AGS FIRP Track 2: Boundary-layer Evolution and Structure of Tornadoes (BEST)

How strong are the winds in tornadoes? How do they cause damage? What causes some tornadoes to be intense and others weaker?

How can we build better to reduce the risks from tornadoes? Observations in and near tornadoes are needed to better answer these questions. But, observations very near the ground, where people live, and inside tornadoes are very rare since they are difficult to predict and even harder to observe.

Some, rare, observations show that tornado winds can exceed 300 mph, and that the most intense winds are very near the ground, where they are especially hard to measure. In order to mitigate the hazards posed by tornadoes, it is critical to better understand their basic structure and intensity. The Boundary-layer Evolution and Structure of Tornadoes (BEST) project will address some of these questions, deploying mobile radars, Tornado Pods, and SwarmSonde balloons in and near tornadoes.

The goal is to resolve tornado structure, evolution, the intensity of winds, and the temperatures and humidities near tornadoes that likely affect how intense they are. BEST will also examine decades of mobile radar and other data collected in and near tornadoes to better understand how strong, large, and potentially damaging they are.

BEST is a multi-focus study of tornado structure and evolution. BEST plans a field phase during which unprecedentedly-fine scale kinematic and thermodynamic data will be collected by proximately-deployed DOW radars, Tornado Pods, and SwarmSonde lagrangian drifter balloons. Dual-DOW baselines of 3-6 km will allow, for the first time, integrated mapping of tornado vector wind structures combined with detailed thermodynamic mapping provided with the densely-deployed Tornado Pods and SwarmSondes.

BEST will compare these new data with a unique database of DOW wind measurements over 200 unique tornadoes. Approximately 20 of these include dual-Doppler vector wind resolving data. One includes data from an extremely fortuitous 3 km - baseline dual-DOW deployment near a very large multi-vortex tornado, with dual-Doppler data uniquely resolving the structure and evolution of sub-tornado vortices.

A critical aspect of BEST is the combination of single-case study analysis of rare or very fortuitously observed events, with broader statistical analysis of several to over 200 events.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.