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Fall 2003
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ICAE Fall 2003 News Letter
RESEARCH ACTIVITY
by Organization
* * *
ATMOSPHERIC ELECTRICITY GROUP (ELAT) - BRAZILIAN INSTITUTE OF SPACE
RESEARCH (Sao José dos Campos - Brazil)
In last summer season (Jan-March - 2003) we continued our campaign initiated
at the end of 2002 to observe sprites and stratospheric electric fields
in the southeast Brazil in collaboration with the Universities of Washington
and Utah State. The results showed larger (over 140 V/m at 34 km altitude)
electric fields in the stratosphere (although not necessarily Next
to sprites) and that the phenomenon is common at this region. For the
next year, similar observations are planned to the South of Brazil. Also,
we continued our triggered lightning campaign recording peak current values
of strokes of an altitude triggered flash with peak currents up to 45
kA. For the next summer season, we are planning to begin X-ray observations
associated with triggered flashes. In the next year, it will be held in
November the IV Brazilian Workshop on Atmospheric Electricity, probably
in Rio.
ATMOSPHERIC ENVIRONMENT RESEARCH GROUP AT ONERA
Alain Delannoy and Alain Broc investigate the atmospheric conditions
which lead to the lightning strike to aircraft over Atlantic Ocean. Two
cases have been studied. The first case is associated with lightning flashes
in winter over the North sea where helicopters are often struck. In this
region, due to the high latitude, the vertical structure of thunderclouds
is strongly different from that of summer cells of warmer countries. The
second case is associated with spring thunderclouds which develop near
the west coast of Portugal. For these two cases, the 3D description of
the convective cell has been performed by using the French meso-scale
non hydrostatic model for atmospheric simulation Méso-NH. The results
compared with NOAA satellite observations are used in a microphysical
dynamical and electrical 1.5 D model from University of Washington, adapted
by Bob Salomon during a post-doc in the Group. This model is used to simulate
the vertical electrification within the cell.
Philipe Lalande and Patrice Blanchet are currently developing a set of
instruments for the observation of lightning flashes :
- PROFEO is a new 3D VHF ground lightning imaging system. The system
based around Paris (France) will be in operation at the end of 2005.
The system could also be moved to be included into international scientific
campaigns.
- ALISDAR is an automatic lightning sensor detection and recording to
be installed onboard airliners. A prototype has been successfully tested
on an airbus A340-600. From this instrument, the intra-cloud lightning
can be characterised.
- New more compact antennae have been designed for the ORAGES project
which objective is to observe the lightning activity from space.
A PhD student, Isabelle L'Helgoualc'h, is developing a physical model
of lightning flash propagation. This model is intended in a near future
to deliver a simulation of the VHF radiation of lightning.
DANISH SPACE RESEARCH INSTITUTE, COPENHAGEN DENMARK
During the summer of 2003 an observational campaign was conducted over
Southern Europe to observe Sprites, Jets and Elves. Instrumentation included
remote-controlled, semi-automatic video cameras at the Observatoire Midi-Pyrénées,
VLF receivers in France and on the island of Crete, HF receivers at 4
locations in France, and more. Simultaneously, teams in South Africa looked
for optical signatures of relativistic electrons injected in Sprites,
precipitating in the magnetically conjugate hemisphere. More than 130
Sprites were recorded along with some Elves and one Jet. The data are
still under analysis. Some first results will be presented at the AGU
Fall meeting in session AE41-B and AE42-B. The Sprite2003 team and some
sample images are shown on www.dsri.dk/~neubert/sprite2003.
The EU FP5 Research Training Network "Coupling of Atmospheric Layers"
was launched last November. The network is a collaboration with 11 institutions
across Europe for the study of Sprites and their effects on the atmosphere
and ionosphere. During the past year, 8 young scientists have been hired.
The work proper will commence in November of this year. More information
on the network is found on www.dsri.dk/cal.
HOLLE METEOROLOGY AND PHOTOGRAPHY (Arizona, USA)
Ron Holle (ron.holle@vaisala.com) presented several papers on lightning
safety and Next demographics at the International Conference on Lightning
and Static Electricity (ICOLSE) in September 2003. They were presented
in the Keraunomedicine sessions during the meeting.
Over 100 cases of lightning deaths and injuries that occurred during
the recreation activities of soccer, baseball, golf, and camping activities
around the world were summarized in Holle (2003). One recurring conclusion
is that casualties occurred not only during the game or at the camping
site, but also during other phases of these activities, such as practice
and seeking inadequate shelter. A second general conclusion is that advanced
planning was typically lacking when the lightning casualties occurred.
Holle and López (2003) identified a major shift away from agricultural
and rural settings of lightning casualties 100 years ago, to urban and
recreation events in recent years. Also identified were the types of shelter
taken, transportation, and gender in these comparisons between centuries.
Such information are useful in identifying the most appropriate audience
and approaches for lightning safety efforts.
Systematic collection of lightning death information exists in only a
few countries. The third presentation (Holle et al., 2003) estimated an
annual worldwide total of 24,000 lightning deaths and 240,000 injuries.
These rates were found by estimating the population living in countries
with lightning rates equaling or exceeding the average US flash rate.
Regions were also identified that continue to have labor-intensive agriculture
and mostly ungrounded housing. Factors that will increase or decrease
these first simple estimates were also provided to make it possible to
adjust the rates in the future with more precise information.
Recent communications:
- Holle, R.L., 2003: Activities and locations of recreation deaths and
injuries from lightning. Preprints, ICOLSE, 16-18 September, Blackpool,
England, paper 103-77 KMI, 6 pp.
- Holle, R.L., R.E. López, and B. Navarro, 2003: U.S. lightning
deaths, injuries, and damages over the last century. Preprints, ICOLSE,
16-18 September, Blackpool, England, paper 103-36 KMS, 11 pp.
- Holle, R.L., and R.E. López, 2003: A comparison of current
lightning death rates in the U.S. with other locations and times. Preprints,
ICOLSE, 16-18 September, Blackpool, England, paper 103-34 KMS, 7 pp.
INDIAN INSTITUTE OF TROPICAL METEOROLOGY - PHYSICAL METEOROLOGY AND
AEROLOGY DIVISION (Pune, India)
Lightning activity over the Indian region from Satellite-based (LIS and
OTD) Observations by S.S. Kandalgaonkar, M.I.R. Tinmaker, M.K. Kulkarni,
Asha Nath and H.K. Trimbake. Indian Institute of Tropical Meteorology
(IITM) is a research institute and has significant contributions in the
challenging areas such as Meteorology and Atmospheric Sciences. Atmospheric
Electricity is the branch of atmospheric physics, which comes under the
domain of atmospheric sciences. The topic atmospheric electricity is divided
into two categories of weather conditions : fair and disturbed weather.
The present contribution is an outcome from the disturbed weather atmospheric
electrical parameter namely, lightning. Since lightning plays an important
role in the global electric circuit, it is essential to examine its distribution
on annual as well as seasonal scale. With this view, the authors have
taken up this study where the lighting data from the satellite (LIS and
OTD) is used.
Information concerning the lightning activity in different geographical
regions is of much interest both in the engineering applications and in
the analysis of interaction between lightning and the earth's atmosphere.
Different techniques for studying lightning activity brought somewhat
a revolution with the development of sensor consisting of lightning detection
and mapping systems that have been developed in past decades. Thereafter
the Optical Transient Detector (OTD) mounted on Micro Lab-I Satellite
was orbiting the earth since April 1995, while the lightning imaging sensor
(LIS) was launched on Tropical Rainfall Measuring Mission (TRMM) in November
1997. In the present study, the authors have utilized the monthly LIS
/ OTD lightning flash grid (5o 5o) data for the period 1995-1999 / 1998-2002
over the Indian land mass region between 8-30oN, and 73-86oE. An attempt
has also been made to examine the activity from the both satellite during
the overlapping period i.e. 1998 and 1999. These data have been analyzed
to obtain their total, seasonal and differential flash count variation.
The results obtained from the 5 year / overlapping period suggests that
there is a significant difference in the total flash count by LIS / OTD
satellite. Total flash count measured by LIS / OTD satellites is 1.76
105 / 8.5 104 (5 year period) and 6.7 104 / 3.1 104 (overlapping period)
and the corresponding flash density values by LIS / OTD are 5.64 km2 y-1/
2.6 km2 yr-1 (5 year period) and 5.1 km2 yr1 / 2.35 km2 yr-1 (overlapping
period) respectively. Seasonal analysis of the flash count suggests that
for all seasons during the 5 year and the overlapping period the density
values obtained by LIS are observed to be higher than the OTD sensor.
