Radar Observations of Tornadoes And Thunderstorms Experiment (ROTATE)
One of the longest-running (1998-2013) CSWR projects (in collaboration with the National Center for Atmospheric Research / Atmospheric Technology Divistion (NCAR/ATD), ROTATE employs the DOW 6 and DOW 7 mobile radars as well as the Rapid-scan DOW. The underlying goal of the project is observe the process of tornadogenesis, tornado structure, tornado lifecycle, and tornado death. Major goals are to collect observations that will enable the evaluation of tornadogenesis hypotheses and to continue studies of tornado vortex structure and climatology. Using the Rapid-DOW system, in which six simultaneous beams scan the sky, permits tilt volumetric updates every 10 seconds, for the first time allowing for the resolution of rapid processes such as tornadogenesis and the evolution of multiple vortices.
The study region includes Oklahoma, Texas, New Mexico, Kansas and Nebraska. Preferred regions are western Oklahoma, the southwestern panhandle of Texas, and western Kansas due to the flat, treeless conditions, and good road networks. Dual-DOW observations permit the synthesis of vector windfields in tornadic and pre-tornadic storms at scales of 60-200 m (200-600 ft), over regions of 40-200 square kilometers (20-100 square miles.) Single Doppler observations occur at scales of 10-40 m (100 ft). Rapid update cycles of 30-70 seconds permit rapidly evolving phenomena to be studied.
DOW deployment strategies focus on establishing a dual-Doppler lobe over the hook echo, rear-flank-downdraft region, and the tornado itself. Three main options, one for deploying south of a storm, and one for deploying ahead of a storm, and one for deploying behind a storm are illustrated schematically below. If the storm passes overhead during the "ahead" option, the radars scan the hook and rear-flank-downdraft region from behind.
Deployment strategies for the ROTATE field campaigns depend upon the position and motion (dashed, black arrow) of a storm (solid, black line)
relative to the DOWs (pink and blue truck icons) and the resulting dual-Doppler radar coverage lobes (shaded, in lavender).
Scanning beams from the two DOWs are represented on these images as the solid blue and red arrows.
The questions driving ROTATE are as follows:
"There are almost no direct measurements from inside tornadoes", says Dr. Karen Kosiba, a lead scientist at CSWR. "ROTATE hopes to change that by collecting integrated radar and in situ wind data and photographs inside the strongest, most damaging, tornadoes."
- How strong are winds in the lowest levels of tornadoes?
- How do tornadoes cause damage? What is the role of changing winds, and airborne debris?
- What causes some tornadoes to be huge and violent, while others are smaller and weaker?
DOW radars: ROTATE utilizes array of 3 of the most advanced Doppler On Wheels (DOW) mobile radars to probe inside tornadoes.
Tornado Pods: 6 instrumented "mobile mesonet" vehicles deploy a total of 22 "Tornado Pods" in front of tornadoes, which are intended to run over the Tornado Pods. The instruments may be destroyed, but data is recorded in armored "black boxes" for later scientific analysis.
Photogrammetry: Tornado Pods and several vehicles video and photograph the tornadoes from inside and out, allowing scientists to study debris impacts and damage the moment they happen.
"The goal is to peel back the mysteries inside tornadoes. How strong are the winds near the ground in tornadoes? 200 mph? 300 mph? Exactly how do they cause damage? We simply don't know." , says Joshua Wurman leader of the DOW program and president of CSWR.
Select the year of ROTATE operations you wish to examine: