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[Programme]
Session 2: "The Leonids Meteor
Shower"
Date: Monday 14.00-16.05
Orbital Perturbations on Dust Trails:
Predicting Meteor Storms
David Asher (Armagh Observatory, UK, and Bisei
Spaceguard Center, Japan)
Although the chaotic nature of planet-crossing
orbits limits the timescale over which their
dynamical evolution can be reliably calculated, a
sufficiently accurate initial orbit can at least be
followed for some time (e.g., centuries) into the
future. When debris is released from a comet during
a given return to perihelion, the first stage of
its evolution is to stretch gradually into a long,
dense, narrow trail of meteoroids and dust.
Perturbations on particles in the trail are a
function of position along the trail, and position
along the trail depends almost entirely on orbital
period, particles of shorter/longer period being
ahead/behind. Therefore perturbations at all points
along the trail, and their consequent effect on the
trail's location, can be reliably calculated until
chaotic behaviour sets in (e.g., for some
centuries). Since meteor storms occur when the
Earth passes near the centre of a trail, where the
particle density is very high, this has allowed
storms and outbursts to be predicted with great
accuracy in the Leonids and many other streams.
2.1
New Type of Radiation of Bright Leonid
Meteors above 130 km
Pavel Spurny, Pavel Koten (Astronomical
Institute, Academy of Science, Ondrejov Observatory
251 65 Ondrejov, The Czech Republic), Hans Betlem,
Klas Jobse and Jaap van't Leven (Dutch Meteor
Society, Lederkarper 4, 2318 NB Leiden, The
Netherlands)
Precise atmospheric trajectories of very bright
Leonid meteors have been determined from the
double-station photographic and video observations
of Leonid meteors in scope of the ground-based
expedition to China during the exceptional
so-called "fireball night " of 1998 November 16/17.
Whereas beginning heights of photographed meteors
are all lower than 130 km, those observed by the
all-sky video system or by the even more sensitive
LLTV system were recorded up to 200 km for the
brightest Leonids meteors. Such high beginnings for
meteors have never before been observed. All cases
with beginnings recorded by sensitive LLTV systems
exhibit comet-like diffuse structures with sizes on
the order of kilometers that developed quickly
during the meteoroids descent through the
atmosphere. For the brightest event with maximum
absolute magnitude of -12.5, we observed an arc
similar to a solar protuberance and producing a jet
detectable several kilometers sideways from the
brightest parts of the meteor head, and moving with
a velocity over 100 km/s. These jets are common
features for all studied very high altitude
meteors. When these meteoroids reached 130 km
height, their diffuse structures of the radiation
quickly transformed to the usual meteor appearance
resembling moving droplets, and meteor trains
started to develop. Recently we observed similar
behavior for two Eta Aquarid, one Perseid and one
Lyrid meteors with beginning heights up to 150 km.
These meteor phenomena above 130 km were not
recognized before our observations, and they cannot
be explained by standard ablation theory. 2.2
Prediction and Observations of Leonid Meteor
Shower in China
Guang-jie Wu (Yunnan Observatory, Chinese
Academy of Sciences, Kunming 650011, and National
Astronomical Observatories, Chinese Academy of
Sciences, Beijing 100012) and Guang-yu Li Yue-hua
Ma (Purple Mountain Observatory, Chinese Academy of
Sciences, Nanjing 210008, and National Astronomical
Observatories, Chinese Academy of Sciences, Beijing
100012)
Recent years, Leonid meteor shower has been paid
more attention in China. Observations by both
visible and radio have been performed under the
organizing of Chinese Leonid Watch. We have
observed some interesting phenomena, like the
filamentary structure of the shower, the variations
of the size distribution of meteoroids and the mass
density. In 1998, Chinese and Dutch astronomers in
Qinghai firstly observed an activity of very bright
fireballs; in Xinxiang, we observed the expected
main shower with radar, and the radio peak was as
high as 2500 hr-1; in Yunnan, the records indicated
that the contour of the peak maximum is asymmetry.