The analysis of differential count suggests that though the OTD satellite
recorded less number of flashes during the entire as well as for the overlapping
period than the LIS, the intra cloud (IC) flash count obtained from both
the satellite is observed to be higher than the cloud to ground (CG) flash
count. This result suggests that the region under study receives more
number of IC flashes. Thus, the net results of the above studies suggest
that the detection efficiency of the LIS sensor is higher as compared
to OTD sensor. This result is in partial agreement with the studies made
by (Bond et al., 2002).
INDOOROOPILLY MEDICAL CENTRE (AUSTRALIA)
The study of human and medical interaction with lightning is continuing
happily. It is a great pleasure to report that Keraunomedicine (KM) has
at last found a "conference home" as part of ICOLSE. A successful
meeting of ICOLSE was held in Blackpool in September, and a significant
KM stream was part of that, to the benefit of all. This stream will develop,
and is set to become the focus of the KM community. I urge interested
people to watch advertising and calls for ICOLSE 2005, and to attend and
contribute to it. I have indicated willingness to coordinate this aspect
of the meeting - c.andrews @ pobox.com. Watch this space for ongoing
advice of the developing major meeting in Keraunomedicine.
Part of the conference was the great pleasure of presenting a Medal of
Honour to one who has contributed greatly to Keraunomedicine over many
years. This was the inaugural presentation, and the first recipient has
graciously given his name to the medal. It was entirely fitting that the
first recipient was Dr Nobu Kitagawa, and the ongoing honour will become
The Nobu Kitagawa Medal in Keraunomedicine.
In the area there is a significant crossover with the study of electrical
injuries, and my activities are spread between both. At present I am working
on projects like - a Handbook for applying IEC479 principles; Analysing
currents flowing via the Fifth Mechansim (Streamer Current) proposed by
Mary Ann Cooper and Ralph Andersen; Neural Pathways and Central Pathways
including the place of the NMDA receptor in Injuries; Home Lightning Location
Systems using GPS technology; and Cohort Analysis of an Electrically Injured
Population.
LABORATORY OF LIGHTNING AND SEVERE STORM, COLD AND ARID REGIONS ENVIRONMENTAL
AND ENGINEERING RESEARCH INSTITUTE, CHINESE ACADEMY OF SCIENCES, LANZHOU,
GANSU 730000, P. R. CHINA
Observations on spectra of natural lightning have been carried out in
Qinghai-Tibetan plateau and coastal area of Guangdong province in China
by using a slit-less spectrograph. There are notable differences between
the spectra features in the coastal area and the plateau region. Parameters
like wavelength, oscillator strengths, transition probabilities, and excited
energies have been calculated for the transitions Next to lightning
spectra. It is deduced from spectra structure and transition properties
that the peak temperature of lightning discharge channel for intense stroke
may be higher than the estimated value in the past,and the peak channel
temperature in plateau area should be lower than the value in other regions.
Radio frequency observations of CG lightning have been made using broadband
interferometer. During the preliminary breakdown and step leaders process,
a sequence of fast negative streamers were observed to start continually
from far or farther away the start region of the flash and progress down
the developing leader channel and supply negative charge that assists
the leader's development. The bi-directional propagations of the lightning
channel within clouds have been observed for both CG and IC discharges.
Radiation field spectra of the two concurrent breakdown processes at the
channel extremities are quite similar, indicating that the both may be
negative breakdown and caused by the same mechanisms. The spectra shapes
for different discharge processes are obvious dissimilar in the interval
from 25 to 100 MHz. Radiation from the CG lightning is stronger in the
lower frequency range than IC lightning.
Lightning activity on the Tibetan Plateau has been being studied by using
the satellite data provided by GHCC in Huntsville and the in-situ observation
data. The Satellite observations of lightning show a clear seasonal and
diurnal variation in this high- altitude region. A non-linear relationship
between lightning activity and monthly averaged convective available potential
energy (CAPE) is found. The flash number per CAPE on the Tibetan Plateau
is much larger than for other prominent lightning activity (but low-altitude)
regions. The ground-based observation shows the special characteristics
of both thunderstorm charge structure and the lightning activity.
