RaXPol: Radar envy

Yesterday saw the arrival in Norman of Howie Bluestein’s new Rapid-Scan, X-band, Polarimetric mobile Doppler radar (RaXPol for short). It’s a radar primarily intended for tornado research, but which also has a myriad of other potential applications.

Yes, we’ve had radars mounted on trucks since the mid-1990s. What makes RaXPol special? Watch this:

That video clip is not sped up; that really is an 8-foot dish rotating at 180 degrees per second! By gradually changing the elevation angle, it can potentially collect a full atmospheric volume of polarimetric data in less than 30 seconds. Why is that important? Tornadoes can change drastically on time scales of only a few seconds, so the faster scientists can collect volumes, the more information we’ll have about those rapid changes. The polarimetric capability will allow researchers to distinguish different types of hydrometeors, debris, and other scatterers in supercells and tornadoes.

One might expect the entire truck to wobble with a giant antenna swinging around on its bed. The engineers addressed that issue from the design stages. As can be seen in the video clip, the entire truck remains surprisingly static, even without the hydraulic levelers deployed. Seasick crew members will not be an issue.

And as for the problem of “beam-smearing” (insufficient dwell time) that might result from such a rapidly rotating antenna, the engineers implemented a multi-frequency Tx/Rx system. Conventional Doppler radar transmits pulses a single frequency, then “listens” for the echo of the transmitted signal. Imagine someone striking a single piano key, then listening for the echo of that note. In contrast, RaXPol transmits consecutive pulses at slightly different frequencies, then listens for the returned signal from all of them simultaneously. In the piano analogy, instead of striking only one key, you would sweep your fingers over several keys, then listen for the combined echoes of all the different notes. Dr. Andy Pazmany explains in this presentation how this “frequency hopping” technique works.

RaXPol panoramaRaXPol was constructed at Prosensing in Massachusetts, funded by a Major Research Instrumentation (MRI) grant* from the National Science Foundation. It will be maintained by the Atmospheric Radar Research Center at OU. It will remain in Norman year-round, and theoretically be available for operations outside of the “normal” chase season (April – May – June), such as hurricane deployments.

I feel a little silly blogging about this radar, because I’m not going to be using it. (That job belongs to Howie’s current crop of grad students.) But, I’ve been hearing about this radar for three years, ever since Howie’s first “woof” when he heard that the grant proposal had been funded, and I’ve never been ashamed to geek out over a shiny new instrument! I can’t wait to see what data the students end up collecting.

* In the abstract, Howie mentions two female Ph.D. students. I was one of them!

Update: The OU College of Atmospheric and Geographic Sciences put out a press release about the RaXPol!

More thoughts about the disaster in Japan

Okay, I know this is supposed to be a blog about my severe storms research. But the Japan earthquake, tsunami, and now nuclear disasters have all hit rather close to home. That’s because Japan was home for me, for the summer of 2005. Japan is the country where I had to re-learn how to go to the bathroom, how to go shopping with the vocabulary of a three-year-old child, and where I joyfully re-established contact with my extended family on my father’s side. I sweltered in the Tokyo summer heat, shouted over deafening cicadas, slurped down bowls of Hakata ramen, and felt the gentle jostle of the trains that took me anywhere I wanted to go. The perpetual chimes and recorded announcements, the exquisite artistry and fashion, the delicate palette of flavors, and the gamut of emotions I experienced in Japan are all packed into a treasured space in my memory. Occasionally, they resurge into my consciousness, stimulated by a taste or a sound. I cherish those memories even more so now that substantial portions of Japan have been changed, many irrevocably.

It’s not like I ever got to visit or travel through any of the areas of northeast Japan that have been wiped away by the tsunami, or that will probably be contaminated for decades by radiation from exposed nuclear waste. (The latter situation is still unfolding as I type this.) It’s not as if I personally knew any of the victims swallowed by the mass of black water and debris that surged horrifically across the perfectly gridded and manicured farmlands of Sendai, crushing house after house in the seaside towns. (My relatives are all on Kyushu, in the southwest, well away from the disaster zone.) I don’t know these places, and yet, somehow, I do. I barely even know the Japanese language, so I have been having to rely on NHK’s own halting English interpretations of their local coverage. I’m not going to pretend to have any particularly apt insight into the Japanese psyche and how it might respond to this compound disaster. What I see is a land I am very fond of, facing its greatest crisis of the modern era. I am sitting comfortably in Norman, Oklahoma, hard pressed to do anything about it. So I think, and write.

Japan erupted (quite literally) out of the ocean when the spine of the Pacific plate butted up against an extension of the North American plate. As a result, the distinctive landscape, with its severe grade and some active volcanoes, is largely uninhabitable, so most people amass around the coasts and in small mountain enclaves. (My own last name, Tanamachi, translates as “shelf village,” in reference to a gently sloping locale on one of these mountainsides where a small contingent managed to get a foothold.) The open fetch of warm ocean to Japan’s south and east provides ample moisture that makes Tokyo a concrete sauna in July and August, but also helps the rice crops growing in the rich volcanic soils to flourish, and fills the surrounding sea with all manner of delectable creatures. The same warm ocean is also fertile ground for the formation of monstrous typhoons. Japan is rocked from beneath by earthquakes and volcanoes, while tsunamis and the ferocious winds and rain of typhoons try to erode Japan back into the ocean from above. It is no wonder that the predominant religion (Shinto) is an animist one – the very earth on which Japan was born is very much alive, and voracious. The other major religion, Buddhism, teaches that life is suffering, and that nothing is permanent.

Time and again throughout history, Japan has seen its cities and people consumed by disasters, and often had to rebuild from scratch. Communities and entire families could be wiped out in a few seconds, historical sites and documents lost forever. Disaster preparedness is ingrained into Japanese culture. Everywhere you go in major cities, signs in many languages point the way to earthquake and tsunami refuge areas. Very small children learn songs and games that teach what to do in an earthquake. The word “tsunami” is itself a Japanese word. On the island of Amami-Oshima in 2005, I watched a city (Naze) hunker down for the passage of a Category 4 typhoon, then resume business as usual the very next day after cleaning up only a few leaves and bits of windblown trash.

The Japanese were certainly not caught unprepared by last Friday’s earthquake. They have learned the lessons of history well, the pain of loss forging links to generations past and future. The billions spent on earthquake-resistant buildings (which I mentioned in my last post) and evacuation procedures doubtless saved thousands of lives. The tsunami was different story. One cubic meter of water weighs 1000 kg, or about 2200 lbs. Knowing this, one can begin to comprehend the destructive power of a 10 m-tall tsunami crashing ashore. Most human-made structures simply buckled under the lateral strain and washed out to sea. The only effective survival strategy was an uphill escape.

The world knows that the Japanese work hard, and play harder. But the earth is continually trying to shrug Japan off, often with devastating consequences for its human inhabitants. In light of this fact, the seeming Japanese national mania for novelty, technology, and connectivity may be a little bit more understandable. What would you do today, if you knew you might not be here tomorrow?

Japan: A few critical seconds

Today’s images of the earthquake damage and tsunami in Japan are gut-wrenching. By now, people around the world have seen the images of the wall of mud and debris sweeping unstoppably across the countryside in Sendai. I have relatives living in Japan that I have not yet heard from. Fortunately, they live on the island of Kyushu, far from the epicenter, so I feel reasonable hoping that they are all right.

On NHK this morning, I heard a Tokyo office worker complain that he felt “seasick” from so many aftershocks rattling his building. I can relate to the feeling, if not the magnitude.

In 2005, I spent an amazing summer in Japan working for WeatherNews, Inc. Every day, I reported to work at their headquarters in Chiba Prefecture, near Tokyo. On the afternoon of 16 August 2005, a 7.2 earthquake rattled our office building. A few items shifted around and fell off of desks, but the electricity stayed on, and the WNI team quickly resumed their work. For several minutes afterward, a peculiar sensation, as if I’d just stepped onto a gently bobbing boat, disoriented me. I found out later that most office buildings in Japan, including the one we were in, are built on “earthquake rollers.” The building literally floats in place as the earth moves beneath it, then distributes the shock of the quake out over time in order to minimize stress on the building.

Today’s quake, like that one, struck in the middle of the afternoon, when millions were at work. It shared its epicenter with the quake I experienced, just off the east coast of Sendai. Between that titanic jolt and dozens of aftershocks, the earthquake rollers certainly have their work cut out for them, and so far they appear to be doing a very good job.

Some dismiss Japan as a nation of superficial novelty – of Pokemon, Nintendo, and Pocky. Some (including myself) criticize its heavily engineered environment for the degradation of its natural beauty. But its people live on the spine of the Pacific, on a land punctured by volcanoes, shuddered by restless faults, and swept by typhoons and tsunamis. I’ve always been amazed at the ingenuity and resilience of Japan in preparing for and dealing with almost any kind of disaster. Billions of dollars and man-hours pour into preparing for those few critical seconds when the earth decides to vent some steam. It is thanks to fantastic engineering and disaster preparedness that the destruction will not be greater, and that the death toll will not be higher. That Tokyo office worker’s building is still standing, and he’s alive to complain about feeling seasick inside of it. I think that’s worth a tip of the hat.

Update: NYT posted some very similar commentary.

Update, 12 March: Good news; all my Japanese relatives are safe and accounted for!

