Thunderstorm Electrification and Lightning Experiment

TELEX 2004 Overview Video transcript

Objectives of TELEX

MacGorman: There were two broad objectives: One was to try to understand better why storms produce a lot of positive cloud-to-ground flashes – we think that's related to severe weather, it's related to storm intensity, so part of our purpose was to try to understand the conditions that are producing those flashes.

Rust: Specifically, we achieved this by making measurements inside of clouds using balloons and combining this with radar and lightning mapping and other sensor outputs

MacGorman: The other part was to start looking at electrification of Mesoscale Convective Systems. We have done a lot of work with balloons alone in the past, but looking at the interrelationships of kinematics or the microphysics – how winds move and how particles form – and relating that to the wind field and the lightning – getting a total picture was a big part of our focus

Collecting Data

Rust: The data for TELEX were collected using a number of sensors. We relied very much on radar including the state-of-the-art polarimetric radar, which allows us to determine the kinds of particles that are inside the storm.

MacGorman: We also had very high-resolution dual-Doppler data taken in TELEX. This consisted of two mobile radars that would drive close to a storm then scan very rapidly through the storm to give us the very fast evolving characteristics of the storm.

Rust: We used the Oklahoma Lightning Mapping Array (OK-LMA), which is unique to central Oklahoma.

MacGorman: That was one of the core instruments for TELEX. It allowed us to look at the structure of lightning inside of clouds as well as seeing the things outside of the clouds, which is what we normally see. So that allows us then to look at where lightning is relative to updrafts; relative to the rain coming out of the storm; relative to severe weather.

Rust: A big part of what we did relied on taking instruments up into the storms on unmanned balloons – so-called weather balloons.

MacGorman: Then we had balloon systems which carried our systems to measure the thermodynamics of storms, the temperature, winds, the humidity and so on, as well as measuring the electrical properties of storms so that we could tell where there were high electrical forces in storms – things that would cause lightning to occur. We also had an environmental sounding system that allowed us to look at the conditions for producing the storms, and this is important for helping us with modeling later on to try understand how all these things work together.

A Typical Day

MacGorman: A typical day would begin with a forecaster looking at the weather.

Rust: Forecasting starts early in the day and continues through the entire mission. We use information from our so-called nowcaster – which is what the forecaster becomes once we go on a mission who provides guidance to us in the field.

MacGorman: Along about 12:30 we would have a weather briefing and that weather briefing would then be where the forecaster presents the days outlook to the rest of the PI's in the project so we would discuss strategy then, and try to aim for the afternoon--or do we try to go at night when do we expect storms to occur, how does that fit in with our objectives and how do we address those storms? Once that decision has been made then we start getting ready. If we are going to go out in the late afternoon we have to start getting ready faster. If we are not expecting to operate that day then we can wait and do things in a more relaxed fashion. So we continue to monitor the data looking at how the weather is developing; where storms are starting to pop up. And then about an hour or two before we expect to actually have to be in position, we try to make a decision that yes, we are going to go out here to this particular location and try to take data. So everybody then deploys – all the mobile crews, which would be the ballooning crew, the environmental ballooning crew as well as the electrical ballooning crew and then the mobile radars.

TELEX in the field

MacGorman: So we have to go out and adjust our positioning to fit where the storms are coming. Because in the case of ballooning crews we have to get balloons right up into the storm we have to be on the storm. In the case of the two radar crews they have to be back a little bit so they can look at the storm and scan through it. In the case of the environmental ballooning sounding crews they have to be well back from the storm but close enough so they can sample the air that is going into the storm. And so all these things have to be coordinated by the different crews, but most importantly by the nowcaster who is standing there looking at the radar watching how things are developing looking at all kinds of data.

Rust: The entire TELEX program I think had about 30 people involved in any one mission. The ballooning effort requires 13 or 14 people to carry it off in the way that we like. The optimal way for us to balloon is where we can put balloons up very quickly one behind the other so it takes launch crews and balloon inflation crews operating at the same time. It is a very complicated effort to inflate and get a balloon loaded with instruments and get it up in what are sometimes very windy conditions and to do it quickly. The crews are extremely valuable and they include both volunteers as well as members of our own research group here.

MacGorman: We have people from the University of Oklahoma, NSSL; some folks came down from the University of Washington, New Mexico Institute of Mining and Technology (NMIMT)--so there was a great team of people working together and each of them contributing an important part to the field program. It was the first time we had very high-resolution Doppler radar data, lightning mapping data and electric fields sensors on the same storm anywhere. We launched into about 14 storms and we launched a total of 36 instruments into the storms.

Rust: Some of those gave us information not only on the way up but also on the way down as the instruments came down. For example that allowed us in one supercell to get 8 soundings through the same storm, which is absolutely a first.

Field Program Success

Rust: I think we met the objectives of the field program, which is what this year was mostly about--in ways that are bigger and better than ever before. I think it is highly successful and we have looked at the data enough that we know that we've got something there – it's not just wishful thinking.

MacGorman: This has been one of the most successful field programs I have ever been involved in. It was very frustrating at times because we had a couple of periods of drought. But then the storms broke loose and from the end of May on it has just been a merry-go-round –it's been a great experience.

Rust: It was the most difficult one I have been ever involved in both here in the Great Plains and in other places the country. And I think, the early indications suggest that it is the most successful one we have ever conducted.