Introduction - Severe Convective Storms and Tornadoes: Observations and Dynamics - page 17

cells, which is still used to this day. Some of the participants in the early NSSL/
OU storm intercept field activities who at the time of this writing are still active in
tornado research include the author and undergraduate students Erik Rasmussen
and Lou Wicker, who accompanied the author on early storm chases.
On May 24, 1973 visual, storm intercept observations were combined with
Doppler radar measurements from a fixed site research Doppler radar at NSSL to
study the complete life cycle of a tornado that struck Union City, Oklahoma.
The data set collected was the first comprehensive combined Doppler radar and
visual documentation of a supercell tornado. Rodger Brown, Don Burgess, Les
Lemon, and Bob Davies-Jones were prominent members of the team that studied
this tornado. Ralph Donaldson at the Air Force Cambridge Research Laboratory
in Massachusetts provided some of the early ground-laying work for the
identification of the mesocyclone in supercells. The addition of a second Doppler
radar west-northwest of NSSL made it possible for dual-Doppler analysis of
the wind field when storms passed through the small NSSL dual-Doppler
network. An outline of dual-Doppler and other analysis techniques is given in the
Appendix.
Under the direction of Peter Ray at NSSL, a number of excellent cases of
tornado formation in supercells were analyzed when the parent supercells tra-
versed the NSSL dual-Doppler network, and were studied in the late 1970s and
early 1980s. In addition, Doppler spectra in tornadoes, from which the maximum
wind speed could be estimated, were collected by the first NSSL Doppler radar
and analyzed by Dusan Zrnic, Dick Doviak, and colleagues at NSSL. Doppler
radar data were also collected in a wide spectrum of storm types during NHRE
(National Hail Research Experiment), conducted in northeastern Colorado during
the summers of 1972-1974 and 1976, mainly to test the usefulness of seeding
clouds to reduce damaging hail.
The main objective of JDOP (Joint Doppler Operational Project) conducted
first in 1978 (and in succeeding years) at NSSL was to provide verification of the
signatures detected on Doppler radar. JDOP was influential in the development of
the future national Doppler radar system (NEXRAD) implemented in the U. S.
more than a decade later. SESAME (Severe Environmental Storms and Mesoscale
Experiment) was conducted during the spring of 1979 in the Southern Plains.
Several large tornadoes that occurred during SESAME were studied extensively.
Storm chasing also took hold in the late 1970s and early 1980s at Texas Tech
University in Lubbock with Erik Rasmussen and Tim Marshall and subsequently
elsewhere. Storm intercept field programs were carried out in eastern Colorado
in the mid-1980s by NOAA's PROFS (Program for Regional Observing and Fore-
casting Services) and by NCAR. Non-supercell thunderstorms and microbursts
were studied extensively in the Denver area, especially during JAWS (Joint
Airport Weather Studies) in 1982. In 1981 CCOPE (Cooperative Convective
Precipitation Experiment) was conducted in southeastern Montana using three
fixed site Doppler radars and aircraft; High Plains supercells were studied and
penetrated by an armored aircraft (T-28) which made in situ measurements of
updrafts and downdrafts and thermodynamic measurements.
Efforts to make in situ ground-based measurements during storm chases began
in the early 1980s at NSSL and OU. TOTO (Totable Tornado Observatory) was