Ground-based observation of NOx generated by lightning has been carried
out, and a very good correlation has been found between the E-field change
and concentration of NOx. The impacts of NOx generated by lightning on
chemical field in East Asia has been simulated. It has been found that
lightning directly controls the average mixing ratio of NOx in the air
during the thunderstorm process.
MASSACHUSETTS INSTITUTE OF TECHNOLOGY (Parsons Laboratory, Cambridge,
Massachusetts 02139, USA)
Harrison (GRL, 2000) has recently published evidence for a secular decline
in the strength of the DC global circuit, attributed to variation in cosmic
radiation. Williams (GRL, 2003) offers an alternative interpretation for
the observations: declining pollution concentrations in England over the
course of the 20th century are associated with increases in electrical
conductivity and hence decreases in the electric field (with no change
in global circuit current) at surface stations used by Harrison.
Following the ICAE meeting in Versailles, Earle Williams made visits
to Gabriella Satori in Hungary and to Sasha Nickolaenko and Sasha Shvets
in the Ukraine. In Hungary, work was initiated on a paper comparing lightning
activity, Schumann resonance intensity and thermodynamics for the Amazon
and Congo basins. This paper was recently submitted to the SPECIAL issue
for JASTP. In the Ukraine, collaboration resumed on a Twinning Foundation
grant, aimed at distinguishing different ionospheric models for their
effect on Schumann cavity quality factor (Q) and resonance frequencies.
Graduate student Kunal Surana is using the expanded bandwidth (2 Hz-
25 kHz) of the new electric field antenna in West Greenwich, Rhode Island
to monitor tweek sferics and the cutoff frequency (~1.8 kHz) of the global
waveguide. Changes in the cavity due to changes in incoming ionizing radiation
from day to night, changes due to solar X-rays, and changes due to lightning
from within the cavity are all targets of interest.
Measurements continue with Mike Valente and Bob Golka on a large (6 ft.
long and 2 ft diameter) air-filled glow discharge tube. This work is aimed
at quantifying the relationship between the absolute radiance (watts/m2/sr/nm)
associated with N21P red light and the electrical power dissipation and
current density in sprites. This interest has led to tube operation in
a range of current density several orders of magnitude lower than in previous
laboratory glow discharge work. Consistent with work on other gases, the
luminous efficiency of the discharge is remarkably stable over a large
parameter space.
The computation of summertime climatologies for wet bulb potential temperature
and cloud base height for the continental U.S. provide a mechanism for
the origin of inverted polarity thunderstorms. All laboratory workers
agree that in the limit of large cloud water content, the rimer charges
positively. Observations from STEPS (Rust and MacGorman, 2002) have shown
the presence of inverted polarity clouds in the presence of both large
instability and high cloud base height. Large liquid water content is
favored under these conditions because cumulonimbus updraft widths increase
with cloud base height (Williams and Stanfill, 2002) and because the water-removing
coalescence zone is shortened with high cloud bases (Rosenfeld and Woodley,
2003). These results have been submitted to the Special Issue of Atmospheric
Research following the ICAE Conference in Versailles.
MASSACHUSETTS INSTITUTE OF TECHNOLOGY (Lincoln Laboratory, Lexington,
Massachusetts, USA)
In March 2003, a global intercomparison of different geostationary satellite
methods for identifying oceanic thunderstorms was carried out, under the
auspices of the FAA-supported Oceanic Weather program. Participants in
this study were NCAR (Cathy Kessinger and Dave Johnson), NRL (Rick Bankert
and Jeff Hawkins), AWC (Fred Mosher), and MIT LL (Mike Donovan and Earle
Williams). NASA's Precipitation Radar and Lightning Imaging Sensor on
board the TRMM satellite were used to validate the oceanic thunderstorms.
The results show that it is difficult to distinguish oceanic thunderstorms
on the basis of satellite visible and infrared methods alone.
Interest continues in the use of DoD satellite assets for the study of
volcanic eruptions and ash cloud production, also in the Oceanic Weather
context. Some opportunity for future work here may be realized in NASA's
ASAP (Advanced Satellite Aviation Products) program.
NATIONAL LIGHTNING SAFETY INSTITUTE (NLSI) (Louisville, Colorado, USA)
NLSI has published a new 65 page booklet "Bonding for Lightning
Protection." More than 100 illustrations describe correct bonding
methods for fences, building exteriors and interiors, radio towers, I.T.
room equipment, cable shields, etc. All recommendations are compliant
with NFPA-780 and IEC 61024-1-2.
The Table of Contents is viewable the NLSI website page:
www.lightningsafety.com/nlsi_bus/bonding_book.html
POLISH ACADEMY OF SCIENCES (Warsaw, Poland)
The atmospheric electricity research group at the Institute of Geophysics
P. A. Sci. is continuing its investigations in the field of thunderstorms
and fair weather electricity.
We cooperate with the Institute of Meteorology and Water Management in
Warsaw using its nine SAFIR stations network for lightning monitoring
and the recently installed new Doppler radar for thunderclouds and lightning
discharges observation in Poland. Now we collect the further data about
the occurrence of multi-stroke lightning flashes and the complex discharge
lightning events (CDLE) in different stages of a thundercloud life. A
part of obtained results about the CDLE's observed in thunderstorms near
Warsaw and their characteristic features was presented by Piotr Baranski
(baranski @ igf.edu.pl) during the 12-th ICAE in Versailles, France,
in this year. The validation of the SAFIR detections, especially these
concerning the multiple cloud-to-ground flashes with bipolar strokes,
is still thoroughly examined (P. Baranski, P. Bodzak).
At the polar station Hornsund, Spitsbergen, the electric field and vertical
air- earth current recordings are continued with simultaneous magnetometer,
riometer as well as meteorological and radioactivity pollution measurements
(M.Kubicki, S.Michnowski, B. Laurikainen). The influences of solar wind
on the electrical element variations at the ground in Hornsund are being
examined with the use of geophysical data from Hornsund, satellite data
on interplanetary magnetic field of solar wind as well as the IMAGE net
of magnetometer and riometer stations (S.Michnowski, M.Kubicki, N.Kleimonova,
S.Israelsson, N.Nikiforova).
Examination of the atmosphere response to solar cosmic ray events is
continued (Z. Kobylinski, S. Michnowski).
At Swider Geophysical Observatory the atmospheric electricity recordings
have been continued on the background of simultaneous observations of
meteorology, aerosol and radioactivity, and pollution parameters (M. Kubicki:
swider @ igf.edu.pl, W. Kozlowski, B. Laurikainen).
New sensors for air-earth current density, electric field and space charge
recordings are designed (J.Drzewiecki, J.Berlinski, M.Kubicki).
SPACE SCIENCE AND TECHNOLOGY DEPARTMENT - RUTHERFORD APPLETON LABORATORY
(Oxfordshire, UK)
Karen Aplin (k.l.aplin @ rl.ac.uk) at the Rutherford Appleton
Laboratory (RAL) is continuing her research into atmospheric ions: both
their measurement and their effects on climate. She continues to improve
the Programmable Ion Mobility Spectrometer (PIMS), originally developed
with Dr Giles Harrison at The University of Reading and now a mainstay
of several experimental campaigns. A recent discovery is a new algorithm
for retrieval of ion mobility spectra (Aplin K.L. (2003), A novel technique
to determine atmospheric ion mobility spectra In: Chauzy S. and Laroche
P. (ed.), Proceedings of 12th International Conference on Atmospheric
Electricity, Versailles, Paris 9th-13th June 2003 (ISBN 2-7257-0008-6),
1, 357-360 ), which permits inversion of spectra from historic ion
measurements in addition to a novel approach for modern spectral measurements.
Dr Aplin is also leading a project funded by the UK Natural Environment
Research Council (NERC) to investigate the infra-red absorption properties
of ions in the atmosphere (Aplin K.L. (2003), Direct radiative effects
of tropospheric ionisation, Atmospheric Chemistry and Physics Discussions,
3, 3205-3222). This experiment comprises laboratory measurements carried
out at the NERC Molecular Spectroscopy Facility, located at RAL, which
will measure the absorption properties of artificially-generated ion concentrations.
Atmospheric measurements of downwelling infra-red radiation will be compared
to background cosmic ray ionisation measurements at a Welsh mountain weather
station, to complement the laboratory experiments. Detailed ionisation
profiles will be obtained in the summer of 2004 using radioactivity-sonde
measurements.
Short term placement available
A six month position (approx May-October 2004) is available at the Rutherford
Appleton Laboratory, near Oxford, for a postgraduate student or recent
graduate to assist with the molecular cluster-ion absorption experiment
above. The student should ideally have some experience of experimental
work in atmospheric electricity, and the position is likely to involve
regular travel to Wales for field measurements. Please contact Karen Aplin
for further details.
TEL AVIV UNIVERSITY, DEPARTMENT OF GEOPHYSICS AND PLANETARY SCIENCES
(Tel Aviv, Israël)
The analysis of the sprite data obtained during the MEIDEX space shuttle
mission in January 2003 is continuing. The video retrieved contains information
from 21 different orbits (out of 24 performed) and a total of 392 minutes
(out of 458 recorded). Yoav Yair (The Open University) and Peter
Israelevitch (Tel Aviv University) are searching each frame of the
video data for sprites and elves. The number of positively identified
events from 7 orbits is 15. The results were reported at the ICAE and
IUGG meetings. The operational procedure for predicting the location of
major storms with a high probability of producing TLEs, developed by Baruch
Ziv and Yoav Yair (The Open University), which was used during
the mission, will be published in the Journal of Applied Meteorology.
Eran Greenberg and Colin Price are developing a new improved
ELF geolocation procedure, by which Schumann resonance (SR) data from
single and multiple stations are used to locate the space-observed TLEs.
This work is being done in collaboration with Gabriella Satori
(Hungary) and Mitsutero Sato (University of Sendai, Japan). Yoav
Yair, Zev Levin and Colin Price have received a 3-year
grant from the Israeli Science Foundation for conducting sprite research
in winter thunderstorms. Observations will be conducted initially from
the Tel-Aviv University campus, with possible future campaigns conducted
from Mt. Carmel and Mitzpe-Ramon.
Olga Pechony, Zev Levin and Colin Price have recently
completed a study of a severe weather event in southern Israel that produced
flash floods, large hail, and large amounts of positive lightning. Bella
Federmesser and Colin Price have completed an analysis of 6-years
of TRMM precipitation and lightning data over the Mediterranean Sea. Interesting
relationships between the precipitation and lightning have been found.
Olga Pechony and Colin Price are developing a theoretical
model of the SR, to simulate the SR observations we collect at our Negev
station. We hope to use the theoretical model to help us interpret the
physical meaning of what we observe experimentally at our field site.
Long-term statistics of the SR parameters at our station have been analysed
by Alexander Melnikov and Colin Price. Two papers have been
submitted to JASTP Next to our observational data. Mustafa Asfur
and Colin Price have been analyzing the experimental SR data Next
to African lightning activity, together with the NOAA NCEP reanalysis
data from Africa. We find remarkable correlations between the SR data
and climate parameters such as surface temperature, vertical mass flux,
upper tropospheric humidity, and total precipitable water.
Colin Price, Michael Finkelstein and Adi Zomer have
started a new project to monitor ULF radiation in the atmosphere. The
ULF radiation (f<1Hz) may show anomalous activity in seismic zones
prior to earthquakes. A new field station has been constructed along the
Dead Sea rift valley near the town of Eilat.
Orit Altaratz has completed her PhD work under Zev Levin
and with the assistance of Tamir Reisin. Her research included
the development of a 3D RAMS model with electrical development in a cloud
field. This is the first time that such a model has been used to test
various electrical processes in a realistic cloud field. As part of her
research she was able to explain the reasons for the high lightning rate
over the sea near the Haifa coast and the higher lightning frequency near
Haifa than near Tel Aviv, just 80 km to the south. Two papers on this
work have been submitted for publication in Atmospheric Research.
TEXAS A&M UNIVERSITY, DEPARTMENT OF ATMOSPHERIC SCIENCES
Our Texas A&M University lightning research efforts received a big
boost with the awarding of the recent NSF-MRI to install an LDAR II Vaisala-GAI
network around Houston, Texas. This network will be comprised of twelve
sensors centered on Houston, the most polluted city in the United States.
The network will be the foundation of the HEAT project, i.e. the Houston
Environmental Aerosol Thunderstorm project scheduled for the summer of
2005.
Interested readers can learn more about this project from the web page:
http://www.met.tamu.edu/ciams/heat/index.html
The idea for the HEAT project developed from the research reported by
Orville et al.
Orville
et al., 2001: Enhancement of cloud-to-ground lightning over Houston, Texas.
Geophys. Res. Ltr., 28, 2597-2600
and by Steiger et al.
Steiger
et al., 2002: Cloud-to-ground lightning characteristics over Houston,
Texas: 1989-2000. J. Geophys. Res., 107, D11, 10.1029/2001JD001142.
A more recent paper published in October provides further evidence of
enhanced ground strike lightning activity associated with human activities,
this time over southern Louisiana:
Steiger, Scott M.; Orville, Richard E., Cloud-to-ground lightning enhancement
over Southern Louisiana, Geophys. Res. Lett., Vol. 30, No. 19, 1975 10.1029/2003GL017923.
October 2003.
We anticipate that the 12-station LDAR II network will be operational
in the first half of 2004. The development of the HEAT project is a large
program whose success to-date has been the result of assistance from many
colleagues, including Paul Krehbiel, John Helsdon, Charlie Knight, Ken
Cummins, Rod Rogers, Don MacGorman, and Dave Rust to name just a few.
Graduate students Scott Steiger, Brandon Ely, and Jamie Smith will be
using LDAR II data for their thesis and dissertation research in the next
few years. It should be noted that the HEAT project is just a small part
of an overall 18-month program supported by the EPA, NOAA, and the TCEQ
(Texas Center on Environmental Quality) beginning in May 2004 and covering
the pollution episodes of two summers.
In addition to the good news of the NSF-MRI award, an equally important
event occurred when Dr. Larry Carey joined our faculty as an assistant
professor in September. Larry Carey comes to us from North Carolina University.
Before that, he was at Colorado State University working and studying
under Professor Steve Rutledge where he received his PhD in 1999. His
most recent paper is:
Carey, Lawrence D.; Rutledge, Steven A., Characteristics of cloud-to-ground
lightning in severe and nonsevere storms over the central United States
from 1989-1998, J. Geophys. Res., Vol. 108, No. D15, 4483, 10.1029/2002JD002951,
August 2003.
UNIVERSITY OF FLORIDA (Gainesville, Florida, USA)
A total of 24 lightning flashes were initiated from June 30 to August
15, 2003 at the International Center for Lightning Research and Testing
(ICLRT) at Camp Blanding, Florida. Of these 24, 12 contained leader/return
stroke sequences and 12 were composed of the initial stage only. All triggered
flashes effectively transported negative charge to ground, except for
one flash that lowered both positive and negative charge to ground. This
flash consisted of an initial stage followed by two return strokes, with
the initial stage and first stroke lowering negative charge and the second
stroke lowering positive charge. Five flashes with return strokes were
triggered using the tower launcher and seven flashes were triggered using
a mobile launcher mounted on the extendable arm of a utility truck. Additionally,
two natural lightning discharges that terminated on site were recorded
by the multiple-station electric and magnetic field measuring network.
Jason Jerauld defended his Masters thesis titled "A Multiple-Station
Experiment to Examine the Close Electromagnetic Environment of Natural
and Triggered Lightning", and Venkateswararao Kodali defended his
Masters thesis titled "Characterization and Analysis of Close Lightning
Electromagnetic Fields". Jason continues his research toward a Ph.D.
degree. Also, Angel Mata defended his Masters thesis titled "Interaction
of Lightning with Power Distribution Lines: 2001 and 2002 Experiments
at the International Center for Lightning Research and Testing (ICLRT)",
and Robert Olsen defended his Masters thesis titled "Optical Characterization
of Rocket-Triggered Lightning at Camp Blanding, Florida".
Vladimir A. Rakov, Martin A. Uman, and Keith J. Rambo reviewed ten years
of triggered-lightning experiments at Camp Blanding, Florida, in a paper
presented at the 12th Int. Conf. on Atmospheric Electricity, Versailles,
France, June 9-13, 2003. The lightning-triggering facility at Camp Blanding,
Florida was established in 1993 by the Electric Power Research Institute
(EPRI) and Power Technologies, Inc. (PTI). Since September 1994, the facility
has been operated by the University of Florida (UF). During the last eight
years (1995-2002) over 40 researchers (excluding UF faculty, students,
and staff) from 14 countries representing 4 continents have performed
experiments at Camp Blanding concerned with various aspects of atmospheric
electricity, lightning, and lightning protection. These countries include
Australia, Austria, Canada, France, Germany, Iran, Italy, Japan, Norway,
Poland, Russia, Sweden, Switzerland, and USA. Since 1995, the Camp Blanding
facility has been referred to as the International Center for Lightning
Research and Testing (ICLRT) at Camp Blanding, Florida. A summary of the
lightning triggering operations conducted for various experiments at the
ICLRT from 1997 to 2002 is presented in Table 1.
