Greeley 2002
Polarimetric radar hydrometeor identification, and NOx production by lightning (CHILL-TEX 2002)


The South Dakota School of Mines and Technology T-28 armored research airplane and its crew of pilots and scientists participated in the Greeley field program from June 3 to June 18, 2002. We were based at the Greeley, Colorado, airport, and coordinated our flight activities with the Colorado State University CHILL polarimetric Doppler meteorological radar facility. The main goal of the operations was to develop a technique for monitoring production of NOx compounds by lightning in thunderstorms using a light-weight relatively inexpensive analyzer. In addition, observations of hail development in thunderstorms were sought to support research by V. N. Bringi and V. Chandrasekar of CSU into hydrometeor identification using polarimetric radar.

The armored T-28 was deployed to work with the CSU-CHILL radar facility for a period of 3 weeks beginning on 3 June 2002. The aircraft was equipped with its complete suite of microphysical and electrical instrumentation, and in addition carried a NOx analyzer. Observations were used to supplement ongoing research into the remote characterization of the microphysical properties of thunderstorms using multiparameter weather radars, and as well into characterization of the production and transport of NOx compounds created by lightning discharges within thunderstorms. In addition, the deployment offered students in Research Experience for Undergraduates (REU) programs within the Departments of Electrical Engineering and Atmospheric Sciences at CSU, and the Department of Electrical Engineering at the South Dakota School of Mines and Technology, experience in the acquisition and analysis of in situ data from instrumented aircraft.

Problems with the recently-rebuilt engine on the T-28 developed during the initial week of the deployment, and the deployment was terminated after a complete engine failure on 17 June. Eight flights were conducted during the deployment, of which 3 were focussed on research observations and 5 were devoted to instrument or engine tests. The clouds sampled were high-base convective clouds with modest updrafts. The aircraft had one encounter with a region of elevated NO produced by a recent lightning discharge. No hail was encountered.

Special thanks to the CSU-CHILL radar facility for their excellent support and collaboration during this deployment, and to Darin Toohey and Linea Avallone of the University of Colorado for loan of their TEI-42C NO/NOx analyzer and advice in how to adapt it to airborne applications.

Research Flights

Measurements and Instrumentation

Preliminary Survey of Observations Instrumentation


None known.

Data Access

CHILL-TEX 2002 Data Access

Other Project Web Pages

None known.