes,
NMF2,
density,
in
in the
winds
Averaged
in a net transport
from
(e. g.,
to changes
see Rishbethsz)
be
electron
disturbances
Duncan36)
the
peak
thus
the
(and
has
density
latitude
shown
that
effect
that
increased
other
light
decreasing
the
-23-
.“,—,..
s
at
..-L:,’-...,,.*,.?.
,
O/N2
ratio.
A lower
atomic
oxygen
ions at all Ievefs
There
have
disturbed
release
been
several
periods.
For
measurements
and
are
induced
the
anti-solar
in part
momentum
mid-latitude
at
the
associated
an aurora,
temperature
very
and
strong
observed
a
stronger
cases,
the
zonal
throughout
speed
the
when
diverging
from
this
looking
the
examined
to
six-year
auroral
Hill
measurements
high
latitude
B.
We outlined
and
zonal
could
Analysis
in Section
(V
found
a
neutral
south,
airglow
* 400 m/see
These
night,
and
were
looking
to the
observations
made
cases
showed
and,
in
remained
a difference
looking
published
substorm.
when
and
suggest
neutral
disturbed
dusk
also
of
of
ion drift
the
temperatures
near
speed
enhanced
the
630 nm airglow
All
present
630 nm
winds
than
are
in
some
westward
meridional
implying
that
wind
the
air
is
E-W extend.
neutral
radar
of
1975,
winds
geomagnetic
were
average
twenty-four
be examined
for
and
observations
there
(daily
over
,north
detected
to
effect
high
made
heating
winds
the
the
nights.
scatter
1970 through
were
Data
compared
of
throughout
westward
thermospheric
was
to
means
during
barium
from
radar
of
Biondiss
600 m/see
reported
also
incoherent
activity
and
persisted
of limited
determine
period
at
by
during
increased
Most
equatorward
enhanced
They
Section,
reported
Sipler
became
a source
obtained
looking
winds,
from
Millstone
been
winds
derived
scatter
for
values.
winds
by the
Winds
have
disturbed
north
cap.
latitudess6.
Roble59
night.
forcing
rate
conducted
equatorward
high
winds
winds
Baxter55
at
four
equatorward
and
strong
polar
density
thermospheric
incoherent
when
of
the
while
and
series
observe
momentum
estimated
faster
Hernandez
during
In
be
to
recombination
ionization
Roper
Roble57
equatorward
to
south
and
winds
lower
Chatanika
forcing
Hays
in a higher
so,
suggested
over
observations
with
and
through
measurements.
results
example,
which
made
ratio
efforts
convection
measurements
strong
O/N2
of
hour
all time
temperatures
(Section
derived
1) have
Over
disturbances.
21 days
of
data
the
for
the
which
Since
AE > 300y).
periods,
been
effect
of
the
the
sectors.
Procedures.
IV-B
and
the
U)
method
over
of deriving
Millstone
Hill
estimates
from
our
of the
meridional
incoherent
scatter
-24-
—..—.
,.—e
observations.
Three
previously
for
disturbed
days.
significantly
quiet
caused
included
in the
of
The
Tm.
collision
turn,
the
were
For
this
values
assuming
of
derivation
and
ambipolar
the
term
disturbed
averaged
north-south
and
exhibits
a
measurements
electric
reflects
the
rapidly
at
remove
only
field
27~61.
twice
field
near
days,
varying
the
it
two
included
a
appears
that
substorm
general
for
of the
trend
fields.
-25-
full
activity,
of the
boundary
to
300 km,
profile.
night,
since
the
frequencies,
but
days
from
dusk,
ten
no
so an
field
does not
slightly
larger.
quiet
which
time field
with
went
this
of
data.
electric
field
an average
introduced
earlier
into
hours
mid-latitude
effects
the
of disturbed
consistent
so that
affect
were
analyzed,
being
twenty-four
the
There
as the
days
vertical
determines
east-west
as large
affect
also will
a number
for
fields
on(y
observed
which
the
during
electric
not
equation.
except
is about
lower
derived
of the
averaged
time field,
Only
model
balance
was constructed
quiet
mode148.
drifts
velocity
The
(MS IS)
collision
equations),
available
WandGo.
densities
parameters
interpretation
heat
In
neutral
magnetospheric
momentum
ion
northward
field
individual
Examining
best
strong
the
neutral
ion-neutral
field
by
and
electric-field-induced
the
ion-neutral
calculated.
of large
measurements
made
from
the
in the
the
estimates
values
temperature
at
was
assumed40.
integrating
derived
be
velocity.
the
neutral
velocity
effect
relative
period
The
disturbed
term
in
field
significantly
reported
in
(through
ion drag
of
density
using
and
winds
derived
density
required
derived
the
frictional
diffusion
Scatter
model
of
to the
neutral
the
observed
diffusion
uncertainty
observations
differ
the
decrease
Large
electric
“averaged”
to
VHn
ambipolar
on the
were
MSIS
and
Millstone.
heating
coincident
the
possible
calculation
frictional
in
is the
of
the
used
to
equation
the
sensitive
of these
found
balance
to reduce
days,
analysis
were
heat
Spectrometer/Incoherent
led to higher
source
over
on quiet
equilibrium
the
appearing
period
densities
lowering
periods
the
the
tended
disturbed
drifts
Mass
temperatures
major
winds
the
employed
contribution
the
highly
is dependent
the
diffusive
thereby
the
the
the
tended
the
for
winds
to
are
‘Hn
computing
in
contained
procedure
higher
A
of
from
times,
of
frequency
analysis,
density
This
used
analysis.
quiet
this
procedures
included
neutral
Tm;
values
were
collisions
of
analysis
derived
ion-neutral
derived
the
IV)
during
derivation
collision
derived
the
than
by
to
(Section
Since
frequency
the
For
days
larger
beating,
variations
model
by
can
electric
c.
To
Results.
illustrate
results
the
for
a
discussed
varied
sample
were
seen
in each
in
disturbed
days.
temperature
Figure
on
the
winter
smoothed
day.
The
m/see.
hours
either
side of midnight,
meridional
than
nighttime
V
is
the
poleward.
during
Figure
20
night
when
quiet
200 m/see
strong
shown
the
days;
the
in many
surge
in
in
Figure
are
the
18.
magnitude
derived
from
the
nighttime
not
the
of
or
the
longer
in
summer.
the
seven
during
longer
to
two
at
to occur
the
than
on
approaching
encountered
one
wind
reversing
for
larger,
freqently
Since
afternoon
period
to be much
at
3-4
persist
midnight
the
day
for
is found
significantly
midnight,
a typical
the
night,
derived
length
for
in the
local
wind
is found
local
of
meridional
reversal
near
is
and
averaged
morning
The
near
the
50 m/see.
direction
One characteristic
winds
each
equatorward
stronger
through
meridional
equatorward
instances.
the
The
irregular
during
turns
diurnally
encountered
smoothed
winds
however,
is
are
eastward
dawn.
large
derived
of about
changes
remains
generally
1974,
winds
wind
day
U,
magnitude
the
on
is poleward
the
the
sunset
zonal
a magnitude
wind,
be
of the exospheric
days,
February
V,
the
their
to
maximum.
and
night,
wind,
and
after
12-13
wind,
with
before
equinox
days
daytime
the
and
just
depicts
disturbed
the
during
zonal
maximum
to westward
earlier
of
equatorward
The
pressure
again
winds
evident
present
effects
Unlike
seen on quiet
meridional
During
although
days.
we
the
variation
disturbed
night
meridional
75-100
poleward
the
All
days,
diurnal
typically
rose above
the
the
periods,
days.
disturbed
are
the
about
the
of
disturbed
equinox
18 shows
temperature
actually
19 shows
and
variation
During
during
of the
a seven
sinusoidal
increases
winter
Figure
seen
unstructured
observed
of
considerably.
temperature
quiet
behavior
is the
hours
after
midnight.
The
smoothed
shown
quiet
in
time
exceeding
eastward
zonal
Figure
winds,
winds
21.
The
with
350 m/see.
and
westward
derived
the
zonal
the
westward
For
most disturbed
winds
at
night
winds
model for
winds
are
in the
days,
has been
the
same seven
much
morning
the
stronger
sector
into the
—.---.,._.__.....,:.
than
the
between
pre-midnight
-26-
.—
are
occasionally
time of reversal
shifted
days
,.=--al,—
sector.
For
from
the
12-13
normal
February
pattern,
and
eastward
through
The
dynamic
model
deriving
the
and
such
of
the
within
a
Thus,
the
longer
period
effects,
the
17-18
couple
than
1970
1200
L.T.
seem
were
evident
nor
to
with
in
has
22.
in
midnight
does
a substorm,
dusk
represent.
but
The
as an equatorward
D.
The
the
To
be
L .T.
be a result
the
Figures
a single
time
and
the
for
hourly
at
L. T.,
, and
their
disturbed
increased
electric
ionization
day
the
AE
L.T.
and
effects
also
The
hmF2.
particular
substorm
may be associated
eastward
field
then
a
forcing
of
0500
and
to any
over
disturbed
average
2200
pulse.
extend
the
20
occurring
different
at 1700 L.T.
from
of the
shown
into
in
The
out.
in
in
period
merged
related
pulse
short
smoothed
ion temperatures
be
data
pulse
substorms
and
to the
wave
the
pulses
fit
gravity
VHn,
with
to
be
differentiate
wind,
(The
lifting
electric
does
would
not
field
properly
be interpreted
wind. )
meridional
occurs
wind
during
near
surge
observed
auroral
oval
polar
cap
where
the
the
midnight64.
auroral
at
Chatanikase.
possibly
easiest
through
heating
polar
is
which
at
method
the
clearly
the
analyses
The
of
for
region
largest
effect
occurring
a
the
horseshoe
the
by
large
experimental
strong
surge
of the
midnight
the
nightside
heated
atmosphere
in the
ion
discontinuity,
convection
equatorward
results,
in
shaped
Harang
the
forcing
is the
along
expanded
near
forcing
in generating
the
of the
creates
of escape
Momentum
effect
is an extension
heating
cleft
midnight
small.
the
probably
Joule
cap also can assist
Detailed
show
disturbances.
midnight,
The
is
winds
local
and
region62’G3
over
2000
Discussion,
observed
which
appear
activity,
resulting
any
to individual
which
reversed
and
that
results
shifted
case.
so
to
the
to
appear
electron
could
sector,
other
compared
not
auroral
tend
and
equatorward
the
are
noon
harmonic
winds,
secure
derived
The
the
surge
is the
been
raising
to
may
to be related
increased
the
really
actually
between
order
pulses,
each
experimentally
Figure
at
surge
a third
wave
of
winds
winds
for
midnight
hours
midnight
in
surge
of
uses
employed
the
derived
and morning.
gravity
smoothing
August
index
night
functions
as
21 is to cause
the
westward
Emery40
forcing
fluctuations,
effect
with
the
of
1974,
such
winds
as
flow
near
those
-27-
.——..
,..-.
-m.
“ ..”.-..—
. -----
,=s.,.-
shown
from
in
Figure
the
The
gravity
computed
support
values
is the
oxygen
consistent
more
feature.
consistent.
period
correlation
and
Figure
mass
23.
surges
these
data
analysis.
The
meridional
observations,
given
the
observed
the
such
I
found
The
very
does
result
of neglecting
latitudes
but
zonal
it
unusual
period
auroral
had
is
winds
not
pattern,
the
for
not
reversed
clear
that
disturbed
wind
the
the
the
of
transport
normal
diurnal
global
of
-28-
the
the
from
the
had
been
auroral
by
latitudes
neglects
local
temperature
global
circulation.
1974
may be a
beginning
over
of the
24 hours
heating
gradient
had ‘reversed,
and
forced
equations
By the
temperature
affect
subauroral
the
wind,
Roper
momentum
February
terms.
circulation
suggest.
of
12-13
there
which
the
our
in the
neutral
reliable.
momentum
forcing
transport
day,
at
periods,
pattern
particular
The
activity.
important
in
theoretically
less
and
experimental
of the
of zonal
of linearized
non-linear
this
are
short-lived
the
fields
be
of heat
employed
to
a
as may
resolved
tied
not
over
circulation,
smoothing
derived
and
be
represent
zonal
are
is
be
significant
from
global
electric
to
pattern
AE
result
representation
and
tend
transport
fully
are
transport
can
during
the
observation
equatorward
Moreover,
Thus,
intense
that
model
winds
field,
analysis
probably
the
densities
zonal
the
not
3 harmonic
good
use in our
transport.
gradient
by
a fairly
the
either
the
(pressure)
convection
(A < 630).
by
that
in the
is not
AE < 300y)
and
may
changes
are
in neutral
However,
ion
overall
of
wind
suggests
activity
the
of
days
this
not statistically
meridional
analysis
but
winds
again
but
days,
the transport
normal,
meridional
is a small
averaged
than
are
uncertainties
have
there
computed
temperature
Baxterss
average
supressed
so they
calculations.
(daily
do not entirely
Some disturbed
than
but
separable
on disturbed
to explain
days,
events
winds
flow
disturbed
days
wind
storm.
dayside
geomagnetic
rather
and/or
on the
present
short-lived
measurements
equa’torward
used
feature
onsetsGs.
meridional
averaged
IV),
with
averaged
of an ionospheric
64 quiet
The
substorm
diurnally
diurnally
associated
and
that
very
(Section
between
in
pulses
on
is a distinct
diffusion”54
winds
The
In analyzing
six-year
seen
phase
with
global
“wind
poleward
surge
associated
increase
negative
equatorward
this
of the diurnally
of the
weaker
that
pulses
of an
basis
and the
do exhibit
indicate
wave
a picture
which
a
22,
to
of
lower
at Millstone,
as the
derived
ACKNOWLEDGEMENTS
We
are
S.
Sawicki
assisted
Mrs.
Alice
1973,
the
the
U.S.
Preparation
Foundation
grateful
and
in
to
R.
others
at
gathering
Freeman
Army
of
under
the
Millstone
with
work
the
at
was supported
ATM75-22193
-29-
Hill
data
Millstone
of
and
L.
Reid,
reported
of a program
report
Grants
W. A.
data
helped
scatter
as part
this
Wand,
the
who
incoherent
H.
radar
by
B.
Hanson,
Observatory
here,
as
reduction.
was
National
ATM79-09189.
well
as
During
supported
propagation
the
who
by
study.
Science
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1965),
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Hill
Lincoln
“Millstone
528,
Lincoln
Thomson
Laboratory,
Hill Thomson
Laboratory,
Scatter
M.1 .T.
Results
(18
for
September
1978).
11.
J.
V.
Evans,
Planet,
Space
‘l&,
!
J.
13.
/
Planet.
Space
Sci.
~,
1387 (1967).
14.
,
Planet.
Space
Sci.
18,
1225 (1970),
15.
r
16.
I
J.
Atmos.
J.
AD-714447
and
18.
,
J.
19.
,
Planet.
V.
Evans,
Measurements
Millstone
(6 February
21.
G.
DDC
Planet,
,
J.
of
1175 (1965),
Phys.
~,
Space
Julian
Technical
21_,
Phys.
Sci.
763
(1970),
DDC
AD-716057.
(1970),
4815
and
593
(1973),
(1973),
DDC
AD-772137/6.
DDC
AD-771877/8.
‘1Incoherent
Reid,
Temperatures
Report
AD-716056.
1461 (1975).
W. A.
Density
AD-614310.
DDC
4803
3&,
23,
and
AD-616607.
respectively.
Sci.
Terr.
DDC
DDC
1629
7&,
AD-714446,
F-region
Hill”,
~,
Res.
Space
Atmos.
R.
Terr.
Geophys.
17.
20.
Res.
1031 (1965),
12.
DDC
Geophys.
Sci.
477,
and
Lincoln
Vertical
Scatter
Velocity
Laboratory,
at
M. I.T.
1970).
W. Armistead,
J.
V.
Evans
and
W. A.
Reid,
Radio
Sci.
~,
153
(1972).
-31-
—.-... ——..,
,—
. ..——.—
22.
w.
L.
Oliver,
Scatter
J.
Measurements
Collision
23.
J.
E.
24.
B.
A.
Salah,
R.
Emery,
Cambridge,
R.
R.
on
Solar
27.
J.
C.
Activity”,
and
V.
H.
J.
Ph.D.
Kirchhoff
J.
V.
Evans,
Density,
“Incoherent
Temperatures,
Technical
V.
Evans,
and
,
Report
Lincoln
of the
347
Mid-Latitude
(1975).
Neutral
of
Meteorology,
of the
Thermosphere
Department
Circulation
M. I.T.
(September
Radar
Department
of
Meteorology,
1978).
Propagation
Lincoln
Laboratory,
and
A.
L.
the
~,
1977).
