of research that we are interested in are listed
below, with a brief description of each and some external links.
1) Electric fields and the distribution
of electric charge in storms -
We study convective regions, stratiform cloud regions,
and everywhere in between. Recently, much of our attention has been
on mesoscale convective systems,
which are thunderstorm complexes that are hundreds of kilometers across
and last for several hours. To study these systems we participated
in a project called MEaPRS, an acronym for MCS Electricity and Polarization
Radar Studies. Based in Norman, Oklahoma, and with the support of
Severe Storms Laboratory, we took part in the field phase of
this project in May and June, 1998. Our goal for the observations
was to acquire electric field soundings in all the different regions --convective
updraft, convective downdraft, transition zone, and stratiform cloud--
of an MCS. Analyses of these data are in progress, and preliminary
results were presented at the 11th International Conference on Atmospheric
Electricity (June 1999) and at the Fall Meeting of the American Geophysical
Union (December 1999). Two manuscripts have been submitted (April
and July, 2000) to the Journal of Geophysical Research - Atmospheres,
2) Charge carried by precipitation in storms -
We have also taken part in studies that concentrated
on supercell storms,
which are the kind that most tornadoes come from. Our goal in these
recent experiments was to get soundings of electric field through the updraft
region, where the upward air velocity can exceed 100 miles per hour.
From a mountaintop in New Mexico, at the Langmuir
Laboratory for Atmospheric Research, we have studied small air
mass storms. In a field project during the summer
of 1999 we investigated the electrical evolution of six thunderstorms by
launching as many as seven instrumented balloons into each storm.
Analysis of these data is currently our main task. Initial results
of this study were presented at the Fall Meeting of the American Geophysical
Union (December 1999).
For this type of study, a particle-charge
instrument is attached to the balloons in addition to
the usual instruments. This instrument measures the amount of electric
charge carried by individual precipitation-sized particles as these particles
pass through it. One result from these
studies is a indication of how much of the total charge in a cloud is carried
by precipitation-sized particles and how much is carried by the much smaller
but more prevalent cloud particles. This fundamental information
is helpful in understanding how the charge in a storm is generated.
3) Electric fields and charges in storms as related
to lightning and sprites -
We have a very basic interest in understanding how the electric fields
that we measure inside storms result in and are affected by lightning flashes.
Our database of nearly 200 electric field soundings through thunderstorms
have helped identify a possible lightning initiation process. Our
data are also proving useful to those scientists trying to understand sprites
and other high altitude luminous events.
4) Enhanced electric fields during fair weather at
We have studied this part of the sunrise
effect phenomenon with a tethered balloon system
at NASA Kennedy Space Center/Cape
Canaveral Air Force Station. The electric fields at the surface there
are sometimes an order of magnitude larger than expected during fair weather.
Results from this study were presented at the 11th International Conference
on Atmospheric Electricity in June, 1999. In the future we would
like to conduct further studies of the fair weather electrical environment.
For more information on our research, please see our List
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Last updated 23 August 2000. Maribeth
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