Jul 13, 2020
Dan Dawson is an Assistant Professor of Atmospheric Science in the Department of Earth, Atmospheric, and Planetary Sciences at Purdue University. Dawson researches the dynamics of severe thunderstorms and tornadoes. He analyzes output from different computer simulations to help better understand different aspects of both storm and tornado behavior. He also uses observational data collected in the field and has participated in a number of field programs to chase severe thunderstorms and tornadoes with instruments for collecting data from these storms. Two of the larger, multi-institutional field programs in which Dawson has participated include the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) and VORTEX Southeast (VORTEX-SE) programs. Dawson speaks about the three-dimensional structures of these storms that produce tornadoes and stresses that scientists need data both within and surrounding these storms, specifically wind flow patterns that surround severe thunderstorms, to best understand severe thunderstorms and tornadoes. The best instruments that scientists can use for obtaining high resolution data over the entire storm system is a Doppler radar. Doppler radar can either be in a fixed site like the XTRRA radar at Purdue. In this case, scientists have to wait for the storms to come to them. Mobile radar is another option in which Doppler radar instruments are installed on trucks that drive near the storms to collect data. Multiple trucks carrying multiple radars, and travelling at different angles to a storm, can synchronize their scans in order to provide scientists with full two-dimensional and three-dimensional views of the winds associated with a storm. Dawson’s particular niche has been the use of in situ precipitation stations designed to collect data from inside a storm. These probes are unique because they include a disdrometer which is a device used to measure the raindrop sizes in a severe thunderstorm. Dawson is interested in understanding raindrop size distribution because it can potentially be used to predict whether a tornado might develop within a severe thunderstorm. Dawson also explains the science behind weather fronts (synoptic or national scale), which he defines as boundaries between air masses with different characteristics. He further explains the difference between synoptic fronts and gust fronts which occur on a more local scale. If you are a student who would like to study storms or meteorology, Dawson recommends setting yourself up for success by taking as many math, physics and computer programming classes as possible.
The XTRRA radar: https://xtrra.eaps.purdue.edu/