AUTHOR = {H. Fukunishi and Y. Takahashi and A. Uchida and
                  M. Sera and K. R. Miyasato},
  TITLE = {Occurrences of Sprites and Elves above the {S}ea of
                  {J}apan near {H}okuriku in Winter},
  JOURNAL = {EOS Supplement},
  YEAR = 1999,
  VOLUME = 80,
  NUMBER = 46,
  PAGES = {F217},
  MONTH = {November},
  ANNOTE = {A42E-07 talk},
  ABSTRACT = {To observe the rapid space-time structures of sprites
and elves, we developed 16-channel array photometers using multianode
photomultipliers. We operated these photometers and CCD cameras at
Dodaira Astoronomical Observatory (36.0 N, 139.2 E) and Sendai(38.3N,
140.9E) in December 1998 and January 1999, and succeeded for the first
time in observing sprites and elves above the Sea of Japan near the
Hokuriku region in winter. These sprites and elves occurrred
associated with the passage of a cold front.  Since the bottom
altitude of thunder clouds in winter is much lower than that in
summer, it is important to investigate the characteristics of wintery
sprites and elves. The two categories of sprites, column-sprites and
carrot-sprites, were observed with various fine structures. The bottom
and top altitudes of column-sprites observed at 1909 UT on January 27,
1999 were precisely estimated to be 73 and 87 km, respectively, on
average by triagulation using simultaneous CCD camera images obtained
at Dodaira and Sendai. It was also found that the vertical lengths of
13 sprite events observed on the same day range from 8 to 15 km, which
are shorter than those of sprites observed in Colorado in summer.  On
the other hand, elves showed a spatial and temporal development
similar to that observed in Colorado. The horizontal extent of elves
were estimated to be 250 - 420 km.  Based on these observed features,
we will discuss the excitation processes of wintery sprites and elves.}
  AUTHOR = {E A Bering and J R Benbrook and J A Garrett and A
                  Paredes and E M Wescott and D D Sentman And H C
                  Stenbaek-Nielsen and W A Lyons},
  TITLE = {The 1999 Sprites Balloon Campaign},
  JOURNAL = {EOS Supplement},
  YEAR = 1999,
  VOLUME = 80,
  NUMBER = 46,
  PAGES = {F216},
  MONTH = {November},
  ANNOTE = {talk},
  ABSTRACT = {There are several competing models for the production of sprites, jets
and elves. It has become clear it is not possible to select between
these models using only ground-based data, owing to the fact that the
ground shorts out the field signatures of interest. Consequently, a
balloon campaign was conducted in June, July and August of 1999. The
1999 Sprite Balloon Campaign conducted three high altitude balloon
flights, one from Palestine, Texas and two from Ottumwa, Iowa. Flight
1, an engineering test, was launched from Palestine at 01:14:31 UTC on
7/06/1999 and cutdown at 09:45:00 UTC on 07/06/1999. Flights 2 and 3
flew from Ottumwa at 23:57:30 UTC on 8/14/1999 to 12:35:00 UTC on
08/15/1999 and at 00:39:32 UTC on 08/21/1999 to 11:12:00 UTC on
08/21/99, respectively. The balloons floated at 32 km and drifted
westward at $\sim$30 knots. The balloon payloads were instrumented
with dual three axis electric field detectors, three axis fluxgate and
induction magnetometers, X-ray scintillation counter, Geiger-Mueller
tube, upward looking high-speed photometer, vertical current density
ammeter, conductivity measurements, and an ambient thermometer. A
redundant telemetry scheme provided five orders of magnitude of
dynamic range in sensitivity. An event triggered on-board memory
sampled 10 quantities at a rate of 50 kHz per channel for 160 ms per
event. Ground observations included low light level TV observations
from three sites, WIRO, on Jelm Mtn., Wyoming, Bear Mtn.\~{o}verlook
fire tower, South Dakota, and Yucca Ridge, Colorado. Jelm Mountain had
a fast photometer and a high speed TV imager. The 3rd flight was the
