Wednesday, October 11, 2023

The LiDAR Tour or Why Todd is Not a Scientist

I'm going to preface this by saying, "I am not a smart man." There's a lot of science talk that goes way over my head, so as cool as this experience was, I'm definitely going to misinterpret some details and forget others. But hopefully this will be a foundation for further inquiry if it catches your interest.

Despite what my previous articles might indicate, Antarctica is not just booze and leftovers with cheese; there's actual science that happens here! The reason we're all here is because Antarctica provides a unique environment for exploration and discovery, and people like me support them. Recently I got to visit one of these science fields and hear about the research they are doing.

I had the chance to visit the New Zealand LiDAR system. And if you're anything like I was when the tour was announced, you might be wondering what a LiDAR is? As I understand it, it's basically like a radar system that uses light instead of radio waves. By using different kinds and frequencies of lasers, the scientists can detect the light refracting off of material to measure certain properties of that material.

At the LiDAR we toured, they were measuring iron and sodium in the metallic vapor layer of earth's atmosphere. Because apparently earth has a layer of metal floating above it all the time! Didn't know that. But by using a specific green laser and a headlight yellow laser, the system can detect the metal and draw conclusions. How it works is that the laser is shot into the air at the resonant frequency of the metal the team is trying to detect. Once it hits that metal in the atmosphere, it refracts off of it and is "caught" by giant telescope lenses back at the station. Using a spectrometer, they get a bunch of data from the test and can move on from there.

So light is the key element at work here. That's one of the reasons that this facility is down in Antarctica. Over the winter, there are months without sunlight, meaning that there is no solar interference that they have to filter through when reading the data from their laser. That said, their system is apparently real smart and can filter out the sun's light pretty well, although it still works better at night.

The metal layer is apparently made up of more metallic elements than oxygen—less air than metal. I don't know what to do with that fact, but I thought it was neat. But that also makes it easier to read certain data points. One thing we were told is that they can learn about the wind speed at that altitude. It's too high for weather balloons, so normal measurement tools aren't as useful. But when using the LiDAR, they can tell if the metal particles are moving and how quickly, giving them a picture of the atmospheric shifts going on up there.

That's pretty cool, but the question as always is: how is this practical? Glad you asked! From the scientist who gave us the tour, this data can show us:

  • How energies at the pole interact
  • How waves transfer energy
  • How the atmosphere reacts to energy inputs
  • How the metal layer effects weather models

I don't know what any of those actually mean! I'm just retelling you what he told us. But this does seem to have some level of use and interest. One of the women that was with us said that her daughter's boyfriend wanted to study this exact thing—which A: small world, and B: seems really specific and I don't know how someone decides that's going to be their specialty.

While we were there, we also had a chance to see some meteors falling, including one of the brightest and greenest shooting stars I've seen in years. It actually prompted an interesting discussion with our guide. Meteors like that are a big reason that the metal layer exists—various kinds of space debris comes into our atmosphere and doesn't make it to land, but burns up and stays in the metal layer. I asked how much that one meteor might add to the layer and apparently that's a really big question in this field. No one really knows, but estimates are that a shooting star like we saw could add literal tons of metal to the metallic later.

I hope that while I'm down here, I can see other scientific efforts and the cool things they're working on. While I didn't understand a whole lot of what we were shown, I did appreciate the brilliance and unique approaches that the scientific world can use in a land like Antarctica. It puts into perspective the "laymen" work that I and the others do to keep this place running. There's a lot of cool things happening, even if I don't see or understand all of it.

And let me just say it took a herculean effort not to look into the one laser we were shown.

The yellow laser used to measure sodium. It's the one that would be most easily visible for us on the tour.

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