Greeley 2003
Polarimetric radar hydrometeor identification, and NOx production by lightning (CHILL-TEX 2003)


The South Dakota School of Mines and Technology T-28 armored research airplane and its crew of pilots and scientists conducted field operations near Greeley, Colorado, from July 21 to August 3, 2003. We were based at the Greeley, Colorado, airport, and coordinated our flight activities with the Colorado State University (CSU) CHILL polarimetric meteorological Doppler radar facility. These activities supported research into polarimetric radar analysis techniques by V. N. Bringi and V. Chandrasekar of CSU, and P. L. Smith of South Dakota School of Mines and Technology (SDSMT). In addition, observations of NO in clouds in which lightning was occurring supported thunderstorm electrical and chemical modelling efforts of John Helsdon at SDSMT.

The armored T-28 was deployed to work with the CSU-CHILL radar facility for a period of 3 weeks, starting near the end of July, 2003. The aircraft was equipped with its complete suite of microphysical and electrical instrumentation, and in addition carried a NOx analyzer. Observations are being used to supplement ongoing research in the remote characterization of microphysical properties of thunderstorms using multiparameter weather radars, radar measurement of precipitation at the ground, and characterization of the production of NOx compounds within thunderstorms by lightning discharges and their subsequent transport. In a 2002 deployment the capability for making NOx observations iwas demonstrated using a relatively inexpensive analyzer on the T-28, and the effort during this deployment was conducted with a high level of reliability.

The weather was quite active, with seven flights during the first ten days of the deployment. Hail up to dime and quarter size was encountered, as well as some episodes of heavy precipitation. The planned three-week stay was ended prematurely shortly after the last research flight on 30 July because of generator problems that could not readily be solved in the field. There was a short test flight on 2 August showing continued generator problems. The NO test conducted on this short flight showed no NO, leading us to suspect a hole in the calibration sample bag. This could explain some of the low readings during calibration tests on the few flights preceding this one. The aircraft was ferried home on 3 August under VFR conditions and battery power.

We thank our collaborators for their support during these operations, including Pat Kennedy, Dave Brunkow, and Bob Bowie of the CSU-CHILL radar facility for superb support during operations, and Drs. V. N. Bringi, V. Chandrasekar, and Wanyu Li (CSU) for their help with the radar hydrometeor ID work.

Research Flights

Measurements and Instrumentation

Preliminary Survey of Observations Instrumentation


None known.

Data Access

CHILL-TEX 2003 Data Access

Other Project Web Pages

None known.