Thesis,
Hill
Radio Sci.
in
M. I.T.
Dependence
507,
F-region
Variations
(May
llMill~tone
Report
and
Hill”,
Thesis,
Massachusetts
Technical
and
Wind
Ph.D.
Ghiloni,
W. J.
Wand
l]The
Wand
press).
“Seasonal
Babcock,
H.
Millstone
(in
H.
E-
Massachusetts
Cambridge,
26.
at
M. I.T.
Thermosphere”,
25.
of
Frequency
Laboratory,
R.
E. Salah,
Study:
instrumentation”,
M. I.T.
(20
J.
Geophys.
Carpenter,
September
Res.
1973).
U,
2737
(1976).
I
28.
J.
L.
Massa,
Exchange
University
between
the
J.
V.
Evans,
30.
J.
V.
Evans
31.
J.
V.
Evans,
Planet.
and J.
J.
J.
V.
Evans
and
Ann
Space
M.
73,
1. J.
Experimental
and
Arbor,
Sci.
HoIt,
Geophys.
, ibid.
32.
and
Ionosphere
of Michigan,
29.
33.
‘iTheoretical
23,
Planet.
Res.
~,
Studies
Plasmasphere”,
Michigan
of
Ph. D Thesis,
(1974).
1611 (1975).
Space
Sci.
Z&, 727 (1978).
4331 (1965).
3489 (1968).
Gastman,
-32-
J.
Geophys.
Res.
~,
Ionization
807 (1970)
The
34.
L.
H.
Brace
35.
L.
H,
G.
36.
and
R.
F.
Theis,
Brace,
E. J.
Maier,
G.
Shepherd,
J.
R.
A.
Duncan,
37.
H.
G.
Mayr
38.
D.
A.
Antoniadis,
39.
R.
G.
Roble,
J.
and
J.
J.
Geophys.
Atmos.
H.
J.
Res.
Terr.
Volland,
J.
Atmos.
J.
E. Salah
J.
Geophys.
Geophys.
fl,
Geophys.
and
J. Whitteker
59 (1969)
Res.
Phys.
A.
1871 (1974).
5211 (1974).
Phys.
B.
~,
Hoffman,
7&,
Terr.
and
H.
Res.
~,
~,
6774
(1972)
187 (1976).
Emery,
J.
Atmos.
Terr.
phys.
x,
503 (1977).
40.
B.
A.
Emery,
41.
, ibid.
42.
G.
Hernandez
43.
R.
E,
&,
and
Dickinson,
~,
5691 (1978).
5704 (1978).
R.
E.
Res.
C.
G.
Roble,
Ridley
J.
and
Geophys.
R.
G.
Res.
Roble,
~,
J.
2065
Atmos.
(1976).
Sci.
%
1737 (1975).
, ibid.
44.
45.
R.
G.
Roble,
R.
E.
Dickinson
and
E.
C.
Ridley,
J.
~,
178 (1977).
Geophys.
Res.
E&’,
5493 (1977).
46.
J. M.
Straus
Distribution
ATR-78(8203)-3,
47.
G.
Hernandez
and
of
L.
A.
Thermospheric
53 pp.
and
R.
Effects
llDyn~mi~al
Christopher,
Oxygen”,
Aerospace
on
the
Corporation
Global
Report
(1978).
G.
Roble,
J.
GeophYs.
Res.
~,
5505
-33-
—-. -,,-
-..-,—.
-..,
,,.l,
(1977).
48.
A.
E.
Hedin,
C.
H.
C.
Brinton,
H.
A.
G.
G.
Reber,
Mayr
and
W.
P.
E.
Newton,
Potter,
N.
J.
W. Spencer,
Geophys.
Res.
~,
2148 (1977).
49.
50.
51.
H.
G.
Mayr,
A.
J.
Geophys.
K.
Mauersberger,
J.
Geophys.
U.
von Zahn
Res,
E.
Hedin,
79,
61,
and
A.
Reber
G.
and
R.
Carignan,
619 (1974).
D.
Res.
C.
C.
W.
Kayser,
E.
Potter
A.
and
O.
Neir,
7 (1976).
K.
H.
Fricke,
Rev.
Geophys.
Space
Phys.
~,
169
(1978).
52.
H.
Rishbeth,
J.
53.
H.
G. Mayr
and
Atmos. Terr.
H.
Volland,
54.
,.1
I
Phys.
Planet.
, J.
and
55.
D.
W. Roper
56.
H.
F.
Bates
57.
P.
B.
Hays
58.
D.
W. Sipler
and M.
A.
Biondi,
59.
G.
Hernandez
and
R.
G.
60.
R.
H.
Wand,
private
61.
J.
V.
Evans,
J.
Geophys.
62.
P.
M.
Banks,
J.
Atmos.
and
and
A.
T.
R.
Baxter,
D.
Roberts,
Roble,
Space
J.
J.
Res.
Atmos.
Geophys.
J.
J.
~,
Phys.
~,
379 (1972).
7&, 2251 (1973).
Terr.
Phys.
Terr.
Res.
Geophys.
communication
Terr.
Sci.
Atmos.
J.
Roble,
Res.
1055 (1975).
Geophys.
J.
G.
37,
phys.
~,
Res.
Geophys.
39,
~,
585
(1978).
87 (1977).
5316 (1971).
~,
Res.
(1978)
2341
~,
(1972).
179 (1977).
37 (1979).
~,
5173
(1976).
63.
J.
S.
Nisbet,
M. J. Miller
and
L.
A.
Carpenter,
J.
Geophys.
2647 (1 978).
64.
J.
65.
A.
M Straus
D.
and M. Schulz,
Richmond,
J.
Geophys.
J.
Geophys.
Res.
(
I
-35-
~,
Res.
4131,
U,
5822,
(1978).
(1976).
Res.
~,
t41LLSi@NEE1LL
2- 3, Ja!4. 1373
1-7
(a)
Contours
of Log10 Ne.
Fig. I(a-d). Results for 2-3 January.
.
277”
.
.
.
.
(b)
Fig.
Contours
1 (a-d).
of Te.
Continued.
LLSTONE
HILL
‘~3. JRN.1973
Ilzgaiai
—.
m
.
m
—————————————
“
-----
.w
s
L---.
(c)
Fig.
Contours
(a-d).
of Ti.
Continued.
==1.
.
k
.,
L
‘m
b
EST
(d)
Fig.
b
Contours
b
of Vz.
(a-d). Continued.
In
b
L
1,
b
.
1’
LLS113NE
HILL
-17. JRN.1973
C,oNE
s
c>
N&@ <.*
,.*
,..
~.
.:~~
.
.
,-~f.,
jsj)
,,,
,, ““’’’:..F_;
. .>.,. ““
c@-_;
.,’
a
.0
“.,
.’
—
,3
,7
EST
(a)
Fig.
2(a-d).
Contours
Results
of Log,. Ne.
for 16-17 January.
:.:
MILLSTONE HILL
:6-17, JI?N,1973
—
.
(b) Contours
of Te.
Fig. 2(a-d). Continued.
;LLST13NEHILL
)-17. JRN, 1973
h
\--f
\,
4!
L+
b,
(c)
Fig.
b
EsT
b
Contours of Ti.
2(a-d).
Continued.
bl
b
L
\,
—.
k
ILLSTONE HILL
j-17, JRN. 1973
_*
(d)
Fig.
Contours
2(a-d).
of Vz.
Continued.
MILLSTL!NEHILL
13-IU. FEB. 1973
LOCIC,NE
.
.
m
EST
(a) Contours
Fig.
3(a-d).
Results
of Log10 Ne.
for
13-14
February.
LLSTCINEHILL
-I U. FEE.1973
o
$2.
Ul
,,
\,
L
h
L
L
h
L
EST
(b) Contours
Fig.
3(a-d).
of Te.
Continued.
k
k
bl
L
L
b
-1==1-
.LSTCJNEHILL
-14, FE8. 1973
.
m
*
—
L
L
k
i,
~,
4!
EST
43
k
of Ti .
Fig. 3(a-d). Continued.
k
b
k
b
1>
LLSTIINE HILL
}-1L4,FEB. 197S
,
f,
h
(d)
Fig.
Contours
3(a-d).
of V7.
Continued.
b
k
b
b
b
\*
L@C,oNG
(a
Fig.
4(a-d).
Contours of Logl~ Ne.
Results
for
19-20
March.
?==L
lilLkTONE HILL
19-20. M%. 1973
&
u]
(b)
Fig.
Contours
4(a-d).
of Te.
Continued.
-
MILLSTO+K HILL
19-20 .IWR. 19?3
Ut
c,
(c)
Fig.
Contours
4(a-d).
of Ti.
Continued.
==a-
MILLS1ONE HILL
19-20, MFIR,1973
* ~z
(d) Contours
of Vz.
Fig. 4(a-d). Continued.
-
IIILLSTM
y-?skwflm
HILL
L\
‘“\\
,
UI
N
(----’l
\
9.*
\
\\\/
\
\/)W
/=----”
i
\)(
\
1
(a)
Contours
of
Loglo
Ne.
Fig. 5(a-d). Results for 24-25 April.
7-’--
.
/.SJ
g“
.LSU3NEHILL
.25, ~PR. 1973
.
.
—.
.
:.
(b) Contours
of
e“
Fig. 5(a-d). Continued.
$’
-J
-_._J
~
‘“
1
.LSTONEHILL
+?S.G%=R.
19TS
,
01
2.
b
k
b
L
k
(c)
Fig.
b
EST
b
Contours of Ti.
5(a-d).
Continued.
b
h
k
b
b
MILLSTONE HILL
;u-25. PIPR.1973
.
===1-
-.
.
.
.
.
#
L.
1.
1.
L.
1.
(d)
Fig.
L
Contours of Vz.
5(a-d).
Continued.
1.
L
1..
1.
L
F+
I~LSTONE HILL
22-23, WY. 1973
l==q-
.
.
.
.
(a) Contours of Log10 Ne.
Fig. 6(a-d). Results for 22-23 May.
.LSTIJNE HILL
-23 MRY,1973
.
.
.
,.
(b)
Fig.
Contours
6(a-d).
of T
e“
Continued.
~am~
LLSTIlf4EHILL
-23. MY. 1973
.
.
.
.
(c)
Fig.
contours
6(a-d).
of
Ti.
Continued.
LLStLINE HILL
‘-23, WY. 1973
.
.
.
.
.
,.
(d)
Contours
of Vz.
Fig. 6(a-d). Continued.
U[LL5 TONE HILL
/WcJJL.
1973
.
. .
.
=
,
m
0
,
‘=-
-~,
(a) Contours
of Log10 Ne.
Fig. 7(a-d). Results for 18-19 July.
LLSKINI HILL
-19. JUL, 19?3
-@EEL
0>
-,
(b) Contours
Fig.
7(a-d).
of Te.
Continued.
HILLSTW
HILL
;8-19. JLL.1973
/’--2--’”
‘=’.-
.
h
b
b
10
12
L
EST
b
k
(c)
Fig.
b
Contours
k
L
of
k
Ti.
(a-d). Continued.
4.
b
h
\,,
.
L
HILLST@NEHILL
p’19. nlL.1973
,.
k
k.
=Q=l-
b
b
b
b
{
mi
b
b
(d)
Fig.
b
Contours
7(a-d).
b
b
of
Vz.
Continued.
k
h
k
b
{,
\,
h
L
I=!!!%
MILLSTOW HILL
7- 8.RUC. 1973
I
. .
..*
.*.
>’
(a) Contours
Fig.
8(a-d).
,*.
.,..
,*.
, *,
,..
of Log10 Ne.
Results
for
7-8
August.
\u
pm%”
HILLSTONE HILL
Q7-OS.mm1973
0>
U1
(b)
Contours
of Te.
Fig. 8(a-d). Continued.
.LSTONE HILL
- 8, WC,1973
.
.
.
.
\\\
.,-
\
.
/“/”
Y
h
k
b
‘1*
i!
\.
43
44
h!
------
16
EST
(c)
Fig.
Contours of Ti.
8(a-d).
Continued.
b
h
L
L
k
LLSTONE HILL
‘-08? RUG,1973
l===.
RI
(d)
Fig.
Contours
of Vz.
8(a-d).
Continued.
EmEL
LLSTGNEHILL
-15,RUC? 1973
-
7’./
m
m
~~
.,.
. >.....,...,,,
..,..
EST
(a)
Fig.
9(a-d).
Contours
of
Results
Loglo Ne.
for
14-15
August.
ILLST13NEHILL
J-15, RuG,1973
0>
u>
,3s7
6
&
(b)
Fig.
4$
EST
Contours
9(a-d).
b!
of Te.
Continued.
b
L
b!
b
\!
HILLSTOHE HILL
~u-ls, WIG. 1973
—
(c)
Fig.
contours
9(a-d).
of
Ti.
Continued.
LLSTONEHILL
,-15. WC. 1973
.1
—.
h
$
h
L
h
(d)
k
h
EST
Contours
of
L
Vz.
Fig. 9(a-d). Continued.
bl
b!
h!
L
LLSTONEHILL
-20. sEP. 1973
.
m
.
.
.
a
.
(a) Contours
of Log10 Ne.
Fig. 10(a-d). Results for 19-20 September.
LLSTIINEHILL
-20. SEP.1973
1
-M-176281
.
I
\,-””-”L
L
b
L
L
ES1
(b)
L
Contours
b:
of
Lls
le.
Fig. 10(a-d). Continued.
L
b
L “–”T-
L
.LSTONEHILL
.20. SEP.1973
.
.
.
(c)
Contours
F g. 10(a-d).
of
Ti.
Continued.
LLSTONE Ml LL
-20. SEP,1973
.
.
.
.
.
m
\,,
$7
L
4!
4!
h
k
EST
(d)
Fig.
Contours
10(a-d).
of
Vz.
Continued.
is
h
L
,,,
HILLSTONE HILL
16-17 .OCT.1973
~
LCiC,aNE
.
-
:
.1
m
z
.
.
.
,.
EST
(a)
Fig.
1
Contours
of
(a-d). Results
Log,. Ne.
for
16-17
October.
MILLSTONE HILL
16-17,0CT,1973
T.
‘yi_
.1
.1
(b)
Fig.
Contours of Te.
(a-d). Continued.
MILLSTONE HILL
16-17 .IICT.1973
.
m
“-
.
.
.
,.
(c)
Contours
of
Ti.
Fig. 11(a-d). Continued.
LLSV3NE HILL
+17.0C,7.1973
s:
.
.
.
.
.
“
(d) Contours
Fig.
ll(a-d).
of Vz.
Continued.
HILLSTONEHILL
13:1$ .NOV.1973
m
c>
t
EsT
(a)
Contours
Fig. 12(a-d). Results
of
Log10
Ne.
for 13-14 November.
‘lzE2zzL
.. ... ...... .
TE
I
m
—,
(b)
Fig.
Contours
12(a-d).
of Te.
Continued.
~
HILL
13-lU, NOV. 1973
T,
HILLSTONE
.
I
----
. .W.w.w
,
,-—
.Y.-
/
‘“‘
.
b
,
h
k
b
b
h
EsT
(c)
Fig.
k
Contours
12(a-d).
w::
b
h
of
Ti.
Continued.
k
b
b
\,
b
\,
m.
-pm!l-
MILLSTONE HILL
13-lIi. NOY.1973
Vz
\,
.
.
o
al
w
.
/-b
,
(d)
Fig.
Contours
12(a-d).
of Vz.
Continued.
--KEEL
60
40
I
20
EzEl
z
..”
~~~
c
:
I
:...
‘0”
::
~~~
~~~
0
+=
6.
,+=+
\...
\
4
fv’
1=
-1A
r
‘t
Ss
SR
I
1
0
1
I
04
00
I
I
I
LOCAL TIME
(a)
Fig. 13(a-f).
Percentage
I
I
I
I
20
16
12
(EST)
725 km on 2-3 January.
concentration
-84-
of H+ ions
for
some
days
in
1973.
100
60
F1
18-DO-11640
t
40
-FLUX
DOWN
1-
+1
LOCAL
(b)
(EST)
725 km on 13-14 February.
Fig.
13(a-g).
Continued.
I
-85-
“j
TIME
I00
60
40
20
10
e
<
I
I
LOCAL TIME
(c)
Fig.
800
km on
13(a-g).
-86-
22-23
(EST)
May.
Continued.
,
w“,
*
,0
LOCb L TIME
,.
m
22
[EST)
(d) 800 km on 18-19 July.
Fig. 13(a-g). Continued.
02
-
,.
,4
100
FLUX
/
DOWN ~
I
725
km
J
j
1
\
i
\
u’
\
A
\
\
\
Ss
SR
t
I
0
1
04
I
I
I
I
16
12
Oa
LOCAL
TIME
1,
,1,’
(EST)
(e) 725 km on 14-15 August.
Fig. 13(a-g).
I
1
-88-
Continued.
20
IOc
--Em_
6C
-FLUX
DOWN+j
4C
MILLSTONE
16-17
OCT
2C
725
HILL
1973
km
I
lC
e
4
2
Ss
SR
J
t
LOCAL TIME
(f)
725
(EST)
km on 16-17 October.
Fig. 13(a-d).
-89-
Continued.
L
20
2
I00
60
40
20
10
6
4
I
0
I
04
SR
Ss
t
t
1,
I
. .
I
“a
I
TIME
[EST)
I
!.
.
1.
LOCAL
(g)
I
,,
725 km on 13-14 November.
Fig. 13(a-g). Continued.
I
-90-
II
I
20
I
2,
bw.K.EL
SUMMER
Wlmm
WIXTEiT& ~MEWR
SEPT 21
PCI.E
OCT 6
m
ma
@a
=E
W:
~s
-.
!2
,W ?
-4
120
-6
lco
-w--mom
-(i)
–
L~%W-
SUMMER
FWE
w
[DEG;E2S)
‘“
‘wl~NTO
‘(b)
6090
–
LATITUW(DEG&S)
‘-
‘-
~UMER
OCT 21
‘WINTSR
DEC 2 I
Ku
OM60
SG
6
-
SGO -,
.
4 -
4G0 2
:W3
2 -
Zo
+ 2= “20
~ 2GQ -
-z 1s0 lulo -*
-,
-4
-
-6
-6a
,
-20-60-30
.(*,
60s0
-3G
LATITUDZ (DEGREES)
LA71Tti0 KEG%
-7C)
Plots
a145.
of the
zonal
mean thermospheric
circulation
according
to
Shown is the transition from the symmetric equinox circulation to the asymmetric solstice circulation. The reverse cell in the
high atitude winter hemisphere is driven by auroral heating (from Roble
et ali 54
J$iel~;
-!31-
SUMMER
SUMMER
S006
WINTER
POLE
POLE
- -
sol -
,.s
4004
soo~
w
N
254
1~ 200
,.s
250.
Z.
-Z
200%
g
10?
m
=1-2
d
1~
-4
?/m z=
2
-
203 -Zo
150 ~
150 -
-2 -
120
[20 -
-4 -
100
ml
-6
1
4
400 -
‘ X4
,
WINTER
POLE
DEC 21
~nso
~ma
10*
z
s
mLE
Too-
100 -
P!!i
-90
:
-60
LAnTuoEO(c&sl%Es
Fig. 15.
solstice
et a145.
-
60
-so
)
-6 u ,
-90-60-300
3040
LATITUDE (OEGREES)
(:i’
Comparison of the zonal mean circulation
of the thermosphere at
for (a)
solar minimum and (b) solar maximum according to Roble
low to drive a
At
solar
minimum, the auroral
activity
is ~
reverse cell
in
the
winter
hemisphere
(from
Roble
et
al
5,.
(b?
100
0
7V
f
i>
-1oo
-200
100
●
x
x
. .
●
x
o -*
I
‘i
g...
1>
-100
-
=
I
I
-200
1974
1973
1975
YEAR
I
!
MILLSTONE
HILL
MEAN MERIDIONAL WINDS
Fig. 16. The diurnally averaged values of the meridional wind at 300 km
over Millstone Hill derived using the model of Emery40. The solid line
is a least squares fit to the quiet days (dots) given by the sum of a
mean and the first three harmonics (Eq.2). Crosses represent dis~urbed
days that were not included in fitting the curve. Note the change In the
equinox winds from generally equatorward at solar maximum to generallY
poleward at solar minimum.
-93-
I -EEmL
.
I
-50
XX**
●x
●
●
xx
*
x
●
1
1
x
1
I
19;1
1970
1972
6
●
x
.
50
.,
-
8
*
●
x
X.o
,
z
<
●
x
●
go
In
-50
-
I
*
x
1
I
1974
1973
1975
YEAR
MILLSTONE
MEAN ZONAL
HILL
WINDS
Fig. 17.
The diurnal1y averaged values of the zonal winds at 300 km over
Millstone Hill.
The solid line is a least squares fit to the data given
by the sum of a mean and the first three harmonics (Eq.3). Because of the
large scatter in the data, the fit is not statistically significant; however,
there is a general trend of eastward winds in winter and westward
winds in summer, with no apparent change in the pattern over the solar
cycle. Crosses represent disturbed days and were not included in the fit.
I
-94-
1350 -
---26-27
—
23-24
JAN 1972
MAR 1972
.-”
—
NOV 1972
OCT 1973
— 15-16
16-17
1
I
I
I
I
–––
12-14
. ... . ..... 2-3
............17-19
FEB 1974
OCT 1974
SEP 1975
1250 -
1150 ,fl\
1050 -
/
‘%,
950 40”
850 ~
750 I I
12
1
0
1
18
LOCAL TIME
1
1
6
12
(EST]
The diurnal temperature pattern on seven geomagnetical1y disturbed
~$~ ‘~~ derived from Millstone Hill data. The nighttime temperatures are
markedly enhanced over the normal quiettime Values, Particularly in the
midnight and post midnight sectors. For 12-13 February 1974, the nighttime
temperature is higher than the daytime temperature.
4
1
-Si5-
NORTH
(East)
200
1
1
,
1
8-9
DEC
1969
MERIDIONAL
SOUTH
(West)
-20(
L
I
n
I
~m
,“
LOCAL
TIME
(EST)
Fig. 19. The diurnal zonal and-meridional
a typical quiet winter day.
