The road to Doppler data


Putting a radar on the road was once a novelty. Doppler on Wheels (DOW) came to life nearly ten years ago, built on a relative shoestring through NCAR, NSSL, and the University of Oklahoma (OU). The truck-mounted radar and its younger siblings soon leapt to prominence on their annual circuit across Tornado Alley. They have since gathered landmark data on multiple tornado vortices, hurricane eyes, and other mesoscale features.

The new rapid-scan DOW at work on a tornadic supercell near Stratford, Texas. (Photos by Carlye Calvin.)

Today, several other portable radars—some solo, some in sets—make up an increasingly crowded, competitive field. They include:

• A series of short-wavelength units built by the Los Alamos National Laboratory and University of Massachusetts since 1987 and deployed by Howard Bluestein (OU). One caught near-surface winds of 460 km/hr (286 mph) in an Oklahoma tornado in 1991. In recent years Bluestein and UMass have deployed a 3-mm–wavelength radar specifically designed to track tornadoes. The biggest success thus far, says Bluestein, was from a 2002 tornado in Happy, Texas. “We have data on the vertical structure of this tornado at unprecedented spatial resolution.” Bluestein also collected data on several tornadoes this spring at close range with multiple polarizations using a 3-cm radar from UMass.

• The Shared Mobile Atmospheric Research and Teaching Radar (SMART-Radar), led by OU’s Michael Biggerstaff and produced through support from NSSL, OU, Texas Tech University, and Texas A&M University. First deployed in 2001, the original SMART-Radar has documented three hurricanes, a number of tornadoes, several mesoscale convective systems, and interactions between fronts and boundary-layer rolls. A second SMART-Radar, delayed by a fire at NSSL in July 2001, arrived in May.

• The Seminole Hurricane Hunter (Florida State University), a portable, dual-polarization radar to be evaluated later this year by a team from Colorado State University and ATD.

This spring the UMass, SMART-Radar, and two DOW units all caught a tornado-producing storm that struck northwest Oklahoma City on 9 May, only a day after the suburb of Moore was pummeled. “Add to this the proximity of the terminal Doppler radar at Will Rogers World Airport and the (NWS) WSR-88D radar, and there should be plenty of data available for intercomparison and case studies of this event,” says OU graduate student and DOW assistant Bob Conzemius.

The latest DOW debuted this spring as the first mobile Doppler to operate in rapid-scan mode. Transmitting through an array of 86 slotted waveguides (pictured at right), the radar sends six simultaneous beams and collects a three-dimensional picture every 10 to 15 seconds. The rapid-scan DOW was built largely at NCAR’s Design and Fabrication Services, with a team of ATD engineers and technicians (including leads Jonathan Lutz and Mitchell Randall) working with DOW founder Joshua Wurman. Now an NCAR affiliate scientist, Wurman operates the NSF-supported DOWs through the nonprofit Center for Severe Weather Research in Boulder.

DOW software engineer Mitchell Randall (second from left) and Joshua Wurman (second from right) join the staff from NCAR's Design and Fabrications Services who built DOW: (left to right) David Allen, Jack Fox, Jerry Dryer, Stephen Rauenbuehler, Edward Mores, Bart Woodiel, and Walter Hodshon.

A few of the new DOW's 86 slotted waveguides.

The new DOW struck pay dirt near Stratford, Texas, on 15 May (see photo above), when it gathered rapid-scan data on a prolific storm that produced two simultaneous cyclonic tornadoes, with an anticyclonic circulation in between. All told, the DOWs saw over a dozen days in action this spring.

 


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The next phase of remote sensing

Spinning up a new GLOBE structure

Is the 1990s decline in grad-school interest reversing?

Affairs of the atmosphere

Geomagnetic storms may spur thermospheric vortices

Mammoth meeting bridges the world of geoscience

Just deserts

President’s Corner: Crossing the valleys of death and lost opportunities: Toward an Earth Information System

Web Watch

UCAR Community Calendar

Governance Update

Science Bit