Storm-generated boundaries are the focal point for tornadogenesis. As such, a more complete understanding of boundary and gust front structure in supercells is required to advance understanding of the processes responsible for supporting or obstructing the concentration of near-surface rotation. Targeted Observation by Radars and UAS of Supercells (TORUS) aims to improve the conceptual model of supercells by explicating the relationship of storm-generated boundaries and coherent structures within storm outflow to the generation/amplification of near-surface rotation. New insight will be enabled through coordinated and tightly-focused deployments of new and established remote-sensing and in-situ instruments tasked to collect thermodynamic and kinematic observations both aloft and at the surface.
Intellectual Merit: Hypothesized mechanisms for tornadogenesis move beyond a focus on just the canonical rear-flank and forward-flank gust fronts and also address the role of boundaries and coherent structures recently revealed in observational and numerical analyses of supercell tornadoes. Accurate identification of these roles will advance the frontiers of knowledge and transform the conceptual model of supercells. Overarching objectives are to 1) expose the 4D character of these boundaries and coherent structures, 2) relate the 4D character of these boundaries and coherent structures to the thermodynamics and kinematics of supercell outflow, 3) associate boundary and coherent structure characteristics to ensuing contraction or failed contraction of near-surface vertical vorticity beneath low-level mesocyclones, and 4) and relate these characteristics to the ambient conditions within which storms reside.
The TORUS field campaign will be executed across 42 days of deployments spanning two spring seasons (May-June 2019 and 2020) over an operations domain covering ~1,300,000 km2 of the central US. Observing platforms involved in TORUS include four unmanned aircraft systems, two mobile Ka-band radars, seven mobile mesonets, one mobile X-band radar, and one mobile sounding systems. Assets will be deployed to focus data collection in different parts of storms.
Broader Impacts: TORUS will promote teaching, training, and learning by involving ~40 students in the project's field deployments. At least three graduate students will use the data collected during the TORUS field deployments for their thesis research. Undergraduate students will also have opportunities to use TORUS data for mentored research projects. TORUS data will be integrated into undergraduate and graduate courses taught by the PIs. TORUS research will also provide students the opportunity to attend and present at national conferences in atmospheric science and aerospace engineering. TORUS will enhance infrastructure for research and education by codifying collaborations between the University of Nebraska-Lincoln, Texas Tech University, the National Severe Storms Laboratory, and the University of Colorado-Boulder and by supporting the refinement of cutting-edge instrumentation. Results from TORUS will be broadly disseminated in an effort to enhance scientific and technological understanding. This will include publication in peer-reviewed journals, presentations to local and regional groups (e.g., K-12 schools, museums, etc.), and seminars at participating institutions and elsewhere. Direct interaction with the operational forecasting community will also be sought (e.g., via local National Weather Service Forecast Offices) so that these results can be expediently and effectively disseminated to operational forecasters.
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.
