Near-Ground Pressure and Wind Measurements in Tornadoes*

Abstract

Since the spring of 2002, tornadoes were sampled on nine occasions using Hardened In-Situ Tornado Pressure Recorder probes, video probes, and mobile mesonet instrumentation. This study describes pressure and, in some cases, velocity data obtained from these intercepts. In seven of these events, the intercepted tornadoes were within the radar-indicated or visually identified location of the supercell low-level mesocyclone. In the remaining two cases, the intercepted tornadoes occurred outside of this region and were located along either the rear-flank downdraft gust front or an internal rear-flank downdraft surge boundary. The pressure traces, sometimes augmented with videography, suggest that vortex structures ranged from single-cell to two-cell, quite similar to the swirl-ratio-dependent continuum of vortex structures shown in laboratory and numerical simulations. Although near-ground tornado observations are quite rare, the number of contemporary tornado measurements now available permits a comparative range of observed pressure deficits for a wide variety of tornado sizes and intensities to be presented. ABSTRACTSince the spring of 2002, tornadoes were sampled on nine occasions using Hardened In-Situ Tornado Pressure Recorder probes, video probes, and mobile mesonet instrumentation. This study describes pressure and, in some cases, velocity data obtained from these intercepts. In seven of these events, the intercepted tornadoes were within the radar-indicated or visually identified location of the supercell low-level mesocyclone. In the remaining two cases, the intercepted tornadoes occurred outside of this region and were located along either the rear-flank downdraft gust front or an internal rear-flank downdraft surge boundary.The pressure traces, sometimes augmented with videography, suggest that vortex structures ranged from single-cell to two-cell, quite similar to the swirl-ratio-dependent continuum of vortex structures shown in laboratory and numerical simulations. Although near-ground tornado observations are quite rare, the number of contemporary tornado measurements now available permits a comparative range of observed pressure deficits for a wide variety of tornado sizes and intensities to be presented.

The Role of Multiple-Vortex Tornado Structure in Causing Storm Researcher Fatalities

“…Samaras had extensive experience deploying instrumentation in and near tornadoes, some of which were large, intense, and complex in structure (Lee et al 2004(Lee et al , 2011Wurman and Samaras 2004;Karstens et al 2010). Since the members of this team died despite having experienced leadership, the circumstances leading to their deaths have particular importance to tornado researchers as well as recreational, media, and storm-tour chasers, whose missions bring them near tornadoes.…”

A Barometric Survey of Dust-Devil Vortices on a Desert Playa

“…In addition to being a convenient measure of the overall intensity of a dust devil (as is also the case with other vortex motions such as tornados, e.g. Karstens et al, 2010), the pressure drop may itself play a significant role in dust-lifting (e.g. Balme and Hagermann, 2006).…”

Anomaly Weather Information Detection Using Wireless Pressure-sensor Grid

“…In addition, it is difficult to forecast where and when tornadoes will occur. If we are able to measure the atmospheric pressure change just underneath c 2015 Information Processing Society of Japan a tornado, we may be able to determine the mechanism of the tornado [13], [14]. In the United States, a Doppler radar network is used for tornado prediction [10].…”