An abnormal peak in the ionosphere characteristic
value was also detected about 18 hours after the
main shower. In 1999 and 2000, the observations
were still obtained greatly. From observed
differences between the longitude of the ascending
node of meteoroids and that of their parent comet,
we find this difference depends on the ejection
position as well as the ejection velocity. We
successfully predicted the Leonids in 1999 and 2000
with a T_{E-C} versus CEOS diagram. We are working
on the research of the orbital evolution of the
meteoroid stream with the calculation of celestial
mechanics. 2.3
Leonid Storm Research in the Near
Future
P. Jenniskens (SETI Institute, at NASA Ames
Research Center)
Recent observations and dynamical models show
that the biggest Leonid storms in this season are
still to come. In November of 2001 and 2002, Zenith
Hourly Rates are predicted to increase to levels
above the storm of 1999. And the next storm is not
until 2099. Results from the 1999 Leonid storm
research were published, recently, in a special
isues of "Earth, Moon and Planets", Meteoritics
& Planetary Science, and the Geophysical
Research Letters. In this presentation, I will
summarize some results from key areas of Leonid
storm and meteor outburst research to date,
elaborate on how those results further other
research fields, and discuss in what areas future
research might make rapid progress. PSA-13
The Activity Profile of Comet
55P/Tempel-Tuttle in 1998 return: Meteoroid Release
Concentration on the Perihelion
J. Watanabe (Nat. Astron. Obs.Japan), H.
Fukushima (Nat. Astron. Obs. Japan) and T. Nakamura
(Canon Co. Ltd)
It is important to know the activity profile of
the parent comets of meteor showers. The activity
of the parent comet of the Leonids,
55P/Tempel-Tuttle had never been followed until the
recent return in 1998 mainly due to the geometrical
difficulty of its orbit relative to the Earth. We
carried out a CCD imaging monitor of this comet
from January through February in 1998 by using
50-cm telescope of National Astronomical
Observatory, Japan. The circular shape of the coma
was not changed during this period for the
pre-perihelion phase. The photometric measurements
of the coma indicated high dependency of the
activity on the heliocentric distance, of which the
parameter index n is derived as about 10. This
large value indicates that the dust release from
comet 55P/Tempel-Tuttle is concentrated at around
the perihelion passage. PSA-14
Theoretical Entry Modeling of Large Leonid
Bolides
Douglas O. ReVelle (Los Alamos National
Laboratory, Los Alamos, New Mexico USA)
We have used the entry model of ReVelle (1979)
using an energy of ablation/unit mass for
vaporization for weak cometary meteoroids of 3.8
MJ/kg (Jessberger et. al., 1988). These model
predictions have been combined with the energetics
model of ReVelle (1993). The energetics model has
been calibrated using the flight data from the
Pribram, Lost City and Innisfree meteorites where
ReVelle (1980) determined that at the observed end
height about 1 % of the kinetic energy of the
original body remained. If the above estimate of
the value of the energy of vaporization/kg of
cometary meteoroids is reduced by a factor of 5,
very good agreement is obtained between the
theoretical, equilibrium flow, entry model and the
observed ablation parameter (0.10-0.21 kg/MJ,
personal communication with P. Spurny, 2000) for
large, low density, Leonid meteor-fireballs.
Predictions of the expected laminar and turbulent
convective heat transfer and of the radiative heat
transfer coefficients (regardless of the gas cap
opacity) are made using entirely analytic
expressions that were developed. These expressions
allow a prediction of the velocity, the ablation
parameter, the percentage mass loss and of the
Knudsen number, etc. to be made. In addition,
values of the line source, nonlinear blast wave
relaxation radius and of the associated infrasonic
wave frequencies are also determined. 2.4
Leonid Entry Modeling: Application to the
Bolide of November 17, 1999
Douglas O. ReVelle (Los Alamos National
Laboratory, Los Alamos, New Mexico USA)
The results of ReVelle (AIAA Aerospace Sciences
Conference, Reno, Nevada, January, 2000) are
compared against atmospheric observations of the
Leonid fireball of 11/17/1999 in northern New
Mexico (NM). These included observations at the
Phillips Laboratory Starfire Optical Range (USAF
facility) near Albuquerque of the so-called
"glow-worm" persistent train which could be tracked
for ~1 hour, intensified CCD camera records at
Placitas, NM, by all-sky video camera records and
infrared radiometers at Sandia National Laboartory
in Albuquerque as well as by 2 ground observers in
the town of Los Alamos. This bolide was also
detected infrasonically at Los Alamos National
Laboratory at the CTBT, IMS (Comprehensive Test Ban
Treaty, International Monitoring System) prototype
array by ReVelle and Whitaker (Meteoritics, 2000).