Table 1.
1997-2002 Triggered-Lightning Experiments
at the ICLRT at Camp Blanding, Florida
The results of triggered-lightning studies at the ICLRT serve (1) to
understand better the physics of the lightning discharge, (2) to improve
lightning protection schemes, (3) to evaluate the performance characteristics
of the U.S. National Lightning Detection Network (NLDN) (e.g., Cramer
et al. 2001), and (4) to test the validity of lightning return-stroke
models (e.g., Rakov and Uman 1998; Uman et al. 2002; Schoene et al. 2003).
The principal results obtained from 1993 through 2002 at the ICLRT include
(1) characterization of the close lightning electromagnetic environment
(Rakov et al. 1998, 2001; Uman et al. 2000, 2002; Crawford et al. 2001;
Schoene et al. 2003);
(2) first lightning return-stroke speed profiles within 400 m of ground
(Wang et al. 1999c);
(3) new insights into the mechanism of the dart-stepped (and by inference
stepped) leader (Rakov et al. 1998; Wang et al. 1999c);
(4) identification of the M-component mode of charge transfer to ground
(Rakov et al. 1995, 1998, 2001);
(5) first optical image of upward connecting leader in triggered-lightning
strokes (Wang et al. 1999a);
(6) electric fields at distances from the lightning channel attachment
point ranging from 0.1 to 1.6 m (Miki et al. 2002);
(7) inferences on the interaction of lightning with ground and with grounding
electrodes (Rakov et al 1998, 2002);
(8) discovery of X-rays produced by triggered-lightning strokes (Dwyer
et al. 2002, 2003; Al-Dayeh et al. 2002);
(9) new insights into the mechanism of cutoff and re-establishment of
current in rocket-triggered lightning (Rakov et al. 2003).
In 2002, the University of Florida acquired an image converter camera
K004M, manufactured by BIFO, Moscow, Russia, for studying the lightning
attachment process at the ICLRT. The camera can be operated in either
streak or framing mode. In the streak mode, record length can be selected
in the range from 0.3 to 1000 us, and the limiting temporal resolution
is about 1 ns. In the framing mode, the number of frames is up to nine,
the exposure time is from 0.1 to 10 us, and the interframe interval is
from 0.5 to 100 us. The results of testing of this and other image converter
cameras using laboratory sparks up to 6 m in length are presented by Shcherbakov
et al. (2003).
THE UNIVERSITY OF READING (Reading, UK)
Giles Harrison (r.g.harrison @ reading.ac.uk) reports:
Work continues at Reading investigating the physical links between atmospheric
electricity, aerosols, clouds and climate. A review paper on this subject,
written jointly with Ken Carslaw (School of the Environment, University
of Leeds, UK), has now appeared in Reviews of Geophysics. It follows the
publication of a paper in Science, on Cosmic rays, Clouds and Climate.
In a new experimental project funded by Natural Environment Research
Council, ion-aerosol interactions in urban air are being studied. Deployment
of several Programmable Ion Mobility Spectrometers (PIMS) developed at
Reading will be central to this work. Richard Wilding and Anna Wilson
have joined Giles Harrison on this topic.
At the ICAE in Versailles, conference papers were presented on long-term
measurements, the link between solar variability, clouds and climate (with
Jasper Kirkby from CERN, Switzerland), radioactive aerosol in the environment
(with Sachchida Tripathi, Oxford) and perhaps appropriately to the conference's
venue, potential measurement made on the Eiffel Tower in the 1890s (with
Karen Aplin, Rutherford-Appleton Lab, Oxon). Work on recovering more of
the long series of UK Potential Gradient, air conductivity and air-earth
current measurements continues. A comparison of the UK results with those
obtained at Nagycenk, Hungary, has been published in Annales Geophysicae,
and an overview of the UK data was presented earlier this year in Weather.
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