About the Project
TWISTEX 2010: An Overview
For 2010, we will be engaging in field research to collect data of the following:
~ Tornadoes and tornado proximity environments
~ Boundaries associated with supercells
~ Study hail 2″ and larger (Measure impact velocity, magnitude, and provide ‘soft-catch’ for later analysis)
The objectives of this research are to better understand tornadogenesis, maintenance and decay processes and to gain insight and knowledge of the seldom sampled near-surface internal tornado environment. Progress on these research fronts is aimed toward increasing tornado warning lead time while the internal tornado near-surface sampling provides essential ground truth data for structural engineering analysis of the interaction of tornadic winds with homes and buildings.
Tornadoes and Tornado Proximity Environments:
Tornado Core Sampling
Several hardened instruments will be deployed in paths of tornadoes to collect the following datasets:
* Wind speed/direction
* Visualization for accurate debris/hydrometeor velocities and for verification of the tornado-relative location of the in situ sampling
The thermodynamic probes are called Hardened In-situ Tornado Pressure Recorders (HITPR). All of the hardened instrumentation can collect/store the datasets. Measurements are recorded at 10 samples/second, and stored on non-volatile flash cards.
HITPR and video probe:
TWISTEX will also have video probes that will provide visualization using 7 cameras each for a total of 14 cameras being deployed into the tornado core. Collectively the two camera probes will be used for photogrammetry purposes to visualize/measure tornado-driven debris and hydrometeors as well as for determining the tornado-relative location of the HITPRs.
New additional technologies will be used by deployment crew members to collect photogrammetric data from tornadoes as close as possible. One technique will be to record close tornado imagery using two digitally synchronized high-resolution high-speed cameras running at 500 frames per second for stereo photogrammetry techniques. This technique will provide excellent time resolution for velocity determination of low-level tornado core winds and lofted debris.
HITPR and video probe
New tornado core instrument for 2010:
Beginning this season, TWISTEX will be deploying a newly developed instrument into tornado cores. The new instrument will be collecting wind data using different methodologies of anemometry at three different heights up to and including 2 meters AGL. Instrument will also have 6-9 video cameras along with a prototype flow visualization technique.
Samaras will coordinating the in-situ tornado core measurements, as well as the overall TWISTEX mission.
Tornado Proximity Environment Sampling
While there are abundant kinematic datasets gathered by mobile radar of the tornadic region of supercells, the number of quality mobile mesonet or sticknet thermodynamic datasets of the flow field proximate to the tornadic region, generally within the supercell rear-flank downdraft (RFD) outflow, are comparatively rare. Even rarer are mesonet datasets reaching within about 1.5 km of tornadoes and datasets sampling the thermodynamic evolution of the RFD outflow. Each of the participating TWISTEX vehicles will have a mobile mesonet (MM) station mounted on the roof including the probe deployment truck. The mobile mesonet will be attempting to gather near-surface thermodynamic and kinematic data in as many quadrants of the RFD as possible. When coupled with the in-situ probe array data which represents another effective mesonet station, it is hoped to obtain thermodynamic and kinematic mapping that will describe characteristics of the flow reaching the tornado. Even if the hardened tornado probes do not take a direct hit, a peripheral tornado sampling is still very worthwhile. Drs. Lee and Finley will be directing the mobile mesonet operations.
Mobile mesonet with probe deployment truck.
The primary investigators are Tim Samaras, Dr. Bruce Lee, and Dr. Cathy Finley. These individuals will provide overall coordination, data quality control, and program management.
In addition to the primary investigators, the project is staffed with graduate and upper-division Meteorology/Atmospheric Sciences students from Iowa State University and Metro State University as well as a few professional Atmospheric Scientists. Research collaborations continue with Iowa State research faculty. There are other volunteers that consists of meteorologists, scientists, and experienced storm chasers.
Coordination with Other Groups:
During or following the field campaign, there may be opportunities for collaboration with other research groups operating in 2010.
Our field campaign will start this year on our about April 21, and end on or about June 30. Due to limitations associated with personnel to staff the mobile mesonet portion of the project, we anticipate the mobile mesonet being operational by sometime in the first week in May. TWISTEX will likely operate with a reduced vehicle compliment on a few select days in April if weather conditions warrant.
A near-daily mission status statement will be sent out on a mass-email listing that will include results from the prior day, forecast/location of the day’s activities, and short/medium range forecasts of potential severe weather and possible operations. The status report will also cover needed logistics and other important information. These fielding updates will also be available through the homepage of the TWISTEX Website.