-96-
I
1
6
12
NORTH
G
“.
200
I
.-<
.--%
---26-27
—
23-24
---15 –16
JAN 1972
MAR 1972
NOV 1972
—
OCT 1973
16-17
–-–
12-14
FEB 1974
. ... .. .. . 23 OCT 1974
SEP 1975
..-.. -17-19
///
//
~----
LOCAL
TIME
\
i,
\
\.
//
(EST)
disFig. 20. The meridional wind patterns for the seven geomagnetically
turbed days shown in Figure 18. The equatorward winds in the midnight and
postmidnight sectors are enhanced markedly over the quiettime pattern shown
in Figure 19.
-97-
EAST
-–-
300
:
in
200
26-27
JAN 1972
—
23-24
.-. — 15-16
—
16-17
MAR 1972
SEP 1972
OCT 1973
\
,..’
>
100
~
Q
o
J
o
w
>
r
a
~ .100
3
-1
s -20C
o
,..
..
..?
./-’\
>;..
)t--~l
/“ f.
/’
;
\
.......
\
.$
““”...
n
$
%.
N
-
---12-14
FEB 1974
......... 2-3
OCT 1974
.............17-19SEP 1975
.>
/\
/.
,.
,..- ...
...
.,
.........
,,..
~
1
I
,
30C
... -----
WE>
- 40C
..=
I
. ..
.-
!
2
0
18
LOCAL
TIME
I
!
6
12
(EST)
cal1y disturbed
Fig. 21. The zonal WInd pattern for the seven geomagnetic
days shown in Figure 18. The westward winds in the morning sector are
Signi
ficant,ly
stronger than on quiet days, and the .tlrne of reversal
from
eastward to westward winds has shifted to the pre-mldnlght sector on most
days. For 12-13 February 1974, the derived wind pattern is reversed from
the normal ~attern, with westward winds in the morning and eastward winds
in the evening.
TE4Ef.L
100
_
4
‘g
0
<
&
c
,,
>=
-1oo
P
I
x
w
a
L’
1000 500 t
I
I
1
18
0
6
12
LOCAL
TIME
(EST)
Fig. 22. The wind component along the magnetic meridian, VHn, derived
from the experimental data for 17-18 August 1970 is here compared to the
hourly avera e of the auroral index, AE. Most of the equatorward pulses
(negative VHn? correlate with aurora, activity except that occurring near
midnight which probably is an extension of the midnight surge seen at high
1atitudes.
I
!
-99-
80
W = WINTER
s
DAY
E = EQUINOX
DAY
s
DAY
= SUMMER
40 -
E
s
s
zj
--”:s;%”
;
~o
P
;
_:
s
,
E
>&
w
14
-40
-
s
s “:+&
s
E
E
I
E
-801
o
I
I
100
200
z
I
t
300
400
500
(y)
The difference
between average meridional
velocity
(V) and that
Fig. 23.
predicted
(VFIT)
from a model fitted
to the 64 quiet days plotted
against
the daily
average auroral
index AE. The straight 1ine is the least mean
While the trend is for the winds to be more equatorwards on
square fit.
disturbed
days, the scatter
is so large that the result
is not significant
statistically.
-
i
100 -
3. Recipient’s Accession No.
IBLIOGRAPHIC DATA
iEET
5. Report Date
Title and Subtitle
22 October 1979
Millstone Hill Thomson Scatter Results for 1973
.
6.
8. Performing Organization Rept.
No. Technical Report 537
Author(s)
John V. Evans, R.R. Babcock, Jr., and John M,. Holt
Performing Organicticn Name and Address
10. Project/Task/Work Unit No.
Lincoln Laboratory, M. I. T.
P.O. Box 73
Lexington, MA 02173 ~~~
Il. Contract/Grant No.
ATM 75-22193 and
ATM 79-09189
13. Type of Report 8 Period
Covered
!. Sponsoring Organization Name and Address
National Science Foundation
Atmospheric Science Section
Washington, DC 20550
Technical Report
14.
5. Supplementary Notes
i. Abstracts
During 1973, the vertically-directed incoherent scatter radar at Millstone Hill (42.6”N, 71.5”W)
was employed to measure electron density, electron and ion temperature and vertical ion velocity in
the F-region over periods of 24 hours one or two times per month. The observations spanned the height
interval 200-900 km approximately, and achieved a time resolution of about 30 minutes. This report
presents the results of these measurements in a set of contour diagrams.
For a number of the days, the results have been used to derive the diurnal variation of the temperature of the neutral atmosphere above 300 km (the exospheric temperature) as well as the speed of the
neutral wind in the magnetic meridian plane at this altitude. These results were used to define a model
for the pressure variation in the thermosphere over Millstone whose E-W varfation is set by the observed
temperature variation, and whose N-S variation was adjusted to reproduce the observed winds calculated
. by solving momentum equations for the neutral air. These results, together with similar results obtained
using data gathered over the six-year period 1970-1975 have been used in a study of the seasonal and sunspot cycle variation of the mean meridional and zonal winds. Also reported are the results of a study of
the effect of magnetic storms on the thermospheric winds observed over Millstone Hill.
‘. Key Words and Document Analysis.
17a. Descriptors
Millstone radar
F-region
diurnal variations
electron density
ionospheric scatter
seasonal variations
temperature effects
magnetosphere
proton flux
b. Identifiers/Open-Ended Terms
‘c. COSATI Field/Group
19.. pey;$
i. Availability Statement
3RM NTIS-91 (REV. 10-73)
ENDORSED BY ANSI AND UNESCO.
Class (This
Pa e
kNCLASSIFIED
THIS FORM MAY BE REPRODUCED
21. No. of Pages
104
USCOMM.DC
8243!PP’Il