Introduction - Severe Convective Storms and Tornadoes: Observations and Dynamics - page 18

designed by Al Bedard at NOAA in Boulder, Colorado and first used by the
author at OU in 1981. After 1984, NSSL continued to use TOTO through 1985.
In situ thermodynamic and wind measurements inside tornadoes were attempted,
but were only minimally successful. In 1986 Fred Brock and colleagues at OU
developed smaller instrument packages named ''Turtles.'' These packages were
much easier to deploy than TOTO and increased the chances of a direct hit by a
tornado. They were used with varying amounts of success in 1988, 1989, 1991, and
1993.
Efforts were also made to make measurements from more conventional
airborne platforms. Stirling Colgate at the Los Alamos National Laboratory
(LANL), carrying through on an idea that originated at Purdue University in the
late 1960s by Ernie Agee and colleagues in the early 1980s, fired instrumented
lightweight rockets from an airplane into tornadoes; however, because the rockets
were required by federal regulations to be lightweight and, therefore, were rather
fragile, they were not successful. Fred Bates at St. Louis University in 1963 first
proposed that an unmanned aerial vehicle (UAV) be used to make in situ meas-
urements near tornadoes. Almost 25 years later, Karl Bergey at OU and his
students developed two RPVs (remotely piloted vehicles) capable of taking video
as they flew by storms. Meteorological instruments, however, were never installed.
A UAS (unmanned aerial system), another name for an RPV, was used with
instruments by a group from the Universities of Colorado and Nebraska in 2010
during VORTEX2 (an experiment to be discussed subsequently).
In 1984 the author first released portable radiosondes into and around severe
convective storms. Subsequent mobile sounding systems were used during
COHMEX (Cooperative Huntsville Meteorological Experiment) in Alabama in
1986 and during CINDE (Convective Initiation and Downburst Experiment) in
1987 near Denver.
While airborne Doppler lidar measurements were first made in waterspouts
during the previous decade, the first measurements using a pulsed Doppler lidar
system, one in which range information is available, were made in 1981 in
Oklahoma along gust fronts and around cumulus towers by the author and his
student Bill McCaul using a NASA Marshall Space Flight Center airborne
system. This lidar system scanned at an angle in the direction of the flight track
and, alternately, at the same angle in a direction opposite to the flight track, so
that in space dual-Doppler analysis is possible if one neglects the difference in
time or the observations ( Figure 1.12 ). Such a dual-Doppler technique is referred
to as pseudo-dual-Doppler analysis. (One may also scan a storm from a fixed site
radar at two different times as the storm propagates by. If the storm undergoes
little if any evolution during the time period between scans, dual-Doppler analysis
may be possible if the difference in viewing angle is appropriate. Such an analysis
is also referred to as ''pseudo-dual-Doppler analysis''.)
The first airborne Doppler radar measurements in severe convective storms
were made by NSSL (at X-band) under the guidance of Peter Ray and subse-
quently Dave Jorgensen. Data in supercells were collected successfully for the first
time in the Southern Plains during COPS-91 (Cooperative Oklahoma Profiler