Rapid-scan Polarimetric Radar Data Collection and Analysis of the Wind Field in Severe Convective Storms and Tornadoes

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The main purpose of this project is to use an advanced, mobile, rapidly-scanning Doppler radar to collect data in severe convective storms in the Plains region of the U. S. during the spring, with the objective of analyzing the data to learn more about why tornadoes form and what the detailed wind structure is of both the tornadoes and their parent storms. The results may lead to improved prediction of severe convective storms and the hazards they produce, thereby promoting public safety. It may also help structural engineers to design buildings more resilient to high winds. This project will also support graduate student education; it is expected that the students will ultimately enter the workforce and contribute to societal goals either through their own research activities or through operations.During this project, a mobile, rapid-scan, X-band (3-cm wavelength) polarimetric Doppler radar (RaXPol) will be deployed to collect volumetric data in supercells, with the objective of documenting tornado formation and structure, especially at low altitudes. Comparing theoretical models of the structure of tornadoes and how they evolve with those found in nature will enhance our understanding of tornadoes. Datasets collected in previous years will be analyzed with the same objectives. In particular, a dataset that documented the genesis and evolution of both a cyclonic and anticyclonic tornado in a supercell in northwestern Kansas on 24 May 2021, including a simultaneous video of where the radar was looking, will be studied. The detailed structure of the rare, anticyclonic tornado will be studied to see determine the wind field in the boundary layer, since the vortex passed almost directly over the radar. In addition, existing polarimetric spectra collected last year in supercells will be analyzed and more datasets collected in an attempt to determine if more information can be obtained about the nature and distribution of hydrometeors within storms; these spectra have the potential for increasing our understanding of the production of cold pools, which is known to affect tornadogenesis, and also increase our understanding of the formation of hail.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.