NOAA had only requested a simple pressure recorder, but Tim has decided the task is far too uncomplicated. Like his chase vehicles, Tim’s probe will amass as many gadgets as it can bear. Plus, if the device is already inside the vortex, why not collect a few other data points while there? He has in mind a complete weather station, equipped with temperature, humidity, and pressure sensors—a much more elaborate piece of equipment.
The project is an exceedingly unusual one for ARA, which typically sticks to military and national security applications over oddball weather science. But Tim is obstinate, cranking out draft after draft, each with the input of a review group of his peers. The work is far more than Tim can do alone. Cramming a twelve-bit, sixty-four-channel datalogger, fifteen pressure transducers, as well as sensors for humidity and temperature, into a space roughly the size of a shoebox is a bit like gaming out a three-dimensional puzzle. There may be only a single workable configuration.
Luckily, Tim belongs to a company with a motley pool of brainiacs. Over lunchtime bull sessions, he and the crew hammer out the details of components, overall design, time frame, and cost. To develop the miniature data-acquisition system, which will record measurements from the various on-board sensors, he taps his old buddy Bob Lynch, a software and hardware magician. Julian Lee, a young whiz from Caltech, has expertise in fluid mechanics and can make sense of the turbulent, debris-choked wind flow. Heyman, the engineer who drew up the launcher design, assists with the scale-down, from ICBM launcher to car-tire-size weather instrument.
Finally, after much deliberating and revision, Tim nails the design: a squat cone some twenty inches in diameter, and a little less than six inches tall. He calls it the Hardened In Situ Tornado Pressure Recorder, or HITPR for short. Now comes the pitch. Why should the NOAA judges award this grant to Tim, who is not a meteorologist or a scientist of any stripe? To the senior researchers behind the bid request, he will be an unknown quantity, with a wholly unconventional area of expertise compared to the atmospheric scientists with whom he’s competing.
Yet that outside engineering expertise might just give Tim an edge where it counts. NOAA is looking for something that can fare better than TOTO in tornadic winds, and of this Tim and his shop of engineers have no doubt: TOTO’s shape was an afterthought, while HITPR’s aerodynamic shell is the product of meticulous design and calculation. On the inside, its instrumentation is research grade and built to specifications. Whereas TOTO documented conditions once per second with the technology of its time—on paper, with a mechanical impact recorder, like a seismograph—HITPR’s onboard datalogger will sample the environment electronically, ten times each second.
HITPR is the Corvette to TOTO’s Model T: a sleek update with all the latest bells and whistles, built to shed the wind.
The real selling point, though, is what Tim believes his device can do for science. Up to now, tornado wind speeds have been derived through the forensic examination of structural damage. Put simply, what would it take to bring this building down? It’s a lower bound, which means that if a record-breaking gust flattens a poorly constructed house, no one will ever know how fast the wind really was. The surveyor can only conclude that, say, a 130-mile-per-hour gust was more than equal to the task. HITPR, Tim explains in his application, will provide a far more accurate wind-speed estimate by basing it on direct pressure and direction measurements—data points that simply do not exist at ground level.
He can’t overstate this point: there has always been a blind spot at the place we most want to see. The ground level is where we live, and in tornadoes it’s where we die. Yet the tornado has remained untouchable at the surface. TOTO couldn’t survive. Radar can’t get there. But HITPR can.
In the long lineage of tornado probes, Tim’s is the first to be inspired by the shock wave—and the first to be shaped by an engineer whose laboratory is the test range. Tim’s gig at DRI and then ARA has never felt exactly like work. It’s more like he’s been transported from his boyhood bedroom floor and his old radios to a place where the toys are exponentially more expensive, and the stakes are as high as they come. But this project—his first as principal investigator—feels different. It’s something closer to a calling, as if this is what he was put on the earth to do.
If HITPR can provide the answers to some of the enigmatic questions that linger—Is the core warm or cool? What are its approximate ground velocities? How far does pressure fall?—then the how and why behind tornado formation can begin to reveal themselves. Its data could be assimilated into a tornado model along with radar and weather-balloon measurements, providing an unprecedented picture of the vortex. Perhaps one day—if the device goes into production—scientists, chasers, companies, and weather firms alike could contribute to a database. Structural engineers could have access to measurements gleaned not by educated guesses but by a finely calibrated instrument. It’s a tall order to build a single-family house that can survive a Jarrell tornado, but the instrument might just give engineers a fighting chance—at safer homes, offices, hospitals. That’s worth something.
As the submission deadline looms, Tim and Brown work through Thanksgiving Day of 1998 and into the wee hours, refining the proposal.