most successful. During this flight, 304 events were recorded in the
burst memory. At least half show waveforms that appear to be lightning
related. All three ground stations had clear skies. There were two
small sprite producing storms, one in eastern South Dakota and one in
central Kansas. Perhaps as many as 20 transient luminous events were
recorded by at least one station. At least four were recorded by two
stations. Two of these were observed at three stations, one of which
was observed by an independent fourth site. Multiple site observations
  AUTHOR = {W. A. Lyons and T. E. Nelson and J. L. Eastman and
                  R. A. Armstrong and E. R. Williams and
                  D. S. Suszcynsky and M. A. Taylor and Y. Takahashi
                  and E. A. Bering and J. R. Benbrook},
  TITLE = {Sprites'99 Campaign Highlights and the {Y}ucca {R}idge
                  {F}ield {S}tation},
  JOURNAL = {EOS Supplement},
  YEAR = 1999,
  VOLUME = 80,
  NUMBER = 46,
  PAGES = {F216},
  MONTH = {November},
  ANNOTE = {talk},
One component of the 1999 SPRITES Campaign was conducted at the Yucca
Ridge Field Station, near Ft.  Collins, CO, during the months of June,
July, and August 1999. The primary emphasis was providing storm
forecasting and optical sprite detection during the June and August
NASA stratospheric balloon missions conducted by the University of
Houston (Gar Bering). On 21 August 1999 Yucca Ridge (along with
several other ground stations) observed several sprites and elves
above storms in South Dakota and Kansas while the NASA balloon was at
32 km over southwestern Iowa. VLF and ELF information were also
obtained. This marks the first coordinated optical measurements by
ground and balloon-borne sensors. A new record for sprites from a
single storm occurred on the evening of 4-5 June 1999. At least 750
sprites were recorded using low-light imagers during a three-hour
period above a large MCC in central South Dakota. Sprite frequencies
as high as 15 per minute were noted. The storm, which may have been
influenced from smoke from western wild fires, attained positive CG
percentages as high as 80\% at times. On 18 August 1999, a massive MCC
formed as predicted over Colorado and moved slowly eastward into
Nebraska. It produced extremely bright sprites, some of which were
visible to the naked eye at 500+ km. Most sprites were recorded by
several low light imagers and a 1000 fps high speed image intensified
camera. Moreover, some of the sprites were also captured on monochrome
and color conventional CCD cameras. This storm also produce clear
evidence of a feature being termed a "troll," a distinct jet-like
structure emanating from near the cloud tops and propagating upwards
to about 50 km at speeds in excess of 100 km/s, apparently along the
trail of a preceding sprite tendril. For a number of sprites,
additional narrow band photometric measurements of first-positive,
second-positive and first negative nitrogen emissions were also
obtained. Detailed cloud-scale modeling of sprite-producing storms is
also underway in order to learn more about the interactions of storm
dynamics, microphysics and electrification.}
  AUTHOR = {C. P. Barrington-Leigh and U. S. Inan and M. Stanley},
  TITLE = {Elves: Photometric and Video Signatures},
  JOURNAL = {EOS Supplement},
  YEAR = 1999,
  VOLUME = 80,
  NUMBER = 46,
  PAGES = {F216},
  MONTH = {November},
  ANNOTE = {poster},
  ABSTRACT = {A horizontal array of fast ($<$30$\sim$ms resolution)
  photometers has proved to be an effective tool for discriminating
  elves (the flash in the lower ionosphere caused by heating due to
  the electromagnetic pulse from cloud-to-ground lightning) from other
  brief ($\sim$1$\sim$ms) atmospheric flashes associated with
  thunderstorms [Inan et al., 1997; Barrington-Leigh and Inan, 1999].
