Advisors: Dave Stensrud and Matt Kumjian

Abstract: Dual-polarization radar provides a wealth of new information about the type, size, and orientation of scatterers
in the atmosphere. This radar information has been interrogated for its applications to hazardous
weather, but a wealth of clear-air radar data exists that is signicantly underutilized. The ability of National
Weather Service WSR-88D radars to detect insects and other biota within the convective boundary
layer (CBL) facilitates estimation of boundary layer depth and characterization of horizontal convective rolls
(HCRs). Bragg scatter signatures in dual-polarization radar observations, which are dened by low dierential
re ectivity (ZDR) values, are used as a proxy for CBL depth in 2014 over Central Oklahoma using data
from the Twin Lakes (KTLX) WSR-88D. The 243 ZDR Bragg scatter and upper air sounding CBL depth
estimates collected during this year have a correlation of 0.90 and a RMSE of 254 m. Additionally, a 10-year
climatology of HCRs in Central Oklahoma indicates that HCRs occur on 75% of days during all months of
the warm-season (April-September). HCRs typically form in the mid-morning and may persist throughout
the day, transition to cellular convection, or develop from cellular convection before dissipating around sunset.
These results should facilitate future studies on convection initiation, HCR formation mechanisms, and
model parameterization. The methods used to estimate CBL depth and identify and characterize HCRs are
potentially applicable across a variety of geographic locations and seasons, and demonstrate the usefulness
of clear-air radar data.