5.2 Comparison of Estimates of Vertical Motion from Vertically-Pointing Lidar and Radar Within Gust Fronts, Bores and Low-Level Gravity Waves

Tuesday, 12 January 2016: 11:15 AM
Room 350/351 ( New Orleans Ernest N. Morial Convention Center)
Kevin Knupp, University of Alabama, Huntsville, AL; and R. Wade, A. W. Lyza, and S. M. Wingo

During the 2015 Plains Elevated Convection at Night (PECAN) field campaign the Mobile Integrated Profiling System (MIPS) was equipped with three remote sensors capable of measuring vertical motion in precipitation-free conditions. These include a 915 MHz Doppler wind profiler (40-60 s resolution), an X-band Profiling Radar (XPR, 6 Hz sampling frequency) and a 1.55 μm Doppler Wind Lidar (DWL, 1 Hz sampling frequency). Vertical motion estimates from all three are compared from several bores (including an intense bore with an updraft to >12 m/s), a bore/gust front hybrid with an updraft magnitude also exceeding 12 m/s, other more subtle gravity waves, and turbulent eddies within the nocturnal boundary layer. Moreover, the depth of sampling will be compared. The relative advantages of each will be discussed. For example, while the DWL measures a “true” air motion at very high spatial and temporal resolution due to scattering from aerosols, clouds, prevent vertical motion estimates within several hundred meters above cloud base. In contrast, the XPR provides vertical motion estimates through clouds at high temporal/vertical resolution (6 Hz and 1.3 deg beam width), but relies on primarily on insect scattering. The 915 MHz wind profiler samples vertical motion at 40 s temporal resolution with a 9 deg beam via Bragg scatter, as well as Rayleigh scatter from insects. A short-term peak in vertical motion can be estimated from Doppler spectra acquired by the 915 MHz wind profiler. The high-resolution measurements from the DWL and XPR can be used to help interpret Doppler spectra from the 915 MHz profiler. This paper will attempt to quantify the radar bias in w (e.g., from insects folding their wings) using simple statistical analyses and results from detailed case studies.
- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner