Wednesday, May 5, 2010


Since it doesn't seem likely that we will be doing any operating today, I thought I would take some time to explain some of our instrumentation. Chris has already mentioned that the Texas Tech suite of instruments includes 24 StickNet probes and 2 Ka-band mobile radars. I'll describe the StickNets in a little more detail, and describe our typical operations plan for deploying them. I'll leave the Ka radar descriptions for Pat....

As Chris mentioned, the StickNets are a rapidly deployable surface observing platform. They all feature two primary parts--an extendable tripod (like the kind surveyors use) and a data aquisition (DAQ) box. All StickNets measure wind speed and direction, temperature, relative humidity, and pressure. They all feature a flux-gate compass so that we don't have to worry about orienting them towards a particular direction when we make the deployments. Beyond that, there are some differences. We have two instrument configurations. The first, called an "A" probe features a standard propeller anemometer to capture the wind data, which is mounted on the top of the tripod, a temp/RH sensor (instrument that measures, you guessed it, temperature and relative humidity) that is mounted on the DAQ box, and a barometric pressure sensor located inside the DAQ box. The second configuration, called the "B" probes features an "all-in-one" sensor, meaning that wind speed and direction, temperature, and relative humidity are all collected by one sensor. In additon this sensor can measure precipitation type (hail vs. rain) and can estimate the quantity. This sensor is mounted on the top of the tripod.

It takes 2 people 2 minutes or less to deploy a StickNet. I'll give you a play-by-play of a deployment in my vehicle.....when we pull up to a deployment site, my partner (fellow blogger Rich) and I jump out of the truck and race back to the trailer. After opening the trailer and securing the doors, I will hop in and unhook a tripod. I will jump out of the trailer and head for the deployment site, calling out the probe number to Rich. He will grab the DAQ box, and run out to meet me. By the time he gets there, I have usually extended one of the three tripod legs, and he will set the DAQ box down and together we will work on the last two legs. Then we will take a moment to ensure the probe is level. Then he will lift the DAQ box into place, while I secure it with a pin. I will then power the probe on, hook up the two connectors to power the GPS and instrumentation and turn the data switch on. The software will run a series of tests and once the data light stops blinking, I know the instruments are ready to sample. While I am working on the hookup, Rich is responsible for driving a stake through each of the three tripod legs to secure the probe into position. We generally finish our tasks at roughly the same time, but whoever finishes first runs back to the trailer to close up the doors. We hop into the truck and drive off to the next deployment location. We also have a third member of our team who remains in the truck. He is responsible for keeping a log of all of the deployments, marking the time, GPS coordinates, any obstructions, and any notes that may come in handy. He can also monitor the radio traffic and internet chat to ensure we don't miss any important messages, and also acts as a spotter, keeping an eye on us as we deploy outside of the truck.

Seems like a lot, but yes, we can do it in under 2 minutes and by the end of the season when we've had a lot of practice, we can get much closer to the 1 minute mark!

Before we begin the deployments, Chris instructs us which road we will be using, and what spacing we should allow between the probes. We do our best to keep to the spacing he instructs, but sometimes towns, trees, buildings, etc., get in the way, so we do the best we can. My truck, pulling a trailer, handles one of the two coarse array deployments. Our probes are generally spaced 1-2 miles apart. As the storm gets closer to the deployment road, the non-trailered trucks (which are much more maneuverable) lay down a fine-scale array, centered near where they think a potential tornado or mesocyclone could cross the road.
I included a picture that Kristina Butler took of Brian Hirth and I doing a mock deployment during local media day. He is getting ready to move the DAQ box into place and I am standing by to secure it with the pin. Even after a year of off-time, we finished the deployment pretty quickly! The StickNets are really remarkable. They were designed and built and are maintained entirely by TTU students. Not only are they rapidly-deployable, but because they are unmanned, they can be placed into parts of the storm that you would not want to send people or vehicles! We can deploy them in plenty of time to retreat to safety.

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