27 February 2011 Grainola, Oklahoma tornado

My chase partners on this day were Dan Dawson and Jana Houser. We were attracted to the area around Enid, Oklahoma as an initial target, because of the strong shear, a narrow corridor of CAPE, and an incipient dryline push indicated in the models (SPC outlook). We intercepted a strengthening cell near Pond Creek, Oklahoma around 5:20 p.m. The reflectivity from KICT (KVNX was down for its polarimetric upgrade) showed a persistent, 60+ dBZ core, so we assume there was hail present.

Storm motions were ENE at 45-55 mph. As we jogged east and then north from Lamont, the cloud base began to lower. The first one quickly bowed out and became a “whale’s mouth”, indicating that a cold downdraft had reached the surface and begun to spread out toward us. Gradually, however, as we passed through Blackwell on OK-11, the storm, now clearly a supercell on radar, began to recover and developed a clear slot on its west side. We continued east in order to keep pace with the storm.

Near Kidare, the paved road T-ed off, and we had to make a choice whether to go north a few miles to Newkirk to keep the base within visual range, or south three miles to continue east on OK-11 through Kaw City. I was driving, so that choice was primarily the responsibility of my chase partners. While most other chasers turned north at the intersection of OK-11 and U.S. Hwy. 77, we turned south, and then continued east across the Kaw Lake Dam. Our view toward the base of the storm now blocked, we began to hear tornado warnings for the storm coming from three different CWAs (Tulsa, Norman, and Wichita) and questioned whether we had made the right decision.

However, as we emerged from the depression around Kaw Lake, we started to see suspicious appendages under the cloud base. It being February, it was close to sunset (around 6:20 p.m.), so the contrast wasn’t great. We turned north on OK-18 at Shidler, Oklahoma; the video sequence above records what we saw after emerging from the north side of that town. One particular appendage caught and held our attention. From a distance, it could have been mistaken for a scud finger, but as we drew closer, its persistence and tapered, conical shape made clear that it was a funnel cloud. In the video, you can hear us debating for a minute or two whether what we’re seeing is a tornado, or not. The funnel never made contact with the ground, but I did note a few puffs of red dirt underneath it.

After the white cone became occluded and dissipated, my chase partners noted a continuation of the tornado in the form of a dust tube extending from the ground to cloud base off to our east. I was still driving and unable to film this phenomenon; however my chase partners documented it.

We continued north on OK-18 until we crossed the Kansas border. At no point did we note crossing a surface damage track; however, it was dark, so we might have missed seeing some damage. As of this writing, I am not aware of a damage survey for this tornado; however, the SPC preliminary report notes an EF-0 rating.

We turned east on U.S. Hwy 166, following the storm as it produced an additional lowering illuminated by lightning. However, this lowering dissipated after a few minutes. We called off the chase near Sedan, Kansas, on account of darkness.

On High Instability

The mp3 version of my 2 March 2011 appearance on High Instability is now available in their show archives (Episode #81). Topics covered include my dissertation work on the Greensburg, Kansas tornado, my exploits with the UMass W-band radar during VORTEX2, and (briefly) infrared thermal imagery of tornadoes. I even manage to get in a plug for this blog as the outtro music is playing. Hanging out with RJ, Gene, and Chuck is always a blast!

Why “tornatrix”?

Every so often, usually when some major transition occurs in my life, I take on a new online persona. This time, the occasion was the completion of my Ph.D., at long last, after six years of hard work and challenges.

So, why the name “tornatrix”?

My dissertation took a great deal of my energy and time, and during the past three years, I more or less disappeared off of forums and chat rooms. As I worked with mobile Doppler radars and made several appearances on national (and international) television, my name recognition grew. I began to sense a demand for an increased presence on the web. I also observed a rise in the number of science blogs being used to disseminate research to the public. I resolved about a year ago that, after successfully defending my Ph.D., I would establish more of an online presence. But I needed an alias – something short, simple, and easy to remember. I can never force myself to come up with such names under duress; I knew I had to let the inspiration come on its own time.

I was lying in bed a couple of nights ago, toying with words that conveyed my specialty (severe weather research), when the word “tornatrix” suddenly popped into my head. I had attached the first part of the word “tornado” to the Latin feminine suffix “-trix”. In this sense, it means something like “twister-ess.”

I Googled the word “tornatrix” and found that it is actually a Latin word meaning “dancer” (i.e., “woman who turns”). I messaged one of my Latin-speaking college friends (Rob, now a Ph.D. candidate in Classics at UCLA) to ask about the propriety of using the word “tornatrix” in the sense that I wanted. He told me that, strictly speaking, the word I wanted was “turbatrix,” because the Latin word for tornado is turbo. Unfortunately, turbo has a different meaning in English, plus, a “turbatrix” sounds like a woman who studies (or perhaps causes) turbulence, which is quite a different specialization.

So, tornatrix it is! And here it begins.