A Summary of Convective-Core Vertical Velocity Properties Using ARM UHF Wind Profilers in Oklahoma

Abstract

This study presents a summary of the properties of deep convective updraft and downdraft cores over the central plains of the United States, accomplished using a novel and now-standard Atmospheric Radiation Measurement Program (ARM) scanning mode for a commercial wind-profiler system. A unique profiler-based hydrometeor fall-speed correction method modeled for the convective environment was adopted. Accuracy of the velocity retrievals from this effort is expected to be within 2 m s−1, with minimal bias and base core resolution expected near 1 km. Updraft cores are found to behave with height in reasonable agreement with aircraft observations of previous continental convection, including those of the Thunderstorm Project. Intense updraft cores with magnitudes exceeding 15 m s−1 are routinely observed. Downdraft cores are less frequently observed, with weaker magnitudes than updrafts. Weak, positive correlations are found between updraft intensity (maximum) and updraft diameter length (coefficient r to 0.5 aloft). Negligible correlations are observed for downdraft core lengths and intensity.

The Green Ocean: Precipitation Insights from the GoAmazon2014/5 Experiment

“…RWP measurement details have been summarized by several recent studies, with precipitation datasets available at high spatiotemporal resolution of approximately 15 seconds and 200 meters (e.g., Tridon et al, 2013;Giangrande et al, 2013). To align with the 5-minute disdrometer measurements, an RWP profile from the mid-point of the 5-minute window are selected.…”

Vertical air motion retrievals in deep convective clouds using the ARM scanning radar network in Oklahoma during MC3E

“…The most prominent features in both retrievals are a deep updraft region above 3 km altitude and strong updraft values greater than 8 m s −1 . The local system advection speed was estimated to be 18 m s −1 by Giangrande et al (2013a), with a north-northeast direction inferred by comparing successive CSAPR-I7 reflectivity displays. The base of the updraft retrieved by UAZR-C1 is first seen at approximately 09:23 UTC, which is near the end of the 3DVAR valid time window.…”

“…Technical details for the convective modes are also listed in Table 2. Vertical air motion retrievals from the wind profilers follow the method outlined by Giangrande et al (2013a) that merges these modes to a single vertical velocity retrieval field (∼ 6 s, 120 m) that is assumed accurate to within 1-2 m s −1 in deep convective drafts. Our study uses datasets from UAZR-C1 and UAZR-I9 to evaluate the 3DVAR multi-Doppler wind retrieval as those operating and/or hit by convective cells for the events of this study.…”

“…However, practical hazards and operational costs have resulted in a valuable, but limited, dataset (e.g., Byers and Braham, 1948;LeMone and Zipser, 1980;Donner et al, 2001). Recent studies using profiling Doppler radars have suggested an ability to retrieve vertical velocities in convective clouds with an uncertainty of the order of 1-2 m s −1 , thus offering a viable substitute for in situ aircraft measurements (Jorgensen and LeMone, 1989;Cifelli and Rutledge, 1994;May and Rajopadhyaya, 1999;Williams, 2012;Heymsfield et al, 2010;Giangrande et al, 2013a;Kumar et al, 2015;Giangrande et al, 2016). Furthermore, profiling radars provide a high degree of detail of convective clouds in time and height, and can sample even the most intense convective cores.…”

Retrieving Vertical Air Velocity in Convective Cloud over the Tibetan Plateau from TIPEX-III Cloud Radar Doppler Spectra

“…The relationship was produced by theoretical derivations and practical observations [19][20][21][22]. Using this relationship, vertical air velocity can be deduced by subtracting V estimated by radar-measured Z from the radar-measured mean Doppler velocity (V ).…”