When birds are migrating over the Niagara region, it is possible to see the migration but
not individual birds on base reflectivity images produced by the Buffalo Weather Radar. What
was not known, when I began my studies, was how intensities on the weather radar images
were related to the numbers of birds in migration. If this relation was understood, the
weather radar could be used to estimate bird numbers over a very large area. In fact,
the many weather radars in various locations in the United States and Canada could be used
to monitor bird numbers over the entire route followed by migrants.
I worked on determining the relation between weather radar intensities and numbers of birds
aloft, in May 1999. During this period, I operated a small (3-cm wavelength) marine radar
on the roof of Brock University, while simultaenously downloading base reflectivity images
from the Buffalo Weather Radar. Thus, I was able to compare the intensity of migration
based on base reflectivity images with the number of birds seen on the 3-cm radar. I obtained a
numerical relation between the two sets of numbers.
This report is divided into seven parts. In Part 2, I present the ground counts of birds
and identify the days on which birds seem to have landed in large numbers. In Part 3, I
explore the results on bird and insect migration obtained on the 3-cm radar. In Part 4,
the evidence for bird migration on the Buffalo Weather Radar is presented. In Part 5,
the possible landings seen on the weather radar are compared with the birds seen on the
3-cm radar and the birds observed in ground counts. In Part 6, the relation between the
birds counted on the 3-cm radar and the reflectivity on the Bufflao Weather Radar over
Point Abino is explored. Finally, in Part 7, the results are summarized and discussed.
This report is a follow-up to the original article in Birders Journal in 1998
(BJ 7:310-5). In the spring of 1999, from April 20/21 to June 10/11, I operated a small
3-cm radar to count birds above Brock University in southwestern Ontario. The radar is
reasonably good at detecting birds in a zone 250 m to 900 m above the ground, but it is
not effective above or below these heights. The number of targets that passed over a
one kilometre line through the University each night is shown in Figure 1 for heights
greater than 250 m and 350 m. There is evidence that insects as well as birds are
sometimes present below 350 m; some of the targets detected from 250-350 m are,
therefore, not birds. I will begin by discussing the bird migration above 350 m and
then return to a discussion of what appears to be occurring at the lower heights.
In earlier studies using the 3-cm conical radar at Brock University, it became evident
that insects might be contaminating the bird numbers obtained in the spring migration.
Accordingly, the study in the spring of 1999 focused on establishing if insects were present,
and if they were present, whether they could be eliminated from contaminating the bird numbers.
Three studies were conducted of which this is the third. The other two,
Brock Physics Report, PR-2000-1 and Brock Physics Report, PR-2000-2 deal
with the distinction between insects and birds and with the Buffalo weather radar,
respectively.
The goal here is to see what can be learned about insects on radar and about their
migration into Ontario by comparing radar data and insect trap data obtained in the spring
of 1999 in the vicinity of St. Catharines, Ontario.
Physics Report, PR-2000-3.
In earlier studies using the 3-cm conical radar at Brock University, it
became evident that insects might be contaminating the bird numbers obtained in the spring
migration. Accordingly, the study in the spring of 1999 focussed on establishing if insects
were present, and if they were present, whether they could be eliminated from contaminating
the bird numbers. Three studies were carried out of which this is the second. The other two,
Brock Physics Report, PR-2000-1 and Brock Physics Report, PR-2000-3, deal with
the distinction between insects and birds and with a comparison of radar data and insect data
from pheromone and blacklight traps, respectively.
The primary goal of this study is to summarize the base reflectivity data from the
Buffalo WSR-88D from April 20/21 to June 10/11, the period when the 3-cm radar was operating
at Brock University. The base reflectivity images are gif files created from the
Freese-Notis bmp images which were downloaded each hour, 24 hours a day throughout
the study period. There are some nights when the WSR-88D Doppler data is also available.
In addition to summarizing the base reflectivity, I searched for cases where the WSR-88D
image reveals signals which are due to weather but could be confused with birds or insects.
Finally, I searched for possible insects on the WSR-88D images in the hours around sunrise.
The second goal of this study is to find the relation between dBZ and density on the 3-cm radar.
This work was undertaken in collaboration with Ron Larkin and Robb Diehl of the Illinois Natural
History Survey.
A third goal of this study was to develop a simple technique for estimating the density
and migration traffic rate (MTR) of birds from the Buffalo WSR-88D.
Finally, I looked in some detail at a single night, May 15/16, when a large movement of
birds took place.
Physics Report, PR-2000-2.
In earlier studies using the 3-cm conical radar at Brock University, it became evident that
insects might be contaminating the bird numbers obtained in the spring migration. Accordingly,
the study in the spring of 1999 focused on establishing if insects were present, and if they
were present, whether they could be eliminated from contaminating the bird numbers. Three
studies were carried out, of which this is the first. The other two, Brock Physics
Report PR-2000-2 and Brock Physics Report, PR- 2000-3, deal with the Buffalo
WSR-88D weather radar and a comparison of radar data and insect data from pheromone and
blacklight traps, respectively.
The primary goal in this report is to ascertain if we can distinguish between birds and
insects on the 3-cm radar during the period of the spring migration of birds. If we can make
the distinction then it should be possible to chart the spring migration of birds using the
3-cm radar after the insects are eliminated.
A secondary goal is to ascertain if we can distinguish between birds and insects on the
Buffalo WSR-88D weather radar during the period of the spring migration of birds. If we
can make the distinction then it should be possible to chart the spring migration of birds
using the weather radar.
Our final goal, based on the results of the 3-cm conical radar and WSR-88D studies is to
produce a chart of night migration totals for the spring of 1999 of what are believed to be
birds
Physics Report, PR-2000-1.
The weather radars can provide the birder with a general idea of the ups
and downs of the spring migration, but how many birds are actually aloft when the
migration shows on the weather radars? To answer this question I operated a small
conical radar at Brock University. The conical radar detects birds above the university
in a small portion of the area that is seen on the Buffalo weather radar. From the conical
radar I can estimate the number of
birds aloft. By comparing the results from the Buffalo weather radar with those from the
conical radar I can calibrate the weather radar to allow estimation of the number
of birds aloft.
Birders Journal, 7, 310, 1998.
It is our belief that weather radars are a powerful tool for monitoring the migration of birds
in North America. We therefore read with interest the article by Gauthreaux and Belser (1998)
dealing with quantification of bird movements using WSR-88D reflectivity data. We wish to note
that the approach to the problem of monitoring migration described in the article may be
somewhat incomplete. It is our goal to discuss here how the migration could be more accurately
estimated using both base reflectivity and Doppler velocity data available from the weather radars.
Weather and Forecasting, 14, 1039-40, 1999.
Abstract: to come.
Surf. Sci., 374, 9-16, 1997.
At night, during the spring and fall, millions of small birds migrate over southern Ontario.
As they fly, they communicate with short call notes or chips, and it may soon be possible for
the chips to be counted and identified using sophisticated computer software, recording the
migration using an automated system. Such a record would complement radar data which, while
it provides data on numbers of birds and their direction of flight, does not allow
identification of the birds.
My study of migration with acoustic microphones was carried out in the spring and fall of
1994 and repeated in the spring and fall of 1995.
Birders Journal, 5, 75-7, 1996.
Number densities of birds flying over Brock University were compared with dBZ values over
the university on the Buffalo NEXRAD radar. A linear relationship was found between density
and z, which is antilog (dBZ/10.0). The relationship between bird densities and z values can
be used in the estimation of the number of birds migrating across the region covered by
the Buffalo radar. The weather radar can therefore be used for monitoring the numbers of
migrants entering Ontario above the Niagara Escarpment each spring. From studies of NEXRAD
data from other locations, the numbers of birds entering Ontario in the spring (or leaving
in the fall) can be estimated. At sunrise, following nights of bird migration, a strong
concentration of birds landing along the south shores of Lake Erie and Lake Ontario was
noted on the weather radar. Ground observations of birds along the Niagara Escarpment,
following nights of bird migration, were made and are described in the report.
Physics Report, PR-1998-2.
A theory of the relationship between the number of nocturnal migrant calls heard at the
ground and the actual number of nocturnal migrants passing overhead is developed. Results
of a study of migrant calls with arrays of acoustic microphones, from which the locations
of the birds could be determined, are then presented. Finally, the theory developed is
used in conjunction with the acoustic microphone data to demonstrate how nocturnal
migration traffic rates can be estimated. The key to the estimation is a knowledge of
the rate at which birds call when they migrate.
Physics Report, PR-1997-3.
In several recent studies (1995, 1996) one of the authors (JEB) has calculated
d the locations (height, bearing and radial distance from the microphone array)
of nocturnal migrants from their calls using time delays obtained from an array
of acoustic microphones. A number of assumptions are involved in calculating
the locations from the measured time delays. The present study is designed to
explore the validity of the assumptions used in the calculations. The
exploration is done by determining the location of an artificial sound source
using the location array
and comparing this calculated location with the measured location of the
artificial sound source. In this report, a brief discussion of the data
gathering procedure and the method of determining the locations is presented.
The results are then discussed in some detail. A number of attempts to
understand why the calculated and measured locations of the artificial sound
source do not agree are described.
Physics Report, PR-1997-1.
In the Spring of 1996 the author and W.E. Evans operated a number of microphone
arrays at the airport in New Smyrna Beach, Florida. The microphones detected
the calls of nocturnal migrants as they passed over the airport runway. The
goals of these microphone studies were twofold. First, to determine the range
of the microphones. Second, to determine the height distribution of calling
birds in the Florida nocturnal spring migration.
In this report the focus is on the data obtained on the night of May 11/12. A
discussion of data obtained on the nights of April 30/May 1, May 3/4, May 5/6,
and April 26/27 is also included.
Physics Report, PR-1996-2.
In the Fall of 1995, the flight calls of nocturnal migrants were recorded on an
array of four acoustic microphones at St. Catharines, Ontario. This is a
continuation of the study begun in the spring of 1995 and reported by Black
and Tucakov (1995). The basic idea underlying this study is to see if one can
obtain the location of the bird from a triangulation procedure based on time
delays between the calls received at each of the four microphones. The primary
goal of the study is to determine whether such a triangulation procedure can be
used in studying the migration of nocturnal migrants, more specifically under
what conditions it can be used. In Part 1 of this report, I describe the
equipment used to record the bird calls and the layout of the microphones.
In Part 2, I describe the software used to determine time delays from the audio
data. In part 3, I present the results of the fall study, and in Part 4, I
discuss the results with emphasis on the usefulness of the procedure and what
further studies should be done to obtain a better understanding of where the
procedure can be used.
Physics Report, PR-1996-1.
We present calculations of the relationship between the number of nocturnal
migrants calls heard at the ground and the actual number of nocturnal migrants
passing overhead. In certain cases we show that the factor linking the two
quantities is the distance travelled between calls by the birds.
Physics Report, PR-1995-1a.
In the Fall of 1995, acoustic microphones and a marine radar were operated
at Long Point in southern Ontario. The microphones were normally operated
for 8 hours each night, starting at 8:00 pm EST, and their output recorded on a
VCR. The marine radar was operated for the same time interval on selected nights.
A simple video camera was pointed at the radar display screen and its output
was put on the VHS tapes. The VHS cassettes obtained were then listened to, and
the number of night migrant contact notes or "chips" was recorded for 10
minutes in approximately each two hours. No attempt was made to identify each
chip, but the chips were divided into two groups; warblers/sparrows and
thrushes/others. This report presents the results of these chip counts. In
addition the radar data was examined and the results are presented
and compared with the results from the chip counts.
Physics Report, PR-1995-6.
In the Spring of 1995 the flight calls of nocturnal migrants were recorded on
an array of four acoustic microphones. The basic idea underlying this study
was to see if we could obtain the location of the bird from a triangulation
procedure based on time delays between the calls received at each of the four
microphones. The primary goal of the study was to determine whether such
triangulation procedure could be used in studying the migration of nocturnal
migrants, more specifically under what conditions it could be used. In Part
1 of this report we describe the equipment used to record the bird calls and
the layout of the microphones. In Part 2, we describe the software used to
determine time delays from the audio data. In Part 3, we present the results
of the spring study and in Part 4, we discuss the results with emphasis on
the usefulness of the procedure and what further studies should be done to
obtain a better understanding of where the procedure could be used.
Physics Report, PR-1995-5.
In the Spring of 1995, acoustic microphones were operated at Long Point
and St. David's in southern Ontario. The microphones were operated
for 8 hours each night, starting at 8:00 pm EST, and their output recorded on a
VCR. The VHS cassettes obtained were then listened to, and the number of
night migrant contact notes or "chips" was recorded for 10 minutes in
approximately each two hours. No attempt was made to identify each chip, but
the chips were divided into three groups: warblers/sparrows and thrushes
and others. This report presents the results of these chip counts. A marine
radar was also operated for 11 days at Old Cut. Preliminary results of the
radar study are presented.
Physics Report, PR-1995-4.
In the Fall of 1994, acoustic microphones were operated at Long Point
and St. David's in southern Ontario. The microphones were normally operated
for 8 hours each night, starting at 8:00 pm EST, and their output recorded on a
VCR. The VHS cassettes obtained were then listened to, and the number of
night migrant contact notes or "chips" was recorded for 10 minutes in
approximately each two hours. No attempt was made to identify each chip, but
the chips were divided into two groups; warblers/sparrows and thrushes/others.
This report presents the results of these chip counts.
Physics Report, PR-1995-2.
The structures formed by one-half and one monolayer (ML) of Pd evaporated onto
Cu(100) at 300 K were studied by low energy electron diffraction (LEED), medium energy
ion scattering (MEIS), thermal desorption spectroscopy (TDS), and embedded atom method
(EAM) calculations. In the half monolayer case, the LEED I(E) curves are consistent
with the established c(2 x 2) surface alloy model. The MEIS data, however, suggest that a
fraction of the Pd (~1/4) in in "second layer" sites , in agreement with previous LEIS,
TDS and XPS forward scattering measurements. The EAM simulations support the formation
of alloy islands, providing a mechanism for the covering of some Pd atoms. As the
deposition proceeds, however, this island formation is indicated to occur preferentially
over clean copper. In the one monolayer case, a p(2 x 2)-peg LEED pattern is observed.
Analysis of the I(E) curves suggests that this arises form (100) Pd packed above
the c(2 x 2) alloy. EAM calculations confirm the stability of this model. Evidence from
MEIS and TDS, however, shows that the monolayer surface as prepared in this work is
inhomogeneous. c(2 x 2) and Cu rich surface domains exist in addition to those having
the p4g Pd/d(2 x 2) PdCu structure.
Surface Science, 337, 79-91, 1995.
Surface phonon spectra on Cu(11n) vicinal surfaces, with odd number n = 1 to
19, are studied by using the continued fraction method and embedded atom potentials.
Vibration frequencies for atoms at step edges are found to be softer along the surface
normal and the step normal directions than those of terrace atoms and bulk atoms. Stiff
frequencies along the surface normal direction are found for those atoms (with bulk
nearest neighbors) located just beneath the step atoms. We find the surface relaxation
induces 10-35% stiffening in the force constants of stepped surface atoms. The mean-square
displacements (MSD) for atoms at vicinal surfaces are calculated at different temperatures.
The surface MSD is found to be isotropic for the (100) surface and anisotropic for the
Cu(11n) surfaces.
Surface Science, 303, 395-408, 1994.
We have explored the structure and the dynamics of a bimetallic system consisting of a
hexagonal (almost) overlayer of Ag on a square lattice (Ni(100) and
Cu(100)), as a function of the surface temperature. In each case the structure is
"nearly" incommensurate giving rise to a low frequency Goldstone mode. Also, the overlayer
atoms slosh back and forth over the substrate in a corrugated fashion. The calculated
dispersion of the Ag/metal vertical mode, at room temperature, is in excellent
agreement with experimental data. At higher temperatures floater atoms appear on top of
the overlayer displaying a variety of cluster formations and also exchanges with the
substrate atoms leading to surface disordering, interdiffusions and melting.
Mat. Res. Soc. Symp. Proc., 291, 205-10, 1993.
We present results obtained from a molecular dynamics study of the behavior
of isolated copper atoms placed on a copper substrate. The atomic
interactions are modeled by the embedded atom method. At 900 K we find
that diffusion frequently proceeds by a two-step exchange-mediated process.
In the first step of the process an isolated surface atom enters the
Cu(100) substrate creating a strain along a close-packed row. In the
second step the strain is relieved by an atom in the strained row returning
to the surface of the Cu(100) substrate. The atom which returns to the
surface may be several atoms removed from the atom which entered the
substrate.
Physical Review Letters, 71, 2445-8, 1993.
In the Spring of 1994, acoustic microphones were operated at Long Point
and St. David's in southern Ontario. The microphones were operated for 8
hours each night, starting at 8:00 pm EST, and their output recorded on a
VCR. The VHS cassettes obtained were then listened to, and the number of
night migrant contact notes or "chips" was recorded for 10 minutes in each
half hour. No attempt was made to identify each chip, but the chips were
divided into warblers/sparrows, thrushes and others. This report presents
the results of these chip counts.
Physics Report, PR-1994-2.
Atoms are known to move rapidly on metal surfaces. At the present time it
is not possible to study these motions experimentally. It is possible,
however, to study the motions theoretically using a technique called
molecular dynamics. In this paper we illustrate the technique for
palladium atoms placed on a copper surface. Experiments at room
temperature have shown that the Pd and Cu atoms form an ordered structure
when a Cu surface is exposed to a Pd gas. Using molecular dynamics we
have searched for the atom movements which are the origins of this ordered
structure. Under certain conditions we find the deposited Pd atoms and
substrate Cu atoms change places. The nature of these Pd-Cu exchange
events and other motions of the Cu and Pd atoms on the copper substrate are
examined. We also present the results of a study of the bombardment of the
Cu surface by Pd atoms.
Comments Condensed Matter Physics, 16, No.5, 281-305, 1993.
We have examined the structure and the dynamics of a nearly incommensurate
monolayer of Ag on Ni(100) for a large range of temperatures using
molecular-dynamics simulations based on potentials from the embedded-atom
method. On the average surface the structure is a nearly hexagonal c(2 x
2) as expected from previous experimental data. At 300 K we find the Ag
overlayer to slide back and forth in the nearly incommensurate direction on
the Ni substrate while the vertical height of the silver atom vascillates
between a lower value (~2 A) at the hollow sites and a slightly higher value
(~2.4 A) at the bridge sites. There exists also a low gap frequency
(Goldstone-like mode) for displacement parallel to the nearly
incommensurate directions along which seven Ag atoms are accommodated in
the spacing of eight Ni substrate atoms. At this temperature the
calculated dispersion of the Ag mode polarized perpendicular to the
surface is in excellent agreement with experimental data obtained from
inelastic electron scattering. Between 1200 and 1600 K the increased (and
anisotropic) mean-square vibrational amplitudes of the atoms lead
systematically to the creation of vacancies and floater atoms, to
clustering and unclustering, to surface disordering, and eventually to
melting. The behavior of the Ni surface with the Ag overlayer is
strikingly different from the bottom Ni surface with no such overlayer.
Physical Review B, 48, 5530, 1993.
The energy per atom of various surface configurations, when a half
monolayer of Pd is deposited on Cu(100), is calculated by using the
Finnis-Sinclair potentials of Rafii-Tabar and Sutton. Long-range order in
the alloyed Cu/Pd surface is also calculated as a function of temperature.
The results of the energy calculations are in agreement with existing
experimental observations, while the results for the long-range-order
calculations suggest that future experimental data may exhibit two
transition temperatures.
Physical Review B, 46, 4292-4, 1992.
Abstract
We present the results obtained from molecular dynamics simulations of an
overlayer of Ag on Cu(100) using potentials from the embedded atom method.
As in the case of an Ag overlayer on Ni(100), the overlayer slides back and
forth on the substrate along the nearly incommensurate direction. The mean
square vibrational amplitudes of the Ag atoms are also largest along this
direction. The Goldstone mode has a frequency of 1.3 cm-1 at 300 K. At
higher temperatures the surface disorders and Ag and Cu atoms interdiffuse.
The dispersion of the lowest frequency vertical mode is in good agreement
with inelastic electron scattering data. We also present some explanations
of the phonons at T and the structure factor of the system.
Surface Science, 291, 215-25, 1993.