85th AMS Annual Meeting

Tuesday, 11 January 2005: 2:45 PM
The Southern Plains Experiment in Cloud Seeding of Thunderstorms for Rainfall Augmentation (SPECTRA) project: Operational tools used towards verifying glaciogenic and hygroscopic seeding conceptual models, case studies and preliminary results.
Duncan Axisa, SOAR program, Plains, TX; and D. Rosenfeld, J. L. Santarpia, W. L. Woodley, and D. R. Collins
Poster PDF (338.5 kB)
The Southern Plains Experiment in Cloud Seeding of Thunderstorms for Rainfall Augmentation (SPECTRA) Project represents a collaborative effort between various organizations in an effort to continue research that has begun in the area of hygroscopic and glaciogenic seeding. Cloud physics measurements using a new Texas based cloud physics aircraft have been conducted throughout Texas, southeastern New Mexico, and Oklahoma in an effort to resolve underlying questions about the seeding efficacy in these regions. The first phase of the project commenced in early August 2004 with the objective to investigate the sizes and concentrations of cloud condensation nuclei (CCN) at cloud base and how these CCN in turn affect the microphysical structure of clouds and precipitation processes. Operational plans for the second phase involve airborne in situ observations of clouds seeded using hygroscopic and glaciogenic materials. The Southern Ogallala Aquifer Rainfall (SOAR) program research aircraft based in Plains Texas was deployed using operational tools such as FX-Net provided by the Forecast Systems Laboratory (FSL) and the Texas regional mosaic IRaDS (Integrated Radar Data Services) WSR-88D Level II data Next Generation Weather Radar (NEXRAD). The new Texas based aircraft is equipped with a permanent dynamic sampling range of 0.1 Ám to 1.55 mm accomplished by a combination of aerosol and cloud droplet spectrometers, in addition to a CCN counter operating at a supersaturation as low as 0.1%. This paper introduces the SOAR research aircraft to the cloud physics community with a description of the instrumentation platform carried on this aircraft. Specific case studies using data collected from the airborne platform during SPECTRA, operational logistics utilized to deploy the aircraft and preliminary results from data collected on the research aircraft platform are discussed.

Supplementary URL: http://www.sandylandwater.com/spectra.htm