Severe Thunderstorm Electrification and Precipitation Study (STEPS)

Overview

The South Dakota School of Mines and Technology T-28 armored research airplane and its crew of pilots and scientists participated in the STEPS field program from May through July, 2000.  We were based at the Goodland, Kansas, airport, and coordinated our flight activities with the many other observing facilities involved in STEPS, including radars, sounding systems, a lightning mapping array, mobile surface observing systems, and volunteer networks of observers. 

The main components of STEPS include (1) precipitation process studies, (2) storm electrification studies, and (3) hydrometeor identification studies, in High Plains convective storms. The main focus is on severe storms producing predominantly positive cloud-to-ground lightning, but there is interest in these processes in all convective storms, with an aim towards improving the understanding of the interrelationships between precipitation processes and electrification in this spectrum of storms. The STEPS field season ran from 22 May through 9 July, 2000, during which almost two dozen field coordinated observing operations were conducted in northeastern Colorado and northwestern Kansas. Observations were obtained using multiple Doppler and multiparameter radars, a lightning discharge mapping system, instrumented aircraft and balloons, and a mobile mesonet comprised of instrumented cars, all in conjunction with standard operational observations by the National Weather Service and the National Lightning Detection Network. 

The only aircraft involved in STEPS was the armored T-28, operated by the South Dakota School of Mines and Technology (SDSMT) under a cooperative agreement with the National Science Foundation. Summarized here are the observations obtained during more than a dozen research flights in support of the STEPS field program.


Figure 1: Picture of a target storm during STEPS Project (Click for full resolution).

The microphysical and electrical observations from T-28 instrumentation and polarimetric radar data are used to study the physical relationships between precipitation development and electrification and to compare between hydrometeor classification derived from the polarimetric radar data and the T-28 measurements.


Figure 2: Picture of the June 29, 2000, storm taken while T-28 was approaching the storm. Time is in GMT.

Research Flights

Measurements and Instrumentation
Preliminary Survey of Observations Instrumentation

Some Data Examples
Examples from Flight 761 (29 June 2000)

Reports
The Severe Thunderstorm, Elecrification and Precipitation Study

Aircraft observations of a lightning channel in STEPS. AGU Geophysical Research Letters

Lightning characteristics of two storms observed during STEPS

Aircraft observations of a lightning channel in STEPS

Goehring, Jason: The Electrification of a Severe Multicell Thunderstorm: A Study of the STEPS 19 June 2000 storm. May 2005. 110 pp. (A. Detwiler)

Holm, Meagan: A Case Study of STEPS 3 June 2000: Electrification of a Low Precipitation Supercell. June 2005. 96 pp. (Helsdon)

Data Access
STEPS 2000 Data Access

Other Project Web Pages
CHILL Radar