We compare model predictions of velocity, mass,
blast wave radius, wave frequency, etc. as a
function of the initial source energy against the
results predicted using the infrasonic wave
arrivals and their properties at the ground
(amplitude, wave period, duration, etc.) at the
observed slant-range from the bolide. The
infrasonic signals were analyzed using the basic
line source model of ReVelle (1976) and were
independently shown to have emanated from a height
region near the Mesopause where the bolide
explosively ended its visible flight, presumably
due to its low material strength. PSA-15
Radioseismology as a New Method of
Investigations of Meteor Streams on the Moon and
Planets
A.A. Berezhnoi (1), E. Bervalds (2), O.B.
Khavroshkin (3) and G. Ozolins (2).
(1) Sternberg Astronomical Institute, Moscow,
Russia, (2) Ventspils International Radio Astronomy
Center, Riga, Latvia, (3) Institute of Earth
Physics, Moscow, Russia
Radioseismology is based on registration and
interpretation of radio emission of seismic origin.
Such radioseismic processes occur on the Moon,
planets, and asteroids. Non-thermal radio emission
of the Moon caused by rock fracturing, seismic
activity, and thermal cracking of the regolith was
detected during observations of the Moon at the 64
m Kaliazin radio telescope at 13 and 21 cm on July
31, 1999. We observed the Moon on November 16 - 18,
2000 with the 32 m Ventspils antenna at 25 mm.
During the morning of November 17 we registered
significant quasiperiodic oscillations of the lunar
radio emission starting near 1:44 UT and contining
until the end of observations at 7:17 UT.
Oscillations were also registered on November 18
starting near 2:28 UT. Intensive oscillations were
registered until about 7:00 UT with bottom to peak
heights of 5-10 K. The time of maxima of
oscillations does not contradict theoretical
predictions about the existence of three maxima of
the Leonid meteor shower on the Moon. Amplitudes of
oscillations were equal to 1-2 K before and after
the time of Leonid's maxima. These results can be
explained as the detection of lunar radio emission
of seismic origin caused by meteoroid impacts. The
implications of the radioseismic method for
determination of the intensity of meteor showers on
the Moon and planets and the internal structure of
the Moon are described. PSA-16
The Global Monitor of Meteor Streams by Radio
Meteor Observation
Hiroshi Ogawa, Shinji Toyomasu, Kimio
Maegawa and Koji Ohnishi
In recent years, in Japan, Radio Meteor
Observation(RMO) has spreads, and RMO has come to
be observed by many observers. Then, to grasp the
whole aspect of meteor stream activity accurately,
the necessity of unifying the observational data
all over the world came out. Then, we tried to
correct and integrate them. To consider the error
by geographical factor or the observational
equipment, the data was divided by average counts
previous one week. The 2000 Leonids RMO result at
eight sites of the world was unified by this
method, and three peaks appeared. This is similar
to the result of Visual Observation. In this time,
however, it was considered without using the radar
equation etc, we could get result as almost same as
Visual Observation. Therefore, the more exact
result could be obtained if we consider of it.
However, it cannot unify easily now, because we
have poor information on the various equipment and
various geographical conditions. It cannot unify
easily at a present stage. Consequently I would
like to collect the detailed data of each
observational site, and to establish the method of
catching meteor stream activity accurately.
PSA-17
The Result of 1999 Leonids Daytime
Observation in Japan
Hirotaka Serizawa and Masayuki Toda
The large appearance of Leonids was observed in
Europe on November 18 in 1999 at the 2:00UT
(11:00JST). Then, daytime-meteor was detected some
observers in each place, and the number of 40
meteors were detected in 4 hours in Japan. Since
globally daytime-meteor observation is rare most
people would have doubt about the objectivity of
data. Therefore, I tried to identify with each
Radio Meteor Observation, in order to acquire the
objectivity of data. Consequently, four shooting
stars were in accorded with the result of Radio
Meteor Observation. Besides, two synchronous
meteors were observed by two observers. Therefore,
these meteors could be reliable. However, there
were few bright (shooting stars>-5 magnitude)
which could be observed in Europe in daytime at the
same time. For that reason, the question arose in
the luminous intensity of the meteor that we
observed. As one of this cause, it can be
considered that the meteor luminescence mechanisms
differ daytime from night. I would like to call
more observers all over the world to carry on
meteor observation from now on to collect the data
about a daytime-meteor. PSA-18
Ground-based Observations of the Leonids
1999-2000
M.D. Campbell, C. Theijsmeijer, J. Jones
(University of Western Ontario, London, ON, N6A 3K7
Canada), R.L. Hawkes (Mount Allison University,
Sackville, NB, E4L 1E6 Canada) and P. Brown (Los
Alamos National Laboratories Los Alamos, NM 87545
USA)
We present video observations of the 1999 Leonid
shower made from Israel and similar observations
collected in Spain and New Mexico for the 2000
shower. During the 1999 Leonid storm a total of 233
double-station Leonids were recorded. The mean
begin, maximum brightness and end heights are 123.3
± 0.7 km, 107.3 ± 0.42 km and 95.0 ±
0.56 km respectively for storm Leonids of average
mass ~10-6 - 10-7 kg. The peak flux at the time of
the 1999 storm was found to be 0.81 ± 0.06
meteoroids km-2 hour-1 brighter than +6.5. using 15
minute binning and 0.99 ± 0.11 meteoroids km-2
hour-1 brighter than +6.5 for 3 minute intervals.
