Sampling Severe Local Storms and Related Phenomena: Using Unmanned Aircraft Systems (original) (raw)
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TORNADOCHASER: A REMOTELY-PILOTED UAV FOR IN SITU METEOROLOGICAL MEASUREMENTS
1st UAV Conference, 2002
The TornadoChaser is a remotely-piloted uninhabited aerial vehicle designed to fly into a pretornadic, severe thunderstorm. The project goal is to provide in situ meteorological measurements during tornadogenesis, the initial stage of tornado development. Past attempts to gather this information have put pilots, and their aircraft, into dangerous situations. A remotely-piloted vehicle removes the pilot from the storm while keeping a human in the loop to make cognitive decisions that are not possible with present fully autonomous system. This paper presents the motivation and requirements for the tornadogenesis mission followed by an overview of the TornadoChaser project.
A REMOTE MICROPHYSICAL STUDY OF SEVERE WIND-PRODUCING CONVECTIVE STORMS
Convective storms that generate hail, lightning, and damaging winds have been identified as a formidable hazard to life and property. Even more impactful are stronger storms that generate and loft liquid-phase hydrometeors to high altitudes where freezing occurs and collisions between drops, graupel, and ice crystals lead to electrification. Condensate loading, sometimes combined with the lateral entrainment of subsaturated air in the storm middle level, initiates the convective downdraft. The subsequent melting of frozen hydrometeors and subcloud evaporation of liquid precipitation, in conjunction with precipitation loading, result in the cooling and negative buoyancy that accelerate the downdraft in the unsaturated layer. A downburst, in general, is defined as a strong downdraft that induces an outburst of damaging winds at or near the ground, and a microburst as a very small downburst with an outflow diameter of less than 4 km and a lifetime of less than 5 minutes. Previous studies of the microphysical structure of downburst-producing convective storms have entailed analysis of polar and geostationary satellite imagery and derived products, meteorological Doppler radar, and in-situ surface wind observations. The current study expands upon previous analysis by incorporating lower tropospheric vertical wind and temperature profile data generated by the Cooperative Agency Profilers (CAP) system that consists of Boundary Layer Profiler (BLP) instruments, operating at a frequency of 915 MHz, and Radio Acoustic Sounding System (RASS) instruments. In addition, Geostationary Lightning Mapper (GLM) data from Geostationary Operational Environmental Satellite (GOES)-16 will also be displayed and analyzed to better explain the role of lightning in a downburst-producing convective storm. Selected thunderstorm events that demonstrate the physical process of downburst generation as observed simultaneously by the GOES-16 Advanced Baseline Imager (ABI) and GLM, Doppler radar (NEXRAD), and boundary layer profilers will be analyzed in this paper. Vertical sounding profile data from the CAP system has been applied as a supplement to Sounding/Hodograph Analysis and Research Program in Python (SHARPpy)-generated thermodynamic profiles to further study the favorable environment for severe convective storm winds. On the afternoon of 1 August 2017, severe downburst-producing thunderstorms occurred in the United States Mid-Atlantic region and over southern California that resulted in tree damage, downed power lines, and traffic disruptions. As shown in Figure 1, for both of these events, GOES-16 ABI water vapor (WV) – thermal infrared (IR) channel brightness temperature difference (BTD) imagery at 2-km resolution displayed a high level of detail in storm structure and was effective in identifying storm-scale features, including cold cloud tops (red shading) and dry-air intrusions (white arrows). Corresponding GLM imagery displayed lightning events in close proximity to downburst events at the time of downburst occurrence.
The Tornadogenesis Phase of a Vortex 2 Supercell Tornado on June 7 , 2010
2012
The NOAA (NSSL) X-band dual-Polarized (NOXP) and three CSWR Doppler on Wheels (DOW5, DOW6, and DOW7) mobile radars scanned the second of two supercells on 7 June 2010 (see Figure 1 for locations). The two supercells on this day occurred during the Verification of the Origins of Rotation in Tornadoes Experiment, Part 2 (VORTEX2) field project (for more background information see Wurman et al. 2012). NOXP first deployed near Lyman, NE at about 2330 Z and collected data on a supercell that produced a tornado north of Scottsbluff, NE. This first supercell weakened and moved too far east to sample, and a second supercell, behind the first, was targeted (Figure 2). NOXP deployed just west of Minatare and collected data on the second supercell from 0112 Z to 0128 Z at the NOXP1 location, as indicated in Figure 1.DOW6 deployed and collected data from 0104 Z to 0118 Z at the DOW6 location marked on Figure 1. This is the only DOW data that has been analyzed thus far. DualDoppler analysis of t...
Atmospheric Research, 2001
. The Tornado and Storm Research Organisation TORRO was formed in the UK in 1974 in order to determine realistic spatial, temporal and intensity distributions of tornadoes in the UK and, eventually, throughout Europe. Currently, TORRO's databases contain nearly 2000 tornadoes and over 550 waterspouts for the UK alone. In 1972, TORRO's founder, Terence Meaden, devised the Tornado Intensity Scale. This scale enables the wind speeds of tornadoes to be rated on a scale Ž . from T0 to T10, or more since it is an open-ended scale . Using this scale, estimates have been made of the statistical return periods of differing intensities of UK tornadoes. TORRO's research into understanding the conditions of tornado development is ultimately intended to lead to issuing forecasts of tornadoes. In 1991, TORRO issued the first tornado watch in the UK for 12 November and this proved to be accurate-not only did three property-damaging tornadoes strike East Anglia but the forecast maximum intensity of T5 was attained. In 1975, TORRO expanded its activities to include conventional thunderstorm reporting and investigations. In 1982, TORRO incorporated the British and Irish thunderstorm data-collection organisation, the Thunderstorm Ž . Census Organisation TCO , which was established in 1924. By the early 1980s, TORRO's network of voluntary thunderstorm observers, located throughout the UK and Ireland and increasingly in other European countries, numbered around 350 and the network continues to grow. In addition to TORRO's early focus on tornadoes and thunderstorms, its data collection and ) Corresponding author. Tel.: q44-1865-483761r483750.