Purdue-UMass Mobile Radar Observations from VORTEX-SE 2017

We present an overview of radar observations collected by Purdue University in collaboration with the Microwave Remote Sensing Laboratory (MIRSL) of University of Massachusetts Amherst (UMass) during the spring 2017 field observation campaign of VORTEX-Southeast. As in 2016, we deployed a vertically pointing, frequency-modulated, continuous wave radar (UMass FMCW), which collected continuous boundary layer profiles at Scottsboro, Alabama; and a mobile, polarimetric, X-band Doppler radar (UMass X-Pol) during intensive observing periods (IOPs).

In 2017, MIRSL upgraded the UMass FMCW transmitter from a traveling-wave-tube amplifier to a solid-state gallium-nitride power amplifier, substantially reducing the noise associated with the tube. In addition, the frequency modulation rate was increased to expand the unambiguous Nyquist interval. The results are cleaner Doppler spectra for vertical velocity measurements and reduced velocity aliasing in precipitation, which we demonstrate by comparison with 2016 observations. We show examples of UMass X-Pol observations of severe convective storms collected during IOPs, including transient supercell structures in isolated storms and quasi-linear convective systems.