The smaller temporal resolution reveals a broad
plateau in flux lasting from approximately solar
longitude=235.276° - 235.285° (J2000.0).
The video mass distribution index over the course
of the Leonid storm was found to be constant
constant near s=1.75 and near s=1.7 in 2000. The
peak time of the storm estimated from 3 minute
resolution video counts place the maximum at
235.281°±0.003° (1h55m ± 4m).
We do not find evidence for any significant high
altitude Leonid population in 1999 at video masses
despite biasing one camera pair to an intersection
altitude of 160 km. The 2000 shower showed two
distinct peaks separated by 24 hours. We recorded a
peak video flux of 0.06 meteoroids km-2 hour-1
brighter than +6.5 near solar
longitude=236.15° during the 2000 Leonids. We
also discuss preliminary radar observations in 2000
which suggests that an earlier peak near solar
longitude=235.29 ± 0.02 is much stronger than
reported by visual observations and dominates the
later visual peak at 236.25 ± 0.02. PSA-19
Video Spectra of Leonids and Other
Meteors
Jiri Borovicka (Astronomical Institute, Academy
of Sciences, 251 65 Ondrejov, Czech Republic)
More than thousand Leonid video spectra were
obtained during the expeditions in the years
1998-2000. A survey of the spectra with the
emphasis to the effect of early release of sodium
will be presented. Leonid spectra will be compared
to the spectra of other meteor showers obtained
with the same instrument at the Ondrejov
Observatory. PSA-20
On Periodic Activity Variations during the
1999 Leonid Meteor Storm in Various Data
Sets
Jurgen Rendtel (International Meteor
Organization, Potsdam, Germany).
Observational data obtained during the 1999
Leonid meteor storm using intensified video cameras
as well as meteor radar systems showed significant
fluctuations of the activity. Applying a wavelet
analysis to the data it is shown that we see
quasi-periodic variations with a typical period of
7 minutes. Given the geocentric velocity of the
Leonid meteoroids, this hints at structures within
the stream at a scale of about 30000 km along the
Earth's passage, or about 9000 km vertical to the
stream's plane. As the distance between the
observing sites at which such fluctuations were
recorded is of the order of several 1000 km in N-S
and E-W direction, the variations should reflect a
characteristic of the stream. Similar observations
are only possible during meteor storms in order to
collect a sufficient sample within 2 minutes or
less. 2.5
The Leonid Meteors Found in Chinese
Historical Records
Y. Fujiwara (Nippon Meteor Society)
Beijin Observatory published the compilation of
the Chinese historical records of meteor showers
and individual fireballs. Since some records of the
fireballs indicate the meteor trail with Chinese
constellation or bright fixed stars and the
directions of the path, we can estimate probable
path of the meteor. So we can identify the
permanent shower meteor not only the aid of the
solar longitude at the meteor apparition but also
the its path. In this paper some Leonid meteor
records found in Chinese chronicles by using this
method are presented. PSA-21
Spectroscopic Analysis of Fine Structures in
Leonids
Toshio Tsukamoto (Nagoya university),
Shinsuke Abe (Institute of Space and Astronautical
Science), Noboru Ebizuka (The Institute of Physical
and Chemical Research), Hajime Yano (Institute of
Space and Astronautical Science), Yasuhiro Hirahara
(Nagoya university) and Jun-ichi Watanabe (National
Astronomical Observatory)
Observations of meteors and the orbital
caluculations lead to understanding behavior of
cometary dust grains in space. Spectroscopic
obserations of meteors enable us to investigate not
only the chemical composition of meteors but also
the chemical heterogeniety among the meteor dust
trails (fine structures) . However, there had not
been enough data to understand fine structures in a
meteor shower until the 1999 Leonids.