  In contrast, video observations with a time resolution of 17$\sim$ms
  or 33$\sim$ms have presented difficulties in discriminating between
  sprites and elves, and have led to different conclusions about the
  occurrence frequency and lightning dependency of elves.  Two events
  recorded with a 3000 frame per second intensified video system
  provide the first true images of elves at a frame rate appropriate
  for distinguishing their temporal dynamics.  A 2-dimensional
  cylindrically symmetric electromagnetic model of the
  lightning-ionosphere interaction is used to relate the signatures of
  elves seen by photometric arrays to the luminous patches seen in
  some normal-speed video images, which often also contain
  sprites. Past observational discrepancies between video and
  photometry are discussed in the context of the lightning radiated
  electromagnetic pulses (EMP) and the quasi-electrostatic (QE) fields
  resulting from a lightning return stroke.}
  AUTHOR = {L.W. Wescott and E.M. Wescott and
                  H.C. Stenbaek-Nielsen and D.D. Sentman and
                  D.R. Moudry and M.J. Heavner and F.T. Sao Sabbas},
  TITLE = {Triangulation of Sprites and Elves from the {NASA}
                  1999 Sprites Balloon Campaign},
  JOURNAL = {EOS Supplement},
  YEAR = {1999},
  VOLUME = {80},
  NUMBER = {46},
  PAGES = {F216},
  MONTH = {November},
  ANNOTE = {poster},
  ABSTRACT = {We have recorded several thousand sprites with low light
  level TV systems since 1993.  Sprites vary tremendously in size,
  from the smallest single spot of a few square km in area to huge
  complex forms covering several thousand square km. There have been few
  good opportunities to make accurate triangulations from two or
  three sites using similar instrumentation.  Elves have not been
  located by triangulation. During August, 1999 the University of
  Alaska made optical observations from two ground sites with a
  baseline of 360 km.  One site was on Jelm Mt. about 50 km SW of
  Laramie WY, and the other was on Bear Mt. near Custer WY. On four
  nights about 30 sprites and 10 elves were recorded by both stations
  in similar narrow field of view TV systems.  All of the common
  sprite types are represented. The night of August 18 UT was the
  most productive, with over 20 simultaneous events.  In this paper we
  present the results of the three dimensional triangulations of the
  various sprite types, and their position in space with respect to
  the reported NLDN CG strokes.  This analysis includes details such
  as hot spots and typical vertical distributions.  These new results
  are compared to previous triangulations.  For the first time we are
  able to triangulate on the altitude and lateral size of elves
  events, and their location with respect to the NLDN strokes.}
  AUTHOR = {M.G. McHarg and R.K. Haaland and D.R. Moudry and
                  H.C. Stenbaek-Nielsen},
  TITLE = {High Speed Photometric Observations of Sprites},
  JOURNAL = {EOS Supplement},
  YEAR = 1999,
  VOLUME = 80,
  NUMBER = 46,
  PAGES = {F217},
  MONTH = {November},
  ANNOTE = {A51B-03 poster},
  ABSTRACT = {A high speed multi-channel photometer was built and
  deployed to the Wyoming Infrared Observatory (WIRO) at Mount Jelm
  Wyoming for the Sprites 99 campaign. The photometer records 16
  channels with a 6 degree field of view at 10,000 samples per second
  on each channel. The photometer is bore-sighted with a high speed
  (1000 frames per second) imager and a narrow field low light level
  scene camera running at standard TV frame rates (30 frames per
  second). We recorded over 30 events on two nights of observations
  during the campaign. We report on statistical distributions of the
  white light optical duration of sprites as a function of sprite
  altitude. We also compare the results of the photometer with the
  high speed imager, and demonstrate that the two instruments give
  complimentary information. Spatial information exists on scales
  smaller than that of the photometer resolution, and temporal
  information exists at time scales shorter than the high speed imager
  can resolve. In combination the two instruments yield a wealth of
  new information about the spatial extent and temporal evolution of

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