Graduate Program

Natural Sciences

Degree Name

Master of Science (MS)

Semester of Degree Completion

2002

Thesis Director

Keith Andrew

Abstract

In this study we characterized vertical wind velocity profiles in the troposphere using the Atmospheric Radiation Measurement (ARM) equipment facility at the Southern Great Plains (SGP) site in Lamont OK established by the Department of Energy (DOE) and administered through Argonne National Laboratories (ANL). Using the Balloon Borne Radio Sonde (BBSS) system launched four times per day, we collected ambient temperature profiles and lapse rates from the period of June to September of

2001. Concurrently the Rass Radar Wind Profiler collected vertical wind speed data at 915 MHz continuously throughout this period. The BBSS data is visualized using a Skew-T atmospheric profile plot allowed calculations of the Convective Available Potential Energy (CAPE) by integrating from the fiducial saturated adiabatic lapse rate curve to the ambient temperature curve. From this we calculated the vertical velocity using ideal atmospheric parcel theory. In addition the linear Brunt-Väisälä convective parcel theory is compared to the Skew-T derived lapse rate velocities applied to the stable regime. A statistical comparison was made to characterize the condensation fraction associated with vertical winds at the topographically unique SGP location. Robustness of the comparison is tested using second, third and fourth order moments and by testing for a normal distribution of the deviations. We found that the χ2 = 0.889 for CAPE and RWP vertical velocities measured in the aggregate. This characterization matches the methodology used at a similar site in Darwin, Australia and was used as input for full scale three-dimensional modeling of the atmosphere over SGP. The CAPE derived vertical wind speed parameter was found to be 0.55 for the SGP site.

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