55P/Tempel-Tuttle, the parent comet of the Leonid
stream, returns to perihelion every 33 years,
generating a new trail of dust each time. During
the 1999 Leonid meteor storm, the Earth encountered
various trails which allowed us to study the fine
structure between those dust trails generated in
different perihelion epochs. We report results of
those fine structures within the 1999 Leonids.
These observations were carried out using Grism as
slitless spectrometer with an image intensifier.
The images were recorded on NTSC video at a rate of
30 frames per second, with 37.1 $B!_ (B20.8 deg,
FOV. The main peak occurred around 2hUT while
sub-peaks stood out around 1h30m, 1h45m, 2h15m,
2h20m, 3h00m UT on 18 November 1999. We examine the
temporal spectroscopic differences among those fine
structures. PSA-22
Persistent Leonid Meteor Trails: Types I and
II
J.D. Drummond, S. Milster, B. W. Grime,
D. Barnaby (Air Force Research Laboratory), C. S.
Gardner, A. Z. Liu, X. Chu (University of
Illinois), M. C. Kelley, C. Kruschwitz (Cornell
University) and T. J. Kane (Pennsylvania State
University)
From our 1998 and 1999 study of Leonid lingering
trails, we have identified two types of trails.
Type I trails are wide (1 km after a minute) with
high diffusion rates (1000 m^2/sec), appear turbid,
optically thick, and 'puffy'. Type II trails are
narrow (< 100 m), often parallel, with low
diffusion rates (10 m^2/sec), appearing optically
thin, smooth, and clean. Of the four trails
extensively studied, one is Type I only, another is
Type II only, and two show both types of trails.
Information (especially altitude) from a sodium
lidar is used to derive detailed geometric
parameters for the trails. For example, diffusion
appears to be a function of altitude, with the
hyperbolic tangent function describing the
transition from low to high rates. A 17 minute
video will be shown, and line emission rates,
diffusion coefficients, and other data will be
given for each. PSA-23
Fine Structures within the Leonid Dust Trail:
Resonant Filament Model Examined by Optical Video
Observations
Hajime Yano (Institute of Space and
Astronautical Science, Japan), Shinsuke Abe
(Institute of Space and Astronautical Science,
Japan) Noboru Ebizuka (The Institute of Physical
and Chemical Research, Japan) Norimoto Fujino
(Science University of Tokyo, Japan) and Jun-ichi
Watanabe (National Astronomical Observatory,
Japan)
We observed the Leonid meteor showers by
real-time video imagery of high definition digital
video cameras with image intensifiers (HDTV-II)
onboard airborne platforms (Leonid MAC) in 1998
(over the Pacific)-1999 (over the Mediterranean),
and NTSC digital video CCD cameras (WATEC) placed
at a 2500-m class mountain in the Canary Islands in
2000. HDTV-II and NTSC videos had different
limiting magnitudes for meteor detection (e.g., the
8th mag. for HDTV-II with a f1.0 50-mm lens) but
both indicated fine structures (in several to a few
tens of minutes) of the flux variation within each
main peak. Such trends became more evident as the
magnitudes of observed Leonids went fainter.
Recently Cevolani and Pupilo reported radio
observations of the 1999 Leonids from Italian
ground stations also found the same as our results.
These temporal flux variations seemed to coincide
with periods that the Earth crossed the $B!H
(Binhomogeneous $B!I (B Leonid dust trail, which is
composed of the smoothed $B!H (Bbackground $B!I (B
component and several narrow, $B!H (Bdust filaments
$B!I (B ejected from the parent comet
P/Tempel-Tuttle in the last several perihelion
passages. Thus, our results directly confirm the
resonant cometary dust trail model proposed by
McNaught and Asher in 1999, especially in the
smaller end of the Leonids. PSA-24
Five-year Cooperative Radio Observations of
the Leonid Meteoroid Stream by the BLM Radar
System
V.Porubcan (1), A.Hajduk (1), G. Cevolani
(2) and G. Pupillo (2).
(1) Astronomical Institute, Slovak Academy of
Sciences, 84228 Bratislava, Slovakia, (2) Istituto
ISAO-CNR, via Gobetti 101, 40129 Bologna,
Italia
A survey of results from joint campaigns of the
Leonid meteoroid stream observed by the BLM
(Bologna-Lecce-Modra) forward scatter system in
1996-2000 is presented. The Leonid radio
observations were carried out on November 10-20,
each year along two baselines: Bologna-Lecce
(Italy) and Bologna-Modra (Slovakia). Trends of
long duration echoes and variations of reflection
time exhibit a multiple peak activity which is
possibly connected with a filamentary structure of
the Leonid meteoroid stream. The mass distribution
exponents of the Leonid meteoroids in the period of
the shower peak activity show significant changes
throughout the 5-year observational period, with a
higher representation of larger particles mainly in
1998 and 2000, and of relatively smaller particles
during the minor meteor storm in 1999. The multiple
peak activity and variations of mass exponent in
the observed period resulting from forward scatter
observations are consistent with the results
obtained by other techniques. 2.6
Radar Observations of the 1999 and 2000
Leonid Meteor Storms at Middle Europe and Northern
Scandinavia
Werner Singer (1), Nicholas J. Mitchell
(2) and Johannes Weiss (1)
1) Leibniz-Institut fuer Atmosphaerenphysik,
18225 Kuehlungsborn, Germany; 2) Department of
Physics, University of Wales, Ceredigion SY23 3BZ,
UK
Observations of the 1999 and 2000 Leonid meteor
storms made with all-sky meteor radars in Middle
Europe (54N) and northern Scandinavia (68N) were
analyzed in terms of height-dependend meteor rates
and entrance velocities. The 1999 Leonid meteor
storm is characterised by a major activity peak on
November 18 at 2h5m UT with a peak rate of about
1400 meteors/h. In contrast to the 1999
observations, we found three activity maxima for
the 2000 Leonid storm. The first peak (170
meteors/h) was observed on November 17, 2000, at
8h15m UT related with the 1932 Leonid dust trail.
The second well pronounced maximum (130 meteors/h)
was detected on november 18 at 7h25m UT associated
with the 1866 Leonid dust trail. The third broad
activity event (about 70 meteors/h on average) was
found on November 18 between 1h UT and 5h UT
related with the 1733 Leonid dust trail. During
both years the Leonid storm activity was dominant
at altitudes above 98 km. PSA-25
Meteor observations from Israel
Noah Brosch (Wise Observatory, Tel Aviv
University, Tel Aviv 69978, Israel)
We observed meteors of the Leonid and other
showers with an L-band radar system. In the case of
the 1999 Leonids we detected a twin-peaked dheight
distribution, where the surprising finding was of a
wide peak centered near 250-km altitude. We present
a possible mechanism to generate radar returns at
such heights. We also describe the development
status of a two-station system to observe video
meteors, which is planned to operate in the second
half of 2001. 2.7
Observations on
Stratospheric-Mesospheric-Thermospheric
Temperatures Using Indian MST Radar and Co-located
LIDAR during Leonid Meteor Shower (LMS)
R. Selvamurugan (1) , C.V. Devasia (2),
A.R. Jain (1), C. Raghava Reddi (2).P.B. Rao (1)
and R. Sridharan (2)
1) National MST Radar Facility, Tirupati, 517
502, India; 2)Space Physics Laboratory, Vikram
Sarabhai Space Centre, Trivandrum 695 022,
India
The temporal and height statistics of the
occurrence of meteor trails during the Leonid
meteor shower revealed the capability of the Indian
MST radar to record large number of meteor trails.
The distribution of Radio meteor trails due to
Leonid meteor shower in space and time provided a
unique opportunity to construct the height profiles
of lower thermospheric temperatures and winds with
good time and height resolution. There was a
four-fold increase in the meteor trails observed
during the LMS compared to a typical non-shower
day. The temperatures were found to be in excellent
continuity with the temperature profiles below the
radio meteor region derived from the co-located
Nd-Yag LIDAR and extend the maximum height of the
temperature profile from the LIDAR to ~110 km.
There are however some significant differences
between the observed profiles and the CIRA-86 model
profiles. The first results on the meteor
statistics and neutral temperature are presented
and discussed below. PSA-